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1
Rossi, Laura, Luiz Miranda de Lima, Yubo Sun, Frank Dehn, John Provis, Guang Ye e Geert De Schutter. "Future perspectives for alkali-activated materials: from existing standards to structural applications". RILEM Technical Letters 7 (12 gennaio 2023): 159–77. http://dx.doi.org/10.21809/rilemtechlett.2022.160.
Testo completoAbstract (sommario):
The production of cement and concrete contributes significantly to global greenhouse gas emissions. Alkali-activated concretes (AACs) are a family of existing alternative construction materials that could reduce the current environmental impact of Portland cement (PC) production and utilisation. Successful applications of AACs can be found in Europe and the former USSR since the 1950s and more recently in Australia, China and North America, proving their potential as construction materials. However, their utilisation is limited presently by the lack of normative and construction guidelines. Raw materials’ non-uniform global availability and variable intrinsic properties, coupled with the lack of specific testing methods, raise questions regarding reproducibility and reliability. The mechanical and chemical behaviour of AACs has been investigated extensively over the past decades, strengthening its potential as a sustainable substitute for traditional PC-based concrete. Although a wide amount of studies demonstrated that AACs could meet and even exceed the performance requirements provided by European design standards, a classification of these broad spectra of materials, as well as new analytical models linking the chemistry of the system components to the mechanical behaviour of the material, still need further development. This report gives an overview of the potential of alkali-activated systems technology, focusing on the limitations and challenges still hindering their standardisation and wider application in the construction field.
2
Elbasha, Nuri Mohamed. "LIGHTER HIGH STRENGTH CONCRETE BEAM". Scientific Journal of Applied Sciences of Sabratha University 2, n. 2 (27 settembre 2019): 17–26. http://dx.doi.org/10.47891/sabujas.v2i2.17-26.
Testo completoAbstract (sommario):
High strength concrete (HSC) has been used extensively in civil construction projects worldwide because it reduces the cross section and the weight of long construction members. In recent years a marked increase in the use of High Strength Concrete (HSC) has been evident in Australian building construction despite the fact that the current Australian design standard provides no design rules for such a material. Very limited information on the properties of HSC and its design and construction processes are available in Australia, although in recent times many studies have been undertaken to produce material and, more importantly, to determine its characteristic. In the last 20 years there has been extensive research to economically utilize new components to improve the quality of HSC. HSC produces smaller but stronger structural elements with large spaces available. It has been studied that the cost of using HSC instead of Normal Strength Concerete (NSC) in different types of constructions. This proved that structures constructed with HSC are lighter and economical compared with those constructed with NSC. In the long term durability significantly affects project costs. In other words after several years a concrete structure needs rehabilitation or in critical cases must be demolished, therefore the price of a project consists of initial costs plus those covering any rehabilitation. A huge amount of money could be saved by utilizing the durability characteristics of high strength concrete. This study presents recent information and the benefits of high strength concrete. Also, provides in brief an experimental proof that installing a helix with a suitable pitch and diameter in the compression zone of beams significantly enhances their strength and ductility. Therefore, designers could confidently use high-strength concrete and helical confinement to design long and light reinforced concrete beams.
3
Gunasekara, Chamila, Charitha Seneviratne, David W. Law e Sujeeva Setunge. "Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate". Applied Sciences 10, n. 15 (28 luglio 2020): 5207. http://dx.doi.org/10.3390/app10155207.
Testo completoAbstract (sommario):
Quarry aggregate reserves are depleting rapidly within Australia and the rest of the world due to an increasing demand for aggregates driven by expansion in construction. The annual production of premix concrete in Australia is approximately 30 million cubic meters, while 3–5% of concrete delivered to site remains unused and is disposed of in landfill or crushing plants. The production of coarse aggregates using this waste concrete is potentially a sustainable approach to reduce environmental and economic impact. A testing program has been conducted to investigate mechanical performance and permeation characteristics of concrete produced using a novel manufactured coarse aggregate recycled directly from fresh premix concrete. The recycled coarse aggregate (RCA) concrete satisfied the specified 28-day design strength of 25 MPa and 40 MPa at 28 days and a mean compressive strength of 60 MPa at 90 days. Aggregate grading was observed to determine strength development, while low water absorption, low drying shrinkage, and higher packing density indicate that the RCA concrete is a high-quality material with a dense pore structure. The rough fracture surface of the aggregate increased the bond between C-S-H gel matrix and RCA at the interfacial transition zone. Furthermore, a good correlation was observed between compressive strength and all other mechanical properties displayed by the quarried aggregate concrete. The application of design equations as stated in Australian standards were observed to provide a conservative design for RCA concrete structures based on the mechanical properties.
4
Shamsaei, Ezzatollah, Owen Bolt, Felipe Basquiroto de Souza, Emad Benhelal, Kwesi Sagoe-Crentsil e Jay Sanjayan. "Pathways to Commercialisation for Brown Coal Fly Ash-Based Geopolymer Concrete in Australia". Sustainability 13, n. 8 (14 aprile 2021): 4350. http://dx.doi.org/10.3390/su13084350.
Testo completoAbstract (sommario):
Utilising geopolymer as a construction material has gained institutional and commercial interest over the past decade, due to its favourable emissions profile as an alternative to carbon-intensive Ordinary Portland Cement-based concrete, which currently accounts for around 7% of global carbon emissions. While significant research has been performed into the material properties of geopolymer, the commercialisation of the technology is still in its infancy, and several key barriers require rectification to facilitate more widespread adoption. This article analyses the current state of geopolymer commercialisation, paying particular attention to its commercial application in Australia, and it suggests key research areas, in particular relating to the utilisation of abundant and cheap low-quality fly ash sources such as brown coal-based fly ash, to promote its adoption and build on the momentum gained from the small scale in situ pours of geopolymer concrete. Our analysis indicated that in addition to the barriers relating to material properties, economic, social, and regulatory issues also require further inquiry. Our review also indicated that it is critical to update and improve economic analysis of geopolymer utilisation to forecast future costs of both geopolymer and concrete mixes, which are especially critical in determining any potential financial incentives for the construction industry. Moreover, it is essential to study the social attitudes affecting future geopolymer consumption and to update the regulatory standards governing geopolymer utilisation in Australia, such as the initial steps undertaken by the Low Carbon Living Cooperative Research Centre. Based on this review, it is suggested that solving these key issues would help proliferate geopolymer technology and further aid efforts to create a more environmentally sustainable construction industry.
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Azman, Mohamed Nor Azhari, Mohd Sanusi S. Ahamad, Taksiah A.Majid e Mohd Hanizun Hanafi. "Status of Industrialized Building System Manufacturing Plant in Malaysia". Journal of Civil Engineering, Science and Technology 2, n. 2 (1 dicembre 2011): 8–16. http://dx.doi.org/10.33736/jcest.89.2011.
Testo completoAbstract (sommario):
The trend construction industry have move from project based to product based in term of long term investment. Industrialized building system (IBS) in Malaysia is defined as a construction system where components are manufactured at factories on or off site, transported and then assembled into a structure with minimum work. IBS also is known as off-site construction or prefabrication. Thus, IBS have the similarity drive and challenge with the United States (US), United Kingdom (UK) and Australia; and among the factors are skilled craft worker, fast track completion, cost and transportation. United States, United Kingdom and Australia have achieved modular building standard while Malaysia still in the hybridization stage. The Malaysian government and researcher have promoted the modern method construction industry to break the ‘traditional technology’. Anecdotally, the total number of IBS manufacturing plant has increased from 21 in 2002 to 143 factories in 2010. From the evolution of the IBS manufacturing component, the most favorable system used in the IBS component is the precast concrete system and followed by the steel framing system.
6
John, Keerthana, Mahmud Ashraf, Matthias Weiss e Riyadh Al-Ameri. "Experimental Investigation of Novel Corrugated Steel Deck under Construction Load for Composite Slim-Flooring". Buildings 10, n. 11 (18 novembre 2020): 208. http://dx.doi.org/10.3390/buildings10110208.
Testo completoAbstract (sommario):
Trapezoidal-shaped thin-walled metallic profiled sheets are used in composite floor construction to enable rapid construction and reduce reinforcement and formwork requirements in concrete casting. However, relevant literature reported the early failure of steel sections due to the buckling and shear of existing trapezoidal and re-entrant decking profiles. There are also limitations regarding design rules for composite flooring systems. Current work aims to develop a new type of composite top-hat section for possible use in composite slim-floor construction. Sinusoidal metallic corrugated sheets that are widely used in building construction were utilized and a new bending technique was used to produce deck components, in which transverse corrugations were introduced along the main direction of the corrugated profile. This paper investigates the structural response of these new sections for several loading and support conditions using a pilot experimental scheme. The developed top-hat sections demonstrated considerable resistance to bending as well as buckling through effective stress re-distributions under considered construction stage loading for single span and continuous span conditions. Currently available design equations recommended by Australian Standards for a similar type of corrugated decks were used to predict the design strength and to compare it with those obtained experimentally. It was concluded that the expressions proposed by the code were inadequate for single span loading cases and would require modifications before being applied to the new profile.
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Fatahi, Behzad, e S. Hamid Reza Tabatabaiefar. "Effects of Soil Plasticity on Seismic Performance of Mid-Rise Building Frames Resting on Soft Soils". Advances in Structural Engineering 17, n. 10 (novembre 2014): 1387–402. http://dx.doi.org/10.1260/1369-4332.17.10.1387.
Testo completoAbstract (sommario):
In this study, the effects of Plasticity Index (PI) variation on the seismic response of mid-rise building frames resting on soft soil deposits are investigated. To achieve this goal, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with a clayey soil representing soil class Ee according to the classification of AS1170.4–2007 (Earthquake actions in Australia) and then varying the Plasticity Index. Structural sections of the selected frames were designed according to AS3600–2009 (Australian Standard for Concrete Structures) after undertaking dynamic analysis under the influence of four different earthquake ground motions. The frame sections are modelled and analysed, employing finite difference method adopting FLAC 2D software under two different boundary conditions: (i) fixed base (no Soil-Structure Interaction), and (ii) flexible base considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results in terms of maximum lateral displacements and inter-storey drifts for the above mentioned boundary conditions are obtained, compared, and discussed. Base on the results of the numerical investigations, it becomes apparent that as the Plasticity Index of the subsoil increases, the base shears of mid-rise building frames resting on soft soil deposits increase, while the lateral deflections and corresponding inter-storey drifts decrease. It is concluded that reduction of the Plasticity Index could noticeably amplify the effects of soil-structure interaction on the seismic response of mid-rise building frames.
8
Wong, Koon Wan, e Vanissorn Vimonsatit. "Determination of Shear Capacity for Load Rating of Concrete Bridges to AS 5100.7-2017". Infrastructures 7, n. 11 (17 novembre 2022): 156. http://dx.doi.org/10.3390/infrastructures7110156.
Testo completoAbstract (sommario):
According to Modified Compression Field Theory (MCFT), the ultimate shear capacity of a reinforced concrete section depends on load effects (shear, moment, torsion, and axial force) caused by factored design loads. In many design standards, including Australian AS 5100.7, MCFT has been incorporated for bridge assessment, which requires a load rating to be carried out according to the loading of the nominated rating vehicle as prescribed in the standard. Recently, some approaches have been proposed for bridge load rating that have suggested using an iterative-search procedure to determine the shear capacity by proportionally increasing the load effects until the shear capacity and shear are equal. This paper describes several adverse effects of using the proportional load, which is not consistent with the characteristic of the vehicle loading, to determine the shear capacity for load rating. Numerical examples of two bridge beams, one simply supported and the other continuous, are presented to demonstrate that the characteristic of the load effects caused by a moving vehicle is not representable by proportional load effects. Furthermore, the current practice in the bridge load rating does not load rate the longitudinal steel capacity in resisting the axial force induced by the load effects of the rating vehicle. This paper presents a new approach to the load rating that separately accounts for the load effect for axial failure mode of the longitudinal steel. Finally, it is pointed out that locating the critical section where the rating factor is minimum is tedious but can be automated by integrating load rating into the analysis of load effects.
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Gaurkar, Prachi P., e Amey Khedikar. "Comparison of Various Codes of Fire on Structural Design". International Journal for Research in Applied Science and Engineering Technology 10, n. 6 (30 giugno 2022): 490–504. http://dx.doi.org/10.22214/ijraset.2022.43781.
Testo completoAbstract (sommario):
Abstract: Fire situation is the significant issue in India and that of different designs is severely impacted by them. A portion of the design might fall after the fire in view of temperature impact. In this research, the primary spotlight on the beam and column of the structure. The standard fire curve is presented in IS code for a substantial steel support however for concrete neither fire curve is created nor any issue proclamation is given with the goal that various codes are utilized for the issue explanation. In this venture IS code, Euro Code, National Building codes of Canada and National code of Construction series of Australia are utilized. In reference of this codes the model to be framed in SAP programming with various information. The temperature for investigation is taken same for the whole model. The failed structures are over and over examined and make the model safe. Then the segment cross-segment and shaft cross-segment are taken and post process for the warm examination in SAFIR Software. This product is an issue sort of GID Software. In this the model are broke down by warm impact and post process in DIAMOND Software for the outcome. The similar examination of the Single bay frame model and 3-bay frame model for various codes is shown with assistance of chart. The correlation is in the middle of between standard fire curve and various codes. Keywords: Fire, SAFIR, DIAMOND, SAP-2000, Various Codes.
10
Hedulian, S. I., O. A. Gara e S. V. Savchenko. "COMPARATIVE ANALYSIS OF THE USE OF EXPANSION AGENTS IN REPAIR SOLUTIONS OF DRY BUILDING MIXTURES FOR IMPROVING HARDENING CONDITIONS". Modern construction and architecture, n. 1 (29 settembre 2022): 55–62. http://dx.doi.org/10.31650/2786-6696-2022-1-55-62.
Testo completoAbstract (sommario):
The article examines the possibility of increasing the compatibility of repair solutions based on dry mixes with damaged concrete and reinforced concrete structures by improving the curing conditions of such materials through comparative analysis of adhesive strength and linear shrinkage of cement samples using different types of superabsorbents, namely SAP Newsorb based on sodium polyacrylates from the Japanese manufacturer Newstone, Chinese MNC-SAP based on potassium polyacrylates from MUHU Construction Materials and AquaGel based on cross-linked copolymer of acrylamide and potassium acrylate from the Australian Baroid. The data obtained during experimental studies show that the use of investigated SAP superabsorbents additives due to the improvement of hydration conditions in the cement matrix of the repair material can partially compensate the growth of shrinkage deformations, which, in turn, slightly improves the indicators of the adhesive strength of the bond with the surface of the damaged structure. A positive effect of the use of the specified polymer admixtures on the investigated cement solutions was established. Compared to the base sample, on average, for each of the studied days of hardening, the shrinkage rate of all samples containing SAP was reduced by 35%, which justifies their use in order to facilitate the creation and further high-quality functioning of the repair system. The addition of the studied SAPs allows to improve the adhesion index by 1.5-2.3 times compared to the basic one, which should ensure the maximum ability of the repaired system to perceive the workload. The optimal contents of SAP additives in the composition of the studied cement mortars to reduce shrinkage and increase the adhesive strength were determined. The compositions of non-structural repair cement mortars of class RM3 and R1-R2 in terms of adhesive strength and classes RM1-RM2 in terms of shrinkage deformation in accordance with Ukrainian and European standards were obtained.
11
Nikitin, A. E. "Monitoring of international standards in the scope of ISO/TC 71 “Concrete, reinforced concrete, pre-stressed concrete”". Bulletin of Science and Research Center of Construction 33, n. 2 (22 aprile 2022): 161–72. http://dx.doi.org/10.37538/2224-9494-2022-2(33)-161-172.
Testo completoAbstract (sommario):
Introduction. At present, various approaches to standardization in construction are used that are often in poor agreement. This hinders international cooperation and collaborative planning, design, and construction of facilities. The harmonization of construction standards has been long overdue.Aim. In this work, international standards were monitored and compared with Russian analogs in order to develop an approach to their harmonization.Materials and methods. The European and American standards of the International Organization for Standardization (ISO) were selected for further comparison with the Russian analogs. A random monitoring, analysis, and comparison of ISO standards and Russian regulatory-technical base were carried out for its timely update, the elimination of emerging redundancies and contradictions, and the improvement of the harmonization of Russian and international standards in construction in the scope of ISO/TC 71 “Concrete, reinforced concrete, pre-stressed reinforced concrete.”Results. The analysis of 14 international ISO standards allowed the documents to be classified into three groups for further work and steps toward their possible harmonization with the Russian national standards and toward the development of analogous national standards to be outlined.Conclusions. Based on the monitoring results, it is recommended to classify ISO standards into three groups: 1. ISO standards of lesser relevance to national standardization due to a complete or, in some cases, more comprehensive regulatory base. 2. ISO standards where the standardization parameters differ from Russian standards or where the subject of standardization is reflected in several associated standards. Such standards should be harmonized with international standards. 3. ISO standards having no national analogs. Therefore, it is recommended to harmonize the Russian standards related to the second group and, in the absence of Russian analogs, develop national standards equivalent to those of the third group.
12
Kurth, Helmut, Karl Heinz Winter e Vaclav Pospíchal. "Ecological Requirements for Concrete Construction". Applied Mechanics and Materials 796 (ottobre 2015): 111–18. http://dx.doi.org/10.4028/www.scientific.net/amm.796.111.
Testo completoAbstract (sommario):
The population explosion has lead to a markedly increased exploitation of our natural environment, hence the expression „sustainable development“ has become a catch phrase. In a historical perspective ecological problems recently became acute and this is why it is necessary to act quickly. It is obvious that we have to pay extreme attention to how we treat our environment and our sources. This necessarily will be reflected in the actions of the lawmakers in the future, and for the building industry the results will be that the authorities will enforce new law and regulations with direct consequences for the choice of materials and building techniques. There will be developed a set of standards dealing with environmental matters, putting limitations especially on the consumption of natural resources. Some countries already has standards dealing with various ecological aspects, like recirculation, down cycling, etc. The customers will prefer building products and systems that can document compliance with environmental attitudes. For all activities the environmental burden will be evaluated and limited by laws and regulations. Consequently the industry’s accountability for the environment will be a prerequisite for remaining in business.
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Mew, Geoff, e Adrian Humphris. "The 102-foot Australian Invasion of Central Wellington in the 1920s". Architectural History Aotearoa 8 (1 gennaio 2011): 30–35. http://dx.doi.org/10.26686/aha.v8i.7098.
Testo completoAbstract (sommario):
A significant change to the building bylaws by the Wellington City Council in the early 1920s allowed for the design and erection of much taller buildings in the central city than had previously been permitted. Coupled with the use of steel frames and concrete floors, buildings started to reach eight or nine storeys; not tall by American standards, but regarded as skyscrapers in a city where three- and four-storey buildings were still the norm. The fact that several of the most prominent of these new buildings were designed mainly by Australian architects, both in the 1920s and the early 1930s, does not seem to be widely known, or has been partially concealed by quoting the local supervising architects as the prime movers in the planning. Some of the buildings were erected to house branches or Wellington head offices of Australian firms but others were solely for New Zealand clients. The firm of A & K Henderson of Melbourne led the way with their 1926 design of the T & G Building (now Harcourts) on Lambton Quay, in association with Atkins and Mitchell. Australian born and trained Llewellyn Williams had already designed the tall, but narrow, Druids Chambers further to the north and went on to oversee more tall structures in the next few years. Hennessy & Hennessy, also Australian, pioneered Wellington Art Deco designs in the early 1930s. Both the building techniques and the architectural styles employed showed strong American influences, particularly the tripartite form developed in Chicago. At first the massing of Inter-War Stripped Classical was employed, later followed by the more flowing lines of Art Deco. Local architects were not slow to accept the new challenges required in the construction of taller, more massive buildings. The firm of Atkins and Mitchell was responsible for the DIC Building (now Harbour City Centre) in 1928 whereas JM Dawson had planned the Hope Gibbons Building, a rather more traditional structure, in Dixon Street in 1925. He was also responsible for Wakefield Chambers on the corner of Wakefield Street and Taranaki Street in 1928. The huge new commercial buildings of the 1920s took advantage of the increasing availability and affordability of electric power for lighting, heating, lifts and the pumping of water. Telephones could be fitted in every office; central heating started to be installed, and there was better fire-fighting equipment. Steel-framed buildings were less susceptible to earthquake shocks. Many of the buildings we describe here are still standing, although often modified for other uses. They have become iconic structures reflecting the marked advances of the 1920s era.
14
Stracchi, Paolo. "Prefabrication of a Thin Concrete Shell: The Case of St Kevin's Church in Dee Why, Australia". Journal of the International Association for Shell and Spatial Structures 62, n. 3 (1 settembre 2021): 227–30. http://dx.doi.org/10.20898/j.iass.2021.009.
Testo completoAbstract (sommario):
Location of Project: Dee Why, NSW, Australia<br/> Structural Type: Prefabricated thin concrete shell <br/> Project Scale: Length 30 m, width 15.5 m, height 12 m <br/> Owner/Client: Warringah Catholic Parish <br/> Architect: Gibbons & Gibbons Architects <br/> Structural Engineer: Concrete Industries Australia (Monier) Engineers Pty. Ltd.<br/> Construction: Concrete Industries Australia (Monier) Pty. Ltd. <br/> Construction year: 1961<br/>
15
Sriravindrarajah, Rasiah, e Elizebeth Tran. "Waterproofing practices in Australia for building construction". MATEC Web of Conferences 195 (2018): 01002. http://dx.doi.org/10.1051/matecconf/201819501002.
Testo completoAbstract (sommario):
Waterproofing is an essential component in building construction to maintain the integrity of buildings with reduced maintenance cost. A comprehensive waterproofing system is an integrated combination of factors, and includes product selection, membrane detail, substrate preparation, design, installation and maintenance. It is designed to work under different environmental conditions, substrates and applications. Proper understanding of the issues related to waterproofing membrane systems is important to minimise the waterproofing failures in both commercial and residential buildings. This paper aims to discuss Standards and Codes; membrane systems and performance, waterproofing practices, design and installation techniques, inspection and testing and quality assurance adopted by the waterproofing industry in Australia.
16
B. Uy. "Modern design, construction and maintenance of composite steelconcrete structures: Australian experiences". Electronic Journal of Structural Engineering, n. 2 (1 dicembre 2007): 42–48. http://dx.doi.org/10.56748/ejse.802.
Testo completoAbstract (sommario):
Modern design, construction innovation and maintenance issues have been extensively utilised for composite steel-concrete building structures in Australia. This paper provides an overview of the design codes, innovative construction applications and maintenance issues for steel-concrete composite members in Australia. The paper initially provides an overview of the various codes of practice for steel-concrete composite members in Australia. In identifying construction innovation significant projects to adopt composite construction techniques are considered. Many of these projects have found that the national codes of practice have been lacking in guidance. This has thus been the focal point for much of the research into the area of steel-concrete composite members over the last two decades. The paper concludes with research that is currently being carried out which considers materials and solutions in composite structural forms which promote the concepts of sustainability and will inevitably be prominent in improved maintenance of steel structures in the future.
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Scutarasu, Constantin Sorin, Dan Diaconu-Şotropa e Marinela Barbuta. "Case Study on Modeling Fire Action Complexity in Fire Safety Engineering of Structures". Advanced Engineering Forum 21 (marzo 2017): 102–7. http://dx.doi.org/10.4028/www.scientific.net/aef.21.102.
Testo completoAbstract (sommario):
Important goals in the fire safety design, such as preventing loss of life and goods damage, are achieved by maintaining the stability of structures exposed to fire for a period of time established by norms and standards. Real fire scenarios confirm that the specific technical regulations which actually have a prescriptive character (both national and international) do not deal with sufficient possibilities regarding the assessment of structural fire safety. The new approach on structural safety, based on engineering notions, gives us additional prospects on it and it is included in the issues of the fire safety design of structures. A relatively new field of study, known by a few professionals focused on fire safety (but well acknowledged in the research area), fire safety design met with lots of changes and restructuring of the governing concepts and procedures and of the information with which they operate, due to the fast accumulation of experience in this area of engineering activity. Consequently, after countries such as Australia, Canada, New Zeeland or USA provided towards professionals specific technical regulations for fire safety design, groups of experts in these aforementioned countries have joined their forces to try to diminish the differences that exists between those regulations and to give a unitary character to them, a better conceptualized engineering approach of the fire safety design. The result: occurrence of the publication International Fire Engineering Guidelines (last edition from 2005). The systematic approach of fire safety design in constructions pointed, once again, the possibility of modular organization of this field of study, the relations between modules being established according to the objective or objectives in the fire safety design for a specified building. This article aims to put forward, from this modularized perspective, the study of the fire safety design of a building exposed to fire; hence, the practical part of the article exhibits the numerical simulation of initialization and development of the fire process for a large scale religious building. The main features of the building represent the amount of space that facilitates the spreading of smoke and warm gases and which increases the risk of damaging the structural reinforced concrete elements. Application calls to specific numerical simulation with a higher degree of credibility, such as those realized by the FDS (Fire Dynamics Simulation) software.
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Nguyen, Kate TQ, Tuan Ngo, Priyan Mendis e David Heath. "Performance of high-strength concrete walls exposed to fire". Advances in Structural Engineering 21, n. 8 (26 settembre 2017): 1173–82. http://dx.doi.org/10.1177/1369433217732500.
Testo completoAbstract (sommario):
High-strength concrete is becoming very popular around the world due to its many advantages over normal-strength concrete. There are significant behavioural differences between high-strength concrete and normal-strength concrete, most notably the brittleness and sudden spalling under elevated temperatures, whereby pieces of hardened concrete explosively dislodge. Although all high-rise and even many medium-rise buildings have high-strength concrete walls, the spalling of high-strength concrete walls in fire has generally been ignored by the designers and the fire resistance of walls has been calculated using the rules specified for normal-strength concrete. Catastrophic failures could occur due to this ignorance of an important issue. Major design codes including the American and Australian Codes do not cover spalling adequately. Even the Eurocode rules are based on limited research. After a brief discussion on the present design practice, this article presents a summary of spalling research. The relevant results from a comprehensive study conducted at the University of Melbourne are briefly discussed. The authors are not aware of any other comprehensive research projects covering the fire behaviour of normal-strength concrete and high-strength concrete walls exposed not only to standard fires but also hydrocarbon fires. The results showed that spalling in high-strength concrete is more significant when subjected to hydrocarbon fire compared to normal-strength concrete. The level of compressive load on the panels was also found to have a significant effect on the fire performance of the high-strength concrete panels. The finite analysis element program, ANSYS, was used to model the concrete walls subjected to load and fire (both ISO834 Standard fire and hydrocarbon fire). The test results were used to validate the computer model.
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Lazovic Radovanovic, Marija M., Jelena Z. Nikolic, Janko R. Radovanovic e Svetlana M. Kostic. "Structural Behaviour of Axially Loaded Concrete-Filled Steel Tube Columns during the Top-Down Construction Method". Applied Sciences 12, n. 8 (8 aprile 2022): 3771. http://dx.doi.org/10.3390/app12083771.
Testo completoAbstract (sommario):
The paper discusses the structural behaviour of concrete-filled steel tube columns (CFT) when applied to the top-down construction method as temporary internal supports for ceilings. Their ultimate capacity to take into account the actual boundary conditions of the column is essential for successful application in construction. The paper presents the full-scale in situ testing of four slender specimens with variable D/t ratios under concentric axial loading. The CFT columns were supported on the previously jacked concrete piles. In addition, detailed finite element numerical models in ABAQUS and PLAXIS computer programs were developed. The models include the nonlinear behaviour of materials and the nonlinear behaviour of soil. The soil–pile–column interaction and impact of the CFT column–pile connection stiffness on global column stability were considered. The numerical model was validated by comparison with the experimental results. In conclusion, the coefficient for the effective buckling length of the studied columns is proposed. Finally, the experimental results of the critical buckling forces were compared with widely used international design codes Eurocode 4-EC4, American standard-ACI and the Australian standard-AS.
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Krylov, Sergey B., Ravil S. Sharipov, Sergey A. Zenin e Yury S. Volkov. "Directions of Convergence of the Requirements of the Main Domestic Standard for the Design of Concrete and Reinforced Concrete Structures SP 63.13330.2012 with the Requirements of the International Standard ISO 19338". Scientific journal “ACADEMIA. ARCHITECTURE AND CONSTRUCTION”, n. 1 (18 marzo 2019): 93–98. http://dx.doi.org/10.22337/2077-9038-2019-1-93-98.
Testo completoAbstract (sommario):
Design standards on building structures should contain, first of all, the performance and assessment requirements of structures. At the same time, design standards should provide the possibility for design and construction of concrete and reinforced concrete parts of buildings and structures that meet the requirements of the Technical regulations "On the safety of buildings and structures".
Taking into account the importance of ensuring the reliability and safety of buildings and structures erected with the use of structural concrete, the technical Committee of the international organization for standardization ISO TC 71 "Concrete, reinforced concrete and prestressed concrete", certifies national standards for compliance with the requirements of the international standard ISO 19338 "Performance and Assessment Requirements for Design Standards on Structural Concrete", developed by the same Committee.
The standard describes the issues that should be included in the standards for the design of concrete and reinforced concrete structures (terms and definitions, basic requirements, performance requirements,loads and impacts, design estimates, requirements for manufacturing and construction, as well as quality control). These requirements are common to all standards in the design of concrete and reinforced concrete structures.
In this regard, it is relevant and important to establish the possibility of presenting the National Code of rules SP 63.13330.2012 "SNiP 52.01-2003 Plain and Reinforced Concrete Structures. General Provisions" for certification for compliance with the requirements of ISO 19338. To achieve this goal, the relevant work has been done, based on the results of which were made the proposals for the submission of SP 63.13330.2012 for certification for compliance with ISO 19338:2014. These proposals are set out in the text of the article.
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Topchiy, Dmitry V., Alina S. Bolotova, Aleksey S. Vorobev e Alevtina V. Atamanenko. "Technical rationing of the construction technology of reinforced concrete floor slabs using non-removable void formers". RUDN Journal of Engineering Researches 20, n. 2 (15 dicembre 2019): 155–62. http://dx.doi.org/10.22363/2312-8143-2019-20-2-155-162.
Testo completoAbstract (sommario):
Technically sound standards of time and production standards are designed to improve production efficiency, technical and economic indicators of construction enterprises, timely commissioning of buildings and structures being erected, as well as ensuring the proper organization of workers' wages. Labor standards are used in determining the need for construction machinery and equipment, the required number of workers, and also serve as the basis for the development of network and calendar schedules that are part of the project of construction organization (PCO) and the project of construction production (PCP). Standards of time and standards for the production of most of the construction work are contained in the collections of common norms and rates and state elemental estimated norms. However, in the conditions of continuous development and introduction of new production technologies, there is a need to update and refine the existing technical regulation database. Standards of time, corresponding to the modern level of technical development and reflecting the advanced experience of workers, allow to make the right choice when analyzing the most economical ways of producing work. Definition and removal of production standards is to determine the weighted average number of working hours to perform a particular technological operation, while taking into account the conditions of production of this workflow, the numerical and qualification composition of workers.
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Senaratne, Sepani, Gregory Lambrousis, Olivia Mirza, Vivian W. Y. Tam e Won-Hee Kang. "Recycled Concrete in Structural Applications for Sustainable Construction Practices in Australia". Procedia Engineering 180 (2017): 751–58. http://dx.doi.org/10.1016/j.proeng.2017.04.235.
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Hooton, RD, e LJ Struble. "Introduction to Symposium on Concrete Fracture Mechanics Standards". Cement, Concrete and Aggregates 19, n. 2 (1997): 77. http://dx.doi.org/10.1520/cca10318j.
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Falikman, V. R., e P. N. Sirotin. "Prospects of using crushed stone in accordance with GOST 32703 to produce concrete for general civil construction". Bulletin of Science and Research Center of Construction 33, n. 2 (14 aprile 2022): 194–212. http://dx.doi.org/10.37538/2224-9494-2022-2(33)-194-212.
Testo completoAbstract (sommario):
Introduction. With the introduction of a new national standard GOST 32703–2014 “Automobile roads of general use. Crushed stone and gravel from rocks. Technical requirements”, mining companies producing crushed stone from dense rocks faced the problem of ensuring the production output in compliance with two significantly different standards, both regulating the properties of crushed stone. The complexity of a balanced approach to production planning and stock reserve maintenance determines the need to assess the possibility of using crushed stone produced according to GOST 32703 when producing construction works, concrete mixes, and concrete for general civil construction.Aim: to define the prospects of using crushed stone produced according to GOST 32703 when producing concrete for general civil construction.Materials and methods. Crushed stone produced according to GOST 8267 and GOST 32703 from solid rocks of various origin—granite, gabbro-diabase, and dense limestone—was used as coarse aggregates for concrete production. Comparative tests of concrete mixes prepared from crushed stone from one deposit but classified in accordance with two different standards were performed. The main quality parameters of concrete mixes were determined by testing methods according to GOST 10181, while the mechanic al and physical properties of concrete mixes were determined by testing methods according to GOST 10180.Results. The study showed a certain compatibility of the quality properties of concrete mixes and the mechanical and physical properties of concrete filled with crushed stone, which is classified according to different standards but having the same content of lamellar and needle-shaped particles.Conclusions. Recommendations are formulated on the prospects of using crushed stone produced according to GOST 32703 when producing concrete for general civil construction. The key issues concerned with simultaneous application of two different standards are indicated.
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Castel, Arnaud, Raoul François, Maria Paola Santisi d’Avila e Doug Jenkins. "New service limit state criteria for reinforced concrete in chloride environments". Corrosion Reviews 37, n. 1 (28 gennaio 2019): 21–29. http://dx.doi.org/10.1515/corrrev-2017-0100.
Testo completoAbstract (sommario):
AbstractIn chloride environments, reinforcement stress limits, intended to control flexural cracking, are one of the most important requirements for service limit state (SLS) design. However, concrete damage at the steel-concrete interface between bending cracks, so called cover-controlled cracking, is always correlated to areas of severe steel reinforcement corrosion. Based on the assumption that cover-controlled cracking should be limited, a model has been developed to provide alternative reinforcement stress limits in marine exposure conditions such as concrete in sea water, including permanently submerged, spray zone and tidal/splash zone, as well as coastal constructions located within 1 km of the shoreline. In this paper, the new reinforcement stress limitation is compared to the Australian Standards AS3600 concrete building code and AS5100.5 concrete bridge code provisions. Analysis shows that the new model is very sensitive to the reinforcement percentage of the cross-section. As a result, the existing AS3600 and AS5100.5 code provisions are more conservative than the new limitation for lightly to normally reinforced concrete cross-section. In this case, crack width control governs the SLS design. However, for normally to heavily reinforced concrete cross-section, the new model provides more conservative results suggesting that cover-controlled cracking governs the SLS design.
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Venkrbec, Václav. "Optimization of Re-Mixing Recyclated Concrete Aggregates". Applied Mechanics and Materials 824 (gennaio 2016): 116–23. http://dx.doi.org/10.4028/www.scientific.net/amm.824.116.
Testo completoAbstract (sommario):
Under the concept of sustainable construction it is necessary to establish harmonized indicators, standards and methods for assessing the impact of building products and technological processes of the construction industry on the environment. One of the basic commodity that have a significant impact on the environment is construction waste and his recycling options. Concrete aggregate (RCA), which can be made from concrete elements, has a great potential in reducing the volume of landfills and full re-using of concrete rubble. It can also fulfill sustainability criteria for construction by the re-use of this stony concrete components. The study takes into account local characteristics RCA, but the aim is to globalize outcomes and evaluate them, especially for parameterization used in the design phase of building information modeling.
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Kumar, V. K. Pradeep, A. Sai Kumar, P. Venkat e J. S. Kalyana Rama. "Economical Robust Mix Proportioning of Self-Compacting Concrete Mixes - A Comparative Study". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, n. 1 (19 dicembre 2022): 171–78. http://dx.doi.org/10.38208/acp.v1.491.
Testo completoAbstract (sommario):
Concrete being the second largest consumed material after water needs attention towards sustainable construction with an increase in infrastructure. The world is moving towards innovative techniques and methodologies for sustainable and durable construction of concrete structures. The selection of suitable ingredients for making concrete and determining the relative amounts with an objective of producing a concrete of required strength and durability is the need of the hour. Standard mix proportioning of concrete should satisfy the workability requirements and also meet the requirement for mechanical properties, durability, economy, and even ecology of engineering applications. The study would focus on quality control aspects in mix proportioning the concrete as per the requirements of the industry. It includes mix proportioning of self-compacting concrete as per the standards prescribed in national construction community and Indian standards, plastic viscosity, and EFNARC based mix proportioning of self-compacting concrete. The mix proportioning would focus on utilizing various industrial and agro wastes as a suitable cement replacement material, locally available fine and coarse aggregate materials along with their alternates, appropriate dosage of admixtures, etc. The outcomes of the study include the formulation of handouts and readymade mix proportions of self-compacting concrete used in the construction of buildings and pavements along with their cost estimation. The study also provides information on some of the key points to be considered in making concrete using optimization concepts which would further reduce the cost of construction. The optimized mix proportions will be handy for the ready-mix plants especially in dealing with multiple large-scale construction activities. Mix proportioning using plastic viscosity approach was proven to be economical compared to other mix design methods.
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Yang, Fang, De Peng Lv, Hua Cao, Yan Fang Zhou e Yu Rong Wu. "The Appraisal Example of the Reliability and Seismic Performance of a Reinforced Concrete Chimney". Applied Mechanics and Materials 204-208 (ottobre 2012): 2399–404. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2399.
Testo completoAbstract (sommario):
In the state that the chimney is being used, we evaluate the seismic performance of the reinforced concrete chimney on the basis of testing the tilt, mechanical properties and chemical composition, configuration of the steel and construction measures, the lining damage, the cylinder damage, the subsidiary systems and dynamic characteristics of the chimney. The results show that: For the long-term wind action, corrosion and hot action, and lower level of construction and lower design standards, the reliability of the chimney structure can’t meet the current standards requirements, and need to take appropriate measures to be reinforced; but the seismic performance of the chimney structure can meet current standards requirements.
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Andrzej Moczko, Vladimir I. Andreev e Marta Moczko. "Concrete quality testing in existing structures. Methods of european standards". Vestnik MGSU, n. 8 (agosto 2019): 967–75. http://dx.doi.org/10.22227/1997-0935.2019.8.967-975.
Testo completoAbstract (sommario):
Introduction: strength testing of cores cut from existing structures, as a rule, is believed the most reliable source of actual concrete quality information. However, this statement is true in part only. Although current European standards allow applying cut core testing for determination of actual structural condition with no restriction, they foresee that the given testing cannot replace concrete quality testing based on standard specimens taken by with the rules in effect. The study purpose is obtaining relevant information on concrete quality and structure, filler type and granularity, and seeking for answers to the following questions: is the tested concrete porous; to what extent the carbonation is developing on the surface layer; are there any defects in the structure.
Materials and methods: the article considers cut core testing methods, elastic rebound measuring, pull-out method, and ultrasonic velocity measurement.
Results: the article presents a review of methods for concrete quality testing in finished construction projects following the European standards. Test conditions, recommendations on specimen trimming, and main requirements for correct interpretation of the data obtained using elastic rebound and ultrasonic measurements are given. Independent methods of nondestructive testing are described.
Conclusions: the study considers European methods of concrete compressive strength assessment in construction structures. One of the most promising nondestructive test methods which can be applied for concrete quality testing in existing structures seems to be a pull-out method, particularly CAPO-TEST. The research showed that the pull-out tests provide an accurate assessment of strength directly in the structure.
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Sun, Fei Long, Shuai Wu, Quan Jiang e Ting Ting Liu. "Study on the Threshold Value and Test Methods for Chloride Ion Content in Sea Sand". Key Engineering Materials 680 (febbraio 2016): 482–85. http://dx.doi.org/10.4028/www.scientific.net/kem.680.482.
Testo completoAbstract (sommario):
The building sand is mainly composed of river sand at early stage. Recently, with the depletion of river sand, the new mined river sand cannot meet the demands for building sand. The sea sand is resourceful and can remedy the deficiency of sand for construction. However, the sea sand contains high content of chlorine salt, shell and lightweight matters. They are harmful for the strength and durability of concrete and will lead to premature corrosion of rebar. This will endanger the safety of construction. The studies demonstrate that high content of chlorine salt in sea sand is the main factor led to the deterioration of sea sand concrete. Therefore, in order to ensure the safety of construction, the threshold value of chloride content is specified in standards about concrete and aggregate. And methods testing the content of chloride ions are provided. However, the criterion in different standards differs from one another, which means their different viewpoints about the harm of chloride ions. In this work, the threshold value and test methods of chloride ion content for the building sand in the national standards and the international standards are summarized. The research has great significant for setting standards about sea sand, determining the rational threshold value of chloride ion content and improving the method testing the content of chloride ions.
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Kropidłowska, Oliwia. "Application of sawdust concrete in construction". Budownictwo i Architektura 21, n. 3 (31 ottobre 2022): 005–18. http://dx.doi.org/10.35784/bud-arch.2927.
Testo completoAbstract (sommario):
Sawdust concrete is a type of lightweight concrete in which some of the mineral aggregate is replaced by sawdust - a by-product of wood processing. It is not a new material, but its potential is not utilised to its full degree. Taking into account the most important advantages of sawdust concrete - lower density and greater thermal and acoustic insulation than ordinary concrete - it is worth to consider the possibilities of its usage in construction wider than currently . In order to present the properties of sawdust concrete, the review of contemporary technical literature has been performed.
For the production of sawdust concretes mineralized sawdust from various types of trees, ordinary cements, mineral aggregates and water, are used. The usage of additives and admixtures is also allowed. The properties of the finished sawdust concrete are mainly influenced by the proportion of its components, especially the amount of fine aggregates replaced by sawdust. The construction products made of sawdust concrete are characterized by a low coefficient of thermal conductivity λ and soundproofing properties. In bending tests, a simply supported sawdust concrete beam behaves similar to a regular concrete beam, cracks first appear in the tension zone. Tensile strength, compressive strength and Young's modulus of sawdust concrete products depend on the proportion of components and the method of sawdust preparation before applying in the sawdust concrete-mix. Compared to ordinary concrete, the obtained values for sawdust concrete are lower, but partially fall within the ranges for the lower classes of ordinary concrete.
There are several possible applications of sawdust concrete in construction. One of the perspectives is to use it to build walls in buildings that require soundproofing between rooms, or to replace wood with it when renovating old buildings. However, further tests of sawdust concrete are needed in terms of the most favourable composition for its mechanical properties, and to define the standards according to which sawdust concrete elements should be produced.
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Lakusic, Stjepan. "Construction of a new day hospital in Zadar using recycled aggregate concrete". Journal of the Croatian Association of Civil Engineers 73, n. 08 (settembre 2021): 833–44. http://dx.doi.org/10.14256/jce.3233.2021.
Testo completoAbstract (sommario):
This paper presents the pilot project of application of recycled aggregate during construction of a new day hospital in Zadar. The project included the demolition of an existing hospital building and the use of generated construction waste as recycled aggregate in the construction of a part of the building. The 16/32 mm fraction of aggregate was obtained by mechanical processing of the generated waste which was then tested in accordance with the HRN EN 206 and HRN EN 12620 standards. Four concrete mixes were prepared, and the fresh (slump, density, air content) and hardened properties were tested (compressive strength, modulus of elasticity, capillary absorption, water permeability, drying shrinkage). The obtained results confirm that by complying with the standards for recycled aggregates and knowing their origin it is possible to produce concrete with properties equivalent to those of ordinary concrete for specified durability conditions.
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Khodakov, Artem, Maksim Tochenyy, Svetlana Belyaeva, Olga Nikonova e Leonid Pakrastinsh. "Features of Using the Russian State Standards and the Eurocodes for the Protection and Repair of Concrete Structures". Applied Mechanics and Materials 633-634 (settembre 2014): 997–1001. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.997.
Testo completoAbstract (sommario):
The corrosion is one of the main deterioration reasons of structural concrete and reinforced concrete. The corrosion is a consequence of unsatisfactory construction maintenances, poor diagnosis of defects' causes and no fracture control of concrete structures and also incorrect repair specifications and incorrect products and techniques selecting for the repair inevitably lead to the concrete structures' deterioration. The most countries are taking care to developing of the national standards for using as manuals for the protection and repair of concrete structures against corrosion to avoid these negative factors. The article authors are offering the comparative analysis of the harmonized Russian state standards and Eurocodes for the protection and repair of concrete structures against corrosion.
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Kessy, J., M. Alexander e H. Beushausen. "Concrete durability standards: International trends and the South African context". Journal of the South African Institution of Civil Engineering 57, n. 1 (gennaio 2015): 47–58. http://dx.doi.org/10.17159/2309-8775/2015/v57n1a.
Testo completoAbstract (sommario):
Durability problems in reinforced concrete (RC) structures are an issue of global concern, since they threaten economic growth, natural resources and human safety. As a result, attempts have been made in design standards developed in most countries to include requirements to provide durable RC structures. This paper examines and compares such durability requirements in standards from the United States, Australia, Canada, Europe, India and South Africa. It focuses on aspects such as exposure conditions, limiting values of material compositions and proportions, and cover depth to the reinforcing steel. The paper describes issues behind prescriptive standards and deals with challenges confronting performance approaches for concrete durability. Following international trends, it is evident that the South African Standards, particularly SANS 10100-2, must undergo substantial updating and improvements to durability requirements. The paper suggests the means of re-drafting and implementing durability specifications in any revised version of SANS 10100-2, taking into account both prescriptive and performance alternatives. Further, a methodology of developing durability specifications suitable for the South African concrete industry is proposed, and recommendations are made for future developments.
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Li, Chuan Xi, e Xin Zhong Wang. "Construction of Steel Tube Concrete Arch Bridge after Axes Change". Advanced Materials Research 255-260 (maggio 2011): 831–35. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.831.
Testo completoAbstract (sommario):
In this paper ,the axes of a three-span dumbbell-shaped steel tube concrete arch bridge was changed due to deviation in bridge piers, tie beam construction and steel tube production, thereby steel tube arch ring can not be closed, and suspender hole can not be aligned. The side-span hollow steel tubes were intercepted and adjusted for three times through calculation and analysis, therefore the structure stress is reasonable and achieved original design standards under the condition of not changing the original arch axes, and the bridge was successfully constructed, thereby providing reference for engineering staff.
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Yu, Le Hua, Shuang Xi Zhou e Wen Wu Deng. "Evaluation on Quality of Cement Concrete in Pavement of Highway". Advanced Materials Research 717 (luglio 2013): 295–300. http://dx.doi.org/10.4028/www.scientific.net/amr.717.295.
Testo completoAbstract (sommario):
According to the construction specification and relevant data collected from construction situ, quality of cement concrete in pavement of highway was evaluated by statistic result of flexural strength in this paper. The assessment and analysis were based on three statistic parameters of flexural strength, which are the qualified value of flexural strength, the minimum of flexural strength and variation coefficient of flexural strength, respectively. The estimating results could be summarized that the pavement concrete had been endowed with stronger flexural strength and better stability so to satisfy relevant target of highway standards. Meanwhile it was discussed that quality characteristics of pavement concrete was changed with main construction factors included milepost distance, section distribution, half-side spatial position, construction time and other environment. Furthermore, the technical methods for enhancing concrete pavement were proposed.
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Makunza, John. "Concrete Technology in a Rapidly Growing Urban Environment – The Case of Dar es Salaam City". Tanzania Journal of Engineering and Technology 41, n. 4 (31 dicembre 2022): 1–14. http://dx.doi.org/10.52339/tjet.v41i4.869.
Testo completoAbstract (sommario):
Concrete is a building material that is used in great quantities second only to our use of water. The ingredient materials of concrete include cement, fine and coarse aggregates plus a reasonable amount of water, and sometimes additives. The construction of various structures like, residential buildings, commercial buildings, hospitals, schools, bridges, etc, needs good quality concrete. Good modern technologies are needed by the construction industry in order to effectively construct buildings which are durable. A study has been done with the main objective of assessing the concrete technologies existing in rapid growing cities in Sub-Sahara Africa like Dar es Salaam, and the challenges faced in attaining good quality constructions. The study was done through site visits, observations, sampling and testing. From the results, it has been found that traditional concrete technologies are still prevailing, while new technologies are starting to be adopted. Also there is a problem of conformance to the standards. It was therefore recommended that investment in Cement production industries is needed and that regulatory bodies must enforce builders to adhere to the standards in order to yield good quality constructions.
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Choong, Wei Sheng, Jian Chong Chiu, Flavio Lopez-Martinez, Abdullah Alaklabi, Mariana Claudia Oliveira, Surya Dewi Puspitasari e Julius Adebayo. "Utilization of Green Material for Concrete in Construction". Civil and Sustainable Urban Engineering 2, n. 2 (24 ottobre 2022): 82–95. http://dx.doi.org/10.53623/csue.v2i2.116.
Testo completoAbstract (sommario):
In this modern technological era today, green materials are highly regarded as one of the most important elements when designing and conducting an environmentally sustainable construction project. The cement that is utilized in conventional concrete today is one of the culprits for the high levels of carbon dioxide generated, which is damaging to the environment. Many researchers have shown and suggested that cement substitution is a favorite technique for minimizing the generation of greenhouse gas (GHG) emissions as well as substituting unused raw materials with concrete. The concept of green concrete promotes sustainable development as it utilizes the least natural resources during production and mainly depends on recyclable waste materials as its main raw material. This paper displays the various designs of green concrete in developed countries by partially replacing cement with recyclable materials such as fly ash, demolished waste from construction sites, electronic waste, carpet fiber waste, palm oil fuel ash, and others. Green concrete endorses the innovative and sustainable use of waste aggregate and unconventional alternative materials to substitute cement within concrete. It is crucial to adopt the use of green concrete, especially in developed countries, as they have the capacity and financial strength to ensure adequate training, public awareness, further research and demonstration projects, as well as suitable standards to be applied to endorse the global application of green concrete in infrastructure projects.
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Lim, Jee Hock, Qing Wei Chan, Yong Eng Tu, Parnam Singh e Siong Kang Lim. "A comparison study on Australia, Eurocode, and US reinforced concrete structure repair codes". E3S Web of Conferences 347 (2022): 01006. http://dx.doi.org/10.1051/e3sconf/202234701006.
Testo completoAbstract (sommario):
Currently, there is no local standard on reinforced concrete structures repairing in Malaysia. The aim of this study is to discuss the similarities and differences of the reinforced concrete structure repair codes of Australia, Eurocode, and United States.In the methodology and work plan stage, preliminary decision for concrete repair is made after the structural assessment. Next, repair work is conducted in relation to the general planning. Lastly, repair products applied in the system are ensured to be mutually compatible in order to accept the repair work. According to the 11 principles listed in EN 1504-9, concrete damages are classified as concrete defects and corrosion on reinforced concrete structure. SA HB 84:2018 is using the fundamental principles of EN 1504 as the main reference. Similarly, all three codes highlight the reinforcement corrosion as the primary reason of concrete damage. The main difference between ACI 546R-14 and EN 1504 is ACI 546R-14 provides no principle for all intended uses in repair works. Two case studies of reinforced concrete structure repairing for irrigation control structures and low-cost flat building are discussed. The case studies reveal a possibility of combining the strengths of a selected standards in reinforced concrete structures repair works.
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Xu, Haixue, e Brahim Benmokrane. "Strengthening of existing concrete dams using post-tensioned anchors: a state-of-the-art review". Canadian Journal of Civil Engineering 23, n. 6 (1 dicembre 1996): 1151–71. http://dx.doi.org/10.1139/l96-925.
Testo completoAbstract (sommario):
Many old dams are in need of strengthening and rehabilitation as a result of aging, deterioration, deficiencies in design and construction, and more stringent safety standards. These standards include the probable maximum flood and the maximum credible earthquake. Post-tensioned anchors are the most practical and cost-effective method of strengthening existing concrete dams subjected to direct tension, sliding, overturning and seismic loading. In some cases, they are used to stabilize rock abutments and concrete locks and to combat the effects of alkaline and aggregate reaction. The post-tensioning technique requires minimum demolition, has only a minor impact on the dam, and is relatively inexpensive using a small number of anchors. This paper reviews about 60 case histories of concrete dams strengthened by post-tensioned anchors. The reasons for strengthening existing dams are analyzed. The general design, construction, drilling, grouting, testing, and performance of post-tensioned anchors for strengthening concrete dams are outlined. Key words: post-tensioned, anchor, multistrand, fixed anchor length, free anchor length, anchor head, strengthening, rehabilitation, concrete dam.
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Chen, Zheng Fa, e Gui Feng Liu. "The Application of Reinforced Concrete Composite Floor System of Superimposing Box and Net Beam to Zibo Athletes Apartment". Advanced Materials Research 163-167 (dicembre 2010): 1732–35. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1732.
Testo completoAbstract (sommario):
According to the construction site of Zibo athlete apartment and the relevant standards, the structure constitution of the composite floor system, construction method and the problems that should be paid attention during construction were introduced in detail. Reinforced concrete composite floor system of superimposing box and net beam consisted of small prefabricated components- two reinforced concrete plates locating at top and bottom of the box and the cast-in-site concrete beam. This composite floor system was a whole structure of beam and plate combination, with a continuous box section. The superimposing box undertook the loads action together with the rib beam. The floor system has many advantages such as the industrial prefabricated components, stable construction quality, reduction of labor intensity in construction site and the environmental pollution, and the integral structure.
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Jeong, Jae-Soo, e Chan-Sik Lee. "An Experimental Study on Quality Control Standards of Exposed Concrete in Construction Stage". Korean Journal of Construction Engineering and Management 13, n. 2 (31 marzo 2012): 48–57. http://dx.doi.org/10.6106/kjcem.2012.13.2.048.
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Peng, Xiao Tao, Yi Xiong, Yong Wu e Dan Meng. "The Alignment Control of Large-Span Continuous Beam Bridge Cantilever Construction Method". Applied Mechanics and Materials 351-352 (agosto 2013): 1226–30. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.1226.
Testo completoAbstract (sommario):
One long-span bridge adopted the cantilever casting method, which is pre-stressed concrete variable cross-section continuous box girder structure. In the construction process, due to the concrete pouring, hanging basket moving, construction loads, pre-stressed tension, concrete shrinkage and creep, temperature, humidity and many other factors. There will be such problems of cantilever beam segment closed error and the bridge line-type do not coincide in design goals. In this paper, we use the bridge dedicated finite element program MIDAS / Civil procedural for modeling and structural analysis. Analyze the problems of deflection control and pre-camber adjustment of cantilever construction, in order to ensure that the bridge closure smoothly in accordance with the design standards.
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Badraddin, Abdulmalek K., Afiqah R. Radzi, Saud Almutairi e Rahimi A. Rahman. "Critical Success Factors for Concrete Recycling in Construction Projects". Sustainability 14, n. 5 (7 marzo 2022): 3102. http://dx.doi.org/10.3390/su14053102.
Testo completoAbstract (sommario):
This study explores the success factors of concrete recycling in construction projects, using Malaysia as a case study. The objectives include (1) identifying the critical success factors for concrete recycling in construction projects, (2) comparing the critical success factors between large enterprises (LEs) and small–medium enterprises (SMEs), and (3) developing constructs that group the critical success factors. First, a list of success factors was identified through semi-structured interviews with fifteen construction industry professionals and a systematic literature review of journal articles. This list was then incorporated into a questionnaire and disseminated to industry professionals. Eighty-nine valid responses were collected and analyzed using mean score ranking, normalization, agreement analysis, and factor analysis techniques. The analyses showed ten critical success factors for concrete recycling. The critical success factors include the availability of uniform standards for concrete recycling, adequate awareness among project stakeholders on concrete recycling, appropriate construction waste management plans, government policies to support concrete recycling, good marketing strategy for concrete recycling, good communication among employees, applications for recycled concrete in sub-industries, provisions in work method statements on concrete recycling, positive legislation toward concrete recycling, and availability of concrete recycling infrastructure. However, the percentage of agreement between SMEs and LEs for the ten critical success factors was only 22%. In other words, there is no consensus on criticality across organizational sizes. Finally, the critical success factors can be categorized into two interrelated groups: external and internal. This study contributes to the literature by analyzing the necessary success factors for concrete recycling. The study findings allow researchers and practitioners to develop strategies to promote concrete recycling.
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Garcez, Estela O., Muhammad I. Kabir, Mahbube Subhani, Alastair MacLeod, Andras Fehervari, Mitchell Hall e Patrick Moulton. "Development of high strength self-compacting fibre reinforced concrete for prefabricated concrete industry". MATEC Web of Conferences 275 (2019): 02011. http://dx.doi.org/10.1051/matecconf/201927502011.
Testo completoAbstract (sommario):
Prefabricated construction is an emerging industry in Australia and considered a key mechanism to boost productivity in the construction industry. The use of fibre reinforced concrete has a huge potential in the prefabricated industry as the concrete can be delivered straight to the precast mould, eliminating in many cases the steel reinforcement, thus increasing production quotas and cost savings. Such results can be further improved by utilising self-compacting concrete reinforced with fibres. Although the use of steel fibres as reinforcement is now well established, in the precast industry thin walls and shape of the moulds can be a limitation to steel fibre as well as work health and safety concerns for handling. Under such conditions, the use of polymeric fibres can be extremely beneficial, reducing labour hours and placement time as well as improving safety. This paper reports the development of high strength self-compacting fibre reinforced concrete for application in prefabricated concrete industry, exploring the effect of Forta-Ferro and ReoShore fibres on concrete fresh and mechanical properties.
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Ohama, Yoshihiko, e Ota Masahiro. "Recent Trends in Research and Development Activities of Polymer-Modified Paste, Mortar and Concrete in Japan". Advanced Materials Research 687 (aprile 2013): 26–34. http://dx.doi.org/10.4028/www.scientific.net/amr.687.26.
Testo completoAbstract (sommario):
The present paper reviews the recent trends in research and development activities of polymer-modified paste, mortar and concrete in the Japanese construction industry. In Japan, the active research and development of the polymer-modified paste, mortar and concrete have been carried out for the past about 50 years, and they are nowadays used as dominant construction materials in various applications because of their high performance, multifunctionality and sustainability compared to conventional cement paste, mortar and concrete. The recent research and development activities of the polymer-modified paste, mortar and concrete are concerned with repair, strengthening or retrofitting systems for deteriorated reinforced concrete structures, liquid-applied membrane waterproofing systems, high-grade redispersible polymer powders, intelligent repair materials, and reaction to fire as repair materials in building construction. Standardization work for the polymer-modified paste, mortar and concrete has been in progress in recent years, and useful national and institutional standards have been published till now.
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Chaturvedi, Shashikant, Ajitanshu Vedrtnam, Maged A. Youssef, Martin T. Palou, Gonzalo Barluenga e Kishor Kalauni. "Fire-Resistance Testing Procedures for Construction Elements—A Review". Fire 6, n. 1 (24 dicembre 2022): 5. http://dx.doi.org/10.3390/fire6010005.
Testo completoAbstract (sommario):
Fire accidents are a significant risk to human life and civil infrastructure. As a countermeasure, the regulatory bodies of different countries have established standards for evaluating the performance of construction elements during fire exposure. ISO 834 is the globally accepted fire-resistance testing standard. Other standards include ASTM E119, BS 476, IS 3809, JIS A 1304, AS 1503, EN 1363, and GB/T 9978, which are utilized by the US, Britain, India, Japan, Australia, Europe, and China, respectively. This article presents a summary and comparison of the fire-resistance testing standards. In reality, standard tests for isolated structural members may not efficiently portray realistic fire scenarios due to the fire location, its intensity, etc. Thus, researchers have utilized a variety of specialized setups and full-scale non-standard fire tests to fulfill their research objectives. The article includes a summary of selected full-scale, ad hoc, and specialized setups that were reported in the literature. The article highlights the need for timely updates of fire standards to accommodate the testing of newly developed construction materials, structural systems, and possible regional fire scenarios. The article also identifies the research areas that require significant focus in experimental structural fire-resistant testing.
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Titus, P. G. "WEST TUNA I BREAM B: APPLICATION OF CONCRETE TECHNOLOGY OFFSHORE AUSTRALIA". APPEA Journal 37, n. 1 (1997): 546. http://dx.doi.org/10.1071/aj96033.
Testo completoAbstract (sommario):
Esso/BHPP's West Tuna and Bream B Platforms are the first completed concrete-based platforms in Australia and are Exxon's first designed, built and operated concrete gravity structures (CGSs). Both platforms were towed to location, complete with commissioned topsides facilities, in fourth quarter 1996 and successfully installed in 61 m of water. They will add in excess of 45,000 BOPD (7200 kl/d) of oil production to Bass Strait volumes. West Tuna, with 48 well slots, will be Esso/BHPP's largest and most complex Bass Strait production facility, whereas Bream B will be an 18-slot, unstaffed minimum facility satellite platform with a 720-tonne topsides. By comparison, West Tuna's topsides weigh 7,300 tonnes.Esso/BHPP chose the CGS concept for the two developments following extensive conceptual studies with selected North Sea designers. Because of rising derrick barge day rates in the early 1990s (required for steel pile jacket installations), coupled with the availability of a suitable casting basin near Sydney, the CGS concept was judged economically attractive, with savings estimated at 10 per cent of the total facilities capital expenditure relative to its steel pile jacket alternative.The project saw a number of firsts, including the use of the world's largest land-based crawler cranes to lift and set the completed production modules over 75 m in the air onto the completed CGS structures. CGS fabrication productivity problems were experienced during the early phase of construction reflecting the complex nature of the construction, however implementation of a number of project management initiatives resulted in achievement of world-class productivity by completion of the works.
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Awoyera, Paul O., Oyinkansola Awobayikun, Ravindran Gobinath e Emmanuel I. Ugwu. "Rheological, Mineralogical and Strength Variability of Concrete due to Construction Water Impurities". International Journal of Engineering Research in Africa 48 (maggio 2020): 78–91. http://dx.doi.org/10.4028/www.scientific.net/jera.48.78.
Testo completoAbstract (sommario):
Various national and international standards recommend potable water for mixing concrete; however, the availability of potable water is virtually a daunting task in some developing communities. Concrete workers in such environments tend to utilize any available water for mixing concrete, and this may be detrimental to the quality of the concrete being produced. This study investigates the rheological, mineralogical and strength variability of concrete due to construction water impurities. Water samples were collected from four different construction sites within Southwestern region of Nigeria for production of concrete. The physical and chemical properties of the waters were determined so as to measure their rate of contamination, prior to their use for mixing concrete. The rheological properties of the fresh concrete, compressive strength, split tensile strength, and microscale features of hardened concrete, that were produced with each water sample were determined. From the results, the rheological features of concrete were found not to be affected by water impurities, however, the mechanical test results revealed about 10% reduction in strength between concrete made with water having least and higher concentration of impurities. Also, it was evident from the microscale tests that the water impurities do alter the hydration rate of concrete, which results in strength reduction. The study suggests pretreatment of concrete mixing water before use in order to avoid its damaging effect on concrete life.
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Pulyaev, I. S., e S. M. Pulyaev. "OBJECTS OF TRANSPORT INFRASTRUCTURE: EXPERIENCE OF SCIENTIFIC SUPPORT IN CONSTRUCTION WITHIN THE “QUALITY” CONCEPT IMPLEMENTATION". Russian Automobile and Highway Industry Journal 16, n. 5 (2 novembre 2019): 618–34. http://dx.doi.org/10.26518/2071-7296-2019-5-618-634.
Testo completoAbstract (sommario):
Introduction. The paper deals with the issues related to the implementation of the “quality” concept in the construction of reinforced concrete transport facilities linked with the scientific support during design and construction. Nowadays this problem particularly relevant in the context of the modern construction solutions, combined with the need to obtain the required properties of concrete structures and ensure the economic feasibility of construction. The aim of the research is to generalize and systematize the main methods and techniques of concrete works, which minimize the defects and cracks while the construction of transport infrastructure.Materials and methods. On the example of different technologies used in the Russian construction over last 10 years, the authors demonstrated the developed methods of obtaining high quality concrete products taking into account tested and proved modern building materials.Results. The results of the research formed the basis of the projects, technological regulations for the production, specifications and standards of organizations, guidelines. Moreover, the results also allowed implementing the concept of “quality” in transport construction based on obtaining defect-free reinforced concrete structures with specified properties, taking into account the use of modern building materials.Discussion and conclusions. The research allows carrying out construction of various massiveness and extent. The obtained results form the basis of construction technology of other industrial and civil construction objects with reinforced concrete application. The paper is interesting and useful for specialists in providing defect-free construction of reinforced concrete building structures, for engineering and technical staff. The authors dedicate the research to the memory of Professor and Doctor of Technical Sciences, A.R. Solovyanchik (1938-2019).