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Статті в журналах з теми "Roads Base courses"
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Jaskula, Piotr, Mariusz Jaczewski, Dawid Ryś, and Marek Pszczoła. "Field assessment of low-temperature cracks and bearing capacity of selected road sections in North-Eastern Poland." Transportation Overview - Przeglad Komunikacyjny 2018, no. 11 (November 1, 2018): 106–15. http://dx.doi.org/10.35117/a_eng_18_11_11.
Повний текст джерелаАнотація:
Article presents the comparison of performance of selected road sections in north-eastern Poland constructed under typical contract conditions, with the usage of High Modulus Asphalt Concrete and typical Asphalt concrete The field investigation comprised of the assessment of: the number of transverse thermal cracking, the bearing capacity and the load transfer coefficient around the thermal cracks. The FWD test confirmed lower deflections of the road sections constructed with base courses made of High Modulus Asphalt Concrete and presented two times higher values of the stiff ness modulus of those pavements. The load transfer coefficient for pavements constructed with base course made of High Modulus Asphalt Concrete indicated almost lack of load transfer around the thermal cracks. In was very surprising as the tested roads were quite new (2-7 years) and with high bearing capacity. The article was made on the basis of the paper presented on BESTInfra conference, which was held in Prague.
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Ndi, Conrad Dieudonné Bébé, Boris Nouaye, Michel Mbessa, and Robert D. Friedman. "Geotechnical characterization of an innovative soil stabilization product (Aggrebind/Road Master) usable in the construction, rehabilitation and maintenance of road infrastructure and the construction of social housing in Cameroon." Journal of the Cameroon Academy of Sciences 17, no. 3 (May 25, 2022): 257–75. http://dx.doi.org/10.4314/jcas.v17i3.5.
Повний текст джерелаАнотація:
Building roads in developing countries has always been very expensive. An efficient and more affordable method is needed. AggreBind’s soil stabilization solutions, known as RoadMaster (RM1 / RM2) and AggreBind (AGB-WT/BT) are offered. The objective of the present study was to make a geotechnical characterization of this product with a view towards its use in the construction, rehabilitation and maintenance of road infrastructure in Cameroon.A series of laboratory tests were carried out; soil identification tests (particle size analysis, Atterberg limits), lift tests (Proctor and modified CBR test), determination of the optimum water content of the material, maximum dry density, immediate CBR index and the CBR index after immersion for 4 days.Only the 95% OPM CBR test was carried out on the soil with the additive AGB-WT/RM1 in order to characterize the effects of the product on the soil.In conclusion, AggreBind/RoadMaster can provide stable, dust-free roads and stabilized base courses for general roads and highways that meet or exceed the bearing capacity requirements of international road specifications. In addition, the use of this product reduces the cost of road construction by 40% to60% and increases in-situ load bearing capacity by 400% to 600%.
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Gražulytė, Judita, Audrius Vaitkus, Egidijus Rytas Vaidogas, and Ovidijus Šernas. "Field Studies Of MSWI Bottom Ash As Aggregate For Unbound Base Course Mixtures." IOP Conference Series: Materials Science and Engineering 1202, no. 1 (November 1, 2021): 012016. http://dx.doi.org/10.1088/1757-899x/1202/1/012016.
Повний текст джерелаАнотація:
Abstract In the European Union, about 30–40 million tonnes of residues known as municipal solid waste incinerator (MSWI) bottom ash is generated and landfilled annually. To address the continuous growth of landfills and to implement zero waste and circular economy policies, researchers are researching ways to turn MSWI bottom ash into a useable resource. The conducted studies show that MSWI bottom ash is suitable for civil engineering, especially for roads, however there is a lack of field studies. As a result, MSWI bottom ash was used to construct unbound base course in heavy vehicles parking lot in 2018 and two pedestrian paths in 2018 and 2020 in Vilnius (Lithuania). This paper focuses on the structures composition and performance of those unbound base courses in terms of stability of particle size distribution, bearing capacity and permeability. The conducted study showed promising results for MSWI bottom ash as aggregate (mixture) to construct unbound base course.
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Barbieri, Diego Maria, Baowen Lou, Hao Chen, Benan Shu, Fusong Wang, and Inge Hoff. "Organosilane and Lignosulfonate Stabilization of Roads Unbound: Performance during a Two-Year Time Span." Advances in Civil Engineering 2021 (September 30, 2021): 1–13. http://dx.doi.org/10.1155/2021/9367501.
Повний текст джерелаАнотація:
The construction of the new Norwegian E39 highway comprises the excavation of extended tunnelling systems, which lead to a tremendous amount of blasted rocks. Among others, a sustainable cost-benefit application of these resources is represented by their local use as construction material in the unbound layers of the roads. Two types of nontraditional additives are investigated to improve the mechanical properties of aggregates; this is particularly useful for those rocks that do not fulfil the design requirements in their natural status. This work focuses on the field application of two innovative stabilizing technologies based on organosilane and lignosulfonate. The performance of these additive agents is characterized by considering three typical road base layer sections built on purpose according to real practice and added with water (no treatment), organosilane, and lignosulfonate. The test sections are subjected to climatic actions only as neither traffic nor surface courses are applied. With the investigation covering two years, the layers’ stiffness, deformation, and resistance to penetration are evaluated by employing a light-weight deflectometer and dynamic cone penetrometer. Both organosilane and lignosulfonate significantly enhance the mechanical properties of the treated base layers.
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Karaşahin, Mustafa, Cahit Gürer, Mehmet Saltan, Murat V. Taciroğlu, and Volkan Emre Uz. "Investigation of chip seal performance under cold climate conditions." Science and Engineering of Composite Materials 23, no. 6 (November 1, 2016): 649–58. http://dx.doi.org/10.1515/secm-2014-0041.
Повний текст джерелаАнотація:
AbstractThe chip seal is an economical type of asphalt pavement that was constructed for single- or double-layer aggregate-bitumen. Chip seals are applied to prime-sealed granular pavement surfaces in order to waterproof the surfaces of sub-layers, produce smooth and high-skid-resistance surfaces for vehicles and protect pavements against the detrimental effects of traffic and climate. Unlike bituminous hot mixtures, numerous factors can affect the performance of chip seal. One of the most important factors is climate. The aim of this study is to determine the performance variation of chip-sealed pavements under cold climate conditions. Three different chip-sealed roads in Erzurum, which is in one of the coldest regions of Turkey, were examined with non-destructive tests. Sand-patch, British pendulum, light weight deflectometer and dynamic cone penetrometer tests were performed. Chip-sealed pavements’ densities and surface temperature variation and base courses layer’s thicknesses were also measured, and deteriorations were observed and scored by researchers. Test results showed that flushing due to the higher temperatures during the short summer season, deficiency of the base course’s bearing capacity and moisture in the base course are the most important causes of deterioration in this type of chip seal, and the chip seals in this region must be resealed in <1 year because of the premature deterioration.
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Zvonarić, Matija, Ivana Barišić, Tihomir Dokšanović, and Martina Zagvozda. "Preliminary Research On Waste Rubber Application In Cement Bound Base Layer." IOP Conference Series: Materials Science and Engineering 1202, no. 1 (November 1, 2021): 012047. http://dx.doi.org/10.1088/1757-899x/1202/1/012047.
Повний текст джерелаАнотація:
Abstract Besides all the positive characteristics of cement bound courses (CBC), it has some detrimental effects on the pavement wearing courses. Due to cement hydration, this mixture is affected by shrinkage. Shrinkage induces cracks in the whole layer which along with weather conditions propagate through asphalt layers in a short period. Also, it’s stiffness negatively affects cracks propagation without providing elastic support for upper layers. As a result, roads are covered with various damages which reduces driving comfort and safety and demand new financial investments. The focus is on reducing the detrimental effect of CBC on the pavement. Nowadays, large quantities of recycled rubber can be found on the market. Wasted rubber is a large ecological problem due to its long decomposition period. On the other hand, by mechanical grinding and separation process, suitable fractions of rubber can be obtained for use in construction. Consequently, the replacement of conventional material by crumb rubber reduces the consumption of natural material and energy for its exploitation. Appropriate amounts and fractions of recycled rubber have the potential to reduce shrinkage and increase the elasticity of CBC. Within this paper, preliminary research results will be presented on the possibilities of crumb rubber implementation in CBC and its effects on mechanical characteristics. By using recycled materials in construction processes we undertake a major step in the sustainable management of natural resources.
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Han, Eui-Seok, Junho Gong, Hoseong Jeong, and Dooyong Cho. "Development of Bonded Natural Stone Pavement Using Ultra-Rapid-Hardening Mortar." Applied Sciences 10, no. 10 (May 21, 2020): 3576. http://dx.doi.org/10.3390/app10103576.
Повний текст джерелаАнотація:
Bonded natural stone pavement has been typically used in historical neighborhoods to satisfy functional and architectural aesthetic standards. Despite its advantages, it has been barely applied to places for heavy traffic volume or high travelling speed because of various structural failures in joints and bedding courses. Ultra-rapid-hardening mortar for natural stone pavement was considered as an alternative to minimize these failures. The objective of this study is to develop bound stone pavement using the ultra-rapid-hardening mortar for high traffic volume and evaluate throughout by carrying out material tests, plate load test, accelerated pavement test (APT), and falling weight deflectometer (FWD) test. For the tests, four types of pavements, asphalt, concrete block, and two bound stone pavements, were produced in a testing facility. The bearing capacity of the sub-base course, which was asphalt and concrete, showed values 1.62 and 2.64 times higher than deemed satisfactory. Additionally, rut depth was measured using a transverse profile logger during the APT test and the test was terminated at 1.97 million cumulative equivalent single axle loads (ESALs). In the rut depth measurements, the deepest deflection (16.0 mm) was made in the asphalt pavement and the depth of the concrete block pavement was 4.5 mm. Vertical displacements of 3.0 and 1.5 mm were obtained in stone pavements A and B, respectively. The maximum pavement vertical deflection response was recorded at 0, 0.4, and 1.97 million ESALs. The response results revealed that they were influenced by the material types of either bedding or sub-base courses. With these outcomes, it would be possible to apply the baseline data for designing rigid small element pavement for heavy traffic volume or high travelling speed roads.
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Kokoszka, Wanda. "The Risk Assessment for a Single Building on the Landslide Areas and Floodplains." Civil and Environmental Engineering Reports 28, no. 4 (December 1, 2018): 36–48. http://dx.doi.org/10.2478/ceer-2018-0049.
Повний текст джерелаАнотація:
Abstract Mass movements and floods are natural hazards posing a threat to the environment and bring significant economic losses. The flooding and landslide are risks in the municipalities of south-eastern Poland. Long-lasting rains cause initialize process of landslides on the slopes above the river valley, as well as flooding of local infrastructures (buildings, roads, railway tracks) located near water courses. Monitoring of geotechnical and hydrological parameters of the area is the base for the prognosis, as well as the risk assessment associated with them. So, in the paper highlights the issue of the consistency of monitoring and warning systems for these two threats. For landslides work SOPO - System Guards Against Landslides. Hydrogeological bases are defined for floodplains as The Computer System of the National Guard - ISOK. However, notable is the lack of integrity of both systems. In this paper a proposal to determine the overall risk for both threats in case of a single building is presented.
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Casarin, Rui Donizete, and Eduardo Luiz de Oliveira. "CONTROLE DE EROSÃO EM ESTRADAS RURAIS NÃO PAVIMENTADAS, UTILIZANDO SISTEMA DE TERRACEAMENTO COM GRADIENTE ASSOCIADO A BACIAS DE CAPTAÇÃO." IRRIGA 14, no. 4 (June 18, 2018): 548–63. http://dx.doi.org/10.15809/irriga.2009v14n4p548-563.
Повний текст джерелаАнотація:
CONTROLE DE EROSÃO EM ESTRADAS RURAIS NÃO PAVIMENTADAS, UTILIZANDO SISTEMA DE TERRACEAMENTO COM GRADIENTE ASSOCIADO A BACIAS DE CAPTAÇÃO Rui Donizete Casarin1; Eduardo Luiz de Oliveira21Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, SP, ruicasarin@ig.com.br2Departamento de Engenharia Civil, Universidade Estadual Paulista, Bauru, SP 1 RESUMO As estradas rurais de terra são estruturas viárias importantes para o desenvolvimento rural econômico e social da nação, sendo que a erosão provocada pelas águas das chuvas no seu leito e margens esta intimamente relacionada à má drenagem, tornando-se um dos principais fatores para sua degradação. Para que o sistema de drenagem funcione de forma adequada é necessário o conhecimento da erodibilidade, capacidade de infiltração de água no solo e adoção de práticas mecânicas de abatimentos de taludes com elevação do greide e interceptação de águas por meio de dispositivos de drenagem e captação. Neste artigo apresenta-se um modelo de drenagem por meio da construção de terraços embutidos com gradiente associados à bacia de captação em solos do tipo Argissolo Vermelho distrófico abrúptico de textura arenosa a média, com base em técnicas de abatimentos de taludes, elevando seu leito transversalmente das estradas com desviadores de fluxo. As frações granulométricas (areia, silte, argila) e a estabilidade de agregados indicam que esse solo sob ação antrópica pode apresentar processos erosivos resultando em escoamento superficial com arrastamento de solos, assoreando mananciais e cursos d’água localizados abaixo das estradas proporcionando grandes impactos ambientais nos corpos hídricos. A redução destes problemas de erosão nestas estradas de terra está na adoção de medidas que intercepte águas do próprio escoamento do seu leito, bem como as águas pluviais vindas de áreas adjacentes da contribuição, que são coletadas e conduzidas para terraços embutidos e bacias de captação. UNITERMOS: erosão em estradas rurais, infiltração de água no solo, práticas mecânicas de conservação de solo, contenção de águas pluviais. CASARIN, R. D.; OLIVEIRA, E. L. CONTROL OF EROSION IN RURALUNPAVED ROADS UTILIZING A TERRACE SYSTEM WITH GRADIENT ASSOCIATED TO CAPITATION BASIN 2 ABSTRACT The agricultural unpaved roads are important road structures for the economic and social agricultural development of the Nation, and the erosion provoked by rain water in the road bed and sides are closely related to bad draining, one of the main factors for their degradation. In order to make the draining system adequate, it is necessary to know about erodibility, infiltration capacity of water in the ground and adoption of mechanical slope abatement with grid elevation and water interception. This study presents drainage model through the construction of terraces with gradient transversally associated to the capitation basin in abruptic red dystrophic argisol soils, medium sandy texture, based on slops abatement techniques, elevating the road bed and deviating flow. The grain sized fractions of this ground (sand, silt, clay) and the aggregate stability indicated that this ground, under anthropic action, presents erosive processes resulting in superficial draining with ground hauling, sanding sources and courses of water situation below roads, providing great environmental impacts in the hydric bodies. The reduction of erosion problems in these unpaved roads is in the adoption of measures that intercept waters from the draining of their stream bed itself, as well as pluvial waters comings from adjacent areas of contribution, that are collected and conducted to inlaid terraces and capitation basis. KEYWORDS: erosion in agricultural roads, water infiltration in the soil, mechanical soil conservation practices, pluvial water containment.
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Softić, Edis, Veljko Radičević, Marko Subotić, Željko Stević, Zlatan Talić, and Dragan Pamučar. "Sustainability of the Optimum Pavement Model of Reclaimed Asphalt from a Used Pavement Structure." Sustainability 12, no. 5 (March 3, 2020): 1912. http://dx.doi.org/10.3390/su12051912.
Повний текст джерелаАнотація:
This paper demonstrates and provides additional findings and instructions to produce new cold-recycled layers of pavement structures spatially and temporally sustainable. At the same time, recycled pavement structures have been enhanced with optimum amounts of new stone materials and binders made of cement and foamed bitumen. The subject of the research is based on the examination of recycled asphalt from surface and bituminous base courses of pavement structures for use on higher-type roads. The aim of the research is to model the process of producing recycled asphalt by cold recycling to optimize the process of influential parameters. In addition, one of the primary goals of the research is to demonstrate a sustainable way of producing new cold-recycled layers of pavement structures. The obtained results indicated the inevitability of the use of recycled material from pavement structures with the possibility of applying secondary and tertiary crushing of recycled mass, which depends on the type of layer for which the recycled material would be used. The research resulted in an optimum mixture variant of the stabilization layer of pavement structure that consists mainly of recycled material from a worn pavement structure improved with a relatively small amount of new aggregate with the addition of minimal stabilizers made of cement and foamed bitumen. The results showed that the optimum mixture variant of the stabilization layer is spatially and temporally stable. Additionally, the presented optimum variant of the stabilization layer enables sustainable development of road networks with minimum consumption of new natural resources.
Дисертації з теми "Roads Base courses"
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Bouchedid, Michel. "Permeability of Base Material for Maine Roads." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/BouchedidM2004.pdf.
Повний текст джерела
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Wong, Harry Kam Woon. "The effect of bridge approach slabs on pavement deformation." Thesis, The University of Sydney, 1991. https://hdl.handle.net/2123/26379.
Повний текст джерелаАнотація:
Because there is a difference in stiffness between a bridge deck and the materials used in the approach embankment, traffic loading will cause the pavement to deform relative to the bridge deck and form a ‘bump’ at the end of the bridge. This causes drivers’ discomfort and accelerated damage to the pavement. The use of concrete approach slabs constructed so as to slope down from the bridge deck beneath the pavement has been proposed as a means of alleviating this problem.
In this thesis, experimental and theoretical work have been carried out to investigate the behaviour of approach slabs under repeated loading.
The work is broadly divided into six sections :
1. The development of a testing facility for the testing of model approach slabs under controlled conditions.
2. The assessment of the capability and performance of the testing facility.
3. The planning and conduct of the laboratory testing for the investigation of the deformation behaviour of pavements subjected to traffic loading.
4. The formulation of a three-dimensional finite element program using Fourier transforms for the analysis of the problem.
5. The planning and conduct of monotonic and cyclic drained triaxial tests for the investigation of residual strain behaviour.
6. The analysis of the residual strains in the model embankments and the development of a numerical method for the prediction of permanent displacements.
A testing facility has been developed to provide simulated traffic loading on model pavements underlain by approach slabs. Three series of tests have been carried out to investigate the effect of the orientation of the approach slab on the deformation behaviour of the pavements.
It is found that with the use of inclined slabs, the deformation in the pavement surface is more gradual than for the case where a horizontal slab is used. In other words, the bump usually formed at the end of a horizontal slab can be eliminated.
A finite layer method is developed in this thesis, which provides an efficient means for investigating by the moving wheel. the cyclic stresses generated in the road embankment The effect of the approach slab orientation and the pavement stiffness on the soil response can be examined.
Cyclic triaxial tests have been conducted using a fully automated GDS triaxial testing system. The aim of these tests was to investigate the soil residual strain behaviour. The cyclic stress paths have been estimated from the finite layer analyses.
The triaxial test results showed that the residual axial strain after the first loading cycle increased linearly with the logarithm of the number of cycles (for the 50 loading cycles carried out for each test). This relationship was to be dependent on the stress level and the gradient of the stress path.
The residual strains in the model pavements have been backfigured from two of the tests. The residual strains after the first loading cycle were found to vary non—linearly with the logarithm of the number of loading cycles. However, the non—linearity was less pronounced for the initial 50 cycles or so.
A stress path method was developed to utilise the cyclic test data for the prediction of residual axial strains in the pavement layers. Based on this method, the residual strains in the pavement layers after the first loading cycle can be computed. The residual deformations are then obtained by integrating the strains obtained for all the layers. This method was applied to one of the model pavement tests and the results are found to agree reasonably well with the observed values.
There are a number of improvements that can be made to this method of prediction, for instance, the incorporation of a non-linear stress-strain law to predict the first cycle deformation. Also, the measurement of the actual stresses acting in the model pavements would be useful in determining the appropriate stress paths for subsequent cyclic tests.
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Al, Hakim Bachar. "An improved backcalculation method to predict flexible pavement layers moduli and bonding condition between wearing course and base course." Thesis, Liverpool John Moores University, 1997. http://researchonline.ljmu.ac.uk/5571/.
Повний текст джерелаАнотація:
The aim of this research project is to develop an improved backcalculation procedure, for the determination of flexible pavement properties from the Falling Weight Deflectometer (FWD) test results. The conventional backcalculation methods estimate the pavement layer moduli assuming full adhesion exists between layers in the analysis process. The method developed in this research can predict the interface condition between the wearing and the base courses in addition to the layer moduli, which can be considered an improvement to the existing procedures. A two stage database procedure has been used to predict the above parameters and to facilitate the determination of the deflection insensitive parameters. The need for this improvement arises from the large number of debonding failures which have been reported in the literature between the wearing and base courses, and the theoretical studies which identified the significance of including the interface bonding condition in the analysis process. The validation of the improved method has been carried out firstly by comparing the backcalculated results for ninety theoretical pavements with their hypothetical values, and secondly by comparing the improved procedure results with other well known programs such as WESDEF and MODULUS. Full scale pavement testing using the FWD has been performed and the backcalculated results compared with measured values for the pavement materials. Indirect tensile tests for resilient modulus of bituminous materials were carried out on cores extracted for the pavements, whereas Dynamic Cone Penetrometer (DCP) tests were conducted for the unbound materials. The Backcalculated and the physically measured results correlated well, validating the improved procedure.
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Siripun, Komsun. "Characterisations of base course materials in Western Australia pavements." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/960.
Повний текст джерелаАнотація:
Western Australia (WA) has a road network of approximately 177,700 km, including a 17,800 km stage highway system (Main Roads Western Australia 2009). This infrastructure supports a population of only about two million, and road funds always have to be carefully considered when allocated to highway authorities or other organisations. Pavement design is a process intended to find the most economical combination of suitable materials and layer thicknesses for construction. The pavement must have a carefully-specified unbound granular base to further reduce construction costs, and must be surfaced with an approximately 30 mm asphalt surface in WA. High quality aggregates are therefore required for the base course layer of a pavement because of its proximity to the road surface. Traffic loads on the road surface result in high stress levels on the base course layer. Consequently, Hydrated Cement Treated Crushed Rock Base (HCTCRB) was developed.Current pavement analysis and design in WA is thought to be sub-standard. A number of highways and roads in WA are exhibiting extensive surface damage as a result of the increasing numbers of vehicles in use. Since pavement analysis and design in WA relies predominantly on empirical design, experience and basic experimentation, explanations for the damage occurring under present conditions are difficult to determine and assess.In most areas of the USA and Europe, pavement design and analysis has entered a new era with mechanistic design replacing empirical design. Unlike the empirical approach, a mechanistic approach seeks to explain pavement characteristics under real operational pavement conditions (loads, material properties of the pavement structure, and environments), and is based on design parameters derived from sophisticated tests which can simulate real pavement conditions in the test protocol (WSDOT 2008). The mechanistic approach to pavement design produces more relevant and useful results and these procedures, along with linear elastic analysis, were introduced into Australia by the 1987 NAASRA Guide (NAASRA 1987), of which the revised version became the AUSTROADS Guide (Austroads 2004) to the Structural Design of Road Pavements. AUSTROADS published a National Pavement Research Strategy which has been the keystone for the national co-ordination of pavement research, both within government and industry.Adaptation of the Cement Modified Crushed Rock Base concept has brought about an excellent road base material for Western Australia (WA) by the addition of a small amount of cement (1-2% by mass) to a fresh crushed rock material. The mix is stockpiled for a hydration period, and after that retreated before construction, unlike the traditional concept for cement modified/stabilised materials. This material is usually called Hydrated Cement Treated Crushed Rock Base (HCTCRB), a name established by Western Australia Mainroads (MRWA). More than 250,000 tonnes of HCTCRB has been used at a cost in excess of $10 million over the last eight years.Recently, as a result of early damage on new highways and roads in WA, MRWA and its contractors and organisations have attempted to identify the cause of this damage. HCTCRB, which is currently the best option for base course materials in WA, and Crushed Road Base (CRB), the original road base material, need to be re-examined to overcome the shortcomings in terms of analysis, design, and application. All of the factors involved in HCTCRB and CRB for today’s pavement conditions have been extrapolated far beyond the bounds of the original data, and current experience shows these require detailed re-investigation.This research aimed to study on the characteristics of CRB and HCTCRB and to determine reliable mathematical material models for the improvement in the current pavement design criteria. This study also investigated both elastic and plastic behaviour of CRB and HCTCRB. In this study, there were two relevant factors of both pavement materials which are considered in order to fulfil a lack of understanding in realistic conditions in pavements of the current pavement design. 1) The material strength which indicates the limitation and stability of pavement materials under traffic loads. This study employed the Mohr-Coulomb failure envelope to define the limitation of material implementation and also brought in the resilient modulus of materials to be the significant input parameter for multilayer finite element analysis to characterise the stress distribution in pavements. 2) The pavement failure of long term road performance relating to the design life of pavements. The permanent deformation behaviour and the shakedown concept under various stress conditions, simulated from repeated load triaxial (RLT) tests, therefore, were taken into account to investigate such long-term performance of HCTCRB and CRB and then the implementation of the findings was made to the current pavement analysis and design. Furthermore, more reliable mathematic models of base course materials for short and long term performance during their service life were established based on the laboratory test results of this study.
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Al-saedi, Mustafa Naeem Kareem. "Characterisation of Road Base Course Materials: The Effects of Waste Material Inclusion and Layering." Thesis, Curtin University, 2020. http://hdl.handle.net/20.500.11937/82485.
Повний текст джерелаАнотація:
This research provides a comprehensive study of the static and dynamic behaviours of rock with various materials and different techniques for use in pavement applications. An improvement in dynamic behaviour of rock was associated with the glass, cement and slag presences. The stiffness of rock/rubber mixtures was found to be affected by the glass addition. Moreover, artificial intelligence approaches appeared a high ability to develop a model to predict resilient modulus of base and subbase.
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Batmunkh, Narantuya. "Engineering characteristics of construction waste for Western Australian road and highway materials." Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/1839.
Повний текст джерелаАнотація:
This study examines the use of concrete waste by-products as a new source of road construction material in Western Australia (WA). The amount of construction waste in Western Australia increases annually, whilst natural rock aggregate is in shortage.This research focuses on whether recycled concrete, derived from various sources such as by-products from the processes of manufacturing ready-mixed concrete and waste from construction and demolition (C&D), is a viable option for use as a base and sub-base course material in road building in WA.A series of laboratory tests were conducted to determine the physical, engineering and performance properties of selected research materials to evaluate their respective potential utilisation. The results demonstrate that the concrete waste materials selected from the companies: Holcim Ltd, All Earth, Capital Demolition and C&D Recycling are suitable for use as base and sub-base layers of flexible pavement in Western Australia.
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Jitsangiam, Peerapong. "Performance, evaluation, and enhancement of red sand for road bases, embankments, and seawall fills." Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/1733.
Повний текст джерелаАнотація:
Australia produces approximately 40% of the world’s bauxite and over 30% of the world’s alumina. Each year, about 25 million tonnes of bauxite residue is produced in Australia, requiring storage and maintenance. The construction and operation of such large impoundment areas is costly. During the extraction of alumina from bauxite ore using the Bayer process, a fine residue is produced called Red Mud. In West Australia, Darling Range bauxite deposits contain high levels of quartz which result in a coarse residue fraction also being produced. This fraction has been termed Red Sand with a typical particle size in excess of 90 microns. Typically, red mud and red sand are produced in almost equal quantity. Processing of red sand can neutralise the residual caustic and lower the salt content as required. Magnetic separation is also possible to produce a high silica fraction having low iron oxide content. The sustainable use of coarse bauxite residues for road construction is an attractive option with a high potential for large volume reuse.This study focuses on whether red sand is a viable option for use as a road base, embankment fills and as seawall fills in Western Australia. Red sand comes from bauxite ore, a product of intense tropical weathering. Hence, there are various physical properties resulting from the weathering process. Thus it is necessary to fully understand the characterisation of red sand with respect to its engineering properties in the initial part of this research. To satisfy minimum requirements of road bases, a soil stabilisation technique (a Pozzolanic- Stabilised Mixture, PSM) was used. The intent of this stabilisation technique was to use Western Australia’s by-products as stabilising materials. A Pozzolanic - Stabilised Mixture consisting of Class F fly ash (a by-product from a coal power station) and activators (the byproduct from the quicklime manufacturing in terms of lime kiln dust) were employed to develop pozzolanic activity. Once the appropriate mixture of red sand, fly ash, and activators was established (based on a maximum dry density and a value of unconfined compressive strength), a set of laboratory tests were performed which included a triaxial compressive strength test, a resilient modulus test, and a permanent deformation test.Comparisons were made between the stabilised red sand and the conventional road base material in Western Australia (crushed rock added with 2% General Purpose (GP) Portland Cement named Hydrated Cemented Treated Crushed Rock Base, HCTCRB). As for the use of red sand for embankments, the representative stabilised red sand (from red sand for road bases) was used to be an alternative fill embankment material. A testing program to evaluate the important properties of stabilised red sand for embankments including permeability, compressibility and strength was undertaken. The permeability, compressibility, and strength of the representative type of red sand were examined to assess the suitability of red sand as seawall fill. The application of red sand and stabilised red sand on three structures (road bases, embankments and seawalls) is also discussed.
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Rashid, Ahmad Haval, and Serafettin Tüdes. "Utvärdering av kalkstens egenskaper med laboratorie- och fältmetoder." Thesis, KTH, Transportvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-43242.
Повний текст джерелаАнотація:
A pavement construction designed to cope with the different type of traffic loads; it is exposed to and at the same time it can resist the effect of the climate. A road structure consists of sub- and superstructure which is divided by a boundary known as terrace. During the construction of unbound layers (base course and sub-base course) in the superstructure, it is always ensured that the material meet the requirements for bearing capacity and the degree of compaction. These parameters are controlled by various laboratory tests and control methods. To obtain increased knowledge of the material and improve the quality of the compaction in the field, it is necessary to perform laboratory tests in order to determine material properties. A base course material 0/ 32 mm limestone from Gotland (Hejdeby) was investigated in this study. To determine properties of the material various laboratory tests such as proctor compaction test, Micro-Deval, Los Angeles, and grain distribution curve are conducted. To investigate how grain size distribution affects technical properties of the material, the 0/32 mm material was modified with two different samples; grain size distribution of 2/32 mm excluding superior material content, and 0+/32 mm with enhanced superior material content. The purpose of this study was to examine changes in material behavior during proctor compaction. Two aspects of changes in material behavior were emphasized in this study; the optimal water content and maximum dry density, as well as changes of both. As a reference for the limestone features, a traditional 0/32 mm tonalite material (granite) from Vällstaverket was used relating to proctor investigation. Material's resistance to abrasion and fragmentation was investigated by two methods: Micro-Deval and Los Angeles. The results were compared with other rock materials. Furthermore the bearing capacity of the material was verified by examination of the Young's modulus and degree of compaction, as well as properties of water content and dry density, at three trial areas on Gotland. This is performed with various methods such as static plate loading test, light weight deflectometer, density gauge/SDG200, and water/sand volume meter measurement test. By comparing results from different methods of measurement, it may indicate a relationship between these. Test area 3 consists of two smaller test areas which have different water content. The bearing capacity (Young's modulus) and the degree of compaction were measured after each roller passage. Different relationships were obtained between the amount of roller overpass, with Young's modulus of material; as well as degree of compaction. It was found in this study that limestone from Gotland (Hejdeby) maintain its position as construction material for the unbound layers of the road. The result from static plate load which indicated high E V2 values (Young's modulus) was obtained from the field, and it suggests that a fine bearing capacity can be achieved in the use of limestone.
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Ferreira, Julio Antonio Zambrano. "Estudo de reforço de pavimentos com ensaios de arrancamento em equipamento de pequenas dimensões." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-19062007-154234/.
Повний текст джерелаАнотація:
Este trabalho apresenta um estudo comparativo da eficiência de diferentes geossintéticos no reforço de base de pavimentos de obras viárias com ensaios de arrancamento de pequeno porte. Utilizou-se geogrelhas de polipropileno, poliéster e de fibra de vidro e geotêxtil tecido de polipropileno. Um solo com 58% de argila (subleito) e um pedregulho areno-siltoso (camada de base) foram empregados. Os ensaios de arrancamento foram executados com diferentes combinações entre solos e geossintéticos. Nestes foi utilizado um novo sistema de medida direta de deslocamentos ao longo da inclusão com sensores óticos a laser. Além de analisar os resultados com curvas força de arrancamento x deslocamentos, foi possível utilizar gráficos rigidez x deformação para determinar o melhor geossintético no reforço de base de pavimentos. Como o corpo-de-prova de geossintético é de tamanho reduzido, garante-se a mobilização completa do reforço durante o ensaio de arrancamento e assim, é possível obter a deformação do mesmo. A abertura frontal da caixa de arrancamento tem influência no valor da força máxima ao arrancamento registrada no ensaio. Os resultados mostram que a interação solo-reforço é mais importante que a rigidez não-confinada do geossintético no comportamento do material em situação de confinamento no interior do maciço de solo. Observou-se que a resistência de junta, a geometria e o agulhamento da geogrelha, além da granulometria do solo, afetam a rigidez inicial do sistema. A melhor opção para os solos e geossintéticos estudados segue a seguinte ordem: (1) geogrelha de polipropileno, (2) geogrelha de poliéster, (3) geotêxtil tecido de polipropileno e (4) geogrelha de fibra de vidro.This work presents an evaluation of various geosynthetics efficiency in reinforced base course of road pavements using small scale pullout tests. It was used polypropylene, polyester and glass fiber geogrids and polypropylene woven geotextile. A soil with 58% of clay (subgrade), and a sandy-silty gravel (base course) were used. The pullout tests were conducted with different combinations among soils and geosynthetics. In these tests, a new system of direct measurement of inclusion displacements with laser optical sensors was used. Beyond analyzing the results with curves pullout force x displacements, it was possible to use graphics rigidity x deformation in order to determinate the best geosynthetic in base course reinforcement. As the geosynthetic specimen is of small size, the complete mobilization of the reinforcement is guaranteed and, therefore, it is possible to obtain its deformation. The frontal aperture of the pullout box influences the maximum pullout resistance. The results show that the soil-reinforcement interaction is more important than the unconfined rigidity of the geosynthetic on the material behavior in confinement situation inside the soil block. The joint resistance, the geogrid geometry and its nailing, besides the soil particles size, affect the initial system rigidity. Therefore, they are important for base course reinforcement of road pavements. The results showed that the best option for the soils and geosynthetics studied are in the following order: (1) polypropylene geogrid, (2) polyester geogrid, (3) polypropylene woven geotextile and (4) glass fiber geogrid.
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Kadlubiec, Janusz. "Dlouhodobé posuzování vozovek opravených recyklací podkladů." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225491.
Повний текст джерелаАнотація:
My work deals with monitoring communications sections, which were renovated zrecyklováním existing surface. I documented these communications and to assess their condition after the time of use. Subscribed sections I put into the database PMS.
Книги з теми "Roads Base courses"
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Hūanthanō̜m, Suphon. Kānkhātkhanē kānsuttūa khō̜ng kānthāng thotlō̜ng bon thanon Phrarām thī 2 dōi withī krapfik khō̜ng ASAOKA. Bangkok: Sūn Wičhai læ Phatthanā Ngān Thāng, Krom Thāng Lūang, Krasūang Khamanākhom, 1995.
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Hūanthanō̜m, Suphot. Kānsưksā prīapthīap phrưttikam kānsuttūa khō̜ng khanthāng thotlō̜ng bon thanon Phrarām thī 2. Bangkok: Sūn Wičhai læ Phatthanā Ngān Thāng, Krom Thāng Lūang, Krasūang Khamanākhom, 1995.
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Scullion, Thomas. Field evaluation of geotextiles under base courses. College Station, Tex: Texas Transportation Institute, Texas A&M University System, 1986.
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Nottingham), International Symposium on Unbound Aggregates in Roads (3rd 1989 University of. Unbound aggregates in roads. London: Butterworths, 1989.
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Perkins, Steven W. In-field performance of geosynthetics used to reinforce roadway base layers: Phase I : instrumentation selection and verification : final report. Bozeman, Mont.]: Montana State University, Civil Engineering Dept., 1996.
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Bowen, Melinda M. Performance evaluation of cement-treated roadway bases. Laramie, Wyo: Dept. of Civil and Architectural Engineering, University of Wyoming, 2000.
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Eggen, Paul. Determination of influences on support strength of crushed aggregate base course due to gradational, regional, and source variations. [Madison, Wis.]: Wisconsin Highway Research Program, 2004.
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Company, APG Lime, and National Lime Association, eds. Handbook for stabilization of pavement subgrades and base courses with lime. Dubuque, Iowa: Kendall/Hunt Pub. Co., 1995.
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Little, Dallas N. Evaluation of bituminous stabilized blow sands and river sands in Texas. College Station, Tex: Texas Transportation Institute, Texas A&M University System, 1986.
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Zhang, Zhongjie. Stability of calcium sulfate base course in a wet environment. Baton Rouge, LA: Louisiana Transportation Research Center, 2006.
Знайти повний текст джерелаЧастини книг з теми "Roads Base courses"
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Rafalski, Leszek, and Jadwiga Wilczek. "Polish Experience with Testing of Selected Shales as Material for Road Base Courses." In Springer Series in Geomechanics and Geoengineering, 295–301. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-32492-5_38.
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Trusheim, Felix, Alexandru Condurache, and Alfred Mertins. "Visual Landmark Based 3D Road Course Estimation with Black Box Variational Inference." In Computer Analysis of Images and Patterns, 332–43. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-64689-3_27.
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Fukubayashi, Yoshinori, Sohei Sato, Atsushi Koyama, and Daisuke Suetsugu. "Evaluation of the Performance of Gravel Road with Base Course Reinforced with Do-Nou." In Sustainable Civil Infrastructures, 40–54. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-62586-3_4.
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Amhadi, Talal S., and Gabriel J. Assaf. "The Effect of Using Desert Sands and Cement to Stabilize the Base Course Layer of Roads in Libya." In Sustainable Civil Infrastructures, 140–50. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95771-5_12.
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Tian, Hong-wei. "Evaluation Method of Interactive Quality of Road and Bridge Construction Course Teaching Based on Principal Component Analysis." In Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 452–64. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-84386-1_37.
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Molenaar, A., M. van de Ven, and M. Miradi. "Backcalculation of the stiffnesses of cement treated base courses using artificial intelligence." In Bearing Capacity of Roads, Railways and Airfields. CRC Press, 2009. http://dx.doi.org/10.1201/9780203865286.ch68.
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Zhang, X., Y. Tan, and X. Wang. "Seal courses for a soft asphalt pavement with semi-rigid base in cold regions." In Bearing Capacity of Roads, Railways and Airfields. CRC Press, 2009. http://dx.doi.org/10.1201/9780203865286.ch113.
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"Seal courses for a soft asphalt pavement with semi-rigid base in cold regions." In Bearing Capacity of Roads, Railways and Airfields, Two Volume Set, 327–32. CRC Press, 2009. http://dx.doi.org/10.1201/9780203865286-39.
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Hojjati-Emami, Khashayar, Balbir S. Dhillon, and Kouroush Jenab. "The HRA-Based Road Crash Data." In Human Performance Technology, 528–43. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-8356-1.ch027.
Повний текст джерелаАнотація:
Human error has played a critical role in the events precipitating the road accidents. Such accidents can be predicted and prevented by risk assessment, in particular assessing the human contribution to risk. As part of the Human Reliability Assessment (HRA) process, it is usually necessary not only to define what human errors can occur, but how often they will occur. Lack of understanding of the failure distribution characteristics of drivers on roads at any given time is a factor impeding the development of human reliability assessment and prediction of road accidents in order to take best proactive measures. The authors developed the complete investigation methodology for crash data collection. Furthermore, they have experimentally tested the proposed predictive behavioral characteristics of drivers in light of their instantaneous error rate over the course of driving period to assist processing and analysis of data collection as part of risk assessment. The findings of this research can assist road safety authorities to collect the necessary data, to better understand the behavioral characteristics of drivers on roads, to make more accurate risk assessments and finally to come up with right preventive measures.
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Tanzmeister, Georg. "5 Road Course and Road Boundary Estimation." In Grid-based Environment Estimation for Local Autonomous Vehicle Navigation, 87–101. VDI Verlag, 2016. http://dx.doi.org/10.51202/9783186246080-87.
Повний текст джерелаТези доповідей конференцій з теми "Roads Base courses"
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Dołżycki, Bohdan, Andrea Grilli, Alex Balzi, Mariusz Jaczewski, and Cezary Szydłowski. "Binder courses using cold recycled mixtures – a novel concept in cold recycling." In 6th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2021. http://dx.doi.org/10.5592/co/cetra.2020.1058.
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Cold recycling with cement and bituminous emulsion is one of the most environmentally friendly techniques to maximize the reuse of reclaimed asphalt (RA) collected during demolition of roads. Cold recycled mixtures are commonly used for base courses in construction or rehabilitation of flexible and semi-rigid pavements. Current experiences demonstrated that cold recycling with appropriate requirements and technical recommendations allows long-lasting pavements to be designed. Those outcomes stimulated researchers and engineers in the new challenge of using the cold recycled mixtures in binder layers that are generally more often included in maintenance planning. This paper summarizes current San Marino and Polish experiences with cold recycled mixtures designed for binder layers. The first part of the paper presents the design phase of the cold recycled mixtures in both countries. It describes and compares the composition of the mixtures, grading curves of the mineral mixtures, binding agents and requirements. The second part of the paper shows laboratory test results of mechanical properties of cold recycled mixtures for binder courses including test results in full-scale application.
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Grober, Florian, Andreas Janßen, and Ferit Küçükay. "Customer-Focussed Automatic Test Course Design." In FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-dgt-007.
Повний текст джерелаАнотація:
Customer centricity gains increasing importance in vehicle development. With respect to durability testing and approval of prototypes, it causes the requirement for testing procedures which highly comply with the occurring loads during customer operation. In this manner, lightweight construction is enabled and considerable economic advantages are raised by avoiding oversizing as well as undersizing of components. As current state of the art, vehicle manufacturers use special test courses on proving grounds or public roads which must be endured damage-free by the vehicle prototype until a compulsory mileage is reached. Alternatively, the course's loads can be reproduced on a test rig to reduce the required test time. The definition of these test courses is based on long-standing experiences. According to new trends in the automotive sector, as for example electrification and shared mobility, it can be predicted that the customer loads will change in accelerating cycles. Correspondingly, these previous experiences cannot be used offhandedly for such new questions and existing test courses become invalid. To solve the described problem of inflexibility, this article presents a technology for automatic generation of appropriate test courses from customer field data. The developed algorithm transforms customer-oriented load spectra into a test course that reproduces the occurred loads as good as possible. For this purpose, digital map data is combined with measured track load data and consecutive road segments are assembled to a complete test course by heuristic methods. This resulting course requires a minimum driving distance and induces approximately the same loads as the destination load spectra derived from customer field data. The optimisation can be processed simultaneously for several different load channels. Via using automation and heuristics, a good performance arises and enables a fast as well as flexible generation of tailored test courses pursuant to current demands. In contrast to the inflexible test course concept used so far, the described technique represents a good improvement of customer-oriented testing methodology. Therefore, it provides a great novelty value. In the article, the process of an automatic test course design is demonstrated and validated by means of a real example, which shows the practical applicability. The latter is also proved by the fact that the described method has already been used successfully in the research and development of Volkswagen AG.
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Bohdan, Dołżycki, Mariusz Jaczewski, and Cezary Szydłowski. "Cold recycled mixtures for binder courses - laboratory evaluation of mechanical properties." In 7th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2022. http://dx.doi.org/10.5592/co/cetra.2022.1388.
Повний текст джерелаАнотація:
Cold recycled mixtures composed with cement and bituminous emulsion are nowadays commonly used material for base layer. Typical pavement with cold recycled mixtures usually consists of two asphalt courses (wearing and binding course) constructed over cold recycled base. Therefore the next step in cold recycling is possibility of design of binding courses with recycled materials, but with potential to obtain high quality mixtures similar to commonly used asphalt concretes. In this case, typical new pavement structure would be designed as two cold recycled mixtures (for base and binding course) covered by wearing course. This publication presents both basic and advanced laboratory results for cold recycled binding course. Cold recycle binding course is characterized by more strict requirements for base material gradation and more strict ranges for possible properties. Also the composition of binding agents is selected to be as similar as for typical asphalt concretes. In laboratory following test were performed: volumetric properties, resistance to water and frost action, viscoelastic properties (dynamic modulus, phase angles) and resistance to fracture in SCB test. For comparison, the same test were performed for asphalt concrete for binder course and for selected test also for cement bound mixtures. Obtained results indicate that cold recycled mixtures for binder course are located between typical asphalt concretes and cement bound mixtures, characterizing by both high bearing capacity and sufficient viscoelastic properties. In the case of resistance to water and frost, cold recycled mixtures are characterized by ratio between 75-85%. Cold recycled mixtures showed good fracture resistance results in SCB test in comparison to other tested mixtures. Laboratory stage of research confirmed very good properties of cold recycled binding course and open possibility for further steps to construct and evaluate the designed mixtures on real life conditions on trial section in real environmental conditions.
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Hodgkinson, John. "Industry Training for Concrete Paving Crews in Australia (2006-2020): The “Grey Card” Course." In 12th International Conference on Concrete Pavements. International Society for Concrete Pavements, 2021. http://dx.doi.org/10.33593/zi0gjbke.
Повний текст джерелаАнотація:
In addition to advances in materials and construction equipment there is a continuing need to ensure adequate skills are available within paving crews. Since 2006 concrete pavement crews and their supervisors in Australia have been required to undertake a mandatory one-day course. Known in industry as the ``Grey Card'' course it was developed jointly by NSW Roads and Maritime Services (RMS) and industry applicable to highway and similar classification roads. It demonstrates a commitment from both sectors to relevant training. Over 180 courses with 3,800 participants have been completed in four States and the Australian Capital Territory. Successful participants are issued with a card that is recognised throughout industry irrespective of changes in an individual's employment. The course is presented by instructors accredited by RMS and drawn from industry professionals who have demonstrated considerable construction experience. There is no other course of this type in Australia. The course has the primary objective of consistently high quality construction. Based on agency Specifications the course sets out the reasons for various construction requirements and site practices necessary to achieve them at paving crew level. Sessions include the basics of making good concrete, setting forms reinforcement and dowels, placing paving and compaction, surface finishing and texturing, curing and protection. This paper sets out the development and presentations of the courses.
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Zagvozda, Martina, Matija Zvonarić, Marijana Cuculić, and Ivana Pranjić. "Waste rubber - sustainable pavements solution?" In 6th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2021. http://dx.doi.org/10.5592/co/cetra.2020.1138.
Повний текст джерелаАнотація:
Cement bound base courses increase pavement bearing capacity and resistance to detrimental effects of frost along with being a good base for surface courses. Due to its stiffness, cement bound base courses reduce vertical deflections and tensile stress in asphalt layers thus reducing fatigue and appearance of alligator cracks in asphalt. But, in order to generate required layer strength and stiffness of cement bound base, appropriate amount of cement is necessary. This in turn can cause shrinkage induced cracks which spread towards surface courses and cause accelerated deterioration of pavements. To prevent rapid deterioration of pavement surface layers and occurrence of reflective cracking, incorporation of recycled rubber from waste tire in mixtures for cement bound base courses is currently being considered. In this paper a short review of waste tire application and its behaviour in pavement structures will be shown. In addition, planned methodology and activities that are going to be conducted with in a research project are going to be discussed.
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Tarta, Ciprian Rares, Nicolae Ciont, Mihai Iliescu, and Gavril Hoda. "Comparative study on using thermoplastic polymers to improve asphalt mixtures characteristics." In 6th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2021. http://dx.doi.org/10.5592/co/cetra.2020.1170.
Повний текст джерелаАнотація:
Asphalt mixtures are composite building materials consisting of a mineral skeleton mixed with a bituminous binder, following a recipe which may also include fibres and/or polymers. The natural aggregates sustain the mixture structure, but adequate bitumen behaviour under various temperature and mechanically-induced stresses is also essential for the structural durability. Much research effort was directed towards improving the asphalt mixtures’ resistance to permanent deformation, implying an increase in mixture stiffness. At the same time, the mixture must exhibit enough low temperature cracking resistance. Six reference asphalt mixture samples were prepared and tested: mixtures M1 and M2 for base and binder courses respectively, as well as four mixtures for wearing courses (two asphalt concrete - AC1 and AC2, a stabilised mixture SMA containing fibres, and a porous mixture - PM). A 50/70 penetration grade bitumen was used to prepare all mixtures. In some cases, the obtained results did not meet the standard requirements. Bitumen or mixture modification is commonly performed by adding thermoplastic or elastomeric polymers, to improve the asphalt mixture behaviour. In this study, the effects of four thermoplastic polymers on the stiffness modulus, dynamic creep and fatigue resistance were studied. All tested polymers were introduced as grains during mixture preparation. Polymer addition led to a 31 % to 104 % increase in mixture stiffness modulus. A 220 % average increase in fatigue resistance was observed for mixtures M1 and M2. For the wearing course mixtures, creep resistance is expressed through a 99 % reduction in deformation speed and a 50 % to 80 % reduction in rut depth. The obtained results met the standard requirements. Using grain polymers is currently an effective alternative to polymer-modified bitumen, because of several technological and economical advantages. Polymer quality is essential to obtain adequate mixture characteristics.
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Dumanić, Daniela, Deana Breški, and Sandra Juradin. "The use of fibers in cement stabilized base course of pavement." In 6th International Conference on Road and Rail Infrastructure. University of Zagreb Faculty of Civil Engineering, 2021. http://dx.doi.org/10.5592/co/cetra.2020.1125.
Повний текст джерелаАнотація:
Nowadays, various materials are being analyzed as a possible component of pavement structure with the goal of using sustainable building materials and protecting the environment. Waste and recycled materials are added to pavement layers in order to improve it. Also, the possibility of using natural, renewable materials by incorporating them into existing standard materials is been examined. Cement-stabilized base course increases load-carrying capacity of the pavement but is prone to cracking which causes reflection cracks in an asphalt surface. Reinforcement of cement-stabilized base course can be achieved by the addition of fibers. Fibers added to the cement stabilization tend to prevent or delay the crack initiation and propagation by redistributing the resulting stresses. Considering the research conducted to-date and the need to use sustainable materials in combination with cement stabilization, some attempts are being made to achieve improvements of this pavement layer. Natural fibers are locally available, economical, renewable and degradable, and can be used as reinforcement. In the Mediterranean area, a possible source of cellulose fibers is found in the wild plant named Spanish Broom (Spartium junceum L). This paper offers an overview of research studies about fiber reinforcement of cement-stabilized base course. It also presents current research on Spanish Broom fibers in cement composites, as well as possible ways of obtaining and treating fibers. Based on the results of this research, a method for obtaining the fibers can be selected which might improve the mechanical properties of cement-stabilized course.
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Kreft, Sven, Ju¨rgen Gausemeier, Michael Grafe, and Bassem Hassan. "Automated Generation of Virtual Roadways Based on Geographic Information Systems." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48141.
Повний текст джерелаАнотація:
Nowadays, interactive driving simulations are well established to support the design of modern vehicle systems, like driver assistance systems (DAS). They enable to validate properties and functions of DAS in the early development phases. Driving simulations consist of several simulation models that work together at runtime. These partial models represent dedicated aspects of the vehicle, individual vehicle systems as well as the environment. In this context, environment models describe the environment the vehicle is driving through, comprising roads, buildings and vegetation. While models of single vehicle systems are currently systematically built with a high level of detail, building virtual environments is still a mostly manual and time consuming process. Particularly, building environment models that represent specific real world roads is laborious — geographically referenced data has to be gathered and integrated. Geographic information systems (GIS) and their underlying data — geo-data — have great potential to accelerate the generation of environment models. In order to achieve this potential, a systematic integration of geo-data is necessary. During this process, the specific requirements of interactive driving simulations have to be considered. This paper describes a method for the automated generation of virtual roadways based on geographic information systems. The method has been prototypically applied for a concrete road course and the results are briefly presented in this paper.
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Nagaytsev, V., and M. Nagaytsev. "APPLICATION OF THE DOPPLER EFFECT IN THE STUDY AND DIAGNOSTICS OF THE HIGH-PRESSURE PIPELINECONSISTING OF A PUMP, FUEL LINE, NOZZLE." In Innovations in road transport. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2022. http://dx.doi.org/10.34220/irt2022_42-47.
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Modern fuel dosing systems in an internal combustion engine are considered. The advantages and disadvantages of stands for diagnosing fuel systems are given. A promising diagnostic device for various fuel dosing systems is proposed, the operation of which is based on the Doppler effect. The design of the proposed device is described, as well as the main advantages and possible characteris-tics removed by it in the course of diagnosing.
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Shafer, Randall, Peter Noble, and Alex Iyerusalimskiy. "Fast Ice Drilling System – FIDS – An Improved System for Shallow Water Arctic Drilling." In SNAME 9th International Conference and Exhibition on Performance of Ships and Structures in Ice. SNAME, 2010. http://dx.doi.org/10.5957/icetech-2010-104.
Повний текст джерелаАнотація:
The Fast Ice Drilling System (FIDS) is a concept to extend the season for Ice Island drilling and to move it into deeper water as an alternative to bottom supported drilling units, such as the Steel Drilling Caisson (SDC). As currently conceived, the FIDS can support drilling of up to four wells during the course of one winter season. The FID System is designed to overcome one of the limitations of current ice island drilling, i.e. the requirement for shore access via an ice road. Building of ice roads can delay season start and shore leads and over-flooding in the spring can make the ice road unusable while the ice island platform is still stable and intact. The FID System is based on using marine logistics and supply which obviates (or minimizes) the need for shore access via ice roads. The FIDS concept uses a marine vessel(s) for early construction of spray ice islands and provides support for construction of ice roads and additional man-made ice islands. The use of logistics vessel(s) within the FIDS concept to position construction and drilling equipment, camps, fuel and other supplies in the vicinity of the target well locations improves overall efficiency and allows for an extended drilling season. This approach allows for the earliest start of ice island construction and correspondingly maximizes the time available for drilling a deep and complex well at this location. After completion of drilling and well testing, all drilling equipment and remaining supplies on the islands are returned to the logistics vessel, which remains in the ice until break-up the following summer, when it can sail to a southern port for replenishment. While the original FIDS study was based on the use of Russia SA-15 arctic logistics ships, it is possible to foresee construction of similar special purpose ships, perhaps with increased capacity which could support the FIDS concept and which might also act as support or wareships for te open-water drilling season in areas such as the Chukchi Sea.