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Liu, Hanbing, Guobao Luo, Longhui Wang, Wensheng Wang, Wenjun Li i Yafeng Gong. "Laboratory Evaluation of Eco-Friendly Pervious Concrete Pavement Material Containing Silica Fume". Applied Sciences 9, nr 1 (26.12.2018): 73. http://dx.doi.org/10.3390/app9010073.
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Pervious concretes, such as sustainable pavement materials, have great advantages in solving urban flooding, promoting urban ecological balance, and alleviating urban heat island effect, due to its special porous structure. However, pervious concrete typically has high porosity and low strength. The insufficient strength and poor freeze-thaw durability are important factors that restrict its wide application, especially in seasonal frozen areas. Improving the strength and freeze-thaw resistance of pervious concrete will expand its application. Silica fumes, as an industrial by-product waste and supplementary cementitious material, play an important role in improving concrete performance. The objective of this paper was to study the effects of silica fumes on properties of sustainable pervious concrete. Silica fumes were used to replace cement with the equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and silica fume-modified pervious concrete mixtures were prepared in the lab. The porosity, permeability, compressive strength, flexural strength, and freeze-thaw resistance properties of all mixtures were tested. The results indicated that the addition of silica fumes significantly improved the strength and freeze-thaw resistance of pervious concrete. The porosity and permeability of all pervious concrete mixtures changed little with the content of silica fumes due to the adoption of the equal volume replacement method.
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Al-Soudany, Kawther. "Remediation of Clayey Soil Using Silica Fume". MATEC Web of Conferences 162 (2018): 01017. http://dx.doi.org/10.1051/matecconf/201816201017.
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This paper evaluates the use of silica fumes as modification of fine-grained soil in order to alter undesirable properties of the native soil and create new useful soils. Silica fume as well as clay material, are used in changing the engineering properties to be compatible and satisfying this is due to their pozzolanic reactivity. The study aims to investigate the uses of these materials in geotechnical engineering and to improve the properties of soils. Four percentages of silica fumes were used in the present study, which is 0, 3, 5 and 7%. Classification, specific gravity, compaction characteristics, swell and swell pressure, CBR and compressive strength tests had been conducted on the prepared and modified soils. Results clarified that the silica fume increasing leads to decrease the plasticity index and liquid limit. Increasing in silica fume causes an increasing in plastic limit and optimum water contents while the maximum dry unit weight values decrease. The compressive shear strength, California Bearing Ratio (CBR), swell and swell pressure is improved by using silica fume so that silica fume can be considered as a successful material in improving the soil properties.
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Torres-Ortega, Ramón, Edgar Quiñonez-Bolaños, Candelaria Tejada-Tovar, Yineth García-Díaz i Ibeth Cabarcas-Torres. "High-strength Concrete with Natural Aggregates, Silica Fume, and Polypropylene Macrofibers". Ciencia e Ingeniería Neogranadina 31, nr 2 (31.12.2021): 27–40. http://dx.doi.org/10.18359/rcin.4394.
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The use of concrete with polypropylene macrofibers can reduce the fragility and shrinkage of silica fume mixtures. Here, we investigated the effect silica fumes and aggregates have on enhancing high-performance concrete with polypropylene macrofibers. Three dosages of polypropylene macrofibers were evaluated (0.39, 0.63, and 0.79 % volume fraction), including silica fume (0.0 and 7.0 % water-cement), for two types of coarse aggregate (limestone and river gravel), with two maximum nominal sizes of coarse aggregate. In total, 96 concrete specimens were subjected to compression and bending tests to evaluate the effect of adding fiber, silica fume, and different aggregate types. The results showed a resistance to compression between 36 and 71 MPa, and that to flexural strengths of 3.6 to 5.8 MPa, which indicates high-performance concrete. The work shows that it is possible to achieve high-strength concrete with 55 mm polypropylene macrofibers combined with silica fumes and natural aggregates of both the limestone and calcareous types, which is beneficial for the local production of high-performance concrete.
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Jiang, Chaohua, Xiaobin Zhou, Shanshan Huang i Da Chen. "Influence of polyacrylic ester and silica fume on the mechanical properties of mortar for repair application". Advances in Mechanical Engineering 9, nr 1 (styczeń 2017): 168781401668385. http://dx.doi.org/10.1177/1687814016683856.
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Experimental investigations on the influence of different amounts of polyacrylic ester and silica fumes on the mechanical properties of mortar such as the compressive strength, splitting tensile strength, bonding strength, and abrasion resistance are presented in this article. The results show that the compressive and splitting tensile strength of mortar can be improved with the addition of polyacrylic ester and silica fumes. Results obtained from both the direct tensile bond test and flexural bond test indicate that the addition of polyacrylic ester and silica fumes improves the bond strength significantly, and the enhancement is more obvious with polyacrylic ester paste as interfacial adhesives. Furthermore, mortar incorporation of polyacrylic ester and silica fumes shows superior abrasion resistance compared to the control mortar. Therefore, the correct combination of polyacrylic ester and silica fumes to produce mortars has been shown to have synergistic effects, which results in excellent properties including high bond strength and superior abrasion resistance. Mortars containing polyacrylic ester and silica fumes are ideal for repairing concrete especially for hydraulic concrete structure.
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Meganadhan, Anand, Kavitha Sanjeev i Mahalaxmi Sekar. "Influence of Silica Fumes on Compressive Strength and Wear Properties of Glass Ionomer Cement in Dentistry". Journal of Evolution of Medical and Dental Sciences 10, nr 20 (17.05.2021): 1457–62. http://dx.doi.org/10.14260/jemds/2021/306.
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BACKGROUND Glass ionomer cements (GIC) are an interesting restorative option due to their biocompatibility. However, it has limitations that challenge its survival in oral environment due its porous set matrix influencing the properties of the cement. This study was conducted to evaluate the influence of the addition of varying concentrations of silica fumes (SF) on the properties of GIC by field emission scanning electron microscopy [FESEM] and energy-dispersive spectroscopy [EDX]. The final set matrix of GIC remains porous, compromising the mechanical properties, limiting its extended use clinically. Incorporation of silica fumes, a pozzolan, as an additive in GIC serves as a potential filler by increasing its compressive strength and reducing wear properties. METHODS The cement was divided into 5 groups based on the absence or presence of varying concentrations (0.5, 1, 1.5, 2 %) of silica fumes; conventional glass ionomer group (CG) (I) and 0.5, 1, 1.5, 2 silica fumes incorporated glass ionomer cement (SG) (II, III, IV & V) respectively. Compressive strength and wear resistance were subjected to Universal Testing Machine and Pin on Tribometer respectively. The microstructure and the elemental composition of prepared specimens of all the groups were evaluated using FESEM and EDX. Data obtained was analysed using Statistical Package for the Social Sciences (SPSS) V22.0 (IBM, USA) followed by one-way analysis of variance (ANOVA) and post hoc Tukey test (P < 0.05). RESULTS Except 0.5SG, increased compressive strength and decreased wear of glass ionomer material was observed as the concentration of silica fumes increased. Of all the concentrations, 2SG had significantly increased compressive strength (221.62 ± 22.84 MPa) compared to CG (167.38 ± 36.94 MPa) (P < 0.05). Significantly increased resistance to wear was noted in 2SG (11.80 ± 2.58 µm) compared to CG (20.40 ± 2.07 µm) (P < 0.05). The set matrix of silica fumes modified GIC showed minimal / absence of pores with dispersion of crystalline particles as the concentration of SF increased. EDX revealed similar constitution of minerals but, varied with increased concentration of silica fumes. CONCLUSIONS 2 % silica fumes incorporated glass ionomer cement (2SG) enhanced the properties of conventional glass ionomer cement. KEY WORDS Compressive Strength, EDX, Field Emission Scanning Electron Microscope, Glass Ionomer Cement, Silica Fumes, Pozzolan
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Sarsam, Saad I., i Ammar Khalaf Jabbar Allamy. "Fatigue Behavior of Modified Asphalt Concrete Pavement". Journal of Engineering 22, nr 2 (1.02.2016): 1–10. http://dx.doi.org/10.31026/j.eng.2016.02.01.
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Fatigue cracking is the most common distress in road pavement. It is mainly due to the increase in the number of load repetition of vehicles, particularly those with high axle loads, and to the environmental conditions. In this study, four-point bending beam fatigue testing has been used for control and modified mixture under various micro strain levels of (250 μƐ, 400 μƐ, and 750 μƐ) and 5HZ. The main objective of the study is to provide a comparative evaluation of pavement resistance to the phenomenon of fatigue cracking between modified asphalt concrete and conventional asphalt concrete mixes (under the influence of three percentage of Silica fumes 1%, 2%, 3% by the weight of asphalt content), and (changing in the percentage of asphalt content) by (0.5% ±) from the optimum. The results show that when Silica fumes content was 1%, the fatigue life increases by 17%, and it increases by 46% when Silica fumes content increases to 2%, and that fatigue life increases to 34 % when Silica fumes content increases to 3% as compared with control mixture at (250 μƐ, 20°C and optimum asphalt content). From the results above, we can conclude the optimum Silica fumes content was 2%. When the asphalt content was 4.4%, the fatigue life has increased with the use of silica fumes by (50%), when asphalt content was 5.4%, the additives had led to increasing the fatigue life by (69%), as compared with the conventional asphalt concrete pavement.
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J, Anitha, i Srividya R S. "Experimental Investigation on performance of silica fumes as a soil stabilizer for oil contaminated strata". International Journal of Civil, Environmental and Agricultural Engineering 2, nr 1 (29.05.2020): 1–16. http://dx.doi.org/10.34256/ijceae2011.
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Oil leakage is an environmental issue unnoticed in the present time. The problem of oil leakage and oil contamination is main concern for petroleum harvesting countries. Oil contamination in soil creates health issues in the area surrounding it. The nutrients in the soil get reduced significantly due to oil contamination which makes the land not suitable for cultivation. The oil produces hydrocarbons which makes the civil structures weak and out at risk. The most harmful effects of oil contamination are excessive settlement of structures, breakage of underground pipes, etc. In this project, we are trying to study the effects of oil contamination in the soil and also to find a sustainable solution for it. The soil is contaminated in the percentage from 0 to 20% and the tests on index and engineering properties have been conducted to find the effect of engine oil. In order to stabilize the oil contaminated soil, we use silica fumes as a stabilizing agent. The optimum percentage of silica fume is chosen based on the tests of Index and Engineering properties conducted on the soil with silica fumes. The percentage of oil where the soil properties need stabilization is known and the soil is stabilized with the optimum silica fume percentage.
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Vyas, Vishal, i Ranveer Singh Shekhawat. "Properties of Self Compacting Concrete Containing Silica Fume as a Sustainable Alternative: A Review". Current Journal of Applied Science and Technology 42, nr 15 (14.06.2023): 1–11. http://dx.doi.org/10.9734/cjast/2023/v42i154121.
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The most frequently used building material on this planet is concrete. Concrete is the supreme user of natural resources as a result of its widespread use as construction material. Cement production produces significant amount of greenhouse emissions. The protection of environment has become challenging in many developing countries, 7-8% of CO2 is produced by the cement industry that causes huge damage to the environment. In concrete production, Silica fumes can be a partial alternative to cement. In this study, the properties of self-compacting concrete incorporating silica fumes are reviewed. Slump flow, funnel, L-box, compressive strength, split tensile strength and flexural strength are among qualities of self-compacting concrete with silica fumes that have been discussed in this study. The cement was replaced by silica fumes in the ratio of 0% to 30% in concrete, cement content can be reduced, which turns into an eco-friendly solution.
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Şenol, Ahmet, i Arzu Guner. "Use of Silica Fume, Bentonite, and Waste Tire Rubber as Impermeable Layer Construction Materials". Advances in Civil Engineering 2023 (17.01.2023): 1–12. http://dx.doi.org/10.1155/2023/7301343.
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To avoid the potential risks associated with all hazardous wastes, it is important that containment methods are intended to prevent the migration of liquid hazardous wastes or leaks containing hazardous components. Therefore, impermeable barriers were used to prevent contamination. In this study, geotechnical tests were performed on samples by mixing rubber and bentonite with silica fume at certain percentages. The aim of the experimental studies is to evaluate the applicability of certain proportions of silica fume, rubber, and bentonite mixtures as impermeable liner material. Possible cracks in bentonite during drying are reduced by the use of silica fume. Absorption of dynamic effects that may occur on the impermeable barrier layer is achieved by adding waste rubber in a uniform size. Several geotechnical tests were performed to examine the mixed rubber and bentonite with silica fumes. Looking at the results of the whole that mixed rubber and bentonite with silica fume yielded usable results and a blend for construction of a liner.
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Tanyildizi, Harun. "Prediction of the Strength Properties of Carbon Fiber-Reinforced Lightweight Concrete Exposed to the High Temperature Using Artificial Neural Network and Support Vector Machine". Advances in Civil Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/5140610.
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The artificial neural network and support vector machine were used to estimate the compressive strength and flexural strength of carbon fiber-reinforced lightweight concrete with the silica fume exposed to the high temperature. Cement was replaced with three percentages of silica fumes (0%, 10%, and 20%). The carbon fibers were used in four different proportions (0, 2, 4, and 8 kg/m3). The specimens of each concrete mixture were heated at 20°C, 400°C, 600°C, and 800°C. After this process, the specimens were subjected to the strength tests. The amount of cement, the amount of silica fumes, the amount of carbon fiber, the amount of aggregates, and temperature were selected as the input variables for the prediction models. The compressive and flexural strengths of the lightweight concrete were determined as the output variables. The model results were compared with the experimental results. The best results were achieved from the artificial neural network model. The accuracy of the artificial neural network model was found at 99.02% and 96.80%.
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Shaukat, Ahmed Jawad, Hu Feng, Anwar Khitab i Ahmad Jan. "Effect of Admixtures on Mechanical Properties of Cementitious Mortar". Civil Engineering Journal 6, nr 11 (1.11.2020): 2175–87. http://dx.doi.org/10.28991/cej-2020-03091610.
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In the current study, the primary focus is to investigate the effect of Styrene Butadiene Rubber (SBR), silica fume and fly ash on compressive and flexure strengths of cementitious mortar. Three types of specimens are prepared; the first series comprises of control specimen; the second one consists of the mortar’s specimen modified with SBR and the third one consists of the mortar’s specimen modified with SBR in a combination of fly ash and silica fumes. Mortar samples are cast in the weight ratio of 1:2.75 (cement: sand). The SBR is added at a rate of 20% of the mass of cement. The water to cement ratio (W/C) is kept at 0.5 for control specimens and the quantity of mixing water in SBR-containing samples is reduced by the same amount as the SBR is added: The adjustment is meant to obtain same consistency for all the specimens. 20% fly ash and 2.5% silica fume are added to the mortar as replacement of cement. Compressive and flexure tests are carried out according to ASTM standards. Moreover, SEM is also performed on samples at the age of 28 days. Studies reveal that SBR and SCMs reduce the mechanical strength of the mortars. SEM and EDS studies show that SBR hinders the formation of albite, whereas silica content from silica fumes and fly ash converts CaCO3 to Wollastonite (a white loose powder), which is responsible for the reduction of mechanical strength. The study also confirms that the addition of SBR in place of water hinders the formation of primary and secondary hydration products. Doi: 10.28991/cej-2020-03091610 Full Text: PDF
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Wu, Ben Ying, Xi Wu Zhou i Jin Zhong Lu. "Preparation and Properties of High-Performance Concrete with Ceramic Coarse Aggregate". Materials Science Forum 852 (kwiecień 2016): 1413–20. http://dx.doi.org/10.4028/www.scientific.net/msf.852.1413.
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High-performance concrete was prepared by using ceramic waste as coarse aggregate. The influences of several factors, such as the contents of ceramic coarse aggregates, fly ashes and silica fumes, on the properties of concrete material were investigated. The results show that the compressive strength of semi-porcelain coarse aggregate concrete are slightly lower than that of natural concrete, and the splitting tensile strength and the ratio of compressive strength and splitting tensile strength is similar to the ones of natural concrete. After fly ash and silica fume mixed, the compressive strength, the splitting tensile strength and the resistance to water penetration of concrete with semi-porcelain coarse aggregate increase significantly with the increase of silica fume content which meet the requirements of high-performance concrete. Concrete with orcelain coarse aggregate is only suitable for low strength concrete.
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Sarsam, Saad Issa. "Detecting the Impact of Micro and Nano Size Additives on Deformation of Asphalt Concrete". January 2023 4, nr 1 (14.02.2023): 1–6. http://dx.doi.org/10.36937/cebel.2023.1769.
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Permanent deformation is considered as one of the major distress type of asphalt concrete pavement in the hot climate region. It can be controlled by the use of additives either for asphalt binder or for the asphalt concrete mixture. In the present assessment, the impact of micro and Nano size additives (fly ash and silica fumes) on the deformation behaviour of asphalt concrete mixtures was assessed. Such additives were implemented as partial substitute of mineral filler. Asphalt concrete slab samples were prepared in the laboratory with the aid of roller compaction. The optimum percentages of the additives are (2 and 4) % of silica fumes and coal fly ash respectively by the weight of the binder. Beam specimens were obtained from the slab samples and tested for fatigue life under three constant strain levels using four point bending beam technique. It was observed that for mixture treated with Nano additive (silica fumes), the reduction in the permanent deformation starts at 0.0001 MJ/m3 loss in energy for 750 microstrain level. However, for mixture treated with Micro size additive (fly ash), as the dissipated energy vanishes, the permanent deformation was in the range of (3 - 4.5) microstrain. It was concluded that as the dissipated energy vanishes, the permanent deformation was lower by (29.4 and 11.7) % for mixtures treated with silica fumes and fly ash additives respectively as compared with the control mixture.
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Sarsam, Saad Issa. "Assessment of Fatigue Life and Stiffness of Asphalt Concrete After Implementation of Additives". Civil Engineering Beyond Limits 2, nr 4 (21.09.2021): 8–12. http://dx.doi.org/10.36937/cebel.2021.004.002.
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Modifying asphalt binder with additives can enhance the overall physical properties of asphalt concrete. In the present investigation, an attempt has been made to use 2 % of silica fumes and 4 % of fly ash class F for modification of asphalt binder in wet process. Asphalt concrete wearing course slab samples have been prepared under roller compaction. The beam specimens of 400 mm length and 50 mm height and 63 mm width were extracted from the slab samples. The beam specimens were subjected to the four-point repeated flexural bending beam test. The flexural stiffness was calculated under three constant micro strain levels of (250, 400, and 750). The fatigue life was monitored in terms the number of load repetitions to reach the required reduction in stiffness of 50 %. It was concluded that the flexural stiffness increases by (11, and 15) %, (17.7, and 63.6) %, (57.2, and 65) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 micro strain levels respectively. However, the fatigue life increases by (40, and 72.8) %, (115, and 220.6) %, (46, and 94.6) % when 2% of silica fumes or 4 % of fly ash are implemented and the specimen’s practices 750, 400, and 250 micro strain levels respectively. It is recommended to use modified binder with silica fumes and fly ash in asphalt concrete to enhance the fatigue life and stiffness.
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Sarsam, Saad Issa, i Nuha Mashaan. "Detecting the Influence of Additives on Asphalt Concrete Durability". Jurnal Kejuruteraan 34, nr 1 (30.01.2022): 51–58. http://dx.doi.org/10.17576/jkukm-2022-34(1)-05.
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Modification of asphalt cement with additives is a sustainable issue. An attempt was made in the present assessment to detect the influence of modification of the asphalt binder by 2 % silica fumes and 4 % fly ash additives on the durability in terms of fatigue life of asphalt concrete mixture under short-term and long-term ageing processes and moisture damage. Asphalt concrete slab samples of wearing course was prepared and compacted by roller. The beam specimens of 400 mm length and 50 mm height and 63 mm width were extracted from the slab samples. The beam specimens had practiced the four-point repeated flexural bending beam test. The fatigue life was monitored as the number of load repetitions to reach the failure under three constant micro strain levels of (250, 400, and 750). The reduction in fatigue life after long-term ageing for control, silica fumes modified, and fly ash modified mixtures was (74.7, 38.4, and 60) %, (66.2, 52.4, and 64.3) %, (63.9, 63.1, and 57.5) % under 250, 400, and 750 microstrain levels respectively. However, the reduction in fatigue life after practicing moisture damage for control, silica fumes modified, and fly ash modified mixtures was (71.2, 59.6, and 37.2) %, (37.1, 64.9, and 11.2) %, (71, 84.8, and 32.2) % under (250, 400, and 750) microstrain levels respectively. It was concluded that Fly ash exhibit lower susceptibility to long-term ageing process as compared to other mixtures, while silica fumes exhibit lower susceptibility to moisture damage as compared to other mixtures.
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Muhammed, N., L. Shihab i S. Sakin. "Ultimate Load of Different Types of Reinforced Self-Compacting Concrete Columns Attacked by Sulphate". Civil Engineering Journal 8, nr 10 (1.10.2022): 2069–83. http://dx.doi.org/10.28991/cej-2022-08-10-04.
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In this study, the effects of the partial immersion of sulphate attack on the ultimate load capacity of reinforced self-compacting concrete (SCC) columns and the sulphate attack resistance improvement using silica fume, steel fibres, and the combination of silica fume and steel fibres were assessed. Twelve short circular self-compacting reinforced concrete columns (0.150 m in diameter and 0.7 m long) were cast and divided into groups according to (1) the three acid-attack groups. The first group was tested without an acid attack (control). The second group was tested after 1 month of exposure to 2% acid. The final group was tested after 1 month of exposure to 4% acid and was then (2) subdivided according to the type of casted concrete. The first group was cast with SCC. The second group was cast with SCC and silica fume (0.1% of the cement weight). The third group was cast with SCC and 1% volume fraction steel fibres. The fourth group was cast with SCC silica fume and 1% volume fraction steel fibre. All columns were tested by axial loading. The ultimate load was increased by 42% with silica fume, 190% with steel fibres, and 238% with silica fume and steel fibres. Exposure to 2% and 4% acid reduced the ultimate loads of the columns casted with SCC by 23% and 47%, the columns casted with SCC and silica fume by 34% and 37%, the columns casted with SCC and steel fibres by 69% and 78%, and the columns casted with SCC, silica fume, and steel fibres by 72% and 79%, respectively. Based on the results, using silica fumes improved sulphate resistance, and using steel fibres enhanced sulphate resistance at an acceptable ratio. Furthermore, the mix with silica fume and steel fibres improved sulphate resistance at a good ratio. We encountered several problems in this study. The partial immersion of sulphate affected the strain in both concrete and steel. Future studies using different immersion ratios are recommended. Doi: 10.28991/CEJ-2022-08-10-04 Full Text: PDF
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Alam, Manawwer, Naser M. Alandis, Naushad Ahmad, Fahmina Zafar, Aslam Khan i Mohammad Asif Alam. "Development of Hydrophobic, Anticorrosive, Nanocomposite Polymeric Coatings from Canola Oil: A Sustainable Resource". Polymers 12, nr 12 (1.12.2020): 2886. http://dx.doi.org/10.3390/polym12122886.
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A novel hydrophobic Canola oil-based nanocomposite anticorrosive coating material with different contents of fumes silica (FS) was successfully synthesized via an in situ method. Firstly, a Canola oil-based hydroxyl terminated poly (oxalate-amide) was prepared by a two-step process of amidation and condensation. Secondly, the dispersion of fumed silica (1 to 3 wt.%) in hydroxyl terminated poly (oxalate-amide) was carried out, followed by reaction with toluene-2,4- diisocyanate (TDI) in order to form poly (urethane-oxalate-amide)/fumed silica nanocomposite. The structure and properties of nanocomposite were analyzed by FTIR, NMR (1H/13C), TGA/DTA, DSC, contact angle, and SEM. The physico-mechanical and electrochemical tests were performed in order to check the performance of nanocomposite coating. The results reveal that FS is homogenously dispersed in poly (urethane-oxalate-amide) matrix with a loading amount of less than 3 wt.%. The performance of nanocomposite coating improved when compared to virgin polymer. The synthesized nanocomposite coating can be used in the field of hydrophobic anticorrosive coatings.
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Caputo, Paolino, Giuseppe Antonio Ranieri, Nicolas Godbert, Iolinda Aiello, Antonio Tagarelli i Cesare Oliviero Rossi. "Investigation of new additives to reduce the fume emission of bitumen during Asphalt Concrete Processing". Mediterranean Journal of Chemistry 7, nr 4 (7.11.2018): 259–66. http://dx.doi.org/10.13171/mjc74181107-rossi.
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Pavement materials play an important role in overall pavement sustainability including material acquisition processing, and transportation. The main objective of the present study is to evaluate the effectiveness of new additives, to reduce bitumen’s fume emission expelled into the atmosphere, during the processing of asphalt concrete. The new additives act by trapping bitumen’s volatile substances avoiding their release at high temperatures. In this paper, we have been tested the performance of 2 types of mesoporous silica-based additives (AntiSmog 1 and AntiSmog 2). The idea of using these additives to reduce the emission of fumes in bitumen has been submitted as a patent. To quantify and characterize the emitted fumes, thermogravimetry (TGA) and gas chromatography-mass spectrometry (GC-MS) technique have been used. Dynamic Shear Rheology (DSR) has been used to check the rheological properties and the possible sedimentation issues that could occur after the addition of the additives
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Al-Gburi, Majid, i Salim A. Yusuf. "Investigation of the effect of mineral additives on concrete strength using ANN". Asian Journal of Civil Engineering 23, nr 3 (11.03.2022): 405–14. http://dx.doi.org/10.1007/s42107-022-00431-1.
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AbstractIn addition to cement, sand, gravel, and water, the current investigation of the influence of additives on the compressive strength of concrete at 28 days includes fly ash, silica fume, and slag. 315 concrete compositions with various amounts of additives are trained and tested using an artificial neural network. Concrete strength is largely affected by the specific gravity of cement and the specific gravity of fine and coarse particles, according to the studies. For greater compressive strength, it is preferable to use materials with a higher specific gravity. Compressive strength has grown as the amount of silica fumes has increased. Increased amounts of slag or superplasticizer resulted in the same behavior. When the amount of fly ash was increased, the compressive strength of the material decreased.
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Kragović, Milan, Nenad Ristić, Jelena Gulicovski, Andrijana Nedeljković, Snežana Pašalić, Ivica Ristović i Marija Stojmenović. "Application of Lignite Combustion Waste Slag Generated in Heating Plants as a Partial Replacement for Cement. Part II: Physical–Mechanical and Physical–Chemical Characterization of Mortar and Concrete". Minerals 11, nr 9 (27.08.2021): 925. http://dx.doi.org/10.3390/min11090925.
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The presented study is a continuation of the research with the aim of finding a useful value of hazardous waste slag generated by the combustion of lignite in heating plants and its application in the construction industry. The different amounts of cement (10%, 15%, 20% and 25%) were replaced with waste slag and silica fumes in mortars and concrete production. Detailed physical–mechanical characterization was performed on the mortar and concrete samples according to standard procedures. Test results indicated that the replacement of cement with slag and silica fumes reduces the physical and mechanical properties of mortar and concrete, but cement composites retained the required structural properties. If 15–20% is considered an acceptable level of compressive strength decrease, then it can be concluded that waste slag can be implemented in practice and be used as a construction material, with cement replacement in the maximal amount of 20% (17.8% of slag and 2.2% of silica fumes). On hardened mortar samples with maximal possible cement replacement (20%), physical–chemical characterizations were performed and included X-ray and infrared spectrophotometry, scanning electron microscopy, and thermal analysis. Results showed the absence of new phases and the presence of only those which were characteristic for starting samples, predominantly portlandite, quartz, calcite and calcium silicate-oxide.
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Ghaffari, Alireza, i Amirreza Ghaffari. "Retrofitting Bond of Damaged Concrete Surface in Harbour Structures". Advanced Materials Research 684 (kwiecień 2013): 177–81. http://dx.doi.org/10.4028/www.scientific.net/amr.684.177.
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An experimental research of the bonds amongst retrofitted materials on concrete structures under seashore climate has conducted. The strength of a bond between repair materials and concrete substratum has been assessed on the base of slant shear test experiment. In this research 52 samples has prepared and used for experiment .The fresh concrete with fine aggregate mix only (less than 9mm particle size without coarse aggregate) and 14% silica fume by weight of cement (normally 8 to 10% but 14% because of high amount of fine aggregate ) added to the mix which improve the properties of concrete such as bond strength as well as compressive strength and reduces permeability of sea water in corrosion or deterioration of steel bars by protecting reinforcing steel from erosion (pivotal aim of research) and even reduces abrasion resistance .Therefore silica fume was rolled an essential repairer materials on seashore structures. The retrofitted specimens were cured on water pool and kept on the seashore simulation climate upto required curing times . The strength of the improved samples has studied in three aspects as bond strength according surface roughness ,curing periods and concrete additives like silica fumes and fibres .
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Ortega, José, María Esteban, Mark Williams, Isidro Sánchez i Miguel Climent. "Short-Term Performance of Sustainable Silica Fume Mortars Exposed to Sulfate Attack". Sustainability 10, nr 7 (18.07.2018): 2517. http://dx.doi.org/10.3390/su10072517.
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Nowadays, the reuse of wastes is essential in order to reach a more sustainable environment. The cement production results in CO2 emissions which significantly contribute to anthropogenic greenhouse gas emissions. One way to reduce them is by partially replacing clinker by additions, such as silica fumes or other wastes. On the other hand, the pore structure of cementitious materials has a direct influence on their service properties. One of the most popular techniques for characterizing the microstructure of those materials is mercury intrusion porosimetry. In this work, this technique has been used for studying the evolution of the pore network of mortars with different percentages of silica fume (until 10%), which were exposed to aggressive sodium and magnesium sulfate solutions up to 90 days. Between the results of this technique, intrusion-extrusion curves and logarithms of differential intrusion volume versus pore size curves were studied. This characterization of the pore network of mortars has been complemented with the study of their compressive strength and their steady-state ionic diffusion coefficient obtained from samples’ resistivity. Generally, silica fume mortars showed different performance depending on the aggressive condition, although the greatest deleterious effects were observed in the medium with presence of both magnesium and sodium sulfates.
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Ahmed, Nivin M., Walaa M. Abd El-Gawad, Ahmed A. El_Shami i Eglal M. R. Souaya. "Electrochemical studies on the corrosion performance of new advanced anticorrosive pigments". Pigment & Resin Technology 46, nr 3 (2.05.2017): 181–93. http://dx.doi.org/10.1108/prt-05-2016-0060.
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Purpose This study aims to synthesize a series of new anticorrosive pigments using a new technique called “core-shell”. This technique is based on depositing thin surface layer of expensive, efficient anticorrosive pigment on a cheap extender. This extender forms the bulk of the new pigments. The new pigments were constructed on cores of either waste silica fume or kaolin comprising 80-85 per cent of their chemical structure, and the ferrite shell was about of 20-15 per cent. Electrochemical studies were undertaken on two series of pigments for comparison between ferrites/silica fume and ferrites/kaolin pigment to show their performance, as the shells are different. Design/methodology/approach The different ferrites/silica fume and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence (XRF) and transmission electron microscopy (TEM). Immersion test and electrochemical impedance measurements were done in 3.5 per cent NaCl. Findings The tests revealed that paint films containing Sr ferrite/silica and Ca ferrite/kaolin were the most effective in corrosion prevention. Practical implications Silica fumes have a large array of uses. These pigments can be applied in various industries such as painting, wooding coating, anti-corruption coating, powder coating, architectural paint and waterproof paints. Treated kaolin can be applied in many industries besides pigment manufacture and paint formulations; it can be applied as a reinforcing filler in rubber, plastics and ceramic composites. Originality/value The new pigments are considered ecofriendly materials, because using them converts a waste product and a natural ore to useful marketable product, leading to reducing cost and saving the environment at the same time.
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Saad Issa Sarsam. "Influence of Additives on the Viscoelastic Behavior of Asphalt Concrete". Britain International of Exact Sciences (BIoEx) Journal 4, nr 3 (15.09.2022): 162–71. http://dx.doi.org/10.33258/bioex.v4i3.751.
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Implication of mineral additives into the asphalt concrete mixture can influence the viscoelastic behavior; change the density, gradation, and strength properties. In the present investigation, fly ash and silica fumes were added to the asphalt concrete mixture. Slab samples were compacted with the aid of laboratory roller, and then beam specimens were sawed from the slab samples. The asphalt concrete beam specimens were subjected to repeated flexural stresses through the four-points bending test at 20℃ and under 400 micro-strain level until failure. The influence of the additives was monitored and compared. It was concluded that the phase angle, flexural stiffness, and the fatigue life declines while the cumulative dissipated energy increases after implication of the additives. However, the silica fumes additives exhibit a significant impact on the viscoelastic properties as compared with the control or the fly ash treated mixtures.
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Swamy, BLP Dheeraj, Vaibhav Raghavan, K. Srinivas, K. Narasinga Rao, Mahadevan Lakshmanan, K. Jayanarayanan i K. M. Mini. "Influence of Silica Based Carbon Nano Tube Composites in Concrete". Advanced Composites Letters 26, nr 1 (styczeń 2017): 096369351702600. http://dx.doi.org/10.1177/096369351702600103.
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This study focuses on the utilization of highly densified materials in cementitious composites with objectives of improving the mechanical performance and minimizing the number and size of defects. Due to their excellent mechanical properties, carbon nanotubes (CNTs) are now viewed as potential candidate for reinforcement in cement composites. The present paper reports the use of carbon nanotubes (CNTs) as reinforcement to improve the mechanical properties of portland cement paste and creating multifunctional concrete. In order to increase the bonding, and strength, a material with intermediate fineness, highly densified silica fumes, was also utilized. The densified silica fumes along with CNT are added to cement mortar in various proportions. Small-scale specimens were prepared to measure the mechanical properties as a function of nanotube concentration and distribution. Furthermore, properties like shrinkage, permeability and alkalinity of the resultant composite were also investigated. The study addresses the significance of CNT as an additive to the enhancement of properties of cement composite.
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Aswini, Gutthi, i Kalpana. "Conventional Concrete Over Polymer Impregnated Concrete Using Silica Fumes". IOP Conference Series: Materials Science and Engineering 923 (8.10.2020): 012046. http://dx.doi.org/10.1088/1757-899x/923/1/012046.
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Malathy, Ramalingam, Ragav Shanmugam, Ill-Min Chung, Seung-Hyun Kim i Mayakrishnan Prabakaran. "Mechanical and Microstructural Properties of Composite Mortars with Lime, Silica Fume and Rice Husk Ash". Processes 10, nr 7 (21.07.2022): 1424. http://dx.doi.org/10.3390/pr10071424.
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A mixture of hydraulic lime and pozzolanic material can be used as a binder in making concrete and mortar for energy-efficient construction purposes. Generally, lime possesses lower strength and higher setting time. By introducing pozzolans in the lime mortar, their cementitious properties could be increased and could compete with the cement mortars. The use of pozzolan-lime binder in mortar reduces the utilisation of cement, and hence reduces the environmental problem originating from cement production. This study mainly deals with the mechanical and microstructural properties of lime and lime composite mortars made up of hydraulic lime, silica fume and rice husk ash. Three composite mortars were made with the following combination such as hydraulic lime-silica fume (LSF), hydraulic lime-rice husk ash (LRA) and hydraulic lime-silica fume-rice husk ash (LSR). Further, their properties were compared with the pure lime mortar. Preliminary investigations were made on the lime reactivity and pozzolanic reactivity tests. It was understood that silica fumes have a (15%) better reactivity than rice husk ash. The introduction of pozzolans in the lime mortar promotes fresh, hardened and microstructural properties. The 28 days’ compressive strength of lime composite mortars achieved more than 16 Mpa, while the lime mortar attained 4 Mpa. The combined effect of pozzolanic reaction, hydration and carbonation in the lime composite mortars achieved four times the strength of lime mortar at 28 days. A high peak of calcium carbonate was detected in lime mortar as a result of carbonation. The well-developed microstructure of calcium silicate hydrate and calcium hydroxide exhibits the formation of hydration products in the lime composite mortars as observed from a scanning electron microscope (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). Similar graphs of Fourier transform infrared spectroscopy (FT-IR) showed the presence of equivalent functional elements in all lime composite mortars.
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Nili, Mahmoud, Hossein Sasanipour i Farhad Aslani. "The Effect of Fine and Coarse Recycled Aggregates on Fresh and Mechanical Properties of Self-Compacting Concrete". Materials 12, nr 7 (4.04.2019): 1120. http://dx.doi.org/10.3390/ma12071120.
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Today, the use of recycled aggregates as a substitute for a part of the natural aggregates in concrete production is increasing. This approach is essential because the resources for natural aggregates are decreasing in the world. In the present study, the effects of recycled concrete aggregates as a partial replacement for fine (by 50%) and coarse aggregates (by 100%) were examined in the self-compacting concrete mixtures which contain air-entraining agents and silica fumes. Two series of self-compacting concrete mixes have been prepared. In the first series, fine and coarse recycled mixtures respectively with 50% and 100% replacement with air entraining agent were used. In the second series, fine recycled (with 50% replacement) and coarse recycled (with 100% replacement) were used with silica fume. The rheological properties of the self-compacting concrete (SCC) were determined using slump-flow and J-ring tests. The tests of compressive strength, tensile strength, and compressive stress-strain behavior were performed on both series. The results indicated that air-entraining agent and silica fume have an important role in stabilization of fresh properties of the mixtures. The results of tests indicated a decrease in compressive strength, modulus of elasticity, and energy absorption of concrete mixtures containing air entrained agent. Also, the results showed that complete replacement (100%) with coarse recycled material had no significant effect on mechanical strength, while replacement with 50% fine recycled material has reduced compressive strength, tensile strength, and energy absorption.
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Gil, Damian Marek, i Grzegorz Ludwik Golewski. "Potential of siliceous fly ash and silica fume as a substitute for binder in cementitious concretes". E3S Web of Conferences 49 (2018): 00030. http://dx.doi.org/10.1051/e3sconf/20184900030.
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Nowadays, concrete constructions are often erected from a material that has been modified with mineral additives or chemical admixtures. Thanks to such modifications, modern and innovative visions of architects and constructors are realizable. Modification of concrete microstructure with mineral additives results in a partial change of its properties as well as physical and mechanical parameters. Ecological and economic reasons are an additional cause of increased interest in the potential use of such additives as fly ash (FA), silica fume (SF), lime powder or granulated blast-furnace slag. The basic physical mechanism of interaction of FA and SF with concrete is primarily to seal the composite microstructure. In the paper a concrete modified with a constant amount of densified silica fume, and a variable percentage amount of siliceous fly ash was analyzed. Concrete samples have been subjected to mechanical and physical tests. Their results allowed to determine the optimal composition of a concrete mix containing the mineral supplements in the context of planned experiments. The use of a combined SF and FA additive as a substitute for a cement binder in a concrete mix allows for an optimal increase in the strength parameters of the concrete, thus not degrading its physical properties. The article presents the characteristics of materials used to make concretes and then analyzes the results of the composites' tests. An in-depth analysis of the results showed the usefulness of silica fumes and siliceous fly ashes as useful raw materials for a concrete production.
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Sarsam, Saad Isaa, i Ali Muhssin Shahatha AL-Shujairy. "Assessing Tensile and Shear Properties of Recycled Sustainable Asphalt Pavement". Journal of Engineering 21, nr 6 (1.06.2015): 146–61. http://dx.doi.org/10.31026/j.eng.2015.06.10.
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Hot mix recycling of asphalt pavements is increasingly being used as one of the major rehabilitation methods by various highway agencies. Besides general savings in costs and energy expended, it also saves our natural resources and environment. Recycling process presents a sustainable pavement by using the old materials that could be reclaimed from the pavement; these materials could be mixed with recycling agents to produce recycled mixtures. The important expected benefits of recycling process are the conservation of natural resources and reduction of environmental impact. The primary objectives of this work are evaluating the Tensile and Shear Properties of recycled asphalt concrete mixtures, In addition to the resistance to moisture damage. The impact of implementing three types of recycling agents on asphalt concrete properties was also investigated. For this purpose, old materials reclaimed from field, (100% RAP), virgin filler at 3 percent content by weight of mixture and three types of recycling agents ( soft asphalt cement of penetration grade 200-300, soft asphalt cement of penetration grade 200-300 blended with 4% silica fumes and soft asphalt cement of penetration grade 200-300 blended with 6% fly ash ) at 1.5% content by weight of mixture have been implemented and used to prepare recycled mixtures. Mixtures were subjected to the following tests: Marshall Test (12 specimens), indirect tensile strength test at 20ºC, 25ºC, 40ºC, and 60ºC (48 specimens), indirect tensile ratio ( 12 specimens), double punch shear test (12 specimens).
It was found that using (soft asphalt cement blended with silica fumes) as a recycling agent revealed better performance results than the other type of recycling agent. The percentages of variation for recycled mixtures with recycling agent of (soft asphalt cement blended with silica fume) when compared to aged mixture were ( -13.8%, -25.05%, 229.5%, -47.67%, ) for properties of ( Marshall stability, indirect tensile strength at 60ºC, tensile strength ratio, double punch test,), respectively.
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Cheng, An, i Wei-Ting Lin. "Abrasion Resistance of Concrete Containing Polyolefin Fibers and Silica Fumes". Polymers and Polymer Composites 22, nr 5 (czerwiec 2014): 437–42. http://dx.doi.org/10.1177/096739111402200501.
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Wan, Wei, Jian Yang, Yong Bao Feng i Tai Qiu. "Mechanically Strong and Hierarchical Porous Silica Ceramics via Gelcasting-Lyophilization". Key Engineering Materials 697 (lipiec 2016): 414–18. http://dx.doi.org/10.4028/www.scientific.net/kem.697.414.
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Highly porous silica ceramics were prepared by in-situ gelation of an aqueous suspension with well dispersed silica particles and N’N-dimethylacrylamide (DMAA) monomer, followed by lyophilization and pressureless sintering. The gelcasting process was imparted by polymerization of DMAA. The silica raw materials used in this experiment are the dusts collected from the exhaust fumes of silicon industry. The as-obtained porous silica ceramics had three-dimensional and hierarchical pore structure and the porosity ranged from 75 to 88 % as the sintering temperature varied from 850 to 1050 °C. In addition, the porous silica ceramics appeared to have strong mechanical strength. Compressive strength of the porous silica ceramics was as high as 3.2 MPa even when the porosity was nearly 80%. The gelcasting-lyophilization method was proved to be a novel and promising route for the preparation of highly porous and mechanically strong materials.
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Murphy, Dan, i David Hutchinson. "Is Male Rheumatoid Arthritis an Occupational Disease? A Review". Open Rheumatology Journal 11, nr 1 (27.07.2017): 88–105. http://dx.doi.org/10.2174/1874312901711010088.
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Background:Rheumatoid arthritis (RA) is a systemic, inflammatory disease with an estimated global prevalence of 0.3–1.0%. An unexplained association exists between low formal education and the development of RA independent of smoking. It is established that RA is initiated in the lungs and that various occupations associated with dust, fume and metal inhalation can increase the risk of RA development.Objective:The objective of this review is to evaluate published clinical reports related to occupations associated with RA development. We highlight the concept of a “double-hit” phenomenon involving adsorption of toxic metals from cigarette smoke by dust residing in the lung as a result of various work exposures. We discuss the relevant pathophysiological consequences of these inhalational exposures in relation to RA associated autoantibody production.Method:A thorough literature search was performed using available databases including Pubmed, Embase, and Cochrane database to cover all relative reports, using combinations of keywords: rheumatoid arthritis, rheumatoid factor, anti-citrullinated peptide antibody silica, dust, fumes, metals, cadmium, cigarette smoking, asbestos, mining, bronchial associated lymphoid tissue, heat shock protein 70, and adsorption.Conclusion:We postulate that the inhalation of dust, metals and fumes is a significant trigger factor for RA development in male patients and that male RA should be considered an occupational disease. To the best of our knowledge, this is the first review of occupations as a risk factor for RA in relation to the potential underlying pathophysiology.
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Sridhar, Jayaprakash, Dhanapal Jegatheeswaran i Ravindran Gobinath. "A DOE (Response Surface Methodology) Approach to Predict the Strength Properties of Concrete Incorporated with Jute and Bamboo Fibres and Silica Fumes". Advances in Civil Engineering 2022 (17.09.2022): 1–13. http://dx.doi.org/10.1155/2022/1150837.
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Design of Experiment approach is adopted for deriving progression variables comprising jute fibres, bamboo fibres, and silica fumes. To obtain the optimal combination of progression variables, the effect of progression variable on the strength properties of concrete, Box–Behnken design of Response Surface Methodology was adopted. Totally four responses like compressive strength and split tensile strength at 14 days and 28 days were considered. Regression models for responses were tested using Analysis of Variance (ANOVA) and Pareto chart. The statistical importance of each progression variable was evaluated, and the attained models were articulated in second-order polynomial equation. The outcomes showed that addition of jute fibres, bamboo fibres, and silica fumes has enhanced the strength properties, but higher level of fibres incorporation exhibited reduction in strength. Surface plot, Pareto chart, and regression analysis outcomes show that the most substantial and influence factor at 14 days and 28 days for compressive strength is Jute fibres and for split tensile strength is both jute and bamboo fibres. The percentage of error of the validation tests is less than 4% for compressive strength and less than 3% for split tensile strength.
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Sarsam, Saad Isaa, i Israa Lutfi AL-Zubaidi. "Resistance to Moisture Damage of Recycled Asphalt Concrete Pavement". Journal of Engineering 21, nr 5 (1.05.2015): 45–54. http://dx.doi.org/10.31026/j.eng.2015.05.04.
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Recycled asphalt concrete mixture are prepared, artificially aged and processed in the laboratory to maintain the homogeneity of recycled asphalt concrete mixture gradation, and bitumen content. The loose asphalt concrete mix was subjected to cycle of accelerated aging, (short –term aging) and the compacted mix was subjected to (long -term aging) as per Super-pave procedure. Twenty four Specimens were constructed at optimum asphalt content according to Marshall Method. Recycled mixture was prepared from aged asphalt concrete using recycling agent (soft asphalt cement blended with silica fumes) by (1.5%) weight of mixture as recycling agent content. The effect of recycling agent on aging after recycling process behavior of asphalt concrete was determine. Aged specimens after recycling process were prepared by subjecting the recycled asphalt concrete to accelerated aging and tested for resistance to moisture damage. The improvement in the resistance to moisture damage of aged mixture after recycling with (soft asphalt cement blended with silica fumes) was 76.17% as compared to the corresponding aged mixture before recycling process. The ITS for unconditioned specimens for aged after recycling process mixture was less than reference by 67.1%, and less than that of aged before recycling process mixtures by 64.1%.
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Bhawna, Satija, U. C. Ojha, Sanyal Kumar, Rajiv Gupta, Dipti Gothi i R. S. Pal. "Spectrum of High Resolution Computed Tomography Findings in Occupational Lung Disease: Experience in a Tertiary Care Institute". Journal of Clinical Imaging Science 3 (31.12.2013): 64. http://dx.doi.org/10.4103/2156-7514.124097.
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Objective: To study the spectrum of high resolution computed tomography (HRCT) findings in occupational lung disease in industrial workers and to assess the utility of International classification of HRCT for occupational and environmental respiratory diseases (ICHOERD). Materials and Methods: Retrospective analysis of radiological data (radiographs and computed tomography chest scans) gathered over a period of 3 years (January 2010- December 2012) of industrial workers in an organised sector who presented with respiratory complaints. The HRCT findings were evaluated using ICHOERD. Results: There were 5 females and 114 males in the study, with a mean age of 49 years. These workers were exposed to different harmful agents including silica, asbestos, cotton dust, metal dust, iron oxide, organic dust, rubber fumes, plastic fumes, acid fumes, and oil fumes. There were 10 smokers in the study. The radiograph of chest was normal in 53 patients. 46% of these normal patients (21.8% of total) demonstrated positive findings on HRCT. When the radiograph was abnormal, HRCT provided more accurate information and excluded the other diagnosis. The HRCT findings were appropriately described using the ICHOERD. Bronchiectasis was the most common finding (44.5%) with mild central cylindrical bronchiectasis as the most common pattern. Pleural thickening was seen in 41 patients (34.5%). Enlarged hilar or mediastinal lymphnodes were seen in 10 patients (8.4%) with egg-shell calcification in 1 patient exposed to silica. Bronchogenic carcinoma was seen in 1 patient exposed to asbestos. Conclusions: Occupational lung disease is a common work related condition in industrial workers even in the organized sector. Though chest radiograph is the primary diagnostic tool, HRCT is the undisputed Gold Standard for evaluation of these patients. Despite the disadvantage of radiation exposure, low dose CT may serve as an important tool for screening and surveillance. The ICHOERD is a powerful and reliable tool not only for diagnosis, but also for quantitative and analytical measurement of disease, thereby contributing to assessing the medical epidemiology of lung disease. It should always be used while evaluating HRCT of a patient with occupational lung disease.
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C, Anbalagan, Thenmozhi S, Gowri V i Banupriya S. "Analysis of computational fluid dynamics (CFD) on fiber reinforced self-compacting concrete". YMER Digital 21, nr 02 (22.02.2022): 525–31. http://dx.doi.org/10.37896/ymer21.02/51.
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An experimental and CFD analysis of self-compacting concrete uses quarry dust and various partial flea ash substitutes, silica fumes, and both flea ash and silica fume combinations to construct a finely-structured polypropylene reinforced concrete beam. Using three different fractions of fiber volume, this article investigates the influence of polypropylene fibers on self-compacting concrete beams (2.0 percent, 2.5 percent and 3.0 percent). The M30 grade was taken into consideration. This study employed a computational fluid dynamics tool to model the experimental beam and failure scenarios. The three-dimensional CFD technique method used to model concrete beams has proven to be a reliable predictive tool for concrete beam analysis. However, when performing non-linear CFD analysis, it is critical to select appropriate finite elements and the correct mesh density in order to obtain a satisfactory solution to the problem. Furthermore, it has been discovered that linear regression may provide a good forecast of first crack load, deflection at first crack load, yield load, deflection at yield load, ultimate load, deflection at ultimate load, and ultimate load, deflection at ultimate load. There is a high level of agreement between the forecast and the test findings.
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Lin, Wei‐Ting, Ran Huang, Jiang‐Jhy Chang i Chin‐Lai Lee. "Effect of silica fumes on the permeability of fiber cement composites". Journal of the Chinese Institute of Engineers 32, nr 4 (czerwiec 2009): 531–41. http://dx.doi.org/10.1080/02533839.2009.9671535.
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Soundararajan, Muthumani, Sridhar Jayaprakash, S. K. Maniarasan i Ravindran Gobinath. "Predicting Strength Properties of High-Performance Concrete Modified with Natural Aggregates and Ferroslag under Varied Curing Conditions". Advances in Civil Engineering 2023 (19.06.2023): 1–16. http://dx.doi.org/10.1155/2023/9960412.
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High-performance concrete (HPC) is obtained by inclusion of mineral admixtures like silica fumes and fly ash to the normal concrete. Consumption of natural materials such as sand, natural aggregates, and limestone produces environmental degradation. Similarly, industrial by-products such as fly ash, silica fume, and ferro slag need to be safely disposed of without negatively impacting the environment. The problem being addressed in this study is the need to develop high-performance concrete (HPC) that is durable and environmentally friendly. In recent years, the use of natural aggregates and ferro slag as partial replacements for traditional aggregates has gained attention as a sustainable alternative in the production of concrete. However, there is limited research on the effect of these materials on the mechanical and durability properties of HPC under varied curing conditions. In this current research, high-performance concrete of M60 grade with partial substitution of coarse aggregate with ferro slag aggregate was formed as per the recommendations of the American Concrete Institute with the inclusion of fly ash and silica fume. Natural coarse aggregate was partly substituted by ferro slag aggregate in proportions from 0% to 40%. Partial substitution of cement was made with 15% of fly ash and 10% of silica fumes. Specimens of normal concrete mix (MF0) and modified ferro slag aggregate concrete mix (MF20, MF30, and MF40) were prepared and subjected to acid test, sulphate test, and alternate wet and drying tests to assess the compressive strength of the concrete mixes. Central composite design (CCD) of RSM modelling was adopted to recommend a regression model to forecast the compressive strength of concrete under wetting drying test, acid test, and sulphate attack. Further, natural aggregate, ferro slag, and duration of curing were considered as basic variables to suggest the model. Regression models for response data were evaluated using analysis of variance (ANOVA) and Pareto charts. The results show that the mix MF30 (30% substitution of natural aggregate by ferro slag aggregate) had higher compressive strength. The residual compressive strength at 270 days under alternate wetting and drying, acid attack, and sulphate attack was obtained as 62 MPa, 62.50 MPa, and 66.50 MPa, respectively. Similarly, the percentage loss of weight was obtained as 12.92%, 12.22%, and 6.60% for alternate wetting and drying, acid attack, and sulphate attack, respectively. The findings of the analysis of variance (ANOVA) indicate that the most significant factors influencing the variables C S W D , C S A T , and C S S T are natural aggregate, ferro slag, and curing period. The regression models for C S W D , C S A T , and C S S T are extremely significant, as shown by the ANOVA and Pareto chart analyses.
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Sarsam, Saad Issa, i Ibtihal Mouiad Lafta. "Assessment of Modified - Asphalt Cement Properties". Journal of Engineering 20, nr 06 (9.07.2023): 1–14. http://dx.doi.org/10.31026/j.eng.2014.06.01.
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The Asphalt cement is produced as a by-product from the oil industry; the asphalt must practice further processing to control the percentage of its different ingredients so that it will be suitable for paving process. The objective of this work is to prepare different types of modified Asphalt cement using locally available additives, and subjecting the prepared modified Asphalt cement to testing procedures usually adopted for Asphalt cement, and compare the test results with the specification requirements for the modified Asphalt cement to fulfill the paving process requirements. An attempt was made to prepare the modified Asphalt cement for pavement construction in the laboratory by digesting each of the two penetration grade Asphalt cement (40-50 and 60-70) with sulfur, fly ash, silica fumes. Three different percentages of each of the above mentioned additives have been tried using continuous stirring and heating at 150 ºC for 30 minutes.
The prepared modified Asphalt specimens were subjected to physical properties determination; the penetration, softening point, ductility before and after laboratory aging. It was concluded that all percentage of additives has reduced the penetration value of asphalt cement, an exception to that could be noticed when using asphalt cement (40-50) and when adding sulfur. Softening point was increased with the addition of all percentage of additives except that with 7% sulfur by wt. of asphalt cement (40-50) it decreased by 8%.
After aging in general, the penetration decreased by about 37% for control specimens and the softening point increased by about 8% for control specimens.
For asphalt cement 40-50 after aging, Sulfur has the least impact on ductility since it reduces it by 20%. Silica fumes have moderate effect on ductility when it reduces it by 35%, while fly ash shows the highest impact of 36%.
For asphalt cement 60-70 after aging, sulfur was able to almost retain its ductility, while fly ash shows moderate reduction in ductility within a range of 20-36% and silica fumes shows high impact on ductility in the range of 30-50%.
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Suriya, D., S. Prakash Chandar i P. T. Ravichandran. "Impact of M-Sand on Rheological, Mechanical, and Microstructural Properties of Self-Compacting Concrete". Buildings 13, nr 5 (23.04.2023): 1126. http://dx.doi.org/10.3390/buildings13051126.
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In construction Industries, superior fresh and hardened concrete qualities play a significant role in which self-compacting concrete (SCC) is widely introduced. On the other hand, considering the depletion of river sand, manufactured sand (M-sand), created by crushing rock deposits, has been recognized as viable. However, still, there is a lack of understanding of the strength aspect of SCC with M-sand replacement along with admixtures such as Alccofine and silica fume. Therefore, experimental investigations are conducted in SCC by partially and completely replacing river sand with M-sand. Furthermore, to reduce the negative impacts of cement, such as energy consumption and environmental pollution, 10% and 12% pozzolanic materials were added, such as silica fumes and alccofine. Moreover, to examine the impacts on rheological and mechanical properties, EFNARC guidelines were used and measured the compressive strength, impact resistance, bond strength, and flexural and splitting tensile strengths. The test results indicate that incorporating the M-sand as a full replacement in the mix increased the compressive strength by 6.82% for M50 grades of concrete compared to reference SCC after a 28-day curing period. Microstructural analyses such as SEM (Scanning Electron Microscope), EDS (Energy-Dispersive Spectroscopy), XRD (X-ray diffraction), and FTIR (Fourier Transform Infrared Spectroscopy) techniques were also used to study the hydration phase of the M-sand SCC mix when compared to the conventional SCC mix.
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Torén, Kjell, Paul D. Blanc, Rajen N. Naidoo, Nicola Murgia, Ingemar Qvarfordt, Olov Aspevall, Anna Dahlman-Hoglund i Linus Schioler. "Occupational exposure to dust and to fumes, work as a welder and invasive pneumococcal disease risk". Occupational and Environmental Medicine 77, nr 2 (17.12.2019): 57–63. http://dx.doi.org/10.1136/oemed-2019-106175.
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ObjectivesOccupational exposures to metal fumes have been associated with increased pneumonia risk, but the risk of invasive pneumococcal disease (IPD) has not been characterised previously.MethodsWe studied 4438 cases aged 20–65 from a Swedish registry of invasive infection caused by Streptococcus pneumoniae. The case index date was the date the infection was diagnosed. Six controls for each case, matched for gender, age and region of residency, were selected from the Swedish population registry. Each control was assigned the index date of their corresponding case to define the study observation period. We linked cases and controls to the Swedish registries for socioeconomic status (SES), occupational history and hospital discharge. We applied a job–exposure matrix to characterise occupational exposures. We used conditional logistic analyses, adjusted for comorbidities and SES, to estimate the OR of IPD and the subgroup pneumonia–IPD, associated with selected occupations and exposures in the year preceding the index date.ResultsWelders manifested increased risk of IPD (OR 2.99, 95% CI 2.09 to 4.30). Occupational exposures to fumes and silica dust were associated with elevated odds of IPD (OR 1.11, 95% CI 1.01 to 1.21 and OR 1.33, 95% CI 1.11 to 1.58, respectively). Risk associated with IPD with pneumonia followed a similar pattern with the highest occupational odds observed among welders and among silica dust exposed.ConclusionWork specifically as a welder, but also occupational exposures more broadly, increase the odds for IPD. Welders, and potentially others with relevant exposures, should be offered pneumococcal vaccination.
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de Larrard, F., J. F. Gorse i C. Puch. "Comparative study of various silica fumes as additives in high-performance cementitious materials". Materials and Structures 25, nr 5 (czerwiec 1992): 265–72. http://dx.doi.org/10.1007/bf02472667.
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Mamatha, K., i M. Mothilal. "Experimental Study Light Weight Concrete Using LECA, Silica Fumes, and Limestone as Aggregates". International Journal for Research in Applied Science and Engineering Technology 10, nr 12 (31.12.2022): 1103–10. http://dx.doi.org/10.22214/ijraset.2022.47916.
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Abstract: This dissertation determines the mix proportions of high-strength lightweight concrete, which uses expanded aggregate clay to decrease the weight of the concrete (LECA). Mineral and chemical admixtures have been used to reduce porosity and enhance strength in order to create light weight concrete. With that some percentage of silica fumes is added to enhance the properties of concrete and to make workability stable. On the specimens, specific gravity, compressive, indirect tensile, and flexural strengths were determined. By exposing certain specimens to air, the impact of curing on compressive strength was studied The findings indicate that by including Leca, a lightweight concrete with a dry density of 1,600– 1,960 kg/m3 and a compressive strength of 35–66 MPa may be produced, based on cube specimens with a 150mm side length. When used with lightweight particles, limestone significantly improved the mechanical characteristics of concrete.
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Chukka, Naga Dheeraj Kumar Reddy, B. Sudharshan Reddy, K. Vasugi, Yeddula Bharath Simha Reddy, L. Natrayan i Subash Thanappan. "Experimental Testing on Mechanical, Durability, and Adsorption Dispersion Properties of Concrete with Multiwalled Carbon Nanotubes and Silica Fumes". Adsorption Science & Technology 2022 (25.03.2022): 1–13. http://dx.doi.org/10.1155/2022/4347753.
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The major goal of this research is to see how carbon nanotubes and silica fume affect the durability and mechanical qualities of high-performance concrete (HPC). Mechanical properties, such as split tensile strength, compressive strength, elasticity modulus, and flexural strength, and durability properties like water absorption, abrasion, chloride penetration, acid, and sea water resistance, impact resistance of HPC consisting silica fume (SF), and carbon nanotubes (CNT) were examined in this study. Varied trail combinations with different proportions of CNT and SF admixtures were created for this reason. Portland cement was partially replaced with 1 percent, 1.5 percent, 2 percent, and 3 percent CNT, while SF was substituted with 5 percent, 7.5 percent, and 10 percent. Both CNT and SF outperform conventional concrete in terms of mechanical and durability attributes, according to the findings. CNT produces superior results than SF due to its smaller size.
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Sharma, Aniket Kumar, Shobhit Pandey, Ayush Jain i Shreya Shekhar. "Effect of Water Temperature on the Compressive Strength of Silica Fumes based Porous Concrete". Journal of Physics: Conference Series 2007, nr 1 (1.08.2021): 012071. http://dx.doi.org/10.1088/1742-6596/2007/1/012071.
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S, Dhipanaravind, Nandagopal B, Divya T i Silpa N. "A Characteristic Study of Concrete Strength And Durability With Fly Ash And Silica Fumes". International Journal of Civil Engineering 9, nr 1 (25.01.2022): 1–6. http://dx.doi.org/10.14445/23488352/ijce-v9i1p101.
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athi, P. Rev, B. Ravi Kiran i G. V. L. N. Murthy. "Effect of Fly Ash and Silica Fumes on Compression and Fracture Behaviour of Concrete". International Journal of Civil Engineering 4, nr 5 (25.05.2017): 70–74. http://dx.doi.org/10.14445/23488352/ijce-v4i5p114.
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Lin, Youzhu, Jiachuan Yan, Zefang Wang, Feng Fan i Chaoying Zou. "Effect of silica fumes on fluidity of UHPC: Experiments, influence mechanism and evaluation methods". Construction and Building Materials 210 (czerwiec 2019): 451–60. http://dx.doi.org/10.1016/j.conbuildmat.2019.03.162.
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Srishaila, J. M., Adarsh Uttarkar, Prakash Parasivamurthy i Veena Jawali. "Influence of Fly Ash and Silica Fumes on the Behavior of Self Compacting Concrete". International Journal of Engineering Trends and Technology 12, nr 5 (25.06.2014): 246–54. http://dx.doi.org/10.14445/22315381/ijett-v12p248.
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