The Experts below are selected from a list of 13608 Experts worldwide ranked by ideXlab platform
Alaa M Rashad - One of the best experts on this subject based on the ideXlab platform.
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cementitious materials and agricultural wastes as natural fine Aggregate Replacement in conventional mortar and concrete
Journal of building engineering, 2016Co-Authors: Alaa M RashadAbstract:Abstract In the last 15 years, the worldwide consumption of natural sand as fine Aggregate in mortar/concrete production is very high and many developing countries have encountered some problems in the supply of natural sand in order to meet the increasing demands of construction development. In many countries there is a shortage of natural sand that is suitable for construction. On the other hand, disposal of wastes such as fly ash (FA), bottom ash (BA) and agricultural wastes can be considered as the major environmental challenges. This challenge continues to increase with the increase of these wastes. Therefore, studies have been carried out to find suitable solutions of the shortage of natural sand and the huge increasing in the wastes disposal. One logical option to solve this problem is employing these materials as a part of fine Aggregate instead of natural one in mortar/concrete. This paper presents an overview of the previous studies carried out on the use of the previous wastes as a partial or full of natural fine Aggregate Replacement in traditional mortar/concrete mixtures based on Portland cement (PC). Other cementitious material such as ground basaltic pumice and metakaolin (MK), which can replace part or full of natural fine Aggregate was also included. Fresh properties, hardened properties and durability of mortar/concrete containing these waste/cementitious materials as natural fine Aggregate Replacement have been reviewed.
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A comprehensive overview about recycling rubber as fine Aggregate Replacement in traditional cementitious materials
International Journal of Sustainable Built Environment, 2016Co-Authors: Alaa M RashadAbstract:Currently, the need to incorporate recycled materials such as rubber in building products is becoming more important than ever before. The use of waste rubber in mortar/concrete mixtures creates landfill avoidance and decreases the depletion of virgin raw materials. Waste rubber can be used as a part of fine Aggregate, coarse Aggregate or both Aggregates. It can be used as an additive to Portland cement (PC). This paper presents an overview of the previous researches carried out on the use of waste rubber as partially or fully natural fine Aggregate Replacement in traditional mortar/concrete mixtures based on PC. The effects of rubber sand on workability, setting time, bleeding, density, strength, impact energy, impact load, toughness, ductility, shrinkage, abrasion resistance, freeze/thaw resistance, fire resistance, thermal insulation, carbonation resistance, corrosion resistance, water absorption, porosity, chloride ion penetration, resistance to aggressive environmental, energy absorption, sound absorption, electrical resistance and cracking resistance of rubberised mortar/concrete were reviewed.
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Recycled cathode ray tube and liquid crystal display glass as fine Aggregate Replacement in cementitious materials
Construction and Building Materials, 2015Co-Authors: Alaa M RashadAbstract:With the rapid advances in the electronic industry, the disposal of cathode ray tube (CRT) glass and liquid crystal display (LCD) glass has become a major environmental problem. One option for safe environmental and economic disposal of these wastes is to reuse them in building materials. Many past studies have reported that the use of CRT glass and LCD glass waste as a part of fine Aggregate and few others reported the possible use as a part of binder material. This paper presents an overview for the previous literature which was carried out on the use of CRT and LCD recycled glass as a partial or a complete Replacement of the natural fine Aggregate in traditional mortars and concretes based on Portland cement (PC). Fresh properties, hardened properties and durability of these mortars and concretes have been reviewed in this paper. This review showed that using CRT and LCD glass sand in the matrix led to some advantages and some disadvantages. The main disadvantages of using these systems are decreasing compressive strength and increasing the expansion of alkali-silica reaction (ASR).
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recycled waste glass as fine Aggregate Replacement in cementitious materials based on portland cement
Construction and Building Materials, 2014Co-Authors: Alaa M RashadAbstract:Abstract Disposal of waste glass derived from container or packaging glass, flat glass, domestic or tableware glass and continuous filament glass fibres is one of the major environmental challenges. This challenge continues to increase with increasing the amount of waste glass and decreasing the capacity of landfill space. Therefore, studies have been carried out to find practical ways to recycle waste glass in building materials such as cement, mortars, concretes and blocks. This paper presents an overview of the previous studies carried out on the use of waste glass as partial or full natural fine Aggregate Replacement in traditional mortar/concrete mixtures based on Portland cement (PC). Fresh properties, mechanical properties, abrasion resistance, water absorption, chloride ion penetration, permeability, chemical resistance, carbonation resistance, drying shrinkage and alkali-silica reaction (ASR) expansion of mortar/concrete mixtures containing waste glass as fine Aggregate Replacement have been reviewed.
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A preliminary study on the effect of fine Aggregate Replacement with metakaolin on strength and abrasion resistance of concrete
Construction and Building Materials, 2013Co-Authors: Alaa M RashadAbstract:Abstract The purpose of this experimental study is to conduct a feasibility of using metakaolin (MK) as fine Aggregate Replacement in concrete. Sand was partially replaced with MK at levels of 10%, 20%, 30%, 40% and 50%, by weight. A reference mixture was designed to have characteristic compressive strength of 30 MPa. Specimens were subjected to abrasion testing in accordance with Egyptian Standard specifications (ES: 269-2/2003). Tests on compressive strength, splitting tensile strength, unit weight density and abrasion were performed up to 500 days. The various decomposition phases formed were identified using X-ray diffraction (XRD). The morphology of the formed hydrates was studied using scanning electron microscopy (SEM). Test results indicated that compressive strength, splitting tensile strength and abrasion resistance of concrete mixtures increased with increasing content of fine Aggregate Replacement with MK up to 40% then decreased at 50% Replacement level. Abrasion resistances of concrete improved by about 23.12%, 36.18% and 46.24% over reference mixture with 40% Replacement level at ages of 28, 91 and 500 days, respectively.
Rafat Siddique - One of the best experts on this subject based on the ideXlab platform.
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effect of fine Aggregate Replacement with class f fly ash on the abrasion resistance of concrete
Cement and Concrete Research, 2003Co-Authors: Rafat SiddiqueAbstract:Abstract This paper presents the abrasion resistance of concrete proportioned to have four levels of fine Aggregate Replacement (10%, 20%, 30%, and 40%) with Class F fly ash. A control mixture with ordinary Portland cement was designed to have 28 days compressive strength of 26 MPa. Specimens were subjected to abrasion testing in accordance with Indian Standard Specifications (IS: 1237). Tests were also performed for fresh concrete properties and compressive strength. Tests on compressive strength and abrasion were performed up to 365 days. Test results indicated that abrasion resistance and compressive strength of concrete mixtures increased with the increase in percentage of fine Aggregate Replacement with fly ash. Abrasion resistance of concrete was improved approximately by 40% over control mixture with 40% Replacement of fine Aggregate with fly ash, and concrete with fine Aggregate Replacement could be suitably used.
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effect of fine Aggregate Replacement with class f fly ash on the mechanical properties of concrete
Cement and Concrete Research, 2003Co-Authors: Rafat SiddiqueAbstract:This paper presents the results of an experimental investigation carried out to evaluate the mechanical properties of concrete mixtures in which fine Aggregate (sand) was partially replaced with Class F fly ash. Fine Aggregate (sand) was replaced with five percentages (10%, 20%, 30%, 40%, and 50%) of Class F fly ash by weight. Tests were performed for properties of fresh concrete. Compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity were determined at 7, 14, 28, 56, 91, and 365 days. Test results indicate significant improvement in the strength properties of plain concrete by the inclusion of fly ash as partial Replacement of fine Aggregate (sand), and can be effectively used in structural concrete. D 2002 Elsevier Science Ltd. All rights reserved.
Qingju Che - One of the best experts on this subject based on the ideXlab platform.
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seismic behaviour of steel jacket retrofitted reinforced concrete columns with recycled Aggregate concrete
Construction and Building Materials, 2018Co-Authors: Jia Cai, Qingju Che, Xinpei Liu, Peizhou Huang, Xuli TangAbstract:Abstract This paper presents the experimental and numerical investigations on the seismic behaviour of steel-jacket retrofitted reinforced concrete (SJRRC) columns with recycled Aggregate concrete (RAC). An unstrengthened reinforced concrete (RC) column and nine SJRRC columns tested under lateral cyclic loading are reported. The experimental results manifest that by using the steel-jacket retrofitting approach with RAC, the initial stiffness, ultimate strength, deformation ductility and energy dissipation ability of the columns are improved significantly. The peak strengths of the SJRRC columns are about 1.86–3.44 times of the counterpart of the original RC column. The retrofitted columns also show ductile post-peak load behaviour with the ductility coefficients ranging between 4.05 and 7.93. As the applied axial compressive loads increase, the failure mode of the SJRRC specimens is transited gradually from tension-controlled failure to compression-controlled failure. The specimens failed in compression-controlled mode exhibit plumper hysteresis curves, better energy dissipation ability, and higher secant stiffness than those failed in tension-controlled mode. The specimen having 100% recycled coarse Aggregate Replacement ratio has slightly lower lateral strength and secant stiffness than the specimens with 0% or 50% recycled coarse Aggregate Replacement ratio, and shows more serious pinching effect on its hysteresis curve. The effects of the preload and pre-damage of original column could be unfavourable on the cyclic performance of retrofitted column. The finite element analyses are also performed to further investigate the lateral behaviour of SJRRC columns. The proposed finite element model is validated by a comparison with the experimental results. By using the developed finite element model, parameter studies are undertaken and indicate that the applied axial compressive load and the thickness of steel jacket are the dominant factors affecting the lateral performance of SJRRC column.
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axial compressive behaviour of steel jacket retrofitted rc columns with recycled Aggregate concrete
Construction and Building Materials, 2017Co-Authors: Jia Cai, Qingju Che, Xinpei Liu, Hua Xue-liAbstract:Abstract It is an effective solution to strengthen structural column by using steel jacket and infill concrete for reinforced concrete (RC) structure retrofitting. In this research, the recycled Aggregate concrete (RAC) is adopted as an infill concrete instead of using the normal concrete, in order to reduce the carbon footprint of construction. Fifteen columns including twelve steel-jacket strengthened columns, one unstrengthened column and two concrete filled steel tube (CFST) columns are tested to investigate the axial compressive behaviour of steel-jacket retrofitted RC columns with RAC. The variables among the tested specimens include the recycled coarse Aggregate Replacement ratio, RAC strength, steel tube thickness and preload of original column. Experimental results illustrate that using steel jacketing approach for retrofitting could significantly improve the strength, stiffness and ductility of the columns. The axial compressive strength of the steel-jacket retrofitted column with RAC is slightly lower than the one with normal infill concrete, but the influence of recycled coarse Aggregate Replacement ratios is negligible. The peak strengths of steel-jacket retrofitted columns can be significantly enhanced by increasing the thickness of steel tube. The performances of the steel-jacket retrofitted columns are similar to that of the CFST columns. The effect of the preload of original column on the ultimate strength of steel-jacket retrofitted column is limited. A finite element (FE) model is also developed by using ABAQUS software to simulate the performance of steel-jacket retrofitted columns. The accuracy of the model is validated through comparing with the experimental results. By using the developed FE model, the mechanical behaviour of the column is further discussed in details and extended parametric studies are undertaken to elucidate the effects of various influencing factors on the behaviour of the column and its components. The design methods for predicting the axial compressive strength of the retrofitted column with RAC are suggested.
Nagesh R. Iyer - One of the best experts on this subject based on the ideXlab platform.
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Studies on ultra high performance concrete incorporating copper slag as fine Aggregate
Construction and Building Materials, 2015Co-Authors: P S Ambily, Chockkalingam Umarani, K. Ravisankar, Prabhat Ranjan Prem, B. H. Bharatkumar, Nagesh R. IyerAbstract:Abstract This paper investigates the technical feasibility of using copper slag as fine Aggregate Replacement in ultra high performance concrete (UHPC). The studies demonstrated that it is possible to produce UHPC having compressive strength greater than 150 MPa by incorporation of copper slag. The complete Replacement of standard sand by copper slag resulted in a maximum decrease in 28-day compressive strength of about 15–25% whereas, the flexural strength, fracture energy recorded was of the similar order. It can be concluded from the results that use of copper slag as fine Aggregate in UHPC is technically viable.
Jia Cai - One of the best experts on this subject based on the ideXlab platform.
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seismic behaviour of steel jacket retrofitted reinforced concrete columns with recycled Aggregate concrete
Construction and Building Materials, 2018Co-Authors: Jia Cai, Qingju Che, Xinpei Liu, Peizhou Huang, Xuli TangAbstract:Abstract This paper presents the experimental and numerical investigations on the seismic behaviour of steel-jacket retrofitted reinforced concrete (SJRRC) columns with recycled Aggregate concrete (RAC). An unstrengthened reinforced concrete (RC) column and nine SJRRC columns tested under lateral cyclic loading are reported. The experimental results manifest that by using the steel-jacket retrofitting approach with RAC, the initial stiffness, ultimate strength, deformation ductility and energy dissipation ability of the columns are improved significantly. The peak strengths of the SJRRC columns are about 1.86–3.44 times of the counterpart of the original RC column. The retrofitted columns also show ductile post-peak load behaviour with the ductility coefficients ranging between 4.05 and 7.93. As the applied axial compressive loads increase, the failure mode of the SJRRC specimens is transited gradually from tension-controlled failure to compression-controlled failure. The specimens failed in compression-controlled mode exhibit plumper hysteresis curves, better energy dissipation ability, and higher secant stiffness than those failed in tension-controlled mode. The specimen having 100% recycled coarse Aggregate Replacement ratio has slightly lower lateral strength and secant stiffness than the specimens with 0% or 50% recycled coarse Aggregate Replacement ratio, and shows more serious pinching effect on its hysteresis curve. The effects of the preload and pre-damage of original column could be unfavourable on the cyclic performance of retrofitted column. The finite element analyses are also performed to further investigate the lateral behaviour of SJRRC columns. The proposed finite element model is validated by a comparison with the experimental results. By using the developed finite element model, parameter studies are undertaken and indicate that the applied axial compressive load and the thickness of steel jacket are the dominant factors affecting the lateral performance of SJRRC column.
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axial compressive behaviour of steel jacket retrofitted rc columns with recycled Aggregate concrete
Construction and Building Materials, 2017Co-Authors: Jia Cai, Qingju Che, Xinpei Liu, Hua Xue-liAbstract:Abstract It is an effective solution to strengthen structural column by using steel jacket and infill concrete for reinforced concrete (RC) structure retrofitting. In this research, the recycled Aggregate concrete (RAC) is adopted as an infill concrete instead of using the normal concrete, in order to reduce the carbon footprint of construction. Fifteen columns including twelve steel-jacket strengthened columns, one unstrengthened column and two concrete filled steel tube (CFST) columns are tested to investigate the axial compressive behaviour of steel-jacket retrofitted RC columns with RAC. The variables among the tested specimens include the recycled coarse Aggregate Replacement ratio, RAC strength, steel tube thickness and preload of original column. Experimental results illustrate that using steel jacketing approach for retrofitting could significantly improve the strength, stiffness and ductility of the columns. The axial compressive strength of the steel-jacket retrofitted column with RAC is slightly lower than the one with normal infill concrete, but the influence of recycled coarse Aggregate Replacement ratios is negligible. The peak strengths of steel-jacket retrofitted columns can be significantly enhanced by increasing the thickness of steel tube. The performances of the steel-jacket retrofitted columns are similar to that of the CFST columns. The effect of the preload of original column on the ultimate strength of steel-jacket retrofitted column is limited. A finite element (FE) model is also developed by using ABAQUS software to simulate the performance of steel-jacket retrofitted columns. The accuracy of the model is validated through comparing with the experimental results. By using the developed FE model, the mechanical behaviour of the column is further discussed in details and extended parametric studies are undertaken to elucidate the effects of various influencing factors on the behaviour of the column and its components. The design methods for predicting the axial compressive strength of the retrofitted column with RAC are suggested.