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Alaa M Rashad - One of the best experts on this subject based on the ideXlab platform.

  • cementitious materials and agricultural wastes as natural Fine Aggregate Replacement in conventional mortar and concrete
    Journal of building engineering, 2016
    Co-Authors: Alaa M Rashad
    Abstract:

    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.

  • A comprehensive overview about recycling rubber as Fine Aggregate Replacement in traditional cementitious materials
    International Journal of Sustainable Built Environment, 2016
    Co-Authors: Alaa M Rashad
    Abstract:

    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.

  • Recycled cathode ray tube and liquid crystal display glass as Fine Aggregate Replacement in cementitious materials
    Construction and Building Materials, 2015
    Co-Authors: Alaa M Rashad
    Abstract:

    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).

  • recycled waste glass as Fine Aggregate Replacement in cementitious materials based on portland cement
    Construction and Building Materials, 2014
    Co-Authors: Alaa M Rashad
    Abstract:

    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.

  • A preliminary study on the effect of Fine Aggregate Replacement with metakaolin on strength and abrasion resistance of concrete
    Construction and Building Materials, 2013
    Co-Authors: Alaa M Rashad
    Abstract:

    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.

  • Influence of high temperature on the properties of concretes made with industrial by-products as Fine Aggregate Replacement
    Construction and Building Materials, 2011
    Co-Authors: İsa Yüksel, Rafat Siddique, Ömer Özkan
    Abstract:

    Abstract Influence of high temperature on the properties of concrete containing non-ground granulated blast-furnace slag (GBFS) and coal bottom ash (BA) as Fine Aggregate was presented. Six series of concrete mixtures were prepared by partially replacing Fine Aggregate separately with GBFS and BA. Replacement percentages were between 10 and 50% with an increment of 10% by dry weight of Fine Aggregate. Then 0.2% polypropylene fibres (PP) were added to last three mixtures that has the same mixture with the first three series. The first series is control concrete, the second series contained GBFS and the third series contained BA. All the concrete specimens were exposed to 800 °C temperature at the age of 90 days. Tests were conducted to determine loss in weight, compressive strength, and dynamic modulus of elasticity. Also surface crack observations were conducted with microscope. Test results showed that it is possible to partially replace Fine Aggregate with GBFS or BA even if such concretes were to be subjected to high temperature response. Performance of BA concrete was found to be better than GBFS as Replacement material.

  • effect of Fine Aggregate Replacement with class f fly ash on the abrasion resistance of concrete
    Cement and Concrete Research, 2003
    Co-Authors: Rafat Siddique
    Abstract:

    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.

  • effect of Fine Aggregate Replacement with class f fly ash on the mechanical properties of concrete
    Cement and Concrete Research, 2003
    Co-Authors: Rafat Siddique
    Abstract:

    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.

Christopher Montague - One of the best experts on this subject based on the ideXlab platform.

  • Acoustic properties of concrete panels with crumb rubber as a Fine Aggregate Replacement
    Construction and Building Materials, 2014
    Co-Authors: Niall Holmes, Alex Browne, Christopher Montague
    Abstract:

    Abstract This paper presents the acoustic performance of small scale crumb rubber concrete (CRC) panels in terms of the sound absorbance and insulation at low (63, 125, 250 and 500 Hz) and high (1000, 2000, 4000 and 5000 Hz) frequencies. Acoustic tests were conducted with differing levels of Fine Aggregate Replacement with crumb rubber (7.5% and 15%) with four different grades following freezing and heating. Analysis of the workability, compressive strength and density are also presented. The results found that CRC performed well in terms of sound absorbance particularly with higher proportions (15% here) and grades of crumb rubber. As an insulator, the CRC was comparable with plain concrete with only marginal differences observed. Effects of freezing and heating were shown to have no significant influence on the insulation properties. The insulation performance for all concretes was found to improve at high frequencies. The results demonstrate that CRC has potential as an external building cladding to absorb sound around high-rise urban structures but requires full-scale testing on site. This approach offers an environmental friendly solution to the ongoing problem of used tyres.

Amir Poursaee - One of the best experts on this subject based on the ideXlab platform.

  • The influence of waste crumb rubber in reducing the alkali–silica reaction in mortar bars
    Journal of Building Engineering, 2015
    Co-Authors: Kaveh Afshinnia, Amir Poursaee
    Abstract:

    Abstract The objective of this experimental work was to study the effect of crumb rubber on decreasing the expansion caused by Alkali–Silica Reaction (ASR) in mortar specimens prepared with highly reactive Aggregate. In this regards, mortar bars containing 0%, 16% and 24% crumb rubber by volume as Fine Aggregate Replacement were prepared for the accelerated mortar bar test (AMBT). Results from this study indicated that the use of 16% and 24% crumbed rubber as Fine Aggregate Replacement decreased the ASR expansion in mortar bars by 43% and 39%, respectively. However, the compressive strength of the mortar cubes containing 16% and 24% crumb rubber reduced by 20% and 47% at 28 days, respectively. While Thermo-Gravimetric Analysis (TGA) showed no reaction between rubber particles and pore solution of concrete, the Scanning Electron Microscopy analysis from mortar bar sections containing crumb rubber confirmed the positive impact of physical damping of crumb rubber particles on reducing the ASR in the mortar specimens.

P S Ambily - One of the best experts on this subject based on the ideXlab platform.

  • Studies on ultra high performance concrete incorporating copper slag as Fine Aggregate
    Construction and Building Materials, 2015
    Co-Authors: P S Ambily, Chockkalingam Umarani, K. Ravisankar, Prabhat Ranjan Prem, B. H. Bharatkumar, Nagesh R. Iyer
    Abstract:

    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.

  • Prediction of compressive strength of concrete with fly ash as sand Replacement material
    Cement & Concrete Composites, 2007
    Co-Authors: N. P. Rajamane, J. Annie Peter, P S Ambily
    Abstract:

    Fly ash (FA) acts as a partial Replacement material for both Portland cement and Fine Aggregate. The published information on FA as sand (Fine Aggregate) Replacement material (SRM) is limited and rational guidelines to estimate the compressive strength of concrete are not available. This aspect was investigated and a formula to predict the compressive strength of concrete at 28 day is suggested in this paper. This formula, containing cementing efficiency factor, k, of FA, is useful also when the quantity of FA used is more than that of sand replaced. Application of the formula to the test data in published literature, indicate that it can estimate the compressive strength of concrete containing different levels of sand Replacement by fly ash.