• Ouf, Mohamed Elsadek
• Mostafa, E. A.
• Jamal, Abdel Latif

Abstract

Portland cement concrete has been used as one ofconstruction materials for buildings and otherstructures. It primarily consists of cement,aggregate, and water. Aggregate is a majorstructural component of concrete and is typicallyobtained from natural stone or quarry. Recyclingthe concrete waste not only reduces the wastedisposal problem, but also reduces the amount ofquarrying of virgin aggregate (VA). Recycledconcrete aggregate (RCA) is produced by properlycrushing and sieving the demolished waste toobtain required size of aggregates that willsubstitute the need for VA. RCA are different fromVA due to the amount of cement paste remainingon the surface of the recycled aggregates afterundergoing the recycling process. The presence ofcement paste increases the porosity of theaggregates, reduces the particle density, and thus,the quality and water absorption capacity of RCAmay vary.The economic and environmental benefits of usingrecycled concrete from construction and demolition(C and D) activities have become clear in the recentyears. Significant use of RCA has been applied bymany countries for local road construction,especially in hot mix asphalt (HMA). The earlyapplication researches are found in reports fromUnited States (Ciesielski and Stanley 1994) andNetherlands (Hendricks and Janssen 2001). It hasbeen reported that RCA in HMA affected thevolumetric properties and performance of HMA. As recycled concrete can be used within the samesuburban area, it can lead to a decrease in theenergy consumption related to transportation with aconsequent improvement in the quality of air as aresult of reducing the emissions of the mobilesource and thus reducing the use of VA. It is worth to mention that there is no testing specification forthe suitability of using RCA as road pavementmaterials in Egypt. The present study is consideredas an introductory step for the expected Egyptianspecifications. The use of RCA in highwayconstruction, especially in HMA, shall alsocontribute in the reduction of the consumption ofVA as natural resources and the elimination of thestockpiles of concrete wastes. II. OBJECTIVES OF THE STUDY The purposes of this study are:  Investigate the optimum percentage ofRCA that can be used in HMA bindingcourse.  Investigate the impact of using differentpercentages of RCA on unit weight, flow,and stability of HMA binder (3B).RESEARCH ARTICLE OPEN ACCESS Abdelzaher E. A. Mostafa et al. Int. Journal of Engineering Research and Applications ww.ijera.com ISSN: 2248-9622, Vol. 5, Issue 12, (Part - 3) December 2015, pp.01-06 www.ijera.com 2 | P a g e  Produce dense graded mixtures thatresistance to rutting and cracks usingdifferent percentages of RCA. III. MATERIALS 3.1 VIRGIN AGGREGATE (VA):Attaka aggregates have been used in thepreparation of the asphalt concrete specimens. Thephysical properties of the aggregate are illustratedin table 1 and the gradation of the used aggregate is identical with the standard specifications(AASHTO T-27). X-Ray diffraction analysis of the virgin aggregates is shown in Figure 1.Table (1): Results of the physical properties of VA Test VirginAggregate

Topics

• density
• impedance spectroscopy
• surface
• x-ray diffraction
• crack
• cement
• porosity