INFLUENCE OF SIZE AND REPLACEMENT RATIO OF RECYCLED CONCRETE AGGREGATE ON CONCRETE PROPERTIES

Abstract

50 Khaled Abd el Samee et al., Influence of size and replacement ratio of recycled concrete aggregate on concrete properties, pp. 50 -63 ABSTRACT This experimental study investigates the influence of replacing certain ratios of natural aggregate by recycled concrete aggregate on properties of fresh and hardened concrete. Two maximum nominal sizes of aggregate used in this study 40 mm and 20 mm, the source of used recycled concrete aggregate comes from the demolitions of the upper skeleton of Al-AZHAR building in Sohag. Thirty six mixes were designed and carried out to study the effect of both aggregate size and replacement ratios on concrete properties, the replacement ratio of recycled aggregate changed from 0 to 50% using of two sizes of aggregate 20 and 40 mm. A slump and compacting factor were measured to express fresh concrete properties, hardened concrete properties were expressed by compressive strength tests after 7 and 28 days, pull out bond strength, splitting tensile strength and flexure strength. Test results shows the bad effect of replacing natural aggregate by recycled concrete aggregate on both fresh and hardened concrete properties.