Influence of Recycled Aggregates and Silica fumes on Compression and Split Tensile Strength of Composite Materials

This research focuses on the production of conventional composite concrete materials by incorporating varying weight percentages of recycled aggregates (RA) in conjunction with silica fumes as a cementitious component. The composite concrete materials design aims to achieve target strength of 31.5 MPa in compression and 3.5 MPa in split tensile strength. Natural aggregates (NA) are substituted with recycled aggregates at levels of 0%, 15%, 30%, 45%, and 60% by weight. This study examined the key factors affecting composite concrete materials strength concerning mixtures involving recycled aggregates (RA) and silica fumes. A result discloses composite concrete materials produced with 60% of RA tend to decrease the compression strength for both 7 and 28 days of curing age. A compressive strength of 10% of silica fumes and 45% of RA shows superior compression strength and split tensile strength compared to other silica fumes-based composite concrete materials. A compressive strength of 10% silica fumes and 60% RA shows reduction in compression strength and split strength by 5% under the target mean strength. Plasticizer is used (or water-reducing admixture) for reducing the water content and enhance its workability, to improve the mechanical strength and durability. SEM analysis employed to examine the composite materials morphology and structural characteristic.