Abstract
This paper study the effects of construction and agricultural wastes (CAW) as coarse aggregates in ternary blends on the properties of concrete. A concrete mix ratio of 1:2:4 by weight of cement, sand and granite was adopted with water-cement ratio of 0.50. Five different concrete mixes were prepared in this study; one natural aggregate concrete (NAC) and four concretes with 10%, 20%, 30% and 40% recycled aggregate and 40%, 30%, 20% and 10% palm kernel shell (PKS) contents in reverse order at constant 50% natural coarse aggregate (NCA). The results of slump tests showed an increase in workability as the percentage replacement level of RCA reduces and PKS respectively. The compressive strength of concrete mixes was observed to be less than the strength of lightweight concrete recommended by standards by 23.2%, 28.87%, 31.2%, 43.2% and 45.6% respectively. Based on the result of calculated thermal conductivity, it was observed that as the %RCA content reduces with increasing %PKS content significant amount of energy was saved. Also, an analysis of variance (ANOVA) was carried out to determine the effect of the % replacement and curing period on the compressive strength of concrete. It showed that % replacement had a statistically significant effect on the concrete performance. This type of concrete can be classified as lightweight concrete based on the strength and bulk density.