Strength and Compaction Characteristics of Recycled Concrete Aggregates

Abstract

Every year, a large amount of construction and demolition wastes are produced worldwide. The use of these wastes in the granular road base (GRB) and granular road subbase (GRSB) layers contributes to sustainability. In Turkey, the necessary attention should be given to the reuse of these materials. In this study, compaction and strength properties of recycled concrete aggregates (RCA) obtained from 3 different building demolitions, one natural aggregate (NA) and one crushed aggregate (CA) from Konya City/Turkey were investigated comparatively. For this purpose, Modified Proctor and unsoaked California Bearing Ratio (CBR) tests were performed on the pure forms of these 5 different aggregates and the mixtures of 25% - 75%, 50% -50%, 75%- 25% ratios of RCAs with CA and NA. As a result of the Modified Proctor tests, it was found that the optimum moisture content of RCAs compared to NA and CA were high due to high water absorption of RCAs and the maximum dry unit weights were low due to low specific gravities of RCAs. As a result of the CBR tests, the CBR values of the RCAs were high enough to be compared to the CA; however, in the mixtures, a decrease in CBR values was observed. The results showed that the RCA in Turkey has some sufficient mechanical properties to be used in GRB and GRSB; however, further studies must be done.