Influence of Recycled Concrete Aggregates on the California Bearing Ratio (CBR) of Granular Sub-bases

Abstract

AbstractRecycled concrete aggregates (RCAs) have a high potential to be used as replacements for natural aggregates in the construction of pavements with similar or even better characteristics. This paper evaluates the influence of RCA as a partial replacement in a granular sub-base of 37.5 mm nominal maximum size (GSB38). Specifically, two replacement percentages of RCA by weight of the coarse aggregate of the GSB38 were evaluated: 10 and 15. To estimate the influence on the mechanical behavior, abrasion tests were carried out in the Los Angeles (LA) abrasion and California bearing ratio (CBR) methods. For GSB38, the average abrasion results were 30.54%. The CBR for the same material at a penetration of 0.254 cm was 26.90, 61.00 and 76.20% and at a penetration of 0.508 cm was 33.00, 65.70 and 82.00% for 10, 25 and 56 blows per layer, respectively. For GSB38 with 10% RCA, similar and even better behavior than natural GSB38 was found in terms of LA abrasion, with an average result of 38.68%. The CBR for the same alternative at a penetration of 0.254 cm was 13.20, 52.80 and 57.70% and at a penetration of 0.508 cm was 18.00, 61.30 and 68.90% for 10, 25 and 56 blows per layer, respectively. But GSB38 with 15% RCA showed an average abrasion of 45.51%, indicating a decrease compared with natural GSB38 and GSB38 with 10% RCA. The CBR for the same alternative also shows a decreasing trend.