Abstract
A considerable amount of concrete is returned from construction sites due to various reasons such as excess quantity remaining after casting, not meeting the site specifications and cancellation of orders. In this study, the hardened returned concrete was crushed and used as recycled aggregate to produce new concrete. However, due to young age and inadequate compaction, the properties crushed returned concrete aggregate (CRCA) are different from those of commonly used recycled aggregates obtained from construction and demolition wastes. CRCA was used as 50% and 100% replacements of natural coarse aggregate (NCA). The effect of CRCA was evaluated by workability, strengths, shrinkage and water penetration under pressure. Decreases of 28 days compressive strength by 10% and 30% were observed in 50% and 100% CRCA concrete mixtures compared to 39 MPa for the control. The correlation between splitting tensile strengths and compressive strengths were found to be the same as that for NCA concrete. At 28 days, the water penetration depth increased by 33% and 67%, water absorption increased by 9% and 52%, and the drying shrinkage increased by 16% and 49% in the 50% and 100% CRCA concretes, respectively. The declines in strength and durability aspects are attributed to the adhered porous mortar and fines content of CRCA. Overall, the results show that CRCA could be used to replace natural aggregates by a substantial percentage helping conservation of natural resources.
Keywords
recycled aggregate, compressive strength, indirect tensile strength, water penetration, drying shrinkage.
DOI
10.5703/1288284318124
Recommended Citation
Humagain, Saugat; Bista, Ashish; and Sarker, Prabir Kumar, "Effect of using Recycled Returned Concrete Aggregate on the Strength and Durability Aspects of Concrete" (2025). International Conference on Durability of Concrete Structures. 10.
https://docs.lib.purdue.edu/icdcs/2025/sce/10
Effect of using Recycled Returned Concrete Aggregate on the Strength and Durability Aspects of Concrete
A considerable amount of concrete is returned from construction sites due to various reasons such as excess quantity remaining after casting, not meeting the site specifications and cancellation of orders. In this study, the hardened returned concrete was crushed and used as recycled aggregate to produce new concrete. However, due to young age and inadequate compaction, the properties crushed returned concrete aggregate (CRCA) are different from those of commonly used recycled aggregates obtained from construction and demolition wastes. CRCA was used as 50% and 100% replacements of natural coarse aggregate (NCA). The effect of CRCA was evaluated by workability, strengths, shrinkage and water penetration under pressure. Decreases of 28 days compressive strength by 10% and 30% were observed in 50% and 100% CRCA concrete mixtures compared to 39 MPa for the control. The correlation between splitting tensile strengths and compressive strengths were found to be the same as that for NCA concrete. At 28 days, the water penetration depth increased by 33% and 67%, water absorption increased by 9% and 52%, and the drying shrinkage increased by 16% and 49% in the 50% and 100% CRCA concretes, respectively. The declines in strength and durability aspects are attributed to the adhered porous mortar and fines content of CRCA. Overall, the results show that CRCA could be used to replace natural aggregates by a substantial percentage helping conservation of natural resources.
