Performance Analysis of Recycled Concrete Aggregates Derived from Construction Waste

Abstract

This paper highlights the potential advantages of incorporating aggregates derived from construction debris, particularly in the context of Libya, where the use of recycled concrete aggregate (RCA) is not yet widespread. This research aims to integrate recycling into state laws and procedures while demonstrating the practical applications of RCA. Three types of aggregates were examined such as natural aggregate (NA) as the reference, recycled concrete aggregate (RCA) from crushed old concrete blocks, and recycled terrazzo tiles (RTT). The characteristics of these aggregates were determined using various tests, including weight, volumetric, relative density (specific gravity), granular gradation, and Los Angeles abrasion (LA) tests. Results indicated a 15% reduction in specific gravity and a 20% decrease in volumetric weight for RCA compared to NA. The LA test revealed a higher abrasion percentage for the recycled aggregates, consistent with previous studies. To ensure a fair comparison, the same aggregate gradation and component proportions, based on the reference design mix, were used across all three mixes. The compressive strength of concrete made with these different aggregates was assessed through compression tests on cubes measuring 15 x 15 x 15 cm. A total of 12 specimens, with a combined volume of 0.0405 m3, were cast and cured by submerging them in water at 25°C for 3, 7, 14, and 28 days. The findings showed that the compressive strength of the NA mixture was higher than that of the mixes containing recycled materials. However, the compressive strength of the recycled aggregates is promising, with only a 21% decrease compared to the NA mixture, indicating potential for their use in construction.