Evaluating Recycled Concrete Aggregate and Sand for Sustainable Construction Performance and Environmental Benefits

This research investigates the potential of utilizing recycled concrete aggregate (RCA) and
recycled sand (RS), derived from crushed concrete cubes, as sustainable alternatives in construction
materials. The study comprehensively evaluates the properties of RCA and RS, focusing on workability,
impact resistance, abrasion resistance, and compressive strength to determine their viability as
substitute construction materials. A notable finding is RS’s enhanced fire and heat resistance when
used as a fine aggregate in mortar blends, mixed with cement and Sinicon PP in a 3:1 ratio. The
experimental analysis included thorough assessments of uniformity, durability, and curing time,
alongside Scanning Electron Microscopy (SEM) for structural examination. Results show that RCA
has an Aggregate Impact Value (AIV) of 5.76% and a Los Angeles Abrasion Value (LAA) of 21.78%,
demonstrating excellent strength of the recycled aggregates. The mortar mix was also prepared
using recycled sand, cement, and Sinicon PP, and its stability was confirmed through soundness tests,
which resulted in a 0.53 mm expansion and a satisfactory consistency level of 44%. Ultrasonic pulse
velocity (UPV) tests also indicated high-quality concrete formation using RCA and RS. SEM imaging
corroborated this by revealing a bond between the cement paste and the aggregates. Incorporating
RS and RCA in concrete mixtures impressively yielded a compressive strength of 26.22 N/mm2 in
M20-grade concrete. The study concludes that using RCA and RS waste materials in the construction
sector underlines that sustainable practices can be integrated without compromising material quality.
This approach aligns with sustainable development goals and fosters a more environmentally friendly
construction industry.