Analysis of the Effect of Substituting Paving Block Waste as Coarse Aggregate on the Compressive Strength of Concrete

Abstract

Demand for concrete as primary building material has increased in Indonesia alongside the ongoing expansion of infrastructure development, the components of concrete rely on natural resources, specifically natural aggregates, which are a finite resource. Similarly, constructuction waste continues to accumulate, according to Law No. 18 of 2008 on waste Management, 3R (Reduce, Reuse, Recycle). This study aims to evaluate the impact of substituting paving block waste as a coarse aggregate substitute on the compressive strength of concrete with a target of f’c=25 Mpa. Material testing, mix design (variations of 0%, 5%, 10%, 15%, 20%), casting of cylindrical test specimens measuring 150x300 mm, concrete curing, and compressive strength testing at 14 and 28 days were conducted in accordance with SNI. The results showed a decrese in compressive strength at 14 days (with the lowest value of 15.7 Mpa in the 5% variation and the highest result of 24,5 Mpa in 0% variation). There was a significant increase in the value at 28 days, with the 20% substitution reaching 25 Mpa. A 20% substitution of paving block waste yields optimal results for sustainable concrete, reduces hazardous constraction waste such as heavy metals, and open opportunities for environmental friendly application.