COAL ASH WASTE UTILIZATION FOR MAKING PAVING BLOCK OF ECO-FRIENDLY

Abstract

Paving blocks are made of mortar, consisting of: fine aggregate(sand/stone ash), cement and water. Paving blocks (precast concrete) can be classified based on their compressive strength, absorption and function, including: class A, B, C and D. Coal ash waste is a mineral additive that can be added, reduce production costs, increase resistance to sulfate attack, durability, compressive strength and reduce porosity.This study aims to obtain the composition of the mixture that will be used to make paving blocks by making a mix design of a cylindrical paving block mixture and printing a hexagon-shaped paving block. The composition of the mixture using fly ash as a cement additive and bottom ash as additional material for stone ash,  variying: 5%; 10%, 15% and 20%.  Paving block specimens will be tested for compressive strength and absorption capacity after being cured for 28 days. The results showed that if 20% of the base ash was used, a class C paving block would be obtained which had the same compressive strength as the paving block without the use of coal ash waste. if the fly ash used is <20%, then class B paving blocks will be obtained.