Cold-Bonded Lightweight Synthetic Aggregate Involving High Reactive Attapulgite at Different Curing Conditions

Abstract

This study aimed to develop an eco-friendly, lightweight, and synthetic aggregate (SLA) based on clay suitable for use in structural lightweight concrete. The researchers utilized the cold-bonded pelletization process to agglomerate pozzolanic materials, specifically attapulgite extracted from a quarry, and crushed into a fine filler. The appropriate calcination temperature for manufacturing this clay as a pozzolanic material is 750°C. A total of 22 mixes were created using a combination of high reactive attapulgite (HRA) and cement (PC), with the attapulgite replacement rate varying from 100-50% by a 10% decrement. Different types of curing methods, including oven-dry, oven-water, room-water, and room-room, were applied. The aggregate properties were evaluated to determine density, specific gravity, water absorption, aggregate impact value, crushing strength, and compressive strength. The results revealed that it could produce lightweight synthetic aggregate from clay-based materials with a bulk density of 793kg/m3 with suitable physical and mechanical properties. As the percentage of cement in the mixture increased, the specific gravity and density were increased to 18.12% and 36.61%, whereas impact and crushing values of aggregate improved by 81.83%. This, in turn, leads to a significant boost in compressive strength up to 100.94%. Furthermore, there is a noticeable decrease in absorption. Moreover, the aggregate held under oven water positively impacts the strength development of cement-based composites.