Comparative aspects regarding concrete of structural grade made with recycled brick aggregate with / without fine particles from crushing

Abstract

Recycled brick aggregate (RBA) is regarded like an eco-friendly aggregate because it contributes to conservation of the resources of natural aggregate. This type of aggregate may come from building construction waste, construction demolition waste (CDW) and ceramic industry waste. The RBA aggregate is obtained through crushing but a substantial percentage of the resulted particles are small in size being included in the fine aggregate category and its use is usually disregarded.Recycled brick aggregate concrete (RBAC) is a conventional making-concrete in which commonly the coarse and fine aggregate consist of coarse recycled brick particles and sand, respectively. Early evidences on RBAC are mentioned in the sixties of the last century in Germany, but many studies were developed after 2000. Nowadays, RBAC is regarded like a sustainable material having a positive environmental impact.This study assess feasibility of using fine particles of RBA obtained through crushing of brick waste from the buildings demolition in the conventional recycled brick aggregate concrete and its influence on some properties of RBAC like density and strength. As reference concrete, RBAC containing RBA aggregate as coarse and sand as fine aggregate was developed. Subsequently considering the same particles size distribution of aggregate, concrete mixes were developed in which each size of sand it was replaced in volume by fine brick aggregate (FBA) of equal size, size by size, until the entire replacement. For a valid comparison, the mix parameters like the water-to-cement ratio, cement content and volume of aggregate were identical for all mixes.The results indicate that replacing consecutively each size fraction of sand in conventional RBAC and thus increasing the replacement volume has in some extent influence on strength at standard testing ages. In this study, replacing entirely sand with fine brick aggregate the density and strength decreased with 150 kg/m3 and 17%, respectively.