PRE-TREATMENT OF RECYCLED AGGREGATES BY REMOVING RESIDUAL MORTAR: A CASE STUDY ON RECYCLED BRICK AGGREGATES FROM A DEMOLISHED COMMERCIAL BUILDING

PRE-TREATMENT OF RECYCLED AGGREGATES BY REMOVING RESIDUAL MORTAR: A CASE STUDY ON RECYCLED BRICK AGGREGATES FROM A DEMOLISHED COMMERCIAL BUILDING

Concrete recycling to produce reusable aggregates from it is a revolutionary subject in the history of the concrete industry. One big challenge in using recycled aggregate is its inferior quality, limiting its proportion of replacement. The present study aims to find a pre-treatment technique to improve the properties of recycled brick aggregate. Concrete blocks from a 7-year-old demolished commercial building are collected and crushed to produce recycled aggregates which are treated thermally (by freezing and thawing) and chemically (with acid and salt). A combination of thermal and chemical treatment is also adopted. Some key aggregate properties such as specific gravity, density, water absorption, and aggregate crushing value are considered for the study. Properties of the recycled aggregate before and after treatment is presented and compared. Pretreatment using 26% Na_2SO_4 solution associated with freezing and thawing is found to give the best result with a 10% decrease in water absorption, 16% increase in density, and 15% increase in strength. Since noteworthy improvement in properties is obtained, a higher percentage of pre-treated recycled aggregates may be used to produce green concrete compared to untreated aggregates.