PERFORMANCE ENHANCEMENT OF RECYCLED FINE AGGREGATES THROUGH CARBONATION

Abstract

To solve the problem of performance degradation of recycled fine aggregate (RFA), this paper adopted accelerated carbonation with saturated lime water solution (CH) pre-soaking, the crushing value, water absorption rate and apparent density were investigated. The carbonation products and microstructure were characterised by thermal analysis (TG), X-ray diffraction, and scanning electron microscopy (SEM). The results indicate that the calcite produced by the accelerated carbonation is closely packed and filled in the microcracks in the RFA, which reduces its water absorption and crushing value, and increases its apparent density; the RFA pre-treated with the CH solution had a higher CO₂ mass absorption rate. Accelerated carbonation can effectively improve the compressive strength of recycled mortar, but it will reduce the flowability of recycled mortar.

Keywords

• recycled fine aggregate
• accelerated carbonation
• co₂ mass absorption rate
• water absorption
• flowability
• compressive strength