Utilization of CO₂ cured CSW-MSWIBA cold bonded aggregate into lightweight concrete products for masonry units

Abstract

Cold bonded aggregate (CBA) produced principally with concrete slurry waste (CSW) and municipal solid waste incinerator bottom ash (MSWIBA) was used to produce lightweight concretes products – precast masonry units (LWCMU). The properties of the concrete products prepared with the 100% coarse CBA and different fractions of mixed fine CBA and hollow glass granulates (HGG) were compared to produce CBA-LWCMU. The tested properties included dry bulk density, compressive strength, absorption, drying shrinkage and thermal conductivity. It is found that CBA-LWCMU can meet the requirement of non-loadbearing and loadbearing LWCMU as per ASTM C129 and C90, respectively. The advantages of using CBA-LWCMU (i.e., as compared to LWCMU made with sintered expanded clay aggregate) include lower cost and thermal conductivity. The thermal conductivity of CBA-LWCMU can lead to better thermal insulation and passive fire protection of masonry. Furthermore, it was discovered from thermogravimetric analysis (TGA) and mercury intrusion porosimetry (MIP) tests that heated HGG (i.e., as compared to CBA) has better thermal stability and its apparent density was increased after being heated. These advantageous characteristics of HGG can lead to the improved fire resistance of CBA-LWCMU exposed to the elevated temperature.