Recycling waste concretes as fine aggregate and fly ash as binder in production of thermal insulating foam concretes

This paper presents the first investigation on foam concretes with fly ash and fine recycled concrete aggregate (RFA). Foam concretes were produced considering 0, 25, 50, 75 and 100% RFA ratio instead of virgin sand. Tests were conducted to assess their porosity, density, compressive strength, dynamic elastic modulus, absorption, ultrasound and thermal characteristics. Scanning electron microscopy analyzes were performed for investigating the microstructure of concretes. Findings show that incorporating RFA results in slight rise in porosity and absorption while decrease in dynamic elastic modulus, ultrasound and thermal conductivity. Observations present an expectancy toward production of light-weight construction material contributing to significant environmental benefits.