Experimental Investigation on Engineering Properties of Concrete Incorporating Reclaimed Asphalt Pavement and Rice Husk Ash

Waste generation from agricultural and construction industries is growing at an upsetting rate that causes a heavy burden on landfill facilities. On the other hand, the construction industry is exhausting natural resources thereby posing environmental problems. This study investigates the potential use of agro-industrial waste such as rice husk ash (RHA) and construction waste like reclaimed asphalt pavement (RAP) as promising construction materials. The durability and physical and mechanical properties of concrete were assessed by partially replacing cement and virgin aggregates with RHA and RAP, up to 20% and 50%, respectively. A total of 22 mixes were studied, twelve of which were devoted to studying the collective effects of RHA and RAP on the engineering properties of concrete. Based on experimental results, RHA and RAP decreased slump, compacting factor, density, water absorption and sorptivity. RHA increased compressive and tensile splitting strength, whereas RAP decreased compressive and tensile splitting strength. Comparable strength and favorable sorptivity values were obtained when 15% RHA was combined with up to 20% RAP in the concrete mix. Thus, utilizing RHA and RAP as concrete ingredients can contribute to solid waste management, engineering and economic benefits.