ABSTRACT
Due to the growing concern about the environmental degradation and increasing awareness of green infrastruture, sustainable development became an indispensable requirement particularly in construction area. Reusing recycled wastes coarse aggregate (RCA) into concrete production, as a sustainable way, has aroused increasingly interest by researchers in recent years. However, the low performance of RCA has limited its largescaled application. The research presented in this paper was aimed to apply biomineralization method to improve the properties including density, water absorption and crushing value of RCA. Three ureolytic bacteria strains including Lysinibacillus fusiformis, Bacillus megaterium and Sporosarcina pasteurii were used for the purpose of biomineralization in RCA/concrete. It was found that after soaking the RCA into bacterial solution, the water absorption was decreased and the apparent density was increased, while this method did not show effect on crushing value. Moreover, replacing 30% of natural aggregates by mass with the bio-treated RCA, the compressive strength of concrete would not decrease, Bacillus megaterium group even showed higher compressive strength compared to concrete only with nature aggregates.
