Study on Improving the Properties of Recycled Aggregate by Microbial Mineralization

Abstract

As one of the most widely used building materials, concrete consumed a lot of raw materials, and the comprehensive utilization of waste concrete had become a research hotspot. Firstly, the basic properties of recycled aggregate were studied, including crushing index, water absorption, apparent density and bulk density. The higher the amount of microorganism, the greater the basic properties. Secondly, the porosity of recycled aggregate was analyzed by MIP. With different microbial dosage, the decrease range of porosity was also different, and the decrease ranges were 15.87%, 27.74%, 31.98%, 32.19% and 35.10% respectively. Finally, the composition and microstructure of recycled aggregate were demonstrated by XRD, SEM and EDS. The results showed that mineralized product was calcium carbonate, and the surface layer of recycled aggregate formed a dense structure.