Core-Shell structured ceramsite made by excavated soil and expanded perlite through cold-bonded technology

Abstract

A large amount of excavated soil (ES) is generated in subway construction. Improper stacking will bring a serious threat to the environment and human safety. To recycle this excavated soil, the method of the cold bonding granulation technique was adopted to prepare core–shell structured ceramsite, which had an ES coating of expanded perlite particles. The effects of the cement content and the curing method on the pore structure, water absorption, and mechanical properties of the ceramsite were analyzed. Scanning electron microscopy (SEM) was employed to investigate the microstructure of the ceramsite. In addition, X-ray micro-computed tomography (XCT) was used to explore the internal core–shell structure of the ceramsite. The results revealed that ceramsite with a water absorption of 26%–55% and a single particle crushing strength of 7.48–22.12 N could be achieved. This core–shell structured ceramsite could potentially be used as water-retaining materials to be applied in landscaping and agriculture.