ORIGINAL RESEARCH article
Front. Earth Sci.
Sec. Solid Earth Geophysics
Experimental investigation on the construction waste recycled sand reinforced by soybean urease-induced calcium carbonate precipitation
Provisionally accepted
- 1Zhejiang Sci-Tech University, Hangzhou, China
- 2Lishui University, Lishui, China
- 3University of Nottingham Ningbo China, Ningbo, China
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Recycled sand from construction waste presents a promising substitute for natural sand. However, such sand typically exhibits low strength, high crushing index, and poor grading, which collectively compromise its performance in subgrade applications subjected to cyclic shear stresses caused by wave, seismic, and traffic loads. This study investigates the application of Soybean Urease-Induced Calcium Carbonate Precipitation (SICP) method to enhance the engineering properties of recycled sands. Firstly, several factors influencing the precipitation process are examined, including soybean powder concentration, cementation solution concentration and the ratio between urea and calcium chloride. Subsequently, unconfined compressive tests are conducted on sands reinforced under various conditions. Results indicate that the sample strength increases significantly with higher cementation solution concentration and grouting frequency; however, excessively high concentrations lead to a decline in UCS, likely due to the reduced calcium carbonate precipitation efficiency under supersaturated conditions. Scanning electron microscopy reveals that the reinforcing effect can be attributed to calcium carbonate crystals formed between particles, which function as binding agents for the recycled sands.
Keywords: Construction waste recycled sand, Soybean urease, Calcium carbonate precipitation, cementation solution concentration, Unconfined compressive strength
Received: 17 Aug 2025; Accepted: 03 Nov 2025.
Copyright: © 2025 Huang, Wu, Wang, Lu, Liu and Zhou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Zhe Wang, wangzhe@lsu.edu.cn
Nan Lu, nan.n.lu@outlook.com
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