Effect of crystal morphology on cementability and micromechanical properties of calcium carbonate precipitate induced by crude soybean enzyme  

作　　者：Kai Xu Ming Huang Mingjuan Cui Shuang Li 

机构地区：[1]College of Civil Engineering,Fuzhou University,Fuzhou,350108,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第12期5095-5108,共14页岩石力学与岩土工程学报（英文）

基　　金：the financial support of National Natural Science Foundation of China(Grant No.52378392);“Foal Eagle Program”Youth Top-notch Talent Project of Fujian Province(Grant No.00387088);Natural Science Foundation of Fujian Province(Grant No.2020J06013).

摘　　要：Enzyme-induced carbonate precipitation(EICP)has emerged as an innovative soil stabilization technology to precipitate CaCO_(3)by catalyzing urea decomposition.Although extensive efforts have been made to increase the calcium carbonate content(CCC)formed in the EICP process for the better biocementation effect,the cementability and micromechanical properties of CaCO_(3)are rarely known.A study of the cementitious characteristics and micromechanical properties of CaCO_(3)precipitates with different mixing percentages of crystal morphology is essential for soil improvement.In the present study,ultrasonic oscillation tests and nanoindentation tests were performed to investigate the cementability and micromechanical properties of CaCO_(3)precipitate.The results show that the cementability and micromechanical properties of CaCO_(3)precipitate are related to the composition of the crystal morphology.A high content of calcite is beneficial to improve the adhesion of calcium carbonate precipitate.Calcite has better mechanical properties(elastic modulus,hardness and ductility)than vaterite,and the presence of vaterite can significantly affect the measured value of mechanical properties in nanoindentation tests.The ductility of CaCO_(3)precipitate induced by crude soybean urease(CSU)is higher than that of CaCO_(3)precipitate induced by commercially available pure enzyme,suggesting that commercially available pure enzyme can be replaced by CSU for cost-effective field-scale engineering applications.This work can provide insight into optimizing the properties of CaCO_(3)precipitate from the micro-scale.

关 键 词：Enzyme-induced carbonate precipitation (EICP) Micromechanical properties Nanoindentation tests Cementability 

分 类 号：TU45[建筑科学—岩土工程]