文献类型：期刊文献

英文题名：Mechanical Properties and Microscopic Mechanism of Cement-Stabilized Calcareous Sand Improved with a Nano-MgO Additive

作者：Wang, Wei[1];Luo, Jiale[1];Li, Na[1];Li, Ben[1];Li, Jian[1];Pu, Shaoyun[1]

机构：[1]Shaoxing Univ, Civil Engn, Shaoxing 312000, Zhejiang, Peoples R China

年份：2023

卷号：23

期号：2

外文期刊名：INTERNATIONAL JOURNAL OF GEOMECHANICS

收录：SCI-EXPANDED(收录号：WOS:000899246300005)、、EI(收录号：20224913200445)、Scopus(收录号：2-s2.0-85141536084)、WOS

基金：Acknowledgments This research was partially supported by National Natural Science Foundation of China (Grant No. 52179107). We thank Prof. Jun Hu from Hainan University for providing the calcareous sand.

语种：英文

外文关键词：Calcareous sand; Cement; Nano-MgO; Mechanical properties; Microscopic mechanism; Strength empirical model

外文摘要：Calcareous sand fractures easily, has poor mechanical properties, and usually needs to be stabilized for engineering applications using additives. In this study, nano-MgO was used to enhance the mechanical properties of cement-stabilized calcareous sand (CCS). Unconfined compressive strength (UCS) and unconsolidated undrained (UU) triaxial shear tests were conducted on nano-MgO-modified CCS (MCCS) specimens, and the microscopic mechanism was investigated using scanning electron microscopy and X-ray diffraction. Finally, models to predict the UCS and shear strength of MCCS were formulated. The results showed that the addition of nano-MgO can enhance the strength and stiffness of CCS, with MCCS reaching its maximum strength of 2.1 MPa at 28 days when the nano-MgO content was 1%. Furthermore, the deviatoric stress first increased and then decreased as the nano-MgO content increased, reaching its maximum value when the nano-MgO content was 1.5%. The optimal nano-MgO content obtained from the UCS tests was different from that obtained from the UU tests. This improvement in CCS strength was due to the nano-MgO filling and cementation of hydrates such as Mg7Si8O22(OH)(2), Mg(OH)(2), and CaAl2Si3O10(H2O)(2). However, too much nano-MgO reduces the strength of CCS because the nano-MgO expands during hydration.