REVIEW ARTICLE


Direct Shear Behavior of Nanometer Magnesia Reinforced Cement Soil with 28d Age



Shuai Zhang1, Wei Wang*, 1, 2, Xinjiang Song3, Xuchao Chi2, 3, Tinghao Lu1
1 Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing, 210092, China
2 School of Civil Engineering, Shaoxing University, Shaoxing, 312000, China
3 Huaihe River Committing Ministry of Water Resources, Bengbu, 233000, China
4 Melbourne School of Design, Melbourne University, Victoria, 3010, Australia


© 2014 Zhang et al

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the School of Civil Engineering, Shaoxing University, Huancheng West Road, Shaoxing, 312000, China; Tel: 1836712859; E-mail: wangwells@qq.com


Abstract

In order to properly understand the modification effects of nanometer magnesia additive on cement soil’s mechanical performance, a consolidated quick shear laboratory test on nano-magnesium-modified cement-soil (NmCS) sample with different mixing ratio at 28-day age was conducted. Eight kinds’ of nanometer magnesia additives with mixing ratios ranging from 0% to 3% were designed to be used in the test. The result shows that: (1) shear stressdisplacement curves of all samples consisted of three distinct stages with brittle failure. Moreover, (2) as the nanometer magnesia mixing ratio increased, the NmCS shear strength also showed an increase at first, followed by a decrease, and the shear strength reached the maximum with the mixing ratio of 1%. (3)In addition, both the friction angle and cohesive force were fluctuating and had a concave and convex shape respectively and (4) with greater deformation resistance, the shear displacement of NmCS was significantly less than the ordinary cement soil in the shear failure process. Finally, according to the test results, the micro-mechanism of NmCS mechanical performance was analyzed from the perspective of cement hydration and particle interaction.

Keywords: Cement stabilized soil, Nanometer magnesia, Mixing ratio, Shear strength.