Experiment on Interface Shear Properties of Previous Concrete-MgO Stabilized Soils of MgO-carbonated Composite Piles

被引：0
|
作者：
Zhang C.-Z. [1 ,2 ]
Liu Y.-Z. [1 ,2 ]
Liu S.-Y. [1 ,2 ]
Zhang Y. [1 ,2 ]
Jiang C. [3 ]
Chen G.-W. [3 ]
机构：
[1] Institute of Geotechnical Engineering, Southeast University, Jiangsu, Nanjing
[2] Nanjing Modern Multimodal Transportation Laboratory, Jiangsu, Nanjing
[3] Jiangsu Provincial Transportation Engineering Construction Bureau, Jiangsu, Nanjing
来源：
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | 2024年 / 37卷 / 06期
基金：
中国国家自然科学基金;
关键词：
carbonation; interface behavior; pile foundation; reactive magnesia; subgrade engineering;
D O I：
10.19721/j.cnki.1001-7372.2024.06.003
中图分类号：
学科分类号：
摘要：
The MgO-carbonated composite pile is a novel composite pile consisting of a previous concrete pile (inner core) in a deep magnesia mixing column (outer core) formed by carbonation with the magnesia-soil admixture. The frictional characteristics of the inner and outer cores interfaces are crucial factors influencing the load transfer pattern of carbonized composite piles. To study the shear behavior of the interface between the inner and outer cores of this composite pile, direct shear tests were conducted on pervious concrete-magnesia (MgO)-trcatcd soil under different normal stresses. In addition, the effects of the carbonation time (Tc), MgO dosage (it'm), and initial moisture content (,ww) on the interface shear characteristics of the specimens were analyzed. The tested results showed that as the carbonization time increases, the curve type transfers from "ideal elastic-plastic mode" to "shear-softening mode," and the shear strength of the optimal specimen with an optimal carbonation time of 6 h is 311 kPa. However, an excessively long carbonation time can result in the formation of cracks within the soil mass, leading to a decrease in the overall strength. Compared with the specimen with ivm of 10%, the shear strength of the specimen with an optimal xum of 20% increased by 37%. The shear strength of the specimen with it>w = 25% was 257 kPa. A low moisture content is unfavorable for hydration and carbonization reactions, which also affects the shear strength of the specimen. For specimens with •ww = 28%, water molecules filled the pores, resulting in a decrease in the gas diffusion rate. Additionally, water molecules formed a film on the surface of the particles, thereby reducing the cohesion and strength of the MgO-treated soil. The interfacial shear strength has an approximately linear relationship with the normal stress and the unconfincd compressive strength of the carbonized soil, and the shear failure of the interface conforms to the Mohr-Coulomb criterion. © 2024 Chang'an University. All rights reserved.
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页码：46 / 56
页数：10
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