Study on Deterioration Mechanism of Lightweight Cellular Concrete with Initial Damage Under Wetting-drying Cycles
LIU Xin1,2,3,*, NI Chengwei1,2,4, SUN Dongning1,2,4, SHAO Zhiwei1,2,4, SHI Yunqiang1,2,4
1 Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University,Nanjing 210098,China 2 Jiangsu Research Center for Geotechnical Engineering Technology, Hohai University, Nanjing 210098,China 3 Institute of Tunnel and Underground Engineering, Hohai University, Nanjing 210098, China 4 Geotechnical Research Institute, Hohai University, Nanjing 210098, China
Abstract: Lightweight cellular concrete (LCC) is a new class of geotechnical engineering materials, which can be produced by physical method mixing cement, water, foaming agent and some additive materials (fly ash, glass fiber, etc.) in a certain proportion. It has been widely utilized in the highway embankment filling, but the durability problem always troubles engineers. In fact, the damage caused by different factors will occur in the whole process of the production of LCC. Therefore, this paper mainly analyzed the initial damage caused by construction technology and external environmental factors. Meanwhile, the deterioration mechanism of physical and mechanical characteristics of samples with initial damage under the wetting-drying (w-d)cycles was studied. In the microscopic test, the damage variable was defined by unconfined compressive strength, and the porosity area ratio was used as a characteristic parameter to describe the damage evolution. MATLAB was used to fit the variation law of strength, versus porosity area ratio and the number of w-d cycles, and the strength deterioration relations of samples with different initial damage forms were obtained. Eventually, the damage evolution equations related to porosity area ratio and the number of w-d cycles were established and verified. The results make clear that, the porosity area ratio of samples with initial damage caused by different construction techniques all increases with the w-d cycles, and the strength decreases nonlinearly with the increase of porosity area ratio. As the number of w-d cycles increases, the different moisture content of the sample causes differences in internal thermal expansion. The temperature stress continues to develop and micro-cracks continue to form, so the porosity area ratio increases, and the strength gradually deteriorates and decreases.
刘鑫, 倪铖伟, 孙东宁, 邵志伟, 史云强. 干湿循环下含初始损伤泡沫混凝土劣化机理研究[J]. 材料导报, 2021, 35(14): 14065-14071.
LIU Xin, NI Chengwei, SUN Dongning, SHAO Zhiwei, SHI Yunqiang. Study on Deterioration Mechanism of Lightweight Cellular Concrete with Initial Damage Under Wetting-drying Cycles. Materials Reports, 2021, 35(14): 14065-14071.
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