| As a cementitious material,cement soil is widely used in engineering,It can be used to form mixing piles for foundation treatment,and can also be used in road engineering.The reasons for the fluctuation of intensity value include cement consumption,water content,compactness,standard curing time limit,cement fineness and composition,specimen molding method,soil quality,etc.Road subgrade and pavement in seasonal freezing area are affected by freeze-thaw cycles,The highway has typical road frost damage.Stable aggregates can guarantee the construction quality in cold areas due to their good material properties.This article is based on the actual road construction project in Zhangjiakou area,to theoretically guarantee the quality of road construction,the main research of cement-based materials is on the strength and the particle structure of the sample under the effect of the frigid district.The research was executed from two aspects: the shallow strength characteristics and the hidden particle structure of the material.Originally,the collected roadbed soil was assorted by particle size.operate routine tests on natural soil to obtain corresponding soil quality indicators and appraise the genre of soil samples;For the cement used in the test,considering the effect of repeated freezing and melting on the material,composite Portland cement was selected.Test the best mixing method of adding cement to the roadbed soil to form a mixture,carry out geotechnical test on stabilized soil mixed with different amounts of cement,obtain the compaction curve under the corresponding cement to dry material mass ratio,and get the basic index of the mixture that can achieve the best compaction state.On the basis of the known material ingredient dosage range,compile the strength test plan to get a more accurate range of each component dosage of the mixture.Design an orthogonal scheme,select the conditions that cause the most significant fluctuations in the strength of cement soil,taking the strength value as the target parameter,the ranking of the correlation of intensity numerical fluctuations is:compactness>standard curing time>cement amount>moisture content.Utilize simulated environment and load test,consider the unique strength properties of cement soil from a visible perspective,and analyze the eigenvalues of the intuitive characterization strength received in the test.Explore the law of strength changes of road materials,reveal the inner reason of the strength fluctuation of cement-soil under the collaborative effect of external environment and applied hoop pressure,the cohesive force decreases as the number of freeze-thaw cycles increases,and the internal friction angle fluctuates slightly with the number of freeze-thaw cycles;lead into the effects of failure strain energy density and dissipated energy,learn from the existing research results of rock on energy,extract the cement-soil mixture after freezing and thawing,execute strength tentative and analyze the energy change in different modules and stages,establish a damage equation related to the number of freeze-thaw cycles;apply electron microscope to observe under different test conditions,aseries of changes on the surface of cement stabilized soil samples.Using a specific surface area analyzer,collect samples after different test conditions are completed,operational micro-means test,and obtain adsorption and desorption isotherms to calculate the fractal dimension.In each test index,the macro-strength value and the micro-parameter value have the opposite trend,and the specific surface area is consistent with the fractal dimension.Microstructure and macromechanics are mutually confirmed,taking the fractal dimension as the connection point,explore the cement-soil mixture under the complex interaction of external conditions and constrained loads,the inwardness traits of the intensity vary of inorganic hybrid materials. |
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