Study On Curing Variability Of Cement Concrete Considering Microscopic

The cement concrete pavement is the main form of the highway in our country, but it grows slowly in the highway pavement. One reason that restricts the development of cement concrete pavement is the poor quality of construction and maintenance. After concrete paving, the curing environment changes with the atmospheric environment, which leads to the different strength development from the indoor standard environment, therefor strength of filed concrete slab varies from standard strength.The concrete strength, which is influenced by temperature and humidity, is studied from the macroscopic and microscopic scale. In the macro scale, the effect of concrete strength under one factor, two factors, is researched. The study has shown that the concrete strength is significantly increased by temperature, especially the low temperature. The effect of humidity is less than temperature, and the concrete strength is linearly decreased as the humidity is decreasing. And then the comprehensive effect of temperature and humidity can be approximately regarded as the linear superposition of independent effect.On the basis of analysis the microscopic structure of concrete, the tensile strength of interfacial transition zone, mortar, and the small-scale concrete is studied, which is influenced by temperature and humidity. In order to study the interfacial bond strength better, this paper developed a new method and test device of the interface. The test has shown that the strength effect about temperature and humidity under microscopic scale is bigger than the macroscopic scale; the range of strength is significantly changed by the environment. The tensile strength under microscopic scale, which is effected by temperature and humidity, has the different influence, especially significantly affect the tensile strength of the interface. In order to connect the strength relation between the macroscopic and microscopic, the power function relationship between the tensile strength under the microscopic and the splitting strength under the macroscopic has been deducted.Curing temperature amd humidity significantly affect concrete strength. In the construction of concrete pavement, increasing the curing humidity and ensuring the curing temperature in the proper scale would make the concrete hydrating better, the internal structure more closely; and then the variability of mechanical properties is reduced, which could improve the durability.