Role of coupled environmental factors on shrinkage properties of concrete at high altitude

Abstract

In this paper, the shrinkage deformation of C35 and C50 concrete and its equivalent mortar by each factor under the complex coupling environment of low air pressure, large temperature difference, windy drying, and strong ultraviolet radiation is systematically studied by using an independently designed complex environment simulation platform. The effects of each environmental factor on the shrinkage and deformation, hydration degree and pore structure of concrete under the complex environment were analyzed. The results showed that the shrinkage deformation of concrete under the complex environment of plateau increased significantly, and the dominant factor was windy and dry, followed by low air pressure and ultraviolet radiation, and the temperature difference did not lead to further intensification of shrinkage. At the same time, the shrinkage deformation of concrete under plateau complex environment was closely related to the degree of hydration and pore structure. Compared with the standard curing environment, the plateau complex environment reduced the hydration degree of concrete and increased the number of various types of pore size, of which the effect of windy drying on the hydration degree of concrete and capillary pore content is particularly significant.