The climate in the Central Asian area is extreme dry, with a large temperature difference between day and night, and the concrete is easy to crack during the construction period under the conditions of traditional external curing. Therefore, this study concerns understanding the application of internal curing materials in a dry and large-temperature-difference environment. The effects of three internal curing materials, namely, Super Absorbent Polymer (SAP), Light Weight Aggregate (LWA) and Perforated Cenospheres (PCs), on hydration and pore structure characteristics of concrete were investigated. Scanning electron microscope and x-ray diffraction were used to observe the microscopic morphology and physical phase composition of concrete, and the evolution of pore characteristics was analyzed using mercury injection apparatus to explore the mechanism of pore structure refinement. Results show that the pores formed by the release of water provide space for the accumulation of hydration products, thereby accelerating the formation of ettringite crystals. Results indicate that the continuous release of internal curing materials allows the interior of the concrete to continue to be hydrated, which greatly promotes the overall hydration of the cement. The effect of supplementary cementitious materials (GGBS, FA) and implications of large-temperature-difference environment on concrete durability are discussed.

The creep characteristics of geogrids is one of the most important factors affecting its permanent in reinforced soil structures. currently, most of the creep tests are under unconfined conditions, the results deviates significantly from the real status in the application . And conventional creep tests are time-consuming and costing.In this paper, time-temperature superposition principle of geosynthetics is used to accelerate creep and shorten test time. This paper presents a new device to perform simultaneously confined and accelerated creep tests on HDPE50 geogrid . According to the results and time-temperature superposition principle of geosynthetics,the master curves are obtained . Finally the creep reduction factor of confined and unconfined conditions is analysed in the actual project .