Cement - Limestone Powder Cementitious Materials Under The Combined Effect Of The Sulfate And Chloride Corrosion Damage

Rich source and low price of limestone powder has been widely applied to the cement industry admixture of concrete mineral admixture. Scientific and rational application of ground limestone, we can achieve the objective of waste, and produce good technical, economic and ecological benefits.Sulphate and chlorine of composite erosion are prevalent in western and coastal areas of china. In order to apply ground limestone safely in the cement - based materials, and this cement - ground limestone cementitious materials at sulphate or chlorine corrosion, and the environment as well as in sulphate and chlorine of corrosion damage, its main research content and conclusions are as follows:1. The performance of cement - ground limestone cementitious materialsGround limestone reduces the fluidity. It promotes early hydration, hydrationslowed in the late. The strength of cement mortar with ground limestone volume increases in the first and reduces at 3 days and 7 days. It reached the maximum value when ground limestone volume at 10%. Ground limestone reduces cement mortar strength after 28 days. The shrinkages of cement mortar reduces with the volume of ground limestone, ground limestone increased water absorption of cement mortar.2. The performance of cement - ground limestone cementitious materials under the environment of sulphateThe formation of gypsum with the lime mortar after 8 months in sulphate erosion, cement mortar splits and damages obviously to the phenomenon. Ground limestone reduces the strength of cement mortar, the strength of cement mortar with ground limestone volume increases in the first and reduces with corrosion time, the strength of cement mortar declines after 2 months. The line length change rate of cement mortar with immersion time rendered early shrinkage and the latter part of the expansion of characteristics, ground limestone increases the expansion of cement mortar. Ground limestone increased water absorption of cement mortar. 2 months later, the water absorption of cement mortar increases with immersion time.3. The performance of cement - ground limestone cementitious materials under the environment of chlorideGround limestone make the corrosion of chloride heavily, the formation of a-C₄A·CaCl₂·10H₂O andβ-C₃A·CaCl₂·10H₂O after 8 months in chloride erosion. The strength of cement mortar increases with immersion time. The strength is not declining trend, and it reduces with adding ground limestone. The shrinkages of cement mortar reduces with the volume of ground limestone, ground limestone increased water absorption of cement mortar.4. The performance of cement - ground limestone cementitious materials under the environment of sulphate and chlorideCement mortar is dipped in sulphate and chloride 8 months later, the sulphate and chloride is not breaking the extent of sulphate corrosion. Adding ground limestone is adverse for the durability of sulphate and chloride. The strength of cement mortar is increased in 2 months, and then the strength of cement mortar will decline. The strength of cement mortar reduced with adding ground limestone. Cement mortar with immersion time rendered early shrinkage and the latter part of the expansion of characteristics. Ground limestone reduces the shrinkage and increases the expansion of cement mortar. The water absorption of cement mortar increases with immersion time. Ground limestone increased water absorption of cement mortar.Ground limestone makes the corrosion heavily in sulphate, chloride and composite solutions. Different solutions led to different destruction of cement mortar. the different levels of destruction of a heavier to lighter order is sulphate>composite solutions > chloride. Sulphate makes the extent of corrosion damage heavily in chloride. Chloride enhances the cement mortar in sulphate.