Research On Proportion Design And Properties Of C80 Self-compacting Concrete

High strength self-compacting concrete is an important research direction of concrete technology which performance a good workability, strength and durability. The paper is aimed to design C80 self-compacting concrete. Based on the components of high strength self-compacting concrete are complex, the major factors influencing the properties are variable, especially the influence of mortar and coarse aggregate content on fresh concrete. This research put forward the calculation method of mortar thickness, and study effect of mortar thickness on the properties of high strength self-compacting concrete. According to the high viscosity of high strength self-compacting concrete, this paper theoretical calculation and the instrument measurement, and research the influence factors of viscosity to reduce viscosity. According to the high shrinkage of high strength self-compacting concrete, this paper studies the effect of different expansion agent to the properties of concrete.The main achievements obtained are as followings:(1) Mortar thickness of concrete is influenced by maximum particle size, size distribution and volume fraction mutual of coarse aggregate. Even though it is increase mortar thickness by different ways, the properties of concrete is different. When decrease the volume of coarse aggregate, the workability is better, but the strength will be lower. When increase the maximum particle size of coarse aggregate, it has fewer influence on properties of concrete.(2) The sand volume of mortar and the dosage of water reducer is an important parameter to change rheological parameters and workability of mortar. When decrease the sand in mortar, it will reduce viscosity of mortar efficiently. When Using lower molecular weight, higher dosage of water reduce agent, the viscosity of concrete is lower.(3) ZY expansion agent has no obvious effect on concrete workability, but it can improve the compressive strength of concrete. under the condition of the constraints or free, increasing the dosage of expansive agent can reduce shrinkage of concrete. SCEA expansion agent will reduce the strength of concrete in high content, In limit conditions, its ability to shrinkage compensation is better than that of ZY expansion agent, but under the condition of freedom, the effect of shrinkage compensation is worse than ZY type.