Experimental Study On Strength And Cracking Resistance Of A New Type Concrete

In last 30 years, great achievements have been made by our country in urban construction. The demand of tall buildings, highways and subways promote the development of high performance pumping concrete. All companies favor high performance concrete. However, in practice, cast pumping concrete structure prevail to generate serious early cracking phenomenon. Early shrinkage cracks reduce the durability of concrete structure, which impedes the use of high performance concrete.Coarse aggregate occupies the largest proportion of concrete component, which impacts workability, dimensional stability, durability and strength of concrete. Taiwan scholar Huang Zhaolong said that we couldn’t get durable concrete if the mix composition was not made up of the minimum amount of cement paste and the maximum amount of aggregate. Numerous experimental studies have shown that the compressive strength and compressive strength will improve with the volume increase of coarse aggregate. However, we still need to study whether the increase of coarse aggregate will improve cracking resistance of concrete.In this paper, I choose secondary filling technology to increase the proportion of coarse aggregate in self-mix pumping concrete. That is to say, before the pouring of concrete, I throw in different proportions of coarse aggregate to increase the content of aggregates. In this way, I can formulate a new better performance concrete.This paper focuses on the influence of coarse aggregate proportion to the self-mix pumping concrete performance, including strength and crack resistance. Firstly, I formulate big slump concrete(C30, C40 and C50), which is called self-mix pumping concrete. Slump value is controlled within the range of 200mm±20mm. Then, I have done the cube compressive strength test and shrinkage resistance test. I choose the secondary filling proportion as 0%,10%,15% and 20%.0% represents reference from self-mix pumping concrete. At last, I have analyzed the effects of secondary filling aggregate ratio to the compressive strength and shrinkage resistance of the self-mix pumping concrete.