Mixed Aggregate Concrete Mechanical Properties And Durability Tests

In the 1960s, combined aggregate concrete is a new type of concrete materials, developing from ordinary concrete and lightweight aggregate concrete. Comparing with ordinary concrete, it has small density, low elastic modulus, good heat insulation performance and refractory performance, etc. and it will bring certain economic benefits, if it is used for the big load and high prestress, ocean engineering and the large span bridge construction engineering. In this paper, the elastic modulus and anti-chloride ion penetration performance was studied.According to the research objective, the writer has made standard specimens of combined aggregate concrete for the sake of doing some researching on compressive strength, tensile and permeability performance specimens of chloride.The test includes a total of 24 mixing concrete and 348 blocks of sample blocks. By the test of combined aggregate concrete, the influence of the different composition ratio between lightweight aggregate and normal aggregate, water-cement ratio on the elastic modulus, the poisson ratio and Anti-chloride ion penetration performance are studied.The results show that:(1)the poisson ratio of combined aggregate concrete has no relationshps with water-cement ratio and replacement ratio.(2) On one hand, the datas of dymatic modulues of elasticity are more than that of statistic modulues of elasticity of combined aggregate concrete.On the other hand, the datas of Ed/Ec have no relationshps with water-cement ratio and replacement ratio.(3) For the combined aggregate concrete, at the same water-cement ratio, the modulues of elasticity decreases, along with the increase of replacement ratio of lightweight aggregate while the modulues of elasticity can rise as water-cement ratio drops for the same replacement ratio of lightweight aggregate. Formula of the modulues of elasticity(Ec=2.02p1/2(fcu,k)1/2) is recommended.(4) With the increase on replacement ratio of lightweight aggregate and decrease of water-cement ratio, chlorine ion diffusion coefficient decreases. As a result, anti-chloride ion permeability performance is better.