Research And Simulation On The Relationship Between The Compressive Strength And Pore Structure Of Basalt Fiber Reinforced Rubber Concrete

In recent years, the research and achievement of concrete composites are emerging. Rubber concrete has been applied in many fields, such as construction engineering, road engineering, etc. with its excellent durability, shock absorption, low cost and low energy consumption. But rubber particles (powder) are improving the performance of concrete while reducing its strength. The fiber has a positive effect on the improvement of concrete strength. Among various kinds of fiber, basalt fiber has the characteristics of natural and mechanical properties, and is known as the "universal" fiber without pollution. Therefore, the compressive strength and pore structure of basalt fiber reinforced rubber concrete were studied by mixing basalt fibers with rubber particles (powder) of different particle sizes.The main results of this paper are:(1) Compressive strength results show that early compressive strength of basalt fiber reinforced rubber concrete has a larger increase than the later. In every age, under the same volume fraction of fiber more rubber content gets less compressive strength. And under the same content of rubber particles, concrete gets the highest compressive strength at the fiber content of 2.0Kg/m3.(2) A composited concrete model is established, and the calculation method of elastic modulus is derived. It has a better explanation to the regular——the elastic modulus of concrete increases with the increase of the content of basalt fiber, and decreases with the decrease of the rubber particle size, and decreases with the increase of rubber content.(3) Damaged constitutive equation of basalt fiber reinforced rubber concrete is established by using the Weibull distribution, the theoretical results are in good agreement with those stress-strain curves obtained from the test.(4) The analysis results by using the multifractal theory to pore structure show that incorporating the basalt fiber and rubber particles (powder) can obviously improve the pore size distribution of concrete, reduce the non-uniform degree, reduce the discrete degree.(5) The analysis based on the grey correlation on concrete strength and pore structure show that the influence of pore structure characteristic parameters sorts:specific surface area> spacing coefficient> average chord length> chord frequency> air content; pore size distribution sorts:less than 100μm> 100-200μm> 200-300μm> 300-400μm>over 400μm; the multifractal parameters sort:D1/D0>D1>D0>Δβ>Δf。(6) The research of ABAQUS on the stress concentration at the tip of the concrete hole shows that the rubber can significantly reduce the stress concentration of the hole.