The Study On Compressive Properties Of Cement-based Porous Solids

Facing the requirement of high performance of building materials and the architectural features of the modern civil engineering industry, lightweight aggregate concrete with excellent performance has broad market space in the building materials market. Therefore, on the air entraining agent, foaming polystyrene(EPS), study on the cement light-weight ceramsite pore has attracted many researchers attention, many researchers mainly cement porous solid for a single pass of mechanics research, the lack of the porous composite cement based porous solids in the research on compressive properties, failure mechanism.This paper mainly studies the gas of EPS composite, EPS composite ceramic air entraining cement porous solid performance analysis of uniaxial compression, EPS, air entraining, ceramsite content change on the peak of cement based composite porous solid stress, elastic modulus, peak strain, ultimate strain, the effect of Poisson’s ratio. Through the porous cement based two-dimensional plate under uniaxial compression experiment analysis of failure process of porous solid compression hole diameter, hole in the two-dimensional 6mm cement substrate analog EPS particles, the failure process of uniaxial compression of two-dimensional plate containing a hole through the analysis of the failure mechanism of the water-based composite porous solid.The research indicates that:1) Gas-EPS composite porous lightweight aggregate volume of sample density is low to 905kg/m3 concrete in uniaxial compression process of collapse failure, the failure surface is perpendicular to the direction of the force. When the air content is 14%, the peak stress, elastic modulus of concrete decreased relative density(EPS content) and a sharp decline, the relative density decreased by 50%, the peak stress, elastic modulus decreased 95.6% and 83.3% respectively. In the mortar containing lead gas agent in the introduction of EPS particles, the ultimate strain and peak strain difference decreases first and then increases, the ductility of the porous solid decreases firstly and then improvement.2) In ceramic material and EPS doped air entraining agent in the concrete, the elastic modulus of concrete decreased significantly, significantly improve the ductility. The relative density of ceramsite lightweight aggregate concrete, Air entrained-ceramsite lightweight aggregate concrete, Gas-EPS composite ceramsite lightweight aggregate concrete are 0.71, 0.6, 0.52. And its elastic modulus are 13.9 GPa, 4.3 GPa, 4.4 GPa, the difference between ultimate strain and peak strain is 0.2×10-3, 1.2×10-3, 2×10-3, respectively. The concrete of air entraining agent and EPS can effectively improve the ductility, to make up for lack of ceramsite concrete brittleness.3) Air entraining cement substrate into two-dimensional 6mm diameter holes can significantly improve the ductility. The relative density of 0.76 dimensional air entraining cement substrate hole 6mm content reaches 0.9%, the difference between ultimate strain and peak strain from 0.1×10-3 to 0.5×10-3, an increase of 4 times. That the air content is high, a substantial increase in 6mm hole can be improve concrete ductility.4) Change the arrangement of the two-dimensional 6mm diameter hole in the gas-cement substrate will influence its performance. In the case of the same number holes in the gas-cement substrate, holes which are staggered arrangement of specimens is more higher 8% than the alignment arrangement of specimen in the stress peak, but the elastic modulus decreased by 19%, the difference between ultimate strain and peak strain is decrease 54%. That hole random permutation lowered cement Quito hole solid rigidity and improve its brittleness.