Experimental Study On Basic Mechanical Properties Of Fiber Toughened Waste Ceramic Aggregate Concrete

With the sustainable development strategy put forward,people pay more and more attention to environmental protection,but the rapid economic development has brought a series of environmental problems.In some places,there is a serious shortage of non-renewable resources such as sand and stones.China’s annual ceramic output is relatively large,up to tens of millions of tons,using waste ceramics as coarse aggregate to replace natural stones can protect the environment and save resources.In this paper,C30 is taken as the reference concrete,and the trial test of ordinary concrete is carried out first,and the water-cement ratio of 0.45 is selected as the initial water-cement ratio of waste ceramic recycled concrete for the compressive strength analysis.Using waste ceramics as recycled coarse aggregate to replace natural coarse aggregate with equal quality,six replacement rates of 0%,20%,35%,50%,65% and 100% were used to make concrete.The mechanical properties and technical indexes of waste ceramic coarse aggregate were mainly studied to find out the optimal replacement rate.Then the effect of coarse aggregate size gradation,silica fume and basalt fiber on mechanical and working properties of waste ceramic concrete was studied by using orthogonal test design.The main research results of this paper are as follows:(1)By studying the basic characteristics of recycled coarse aggregate of waste ceramics,the test shows that the gradation of recycled coarse aggregate is reasonable,and the size control of ceramic coarse aggregate within 5 mm~20 mm can reduce the number of needle-like particles.The crushing value index of coarse ceramic aggregate is higher than that of natural stone,and its own strength is relatively low.It is not easy to absorb water and saturate in a short time,and the water absorption rate after saturation is much higher than that of natural stone.(2)The results show that the slump of the recycled concrete increases with the increase of the replacement rate of coarse ceramic aggregate.The mechanical test showed that the mechanical properties of RACA were greatly affected by the replacement rate of coarse aggregate.With the increase of substitution rate,the compressive strength,fracture strength and splitting tensile strength all decrease,among which the compressive strength is most affected by substitution rate,and the failure forms are all interface failure.Compared with ordinary concrete,waste ceramic recycled concrete has better toughness.When the substitution rate is 50%,the axial compressive strength reaches the maximum value,and the functional model of elastic modulus changing with the substitution rate is fitted.(3)The range analysis was carried out on the mechanical property improvement test of waste ceramic concrete.When the volume content of basalt fiber was 0.15% and the weight ratio of coarse aggregate particle size range was 10~20 mm: 5~10 mm=5:2,the strength improvement of compression resistance,splitting tensile resistance and flexural resistance was the largest.Silica fume and other qualities replace cement.When the content of silica fume is 10%,the increase of breaking strength and splitting tensile strength is the maximum,while when the content of silica fume is 15%,the increase of compressive strength is the maximum.Under the condition that the strength of ordinary concrete is not lower,basalt fiber volume content of 0.15%,silica fume content of 15%,coarse aggregate particle size range weight ratio of 10~20 mm: 5~10 mm=5:2 are selected as the optimal combination for improving the mechanical properties of concrete.