Performance Evaluation Of Recycled Aggregate Permeable Brick With Through-holes

Chinese urbanization and industrialization drive the rapid development of the construction industry,the demolition of old buildings produced large number of construction waste,of which the content of waste concrete and brick reached more than60%,it is of great significance to realize the construction waste resource utilization if these wastes can be reasonable recycled.Therefore,this article produces recycled concrete using concrete and brick waste as the raw material,the working performance and shrinkage performance of recycled concrete is studied.Besides,recycled concrete is used to produce a new kind of permeable brick in this article,experimental researches are launched to explore the mechanical and antifreeze properties of the permeable brick,the main research results of this paper are as follows:(1)The slump of recycled concrete with additional water is still lower than that of natural concrete,and the shrinkage of recycled concrete is higher than natural concrete.The slump,30 min slump loss and shrinkage of recycled concrete both increased with the increase of brick RCA content and water-cement ratio.The increase of water-cement ratio from 0.34 to 0.60 increases the slump of concrete by 47 mm at most and the shrinkage rate by 20%～30%.(2)The permeability coefficient of permeable brick with through-holes is directly proportional to the porosity.When the porosity is only 0.982%,it has a permeability coefficient of 2.36mm/s,far exceeding the requirement that the permeability coefficient of A-grade permeable brick should be no less than 0.2mm/s,so it has excellent permeability.(3)The compressive strength of RCA permeable brick with through-holes can reach up to 46.6MPa in this experiment.With the increase of water-cement ratio,brick RCA content and the number of through-holes,the compressive strength of permeable brick decreases gradually and the crack will develop from the top corner of the permeable brick to the through-hole.The relationship between the compressive strength of permeable brick with different number of through-hole and the content of brick RCA with three water-cement ratios was established.The splitting strength of RCA through-hole permeable brick decreases with the increase of water-cement ratio and brick RCA content.With the same water-cement ratio and brick RCA content,the splitting strength of 10 holes permeable brick was the highest,and that of 21 holes permeable brick was the lowest.The relationship between compressive strength and splitting strength of 10 holes,21 holes and 36 holes permeable brick was obtained by Origin software.(4)The antifreeze coefficient of RCA through-hole permeable brick decreases with the increase of water-cement ratio,brick RCA content and the number of throughhole.The antifreeze coefficient of all specimens is more than 90%,and the antifreeze performance of through-hole permeable brick is superior.(5)The compression process of RCA permeable brick with through-holes was simulated by ANSYS finite element software,the influence of the number and distribution of the through-hole on the strength of permeable brick was analyzed,and the strain distribution of RCA permeable brick under pressure was obtained.