| With the acceleration of urbanization in China,the area of urban impervious pavement has increased dramatically,which hinders the water cycle of nature and leads to the increasingly prominent problem of urban waterlogging.At the same time,with the upgrading of China ’s infrastructure,the reprocessing of a large amount of construction waste generated by the demolition of old buildings has also become an urgent problem to be solved.The use of recycled brick aggregate for both permeable pavement surface and base layer can not only effectively reduce surface runoff,but also store rainwater,which is of great significance for alleviating urban waterlogging.In this paper,the preparation of pavement layer and the infiltration performance of pavement are studied.The runoff reduction and infiltration performance of different permeable pavement models under different rainfall conditions are analyzed by model test and numerical simulation,which provides reference for the design of permeable pavement.The main research contents are as follows :(1)The orthogonal test method was used to study the mix ratio of permeable concrete for permeable pavement.The range analysis shows that the main factors affecting the water permeability and mechanical properties are the target porosity and the replacement rate of recycled brick aggregate.Through the comprehensive analysis of orthogonal test,taking the compressive strength and water permeability as the evaluation indexes,under the premise of satisfying the compressive strength greater than 20 MPa,the mix ratio of recycled brick aggregate pervious concrete is optimized as follows : target porosity 21 %,water cement ratio0.32,recycled aggregate replacement rate 20 %,imitation steel fiber volume content 0.45 %.At this time,the compressive strength of pervious concrete is not less than 20 MPa,and the permeability coefficient is 10.81 mm / s,which can be used for pervious pavement surface.(2)Three kinds of rainfall intensity,three kinds of rainfall duration and four kinds of permeable pavement models were designed.A total of 36 working conditions were used for artificial rainfall test.The runoff control effect and seepage storage performance of four kinds of permeable pavement under different rainfall conditions were compared and analyzed.The results show that the surface layer has a significant effect on runoff control within 60 minutes of three rainfall intensities and rainfall duration.The runoff control rate of permeable pavement is higher than that of impervious pavement by more than 60 %.When the rainfall intensity is 3kinds and the rainfall duration is 120 min,the runoff control effect of recycled brick aggregate base is the best.In terms of water permeability,different filling methods have little effect on water permeability,and the water permeability of ordinary gravel base is better than that of recycled brick aggregate base.In terms of water storage performance,the permeable pavement with recycled brick aggregate has the best water storage performance.(3)The seepage model of permeable pavement structure under rainfall conditions is established by numerical simulation software.On the basis of verifying the reliability of the numerical model,the influence of aggregate properties and base structure on the seepage and storage performance of permeable pavement is studied.The results show that the properties of aggregate have a significant effect on the seepage performance of permeable pavement.The smaller the aggregate size is,the stronger the water storage capacity is.With the increase of the volume content of recycled brick aggregate,the permeability of permeable pavement decreases and the water storage performance increases.Different layer thickness combinations have little effect on the seepage storage performance,while the thickness of the base layer has a great influence on the water storage performance. |
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