Research On Anti-clogging Performance Of Pervious Pavement Structure Based On PFC3D

Pervious concrete is a kind of environment-friendly material with high permeability,which has the advantages of sound absorption,noise reduction and alleviating the urban"heat island effect".Mechanical properties,permeability and anti-clogging performance are important performance indexes in the application of pervious concrete.In this study,the mixture ratio of pervious concrete is optimized by using the simple centroid design method,and the clogging process of pervious pavement structure is analyzed from the mesoscopic level.The effects of aggregate gradation,clogging particle gradation,single-double layer structure and top layer thickness on the anti-clogging performance of pervious pavement structure are comprehensively considered.The effects of aggregate gradation and grout thickness on the compressive strength and permeability coefficient of pervious concrete are studied,and the test mix ratio is optimized.The conclusions are as follows:（1）the aggregate gradation of three groups of pervious concrete with better compressive strength and permeability is 5-10 mm:15-20mm=7:3,5-10 mm and 10-15 mm:15-20 mm=3:1,respectively.（2）The compressive strength of three groups of pervious concrete specimens with optimized grouting thickness are 27.92 MPa,25.31 MPa and 21.07 MPa,respectively,which meets the requirements of the specification of pervious concrete pavement and is used to study the anti-clogging performance of pervious pavement structure.The real aggregate model is reconstructed by the combination of 3D laser scanning technology and numerical simulation,and the pervious concrete test clogging model is established by using the two-way coupling method of PFC-CFD.The effects of single-double permeable structure,different aggregate gradation,different clogging particle gradation and layer thickness on the anti-clogging performance of pervious pavement are analyzed.The results show that:（1）when the clogging material in P_A1,P_A2 and P_A3 tends to be steady.The volume fraction of clogged particles is 28.6%,36.9%and 25.5%,respectively.（2）when the clogging particles are fine sand,the maximum volume fraction of clogging particles in P_A1 and P_A2 reaches 36%and 50.4%respectively;when the clogging particles are coarse sand,the maximum volume fraction of clogging particles in P_A3is 28.5%.（3）the volume fraction of clogging particles in P_A1 and P_A2 decreased by3.2%and 3.6%respectively compared with P_A1-30 and P_A2-30 of double-layer permeable pavement.P_A1 was selected as the top layer of the double-layer pervious pavement.（4）the volume of clogging particles in P_A1-30 is 25.4%,while the volume fraction of clogging particles in P_A1 is 28.6%.The shielding effect of double-layer structure is obvious and the anti-clogging performance is better.（5）when the particle size ratio of the top aggregate of the double-layer permeable pavement structure is 5-10 mm:15-20 mm=7:3 and the top layer thickness is 30 mm,pervious pavement structure has good compressive strength and anti-clogging performance.