Study On The Treatment Of Crack Grouting In Highway Asphalt Pavement

More than 90% of the expressway pavement in our country is semi-rigid base asphalt pavement.Generally,the design service life of this kind of pavement is 15 years,and most of the roads have obvious damage or disease within 5 years of opening to traffic.The reflection crack of semi-rigid base causes the asphalt pavement crack is very common.At home and abroad,the maintenance methods of reflective cracks of pavement caused by semi-rigid base structure are mostly limited to closed surface cracks,and few work is carried out to improve the strength of semi-rigid overall structure;at the same time,the concealment of road maintenance makes it difficult for scholars to determine which cracks are suitable for grouting technology,and the application effect of base reinforcement cannot be effectively evaluated The development of semi-rigid base grouting technology lags behind.Therefore,this paper first analyzes the highway pavement diseases in service in Liaoning Province through a large number of investigations,establishes the relationship between the road surface crack type,damage degree and the base layer diseases,verifies this correlation by using FWD,3d-radar non-destructive testing technology,and puts forward the basis for grouting treatment,at the same time,evaluates the effect of the road section maintained by grouting technology,and then through the test The ideal grouting materials and grouting technology suitable for the characteristics of grouting construction in Liaoning Province are selected.Finally,the long-term performance simulation test of the grouting disposal section is carried out by using accelerated loading equipment.The main conclusions are as follows:(1)The crack of semi-rigid base asphalt pavement will cause the pavement to lose the function of longitudinal force transmission,which will increase the vertical deformation of the pavement at the edge of the crack under the vehicle load(compared with before the crack),resulting in the decrease of the fatigue life of the pavement base and asphalt surface materials,and in some cases,there will be diseases such as slurry pumping at the crack location.(2)Adjust the formulation of grouting materials and test the corresponding basic performance,put forward the basic performance indexes of grouting materials suitable for different technical requirements,and determine the control points,evaluation standards and acceptance standards of each process in the construction process.(3)The relationship between the deflection value and the distance from the crack center can be analyzed by using FWD detection technology,and it is proposed that the deflection difference of the original pavement surface crack is greater than 30(0.01mm)as the basis to judge whether the road section location needs grouting treatment.The average reduction of deflection before and after grouting is more than 30%.(4)3d-radar detection technology can be used to judge the internal damage state of the pavement structure,identify the structural cracking,subsidence and other disease forms,and judge the severity;3d-radar detection technology based on CMP method can judge the internal damage and looseness of the structural layer by calculating the dielectric constant.(5)The accelerated loading test proves that the vertical deformation is weakened after the base course is effectively repaired,so that the bending tensile strain at the bottom of the asphalt layer is reduced,the shear fatigue resistance of the whole pavement is improved,and the service life of the road is extended.