Study On Reflection Crack Treatment Of New Pouring Asphalt Mixture

Reflection crack is one of the reasons for shortening the service life of pavement.Whether it is the solution of filling joint treatment + anti-crack paste after paving,or milling and resurfacing,the pavement will appear water seepage and reflection crack cracking in a short time after treatment.Therefore,a new pouring material with good rutting resistance,tensile deformation ability and stress dissipation ability is developed in this paper,and a new pouring asphalt mixture reflection crack treatment technology is proposed.The new pouring material is used to treat the reflection cracks,and the appropriate width and thickness are used to open slots and expand the cracks,and the pouring process is used to fill the new material at the slot,which increases the penetrating layer thickness of the reflection cracks,prolongs the recracking time of the reflection cracks,and achieves the effect of rapid treatment of the reflection cracks.In this paper,based on the skeleton structure and volume method filling asphalt mortar for the new pouring asphalt mixture design,the skeleton structure is determined to use 4.75mm～9.5mm,9.5mm～13.2mm coarse aggregate,the ratio of4.75mm～9.5mm,9.5mm～13.2mm =62.7:37.3,The calculation method of the amount of asphalt mortar is determined.The road performance test of the new pouring asphalt mixture is carried out.The results show that the new pouring asphalt mixture has good rutting resistance at high temperature,dynamic stability of more than 3000 times/mm,and excellent cracking resistance at low temperature.By establishing ABAQUS three-dimensional finite element model,the stress variation law of pavement structure under different groove expansion forms,different load positions,different width and depth of crack expansion is analyzed,and the optimal width and depth of reflection crack groove expansion treatment is recommended.The width of the crack expansion is 45～50cm,and the depth is the whole pavement layer.The treatment effect of the new pouring asphalt mixture is compared and analyzed.It is found that the new pouring asphalt mixture has obvious advantage in treating reflecting cracks by opening slots and expanding joints.Through drawing test and shear test,the influencing factors of bond performance between the new pouring asphalt mixture and the old pavement structure were analyzed.The interface between the new and old pavement was treated,and three types of old pavement surface untreated,emulsified asphalt applied on the surface and rough surface were tested at different temperatures.The comprehensive test results were analyzed.It is found that the order of bonding effect is emulsified asphalt on the surface > rough surface > no surface treatment,which can provide reference for the actual construction.Finally,based on the Beijing-Hong Kong-Macao expressway pavement maintenance project,the experimental section is selected to study the new pouring asphalt mixture rapid treatment technology.