Application Research Of Epoxy Modified Polyurethane Materials For Existing Crack Repairing In Asphalt Pavement With Semi-Rigid Base

On the highway construction of our country, asphalt concrete pavement becomes widely available due to its surface smoothness, no connection joints, driving comfort, low noise, small vibration and simpler to fix in performance, especially for the asphalt pavement with semi-rigid base. However, with the increasing of traffic volume and axle load, the problem of pavement cracks becomes worse and worse. At present, crack repairing technique of asphalt concrete pavement with semi-rigid base in our country gives priority to caulking or sealing using crack stick, which has a poor durability and high failure rate. So it has a great significance to study on the crack repairing technique of asphalt concrete pavement with semi-rigid base course.This paper depends on a expressway of asphalt pavement entitative engineering in Hunan province, viewed from the performance of repairing material of pavement crack, diagnosis and analysis of disease, and final determination of construction technology scheme points, put forward a set of effective repairing and treatment process of crack. The main research content is as follows:① Through the experimental study on the properties of epoxy modified polyurethane material, and inspecting its physical and chemical properties, tensile strength and elongation and bonding strength. it turns out that the material has a good expansibility and permeability resistance. The curing tensile strength and elongation test on the cured products indicates that the repairing material of crack has a strong tensile strength and good ductility. The test and analysis of wet bonding and dry adhesive of epoxy modified polyurethane material proves that the repairing material of crack has a good adhesive performance.②The test and analysis on the repairing effect of crack for semi-rigid base indicates that the specimen of cement stabilized macadam after being repaired by epoxy modified polyurethane material has larger compressive and flexural strength, and the shrinkage performance of the water stability base is good in the condition of free shrinkage. The residual stability of Marshall specimen of composite structure after repaired did not have a significantly decrease, and the numerical value is 85.4%, which reaches to 95.2% of the standard Marshall specimen. The freeze-thaw splitting tensile strength ratio of composite structure whose crack repaired reaches to 83.02%, while the undisturbed specimen reaches to 85.19%, and the TSR specimen whose crack was repaired reaches to 97.5% of the undisturbed specimen, the maximum flexural-tensile strain between the composite structure system and undisturbed specimen is similar at low temperature. There is a coordinated deformation between repairing material of crack and asphalt mixture under the pressure, which proves that the performance of resisting bending and fracture of the repairing structure of pavement crack at low temperatures is good.③According to the characteristics of the entitative engineering and repairing method, this paper puts forward a set of reasonable and efficient construction technology to repair the cracks by pressure grouting. Through a series of experimental analysis of core sampling after construction, the result shows that the repairing effect of road is better after repairing crack by pressure grouting.