Research On Highway Asphalt Pavement Inner Disease Quick Maintenance Of High Polymer Grouting And Application

Along with highway constructions in our country are increasing year by year, highway maintenance and reconstruction will become the main task of the road construction industry, especially of asphalt pavement preventive maintenance measures, which would have inhibitory effect on the development of road potential diseases, and also greatly improve pavement technology condition, prolong the service life of pavement. High polymer chemical grouting technique is used in highway maintenance in recent years, such as roadbed subsidence, interlayer pavement, cracks at the base level, etc., but the study of high polymer grouting mechanism is relatively lag, the engineering design and construction of long term depends on the construction experience, so that it has not been widely used in our country in the field of road repair. In this paper, with reference to relevant polymer grouting material research and its application instances, polymer grouting material’s diffusion mechanism inner asphalt pavement and its construction technology were studied, combining with the practical construction.There are generally two categories of asphalt pavement diseases, one is road surface disease, the other is deep disease, the deep diseases mainly embody those diseases in road base; combining with the principle and characteristics of polymer grouting to determine the occasion of this technology; based on the theory of fracturing grouting, as well as the polymer materials fluidity, to discuss its diffusion mechanism of the flowing inner asphalt pavement, which can be simulated by the diffusion model of point source, so as to analyze the correlation between the grouting pressure, diffusion radius and grouting quantity. The main results are as follows:(1) Grouting material’s liquidity is extremely relevant to reaction temperature and time, viscosity of the mixture increases with rising temperature, which promotes the reaction, the quicker of the solidification, the faster viscosity increases; the viscosity increases as time goes by under one level temperature;(2) Polymer grouting diffuses inter road in three ways, of which are fill compaction, layers oriented fracturing, and bubbling compaction undirected fracturing, the process of splitting grouting is in line with the principle of energy and body conservation that the grouting pressure and fracture thickness decrease as the grout diffusion radius increases.This polymer grouting material is made of two components by half and half, which are called the black and white, characterized by free volume expansion ratio of 1:15-1:20, free expansion density range of 50-100 kg/m3, gel time of 15 seconds, and the curing time of about 1 min. Using this polymer grouting material to make cylindrical polymer foam specimen of capacity of 309 cubic centimeter in different foaming ratio of 10, 12, 13, 14, 15. Then to test these specimens in the experiment of water absorption, unconfined compressive strength, soaking unconfined compressive strength and immersion water PH, so as to obtain the correlation between material density, water absorption rate and the compressive strength, preliminary judging its applicability in the highway maintenance. As the density of polymer specimens comes down, water absorption trends to increases, the specimens compressive strength get little effect both by the density and water. Also, this material has almost no impact on the water PH value. Therefore, to preliminary judge that this material is available to be applied to road maintenance.Before the application to the Guanghui expressway in Guangdong province, pavement technology and investigation of surrounding conditions are evaluated to make rational grouting scheme and select grouting sections; by grooving, observed is the polymer grouting flowing way within the pavement structure; referring to the paper of ‘Polymer grouting treatment method for highway diseases maintenance’, and according to the practical application, discussed are the grouting hole layout and grouting pressure control method, then with non-destructive apparatus of Falling Weight Deflectometer(FWD), to put forward a new deflection control standard of polymer grouting, theoretically analyze the service life of the asphalt pavement after grouting.Here are the conclusions of grouting application as follows:(1) The range diffusion radius is from 1 to 4m, and with comprehensive consideration, to make some complements of grouting holes layout: ① surface without obvious diseases, and small deflection, longitudinal distance of covered holes is from 1.2m to 1.5m; ② surface without obvious disease, longitudinal distance of covered holes is from 1.5m to 2m; ③ set the longitudinal distance along the crack as 1.5m;(2) When grouting pressure gets a sudden increase and reaction force, immediately stop grouting, then hold the grouting gun around 15 to 30 s, when grouting pressure suddenly decreases, which means encountering splitting voids, or slurry begin to flow, or the expansive slurry has begun to uplift surface, right the time to pay attention to the surface elevation within a radius of 1m around the grouting hole. Also, after grouting pressure drops down, it can be only continually grouted within 1 to 2 min in case of uplifting.The deflection value and the subgrade modulus both increase after grouting, and the pavement life is theoretically raised by 27%.