Key Technology Research On Preventive Reinforcement In Highway Semi-rigid Asphalt Pavement

Highway in China develops fast, by the end of 2014, the total mileage is more than 100000 kilometers, rank first in the world, but the service life of the road is serious short, early stage was badly damaged especially. Around 90% of highway use of asphalt pavement in our country, more than 95% using semi-rigid base which causing disease caused by a lack of strength at the grass-roots level is very common. To explore new and scientific maintenance way and carry out technology research of asphalt pavement semi-rigid base preventive reinforcement is necessary. Reference on the basis of preventive maintenance management technology and engineering technology research and practice at home and abroad, this paper studied the key technology of asphalt pavement semi-rigid base’s preventive reinforcement.Therefore, the concept of the basic preventive reinforcement is introduced on the basis of the surface preventive maintenance, established the macroscopic and microscopic traffic standard to the highway asphalt pavement preventive reinforcing and put forward 5 kinds of road conditions which are not suitable for preventive reinforcement. This paper expounds the nature characteristics and application scope of cement grouting and polymer-injection grouting, and analyze the adaptability and limitations for the common measures of semi-rigid base preventive reinforcement. According to the characteristics of the highway preventive reinforcement, determine the timing of the preventive reinforcement by life cycle analysis methods and shows the life cycle cost composition and calculation method, the analysis results demonstrate that the best time for preventive maintenance is the time when the effect expense ratio achieve the maximum.This paper studied on preventive reinforcement measures of polymer-injection grouting. Make polymer grouting material by indoor experiment for a two-component polyurethane black and white material mass ratio of 1:1, gel time to 15 seconds, curing time to 1 minute, the volume expansion ratio of 1:10 ~ 1: 15, including water absorption test, unconfined compressive strength test, unconfined compressive strength test and PH test. Tests show that polymer grouting material has good liquidity and high resistance to water, the compressive strength meet the requirements of pavement base and do not pollute the water and soil, it is security and environmental protection.Select K778 + 200 ~ K778 + 400(downward direction) of Huang-Huang highway in Hubei Province as the test section and conduct polymer-injection grouting site construction. This paper according to the grouting reinforcement road traffic investigation and basic preventive standard to determine grouting sections, conduct grouting hole arrangement and drilling grouting construction by the polymer-injection grouting construction technology and take FWD and GPR for nondestructive testing. After more than three months driving load, no new pavement diseases occur and the deflection values with little change after grouting, the analysis results demonstrate that the effect of polymer-injection grouting preventive reinforcing is good.