Study On Adhesive Wearing Surface For Preventive Maintenance Of Asphalt Pavement

With the rapid development of China’s highway construction,the routine maintenance of the pavement maintenance department has shifted from“large-scale construction”stage to“synchronized construction and maintenance”stage.The performance and life span of pavements could be improved by Pavement Preventive Maintenance Technology(PPMT).PPMT is an important technique for realizing the preservation of road assets.At present,China’s road maintenance departments have basically accepted the viewpoint of PPMT,and have begun to adopt traditional maintenance techniques such as fog seal,nova-chip.chip seal and micro-surfacing to improve pavement performance.However,there are some disadvantages in traditional maintenance techniques,such as complicated construction,insufficient durability and poor stability at high temperature.The chip seal is prone to flaking,bleeding and other water damage,and pavement skid resistance tends to decay rapidly,so it was only applied in low grade highway asphalt pavement.In this paper,the technology of high performance double-layer chip seal named Adhesive Wearing Surface for high grade asphalt pavement is studied.This paper studied the bonding mechanism and bonding influence factors of aggregate and asphalt.The basic characters of four different emulsified asphalt and three different lithology stones were tested,then the water-boiling method,Vialit test,surface energy test,Pull-Off test were used to analyze the adhesion of four kinds of emulsified asphalt and three kinds of aggregate.It is concluded that bonding effect between the SBS-1 emulsified asphalt and the basalt is best,so the SBS-1 emulsified bitumen and basalt is the optimum combination.The interlayer interface agent is a kind of special bonding layer material.After the performance of the shear,Pull-Off resistance and liquidity for different dosages interlayer interface agent are tested,it is confirmed that the best content of interlayer interface agent was 0.25kg/m~2.Considering reducing noise and improving the performance of anti-sliding and connecting with the traditional design method of chip seal,the paper put forward the design principles about aggregate gradation,particle size,spraying style and structure.Adhesive Wearing Surface is based on double chip seal,used the"sandwich"spraying method rather than the traditional one.The dosages of aggregate and the range of asphalt were confirmed by the test of aggregate stripping rate.Based on the orthogonal experiment,the optimal gradation and material consumption of Adhesive Wearing Surface were obtained by regarding aggregate gradation and asphalt dosage as the influencing factors,while anti-slip performance,noise level and anti-wear performance are the indexes.An Adhesive Wearing Surface test road was built by the research team in Guangzhou city,and at the same time the construction technology of adhesive wearing surface was also put forward.The anti-skid performance,roughness,noise level and economic benefits of the test road were investigated.The results showed that the BPN of the adhesive wearing surface after a half year construction is above 70,and the noise level was 2-3 dB lower than which of the original road.the price of adhesive wearing surface is 38 yuan/m~2 by calculating the actual expenditure of the test road.