Application Research Of Warm Mix Asphalt Used In Undersea Tunnel Pavement Paving

Application research of warm mix asphalt used in tunnel pavement is done relying on Qingdao undersea tunnel project in this paper. The performance of asphalt and asphalt mixture with Sasobit, Leadcap and Evotherm(?)-DAT are studied systematacilly, and the warm mix technique which is suitable to use in tunnel is proposed, lastly the test road is constructed. The major research content and conclusion as follows:The influence law of additives on asphalt cement performance is studied. The results showed that:Sasobit (organic additive) reduces the low-temperature performance of asphalt seriously, such as low-temperature ductility attenuate significantly; DAT (surfactant) has little effect on asphalt performance; Leadcap(organic additive) can significantly improves low-temperature performance, which has excellent application advantage. Meanwhile, the distribution and micro structure of different additives in asphalt is studied using fluorescence microscopy analysis techniques and result show that there is a close relationship between the microstructure and distribution patterns of asphalt and performance。Interior design method and road performance of WMA were studied. By a large number of experiments and data analysis, the following conclusions are obtained: the cooling amplitude of WMA which determined using viscosity-temperature curve is small, it is unreasonable, but the method of identical volume parameter (void radio) of SGC specimens can reasonably determine the molding temperature of the mixture; the construction temperature of D-WMA, L-WMA and S-WMA were reduced by30℃,20℃,20℃in this condition the asphalt fume can be reduced by90%,61%, 61%respectively in paving process of mixture, and the fuel savings of them is24%,19%and19%. Compared with the HMA, the dynamic stability of the D-WMA and L-WMA decreased by11%,17.5%, the S-WMA is not reduced; the failure strain of L-WMA and S-WMA at low temperature decreased by14%and35%, but D-WMA and HMA had the same low temperature crack resistance; the freeze-thaw cleavage strength of the D-WMA and L-WMA was better than HMA, but the S-WMA was worse, only meet the minimum requirements. Meanwhile, the dynamic modulus of WMA was studied and results showed that the Mechanical Properties of D-WMA was better than HMA, but L-WMA was slightly worse.According finite element calculation results and practical experience, pavement structure is recommended which had good durability.At last, the testing road was builded and test results showed that Warm Mix asphalt technology could not only ensure the road quality, but also achieve the purpose of the energy saving and smoke-free construction.