Study On The Synthesis Of Different Anti-stripping Agents And Their Water Stability On Asphalt Mixture

The asphalt road's damage caused by the erosion of the water is one of the main format of the early damage of the asphalt road. The main form of the damage is that the asphalt stripping from the surface of the aggregate, and the reduction of adhesion, which result in the reduction of strength and stability of the road surface. Many damages would emerge which could have serious effects upon the usability and the durability of the road. Therefore, the research on how to prevent the early stage damage caused by the erosion of the water has important economic and social meanings. The present measure is mainly to add anti-stripping agents. The common products in the market are amine compound, which has week stability and co uld cause pollution. Therefore, finding a more effective, more environmental, more convenient, more stable and more economic anti-stripping agent means a lot. Coupling agent is a kind of organic compound with a special structure which has some functional g roups with different properties. Some of the functional groups can bind inorganic materials while other functional groups can bind organic materials. With this property, the coupling agent can act as a ‘molecule bridge' between the inorganic materials and organic materials. At present in civil engineering industry, some materials such as coupling agent, organic silicon have been used to improve the performance and lower the cost of the building materials. This thesis studied the anti-stripping performance of the asphalt compound respectively by synthesize new silane coupling agent and by coupling agent mixture. Meanwhile, the degradation product of the PET plastic bottle which has the similar chemical structure as the coupling agent has been added in the asphalt compound to study its anti-stripping performance.Firstly, a new silane coupling agent was synthesized based on ?-(methacryloyloxy)propyltrimethoxysilane(KH570). Then the new silane coupling agent was used to modify the basalt. Many analyzing and tes ting methods such as IR, XPS, SEM have been taken to explore the reaction mechanism of the silane coupling agent and the basalt interface. The results indicate that the new silane coupling agent is bound the basalt by chemical bond rather than physical ads orption. The water absorption of the basalt modified by the new silane coupling agent is 0.212%, which is well below the water absorption of the basalt without modification. Lower water absorption indicates better hydrophobicity. The adhesion level between asphalt and aggregate in asphalt concrete increased from grade 2 to grade 5 after modification. The Retained Marshall Strength of the asphalt mixture improved from 71.74% to 87.79% after modification.Secondly, mix KH570 and DL411 by a ratio of 1:1, and a dd the mixture coupling agents in the asphalt. The optimum additive amount of different anti-stripping agents was discussed, so as the mechanical properties and anti-stripping performance of the asphalt mixture with the optimum additive amount of coupling agent. Meanwhile, contrast studies of multiple properties among asphalt mixture with different coupling agents have been taken. Further more, the mechanism has been discussed briefly. The results indicate that the optimum additive amount of the mixture cou pling agents is 0.4%, the Retained Marshall Strength of the asphalt mixture is 85.56%. While the Retained Marshall Strength of asphalt mixture using KH570 and DL411 on its own respectively are 83.12% and 80.25%. The water stability of the asphalt mixture u sing the mixture coupling agent is better then that of the asphalt mixture using single coupling agent.Lastly, the recovered PET fibre was depolymerized and purified by adding excessive EG and using Zn(AC)2·2H2O as the catalyst under the protection of nitrogen. The influences on degradation productivity of temperature, reacting time and catalyst dosage have been explored. The degradation product's structure and thermostability have been characterized by analyzing and testing methods such as IR, HNMR and TG-DSC. Further more, contrast studies of anti-stripping performance among asphalt mixture with different additive amount of degradation product have been taken. Results indicates that the alcoholysis productivity reach the maximum when the alcoholysis temperature is 196 ?, reacting time is 3 h and the catalyst dosage is 0.6% of the PET mass. The thermostability of the PET degradation product is very good. The PET degradation product will not decompose at the temperature of 160 ? while mixing the asphalt mixture. The Retai ned Marshall Strength of the asphalt mixture reaches 90% when the additive amount of the PET alcoholysis product is 4%.