| Gussasphalt, marked by high-viscosity asphalt, small porosity and more contents of fine aggregate, has good waterproof property, aging resistance, fatigue performance,low temperature crack resistance and good bonding with steel deck. It has been adopted widely in the deck pavement of long span steel box girder bridge since it was introduced from the abroad. However, the paving layers of the gussasphalt designed in accordance with European standards, due to the complicated geographic and climatic environment of China, all have damages of different degrees. Among these damages, the most severe damage is the serious shortage of high temperature stability of pavement surfaces,which is caused by the prevalent high temperature in most of our country in summer.This case is particularly outstanding in Yangtza river basin where the temperature of pavement surface can reach to 70℃, much higher than the experimental temperature of40℃ of the foreign. Therefore, the gussasphalt of our countries can’t be designed with the foreign standards and the actual conditions of our country should be considered to design a kind of gussasphalt which is consistent with the climatic environment of our country. According to the climatic characteristics of our country, gussasphalt which adopts the polymer modified asphalt instead of the modified asphalt, has wide application perspective in the improvement on the high stability of steel deck.The properties on high temperature and low temperature of the CRP-modified asphalt are studied through the experiments on penetration, softening point and ductility.The changes of CRP-modified asphalt, SBS-modified asphalt and CRP compound modified asphalt on the validity performance are studied through the experiment on rotary micrometer. The modified asphalts of different kinds adopt the same aggregate and gradation, and the asphalt-aggregate ratios of them are decided by the experimental data such as the fluidity, penetration and penetration increment of the gussasphalt. The rutting resistance at high temperature, the crack resistance under low temperature and water damage resistance of the CRP compound modified poured asphalt mixture are researched through the rutting tests at 60℃ and 70℃,bending tests at low temperature,adhesion tests and freeze thaw split tests on the poured asphalt concretes made under their respective asphalt-aggregate ratios. The experiment proves the following results:The rutting resistance at high temperature of the CRP compound modified gussasphalt is striking, much better than those of SBS-modified gussasphalt and CRP-modified gussasphalt. The low temperature performance of the CRP compound modified gussasphalt falls in between that of the SBS-modified gussasphalt and that of the CRP-modified gussasphalt, which means the low temperature performance of the CRP-modified gussasphalt isn’t improved.Through the demonstration given by the paper and various experiments, such as laboratory conventional experiments on asphalt, the rutting tests at 60℃ and 70℃,bending tests at low temperature, adhesion tests and freeze thaw split tests,we can achieve a conclusion: ⑴CRP composite modified casting type high temperature anti-rutting performance of asphalt concrete, the SBS modification and CRP single single modified cast rutting of asphalt concrete to improve a lot;⑵CRP composite modified cast asphalt concrete with low temperature performance between CRP single modification and SBS single modification between cast asphalt concrete; ⑶CRP composite modified cast asphalt concrete water damage resistance was improved obviously。The mix proportioning of gussasphalt which is most suitable for the steel bridge surface pavement is the GRP-modified gussasphalt in which CRP accounts for5%, matrix asphalt for 70%, lake asphalt for 33.3%, rock asphalt for 5% and SBS for4%。... |
PDF Full Text Request