Study On Salt Corrosion Deterioration Characteristics Of Asphalt Mixture Under Multi-factor Action

The durability of asphalt mixture has been one of the most important problems in road engineering at home and abroad.In southeast coastal and inland salt lakes,saline land areas of our country,the natural conditions are particularly harsh,and the "salt" is spread all over the area.In addition,asphalt pavement is frequently subjected to dry-wet / freeze-thaw cycle and intense ultraviolet radiation,which makes the durability of asphalt mixture greatly reduced and the service life of asphalt pavement shortened.In order to objectively evaluate the durability of asphalt mixture under salt corrosion environment,the influence of dynamic water/ static water/ salt/ temperature/ ultraviolet ray on the performance of asphalt mixture is comprehensively considered in this paper.The dynamic water / salt erosion scrubber for asphalt mixture was developed independently.Taking the splitting strength at room temperature(25?)and low temperature splitting strength(-10?)as evaluation indexes,experimental study on performance damage of asphalt mixture under the action of each single factor.On this basis,salt-dry-wet cycle test,salt-freeze-thaw cycle test,salt-dynamic water scour test and temperature-ultraviolet radiation test were carried out to explore the asphalt mixture in more complex environment.The performance change rule of asphalt mixture under salt-dry-wet/ freeze-thaw cycle was further studied and the corresponding Logistic performance damage prediction model was constructed.The study found that,the performance of asphalt mixture decreases under the action of each single factor;The loss of asphalt mixture strength caused by dynamic water is more serious than that of static water;Ultraviolet radiation has little effect on the strength of asphalt mixture;The effect of salt on the performance of asphalt mixture is mainly due to physical action,and sulfate results in greater loss than chlorine salt;Scour effect and temperature effect are the main reasons leading to the deterioration of asphalt mixture performance;Salt-freezing cycle aggravates the decrease of adhesion between asphalt and aggregate and the loss of strength of asphalt mixture,and the strength loss of asphalt mixture is greater due to the lower concentration of salt-frozen circulation medium.The strength loss of asphalt mixture under the action of salt-water-temperature-ultraviolet radiation is serious.The Logistic damage prediction model of splitting strength of asphalt mixture is reasonable and applicable and the precision is high.The results can provide a useful reference for the composition design and durability prediction of bituminous mixtures in salt-rich areas.