Preparation And Properties Of Inorganic Layered Silicates Modified Warm Mix Asphalt

Warm mix asphalt(WMA)have merits of low temperature of mixing and rolling,energy saving and environmental protection.The warm agents can reduce the aging of asphalt in the process of preparation and construction,thus obviously improve the short-term aging effect.But the improvement of asphalt on long-term anti-aging performance is limited.The layered silicate can significantly improve the long-term anti-aging performance of asphalt.Therefore,layered silicate is employed to modify the warm mixed asphalt,intending to further improve the anti-aging performance.In this paper,two kinds of organic modified layered silicates(organic expanded vermiculite,OEVMT;and organic montmorillonite,OMMT)are used to modify the warm mixed asphalt respectively,and the effects of different organic layered silicates on the physical and rheological properties of warm mixed asphalt are investigated.And then the OEVMT which works better is added to warm mixed SBS modified asphalt.The effects of OEVMT on the physical and rheological properties of unaged and aged warm mix SBS modified asphalt are studied,respectively.FIRT is employed to characterize the chemical structures of un-aged and aged modified warm mix asphalt.The main conclusions are as follows:(1)The effects of different layered silicates on the physical and rheological properties of warm mix asphalt after short-term and long-term aging are investigated.It is shown that the dosages of layered silicate greatly affect the properties of warm mixed asphalt,and OEVMT works well than OMMT.(2)Both OEVMT and OMMT can enhance the high temperature stability and rutting resistance of WMA,but somewhat reduce its plastic deformation ability.Both of them can improve the physical and rheological properties and rutting resistance of WMA after short-term aging.OEVMT can improve the anti-fatigue properties of the warm mixture asphalt,while OMMT reverses this effect.After adding OEVMT and OMMT,the low values of creep stiffness of the WMA reduce;however,their abilities to disperse stress are improved to different extents.(3)Similarly,OEVMT can enhance the high temperature stability and rutting resistance of warm mixed SBS modified asphalt,but somewhat reduce its plastic deformation ability.And OEVMT can slightly reduce the rutting resistance of warm mixed SBS asphalt after short-time aging,but significantly improve its anti-fatigue performance after long-term aging.Onsidering the physical and rheological properties,we can conclude that the optimum dosage of OEVMT is 4%.(4)The results of FIRT show that compared to WMA,OEVMT and OMMT could significantly inhibit the formation of carbonyl groups of warm mix asphalt and warm mix SBS modified asphalt during the aging process of short-term and long-term,and make warm mix composite modified asphalt reveal good thermal aging resistance.