Study On Preparation And Properties Of Asphalt Modified By Waste Rubber Powder Activated By Additives

Because the waste rubber powder has the characteristics of heat insulation,elastic recovery,etc.,it was added to the asphalt as a modifier to improve the road performance and reduce environmental pollution.However,the internal cross-linking structure of waste rubber powder had not been completely destroyed in the process of physical crushing,and the surface of rubber powder was inert,which led to the problems of poor thermal storage stability and high viscosity of rubber powder modified asphalt.To this end,this article used additives to activate the waste rubber powder to improve the storage stability and other properties of the waste rubber powder modified asphalt,and expanded the application of waste rubber powder in asphalt pavement engineering.This article started with the activation of waste rubber powder and selects three auxiliary systems to activate waste rubber powder,it included the following three kinds:waste engine oil,polyalkyl phenol disulfide + plasticizer+catalyst,tetramethyldecynediol+plasticizer.According to the test,the optimal process parameters of the three activated rubber powder modified asphalt were determined.The results were as follows:waste oil activated rubber powder modified asphalt:shear temperature 180℃,shear time 60 min,shear rate 3000 R/min;polyalkyl phenol disulfide auxiliary system activated rubber powder modified asphalt:shear temperature 190℃,shear time 60 min,shear rate 5000 R/min;tetramethyl decane diol auxiliary system activated rubber powder modified asphalt:shear temperature 180℃,shear time 60 min The shear rate is 4000R/min.Secondly,three types of activated rubber powder modified asphalt and common rubber powder modified asphalt with the rubber powder content of 15%,20%,25%,30%,and 35%were prepared.The four kinds of asphalt were evaluated from the conventional properties,rheological properties and aging properties.The results showed that compared with the conventional crumb rubber modified asphalt,the separation and viscosity of the activated rubber modified asphalt improved by about 40%,the aging resistance increased by 40%,and the low temperature performance was improved.Especially,the stiffness modulus of the waste rubber modified asphalt was reduced by about 120%,and the m value increased by 45%.According to the research results,it is recommended that the amount of waste engine oil activated waste rubber powder is 35%,the amount of polyalkyl phenol disulfide activated waste rubber powder is 30%,and the amount of tetramethyl decyne diol activated waste rubber powder is 30%.Finally,the mechanism of modified asphalt with activated rubber powder was analyzed by means of SEM,IR and DSC.The results show that the modification process includes physical modification and chemical modification,mainly physical modification;after activation,the rubber powder can fully swell and crack in asphalt,evenly distribute to form a uniform and continuous network structure,reduce the occurrence of agglomeration,and increase the compatibility;in addition,the thermal stability of the activated rubber powder modified asphalt is improved.