Study On The Preparation Of Organic Rectorites Suitable For The Formation Of Asphalt And On The Properties Of Their Modified Asphalts

The asphalt is an important road building material.But the base asphalt is apt to soften at high temperature and crack at low temperature,which is difficult to meet the demand of current traffic,so the base asphalt should be modified to improve its performance.Now the most commonly used modifiers are polymer modifiers.However,they usually have bad compatibilities with base asphalt,and the polymer modified asphalt(PMA)is an unstable system,owning poor thermal storage stability.Recently,rectorite(REC)/asphalt nanocomposites have been developed quickly,showing a wide range of application prospect because of their good properties,such as good high temperature stability,storage stability and aging resistance.This paper refers to relevant literatures,selecting dodecyl trimethyl ammonium chloride(1231),dodecyl dimethyl benzyl ammonium chloride(1227),octadecyl trimethyl ammonium chloride(1831)to modify the sodium rectorite(Na-REC),in order to prepare three kinds of organic rectorite(OREC1,OREC2 and OREC3).The optimum stirring temperature between organic reagents and Na-REC was determined by XRD,FTIR,SEM and lipophilic test.Based on the analysis of ORECs prepared by different organic chemical process conditions,the optimum organic reaction temperature was determined,then used as the optimum temperature to prepare ORECs.Three kinds of ORECs prepared at the optimum reaction temperature were used to modify base asphalt respectively,in order to obtain three kinds of OREC modified asphalts owning the optimum performance.Using penetration,softening point and ductility test,viscosity test,segregation test,RTFO test and DSR test,effects of the kind and content of the OREC on the routine physical properties,storage stability and construction temperature,aging resistance and the rheological properties of asphalt were studied.The result shows,the addition of the REC(Na-REC,OREC1,OREC2 or OREC3)has an improvement in high temperature stability,temperature stability,storage stability and aging resistance of asphalt,and OREC3 has the best improvement.Moreover,the optimum content of the Na-REC may be more than 5wt%,while the optimum contents of the OREC1,OREC2 and OREC3 are all 3%.The effect of modification mechanism and microstructure of asphalt on the kind of RECs were studied by XRD,DSC,TG,fluorescence microscope and AFM test.The result shows,The OREC3 modified asphalt forms exfoliation structure,and other kinds of modified asphalt all form intercalation structure.The OREC(OREC1,OREC2 or OREC3)has the better compatibility with asphalt than the Na-REC.