Study On Preparation And Key Properties Of Modified Asphalt Binder Using In Chip Seal

The objective of this paper is to improve the compatibility,thermo-rheological behavior of SBR modified asphalt through chemical reaction with PPA.The PPA-SBR composite modifier with various PPA contents and asphalt with different compositions were proposed to prepare high-performance PPA/SBR composite modified asphalt.The effects of PPA and asphalt composition on conventional performance,toughness and tenacity,viscoelastic behavior,creep and recovery behavior,cracking resistance,compatibility and morphology of PPA/SBR modified asphalt were characterized by conventional test,adhesion test,temperature sweep test,multiple stress creep recovery(MSCR)test,bending beam rheometer(BBR)test,Cole-Cole plots and fluorescence microscopy,respectively.Meanwhile,the aggregation retention of chip seal with various asphalt binders were investigated by vialit test,the correlation between the performance of asphalt binder and the aggregation retention of chip seal was studied by means of linear correlation analysis and grey relational analysis.It was demonstrated that,SBR remarkably increased the ductility of asphalt at 5 ?,while slightly increased the softening point,toughness and tenacity of base asphalt,implying the limited effect of SBR on high temperature property of asphalt.With the addition of PPA,the softening point,toughness and tenacity of PPA/SBR modified asphalt increased markedly and the improvement was evident when the PPA concentration was not less than 1.0 wt%.The results indicate that PPA can remarkably enhance the high temperature and adhesion ability of SBR modified asphalt.From the thermo-rheological point of view,PPA dramatically enhanced the adhesion ability,high temperature elasticity and anti-rutting ability of SBR modified asphalt through deflocculation effect.The resistance against low temperature cracking of PPA/SBR modified asphalt underwent a degradation after first improvement as PPA increased.PPA also improved the compatibility between SBR and asphalt and decreased the dispersed polymer phase size,thus a more desirable microstructure was formed.Furthermore,relatively high asphaltene content of base asphalt was beneficial to achieve desired rheological properties of PPA/SBR modified asphalt.As a consequence,chemical reaction with PPA is an effective way to comprehensively improve the compatibility and thermo-rheological behavior of SBR modified asphalt.From the vialit test and correlation analysis,SBR improved the adhesion of asphalt at low temperature,but stone exfoliation phenomenon is still severe.The addition of PPA has positive effect on the adhesion of SBR modified asphalt.As PPA increases,the aggregation retention rate of PPA/SBR modified asphalt binder increased remarkably.The toughness and tenacity and high temperature properties showed good relation with the aggregation retention of chip seal.Lower penetration,higher non-recoverable creep compliance,softening point,viscosity and toughness is beneficial for obtaining desired aggregation retention.While low temperature properties of asphalt binder showed bad relation with the aggregation retention of chip seal.