| As a viscoelastic material, the rheology of asphalt is greatly influenced by temperature and time. It easily become brittle at low temperature and soft at high temperature, the application temperature range is narrow. Polymer can greatly enhanced the properties of asphalt, but the dispersion, stability and high cost inhibit its applications. Among those polymers, SB (SBR, SBS) type polymer was widely used. The state of S and B, S/B ratio, and linkage of chain influence the dispersion and properties of modified asphalt. In this paper, good dispersion and hot storage stability SBS modified asphalt was prepared by substrate method. The substrate composed the components which have good interactions with S or B block of SBS. In order to enhance the interactions between SBR molecular in the asphalt to approach the properties of SBS modification effect, crosslinking and carbon black reinforcement methods were used. This work is very meaningful for making easy dispersion, good modification effect and lower price PMA. The interactions between asphalt and SBS in the substrate was analyzed by DMTA, optical microscopy and basic property measurement. It found that the asphalt enter into domain of PS and PB respectively. The dispersion effect increased with the amount of asphalt in the substrate. Effect of different structure SBS and different kind of asphalt on properties of modified asphalt was studied. The result showed that SBS which has more PB domain was more compatible with asphalt, and Maoming Asphalt has better modification results than Dagang Asphalt. Morphology study showed that with the increase of SBS amount, there is a phase change between 5~7% amount. The temperature susceptibility of dynamic elastic modulus was reduced as increase of SBS amount, and loss tangent leveled at high temperature range(around 50℃). TFOT aging indicate that both the asphalt and modified asphalt changed in the same way, the elastic modulus increased, loss tangent decreased. In order to further increase the dispersion of SBS into asphalt. Low molecular cycloalkane oil and aromatic oil, high molecular T resin and G resin which are compatible with SBS were selected to decrease the interactions of SBS molecular, and then enhance the dispersion of SBS. Interactions among oils, resins, aspalt and SBS were analyzed by DMTA and basic properties test. The modification effects were also characterized through these ways. T resin and G resin can reduce the SBS particle to 2.5 micrometer. cycloalkane oil and aromatic oil, T and G resin have different effects on the elastic modulus at low temperature range and high temperature range. T and G resin were better to enhance the softening point than cycloalkane oil and aromatic oil. They all had good effects on hot storage stability, and T resin is the best. They also lowered the viscosity at 135℃, which is good for application. Structure and properties of SBS combined with carbon black modified asphalt prepared by substrate method were studied. The results showed that carbon black and SBS finely dispersed into asphalt together, carbon black can enhance the high temperature properties of SBS modified asphalt with no decrease ductility at low temperature. And the hot storage stability was improved with carbon black. Effects of crosslinking and carbon black on structure and properties of SBR modified asphalt were studied. Agglomeration was formed after SBR modified asphalt crosslinked by conventional sulfur vulcanization system in static state, while small viscosity modified asphalt was acquired in dynamic state. Crosslinking can greatly enhance the properties of toughness, elastic recovery and stress keeping ability. However, carbon black has little reinforcement in this system. At last, part of this research put into pavement application in heavy road. The high performance modified asphalt was produce by substrate method in stead of grinding technology. It showed good result after 18 months application. |
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