| Current studies at h ome and abroad show that bio-asphalt has certain advantages as a new road material,but it also has problems in high temperature and anti-aging properties.In order to enable bio-asphalt to be applied to actual road engineering early and effectively,research and improvement of various disadvantages of bio-asphalt to meet the required road performance requirements has become the focus of current research on bio-asphalt.Two types of polymers were studied: Poly-Phosphoric Acid(PPA)and Amorphous poly alpha olefin(APAO)were separately mixed with bitumen and bio-oil obtained by fast pyrolysis.The high temperature properties,aging properties,fatigue properties and thermal storage stability of different PPA dosage(0%,0.5%,1%,1.5%),different APAO dosage(0%,2%,4%,6%)and different bio-oil dosage(0%,5%,10%,15%)were carried out through experiments.The modification mechanism of polymer composite bio-asphalt is also studied.The suitable type and dosage of polymer were recommended,and the high and low temperature performance and water stability of the mixture were verified in this study.The high temperature performance of PPA composite bio-asphalt and APAO composite bio-asphalt were studied by penetration,softening point,rutting factor,and non recoverable creep compliance.The results showed that both PPA and APAO reduced the penetration and non recoverable creep compliance,increased the softening point and rutting factor,and the bio-oil was the opposite.The result indicated that PPA and APAO could improve the high temperature performance of bio-asphalt and bio-oil reduced the high temperature performance of bio-asphalt.By measuring the softening point increment,residual penetration ratio and failure temperature of two kinds of polymer composite bio-asphalt after short-term aging,it is found that the anti aging performance of bio asphalt decreases with the increase of bio-oil,while PPA and APAO polymers can improve the aging resistance of bio-aspahlt,and the effect is different when polymer content change.The fatigue test of asphalt showed that PPA and APAO could improve the aging performance of bio-asphalt.The study also found that PPA and APAO could not improve the thermal storage stability of the bio-asphalt by the softening point difference and the segregation rate index.The modification and aging mechanism of two kinds of polymer composite bitumen were studied by FTIR and TG.The results showed that the chemical reaction between PPA and bio asphalt had a chemical reaction,and the material composition of the aging process was basically unchanged,while APAO did not react with the biological-asphalt,but it was only physical phase dissolving.Both PPA and APAO can reduce the heat loss of bio-asphalt,indicating that PPA and APAO can inhibit the aging of bio-asphalt.The cost of two kinds of polymer composite bio-asphalt was analyzed.The best polymer type is PPA,and the best dosage is 1%.The performance of 1.0%PPA composite bio-asphalt mixture was verified.The results showed that PPA could improve the rutting resistance of the asphalt mixture at high temperature,but had little effect on the low temperature and water stability. |
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