路用生物沥青及混合料性能研究

选择以木屑为原材料生产出的生物质重油,将其加入50号基质沥青,并掺入外掺剂,制备不同生物质重油掺量的生物沥青,对RTFO老化前后生物沥青样品的针入度、软化点、延度(10℃)、质量变化进行分析,通过结合料试验优选出符合规范要求的生物沥青结合料,然后制备生物沥青混合料并对其进行车辙试验、冻融劈裂试验、小梁弯曲试验和低温黏结性试验等,考察生物质重油掺量变化对生物沥青混合料路用性能的影响。结果表明:随着生物质重油掺量的增加,生物沥青的针入度增加、软化点降低、延度增加,高温性能受到一定程度的影响,但低温抗裂性能得到提高;与50号基质沥青混合料相比,生物质重油掺量(w)为10%的生物沥青混合料的最大弯拉应变比提高20.90%,低温性能有所提高,冻融循环后的劈裂抗拉强度提高12.56%,水稳定性有所提高,黏附性能大幅提高,高温性能有所降低;生物质重油掺量(w)为10%的生物沥青混合料的各项指标均满足《公路工程沥青及沥青混合料试验规程》(JTG E20—2011)的要求。

PROPERTIES OF ROAD BIO-BINDER AND ITS MIXTURE

Bio-oil was prepared using wood powder，and then mixed with 50＃asphalt product and additives to obtain bio-binders with different bio-oil/asphalt ratios.The penetration，softening point，ductility（10 ℃）and other properties of the samples before and after RTFO aging were investigated.The bio-binder meeting the requirements of the specification was selected followed by preparation of bio-binder mixture.The rutting test，freeze-thaw splitting test，small beam bending test，low temperature bonding test were conducted for the mixture to investigate the effect of the amount of bio-oil blended into asphalt on the performance of the road bio-binder.The results showed that with increasing the bio-oil amount added，the penetration and ductility along with the low temperature crack resistance are improved；the softening point is reduced，indicating the negative effect for the high temperature performance.Compared with that of 50＃asphalt mixture，the maximum bending strain ratio of the bio-binder mixture with 10%w bio-oil is improved by 20.90%，the splitting tensile strain of freeze-thaw cycle samples increases by 12.56%，the water stability and low temperature performance are all improved； the bond ability is improved greatly while the high temperature performance is decreased in some extent.The properties of bio-binder mixture satisfies with the requirements of specification（JTG E20—2011）when the bio-oil content is 10%.