硫酸钙晶须/SBS复合改性沥青性能研究

Study on performance of calcium sulfate whisker/SBS composite modified asphalt

为分析硫酸钙晶须(Calcium Sulfate Whisker,CSW)与苯乙烯-丁二烯-苯乙烯嵌段共聚物(Styrene⁃buta⁃diene⁃styrene Block Copolymer,SBS)复合改性沥青的常规物理性能和高低温流变性,采用沥青三大指标、动态剪切流变(Dynamic Shear Rheology,DSR)和弯曲梁流变(Bending Beam Rheology,BBR)试验,研究了不同CSW掺量对复合改性沥青基本性能和高低温流变性能的影响,并设置CSW改性沥青为对照组。研究结果表明:随着CSW掺量增加,CSW改性沥青的温度敏感性和高温性能提高而低温性能下降;掺量10%CSW改性沥青的针入度指数PI为-0.83,车辙因子G^(*)/sinδ为27.70 kPa,蠕变劲度模量S为368 MPa,蠕变速率m为0.271;CSW/SBS复合改性沥青的温度敏感性和高低温流变性能较CSW改性沥青均明显提高,其中,PI、G^(*)/sinδ和m分别提升了147.0%、82.3%和7.4%,S降低了19.5%。同时,掺量8%CSW/SBS复合改性沥青的高温、低温PG等级分别为82℃和-18℃,比CSW改性沥青的高低温等级分别升了两级和一级。因此,CSW可明显改善沥青的高温性能和温度敏感性,但对沥青低温性能稍微不利,若将其与SBS进行复合改性,可保证沥青的低温性能。

In order to investigate the physical and high/lowtemperature rheological properties of asphalt modified with calcium sulfate whisker(CSW)and styrenebutadienestyrene block copolymer(SBS),three major indicators,dynamic shear rheology(DSR),and bending beam rheology(BBR)tests were conducted to investigate the effects of different CSW contents on this composite modified asphalt.Meanwhile,CSW-modified asphalt was set as a control group.The results showed that with the increase of CSW content,the temperature sensitivity and hightemperature performance of CSW-modified asphalt were increased while the lowtemperature performance decreased.The penetration index(PI),rutting factor G^(*)/sinδ,creep modulus S,and creep rate m of the CSW-modified asphalt with 10%CSW were-0.83,27.70 kPa,368 MPa,and 0.271,respectively.The temperature sensitivity and high/lowtemperature rheological properties of CSW/SBS modified asphalt were significantly improved compared with those of CSW-modified asphalt.PI,G^(*)/sinδ,and m were improved by 147.0%,82.3%,and 7.4%,respectively.But S was decreased by 19.5%.At the same time,the hightemperature and lowtemperature PG of the CSW/SBS modified asphalt with 8%CSW were 82℃and-18℃,respectively,which were elevated by two and one levels,respectively.Therefore,the hightemperature performance and temperature sensitivity of asphalt binders could be significantly improved by the addition of CSW,but the lowtemperature performance was slightly decreased.The lowtemperature performance of asphalt binders could be maintained while CSW was composited with SBS.