耦合老化作用下混合料中SBS改性沥青的老化行为研究

Aging Behavior of SBS Modified Asphalt Mixture under Coupled Aging

通过动态剪切流变试验(DSR)和弯曲流变试验(BBR),测试了老化前后苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改性沥青的复数模量G*、相位角δ、劲度模量S和蠕变速率m,对比研究了热、紫外光、荷载3种环境因素两两耦合老化对SBS改性沥青性能的影响,并用红外光谱(FTIR)分析了经不同耦合老化方式作用后SBS改性沥青的官能团变化情况.结果表明:光热耦合作用对SBS改性沥青老化程度的影响相对严重,其余2种耦合老化下沥青老化程度较小;3种耦合方式对SBS改性沥青官能团的影响不同,光热耦合老化后的沥青主要表现为丁二烯键的断裂和羰基增加,热荷耦合老化主要使沥青中羰基增加,光荷耦合老化主要使沥青中部分丁二烯基的降解和羰基微量增加.

The rheological indexes of complex modulus G~*, phase angle delta, stiffness modulus S and creep slope m were measured by dynamic shear rheological test(DSR) and bending rheological test(BBR). The effects of coupled aging of heat, ultraviolet light and load on the performance of styrene-butadiene-styrene block copolymer(SBS) modified asphalt were investigated. Infrared spectroscopy(FTIR) was used to analyze the changes of functional groups of SBS modified asphalt after coupled aging. The results show that the aging degree of SBS modified asphalt is relatively serious due to the photothermal coupling effect, while the other two kinds of coupled aging make the aging degree of asphalt smaller. In addition, the effects of three coupling modes on SBS modified asphalt functional groups are different. The photothermal aging of asphalt mainly manifests in the breakage of butadiene bond and the increase of carbonyl group;the thermal-charge coupling aging mainly increases the carbonyl group in asphalt;the photothermal coupled aging mainly causes the breakage of butadiene bond and the increase of carbonyl group in asphalt.