ATH/MMT阻燃剂对沥青混合料性能的影响

Influencing of compounding flame retardants with ATH/MMT on performance of asphalt mixture

为降低公路隧道沥青路面存在的火灾隐患,提升公路隧道沥青路面阻燃性能,采用金属氢氧化铝(ATH)和蒙脱土(MMT)复掺制备SBS改性阻燃沥青混合料,通过氧指数试验、直接燃烧试验、车辙试验、低温弯曲试验、冻融劈裂试验等方法,分析ATH/MMT复掺阻燃剂对沥青混合料的阻燃抑烟性能和路用性能影响。研究结果表明:ATH/MMT复掺阻燃剂可以将沥青材料的极限氧指数从21.2%提升至25%以上,使沥青材料燃烧级别达到难燃级别,基本可达到自熄材料的标准;掺加ATH/MMT复掺阻燃剂可以减少沥青混合料的燃烧持续时间,MMT和ATH的掺量(质量分数,下同)分别为3%、10%的复掺阻燃剂,其混合料的燃烧时间可以缩短近1倍;能降低沥青混合料的燃烧质量损失率,保证燃烧后的马歇尔试件结构的完整,并可提升沥青混合料的燃烧残留马歇尔稳定度,使沥青混合料燃烧后仍具有较好的力学性能;同时还可降低沥青混合料燃烧过程中挥发性有机化合物(VOC)的挥发量和峰值浓度,加快VOC产物的扩散速度;ATH/MMT阻燃剂可以显著改善沥青混合料的阻燃抑烟性能,且其可有效改善沥青混合料的高温稳定性和水稳定性,但是会在一定程度上降低混合料的低温抗裂性,虽仍能满足较高的路面性能要求,但其阻燃剂掺量不宜过大。

In order to solve the existing security issues of long tunnel’s asphalt pavement currently, and improve the flame retardant performance of highway tunnel asphalt pavement, metal aluminum hydroxide(ATH) and montmorillonite(MMT) was chosen as compounding flame retardants and then SBS modified asphalt mixture were prepared. Rutting test, low temperature blinding, Marshall submerge experiment, freeze-thaw indirect tension test were used to analysis the impact of ATH/MMT mixed flame retardant on asphalt mixture’s paving performance and flame retardant performance. The results show that ATH/MMT compounding flame retardant can improve the asphalt materials’ limiting oxygen index(LOI) by 21.2% to above 25%,and can increase asphalt material’s flammability rating from flammable to flame retardant, and can reach the standard of self-extinguishing materials. ATH/MMT compounding flame retardant can reduce the burning duration of asphalt mixture. The burning duration can be reduce by nearly double, when the dosage of MMT and ATH is 3% and 10%, mass fraction, same below. ATH/MMT compounding flame retardant can also reduce the loss rate of combustion quality of asphalt mixture, and improve the burning residual Marshall stability of the asphalt mixture. It also can ensure that the burned Marshall test piece is basically complete in structure and has good mechanical properties. At the same time, ATH/MMT compounding flame retardant reduce the volatile organic compounds(VOC) volatilization during the burning process of asphalt mixture, reduce the peak concentration during VOC volatilization and accelerate the diffusion rate of VOC products. These all explain that ATH/MMT flame retardant can significantly improve the flame retardant and smoke suppression performance of asphalt mixture, and can improve asphalt mixture’s high temperature stability and water stability, but reduce the low temperature crack resistance of the asphalt mixture to some extent. Although it can still meet high performance requirements, but the amount of flame retardant should not be too large. 8 tabs, 11 figs, 30 refs.