竹纤维预处理对沥青胶浆流变和开裂特性的影响

Influence of bamboo fiber pre-treatment on rheological and cracking properties of asphalt mortar

为解决竹纤维在沥青及混合料使用过程中分散不均、易结团等问题,对竹纤维采用硅烷偶联剂、碱处理、热处理进行预处理,通过对预处理的3种竹纤维沥青胶浆进行温度扫描和频率扫描等流变性能测试,分析纤维预处理对竹纤维沥青胶浆的复数剪切模量和相位角的影响,计算G-R常数、R参数并构建黑色空间图,对沥青胶浆的开裂风险进行评估。结果表明:经硅烷偶联剂处理的竹纤维沥青胶浆的改善流变性能最优,复数剪切模量较基质沥青提升了140%,相位角减少了3.6%;热处理方式次之,复数剪切模量提升了49.1%,相位角减少了2.4%,且开裂风险小,但是经硅烷偶联剂处理的竹纤维沥青胶浆其G-R常数达到了306.53,有较大的开裂风险。综合3种预处理方式对竹纤维沥青胶浆流变性能和开裂性能的影响,在沥青中添加经过热处理的竹纤维能够更好地改善沥青的流变性能并规避较大的开裂风险。

To solve the problems of uneven dispersion and easy agglomeration of bamboo fibers in the use of asphalt and mixtures,bamboo fibers were pre-treated with a silane coupling agent,alkali treatment,and heat treatment.Rheological properties such as temperature and frequency scanning were tested on the three types of bamboo fiber asphalt mortars that had been pretreated,and the effect of fiber pretreatment on the complex shear modulus and phase angle of bamboo fiber asphalt mortar was analyzed.Its G-R constant and phase angle were calculated to evaluate the cracking risk of asphalt mortar by constructing a black space map with R parameters.The results show that the bamboo fiber asphalt mastic treated with silane coupling agent has the best improved rheological properties,with the complex shear modulus increased by 140%and the phase angle decreased by 3.6%compared with that of matrix asphalt;the heat treatment method is the second best,with the complex shear modulus increased by 49.1%,the phase angle decreased by 2.4%,and the risk of cracking is small;however,the G-R constant of bamboo fiber asphalt mastic treated with silane coupling agent reaches 306.53,which has a greater risk of cracking.Taking into account the effects of three pre-treatment methods on the rheological and cracking properties of bamboo fiber asphalt mortar,it is found that adding bamboo fibers to asphalt through heat treatment can better improve the rheological properties of asphalt and avoid significant cracking risks.