改性乳化沥青冷拌碎石封层高温性能研究

Evaluation of High Temperature Performace of Modified Emulsified Asphalt Cold-Mixed Chip Seal

选用SBR胶乳对基质乳化沥青进行改性,通过多重应力蠕变恢复(MSCR)试验,研究了SBR胶乳掺量对乳化沥青残留物高温流变性能的影响;利用60℃及25℃的负荷轮试验,分析了SBR胶乳用量及乳化沥青用量对冷拌碎石封层构造深度变化率的影响;并对不可恢复蠕变柔量Jnr及构造深度变化率进行了相关性分析.结果表明:SBR胶乳掺量的增加,使乳化沥青残留物的不可恢复蠕变柔量降低,使蠕变恢复率增大,且降低了乳化沥青的温度敏感性;此外,随着SBR胶乳用量的提高,构造深度变化率逐渐降低,尤其是SBR胶乳掺量为6%时,构造深度变化率小于30%,可以显著改善冷拌碎石封层的高温稳定性;乳化沥青用量的提高,使构造深度变化率逐渐增大;与乳化沥青相比,SBR掺量的增加对构造深度的变化影响更加显著;推荐冷拌碎石封层乳化沥青用量为14%、SBR胶乳用量为6%.

SBR latex was used to modify the neat emulsified asphalt, and the multiple stress creep recovery(MSCR) test was employed to study the effect of SBR latex contents on the high temperature rheological properties of the emulsified asphalt residues. The loaded wheel test at 60℃and 25℃ was used to analyze the effects of the SBR latex content and emulsified asphalt content on the change of structural depth of the cold mixed chip seal. Correlation analysis was carried out on the non-recoverable creep compliance(Jnr) and the change of structural depth. The results show that the increase in the SBR latex content reduces the non-recoverable creep compliance of the emulsified asphalt residue, increases the percent recovery, and reduces the temperature sensitivity of the emulsified asphalt. In addition, the increase in SBR latex content also decreases the change of the structural depth gradually. Especially the change of structural depth is less than 30% when the amount of SBR latex is 6%. The increase in the amount of the emulsified asphalt can improve the change of structural depth gradually. Compared with the emulsified asphalt, the increase in SBR content has a great significant influence on the variation of the structure depth. It is recommended that the consumption of the emulsified asphalt for the cold-mixed gravel seal layer is 14% and that of SBR latex is 6%.