改性再生沥青混合料配合比设计及性能验证

Mix Design and Performance Verification of Modified Recycled Asphalt Mixture

废旧沥青混合料因其服役层位和服役年限的不同常常存在空间与时间上的性质多变性,导致再生沥青混合料的配合比设计变得复杂。废旧沥青混合料的评价方法与标准是再生的基础,再生沥青混合料的使用性能是判别再生技术成功与否的关键,而合理的设计方法的制定是提高再生沥青混合料路用性能的关键,路用性能的评价方法以及配合比的设计直接影响到再生效果及其推广应用。针对该问题,首先分析了改性再生沥青混合料的总体设计原则,测试了原材料的基本性能,选取不同旧料掺量分别进行了配合比设计,然后通过改进的组合式车载试验测试了改性再生沥青混合料的高温性能,最后通过对其水敏感性和低温性能进行的试验验证等对改性再生沥青混合料的使用性能进行了全面的评价。研究表明:随着回收沥青混合料添加量的增大,单层车辙试验和改进的组合式车辙试验均呈现出动稳定度增大的趋势,说明改性再生沥青混合料的高温抗变形能力增强。改性再生沥青混合料的冻融劈裂强度比随着回收旧料的增加逐渐降低,说明回收旧料会破坏改性沥青混合料的水稳定性。20%和25%旧料用量的改性再生沥青混合料均具有较好的抗低温性能,但20%用量有着更为优异的性能。再生剂可以明显改善改性再生沥青混合料的水稳定性。

Due to the difference Of service thickness and time of waste asphalt mixture,the property usually changes a lot in space and time.This could make the mix design of asphalt mixture containing recycled asphalt pavement (RAP)more complicated.The evaluation method and crite on for waste asphalt mixture is the foundation of regeneration,and the performance of recycled asphalt mixture is the key to the success of judging regeneration technology,the reasonable design method is the key to improve the road performance of recycled asphalt mixture,and the evaluation method of road performance and the mix design directly affect the regeneration effect and its popularization and application.In view of these,first,the general de.sign principle of modified recycled asphalt mixture is analyzed,the basic properties of raw materials are tested, and several RAP contents are selected for mix design.Then,the modified combined vehicle rutting test is conducted to evaluate the high-temperature performance of the modified recycled asphalt mixture.At last,the performance of the modified recycled asphalt mixture is evaluated comprehensively through the experimental verification of its moisture sensitivity and low temperature performance.The result shows that (1)with the increase of RAP content,both monolayer rutting test and modified combined rutting test show increasing of dynamic stability,indicating that mgh-temperature aelormatlon resistance ot the moaltleci recyciecl aspnait mixture is improved;(2)meanwhile,its freeze-thaw splitting strength ratio is reduced,which demonstrates that the moisture sensitivity will be degraded by the RAP;(3)the modified recycled asphah mixtures with both 20%and 25%RAP have good low-temperature resistance performance,and that of the mixtures with 20%RAP is better;(4)the recycling agent can significantly improve the moisture sensitivity of the modified recycled asphah mixture.