不同级配类型薄层混合料中长期性能跟踪观测与耐久性分析

Tracking Observation and Durability Analysis on Long-term Performance of Thin-layer Mixtures of Different Gradation Types

摘要:

针对不同结构类型薄层混合料耐久性参差不齐的问题，选取骨架密实型bc-1、悬浮密实型bc-2以及骨架空隙型bc-3，开展室内性能评价和试验段跟踪观测。首先，通过车辙试验和小梁低温抗裂试验分别对3种混合料的高、低温性能进行评价；其次，采用冻融劈裂和四点弯曲疲劳试验进行耐久性评价；最后，对3种混合料近五年的路面技术状况指标数据进行分析，以评价其实际路用效果。结果表明：bc-1的动稳定度为9 041次/mm，高温稳定性较bc-2和bc-3分别提高15.25%、12.16%；bc-1低温弯曲应变为2 948με，较bc-2和bc-3分别提高了9.92%、15.88%；3种薄层材料的疲劳寿命试验结果为bc-1＞bc-3＞bc-2；从路面技术状况指标来看，3种混合料在应用五年后均为优等，路况指标的年均衰减率分别为0.42%、1.10%、1.16%。

Abstract:

In response to the issue of varying durability of thin-layer mixtures of different structural types, the skeleton compact type bc-1, the suspended compact type bc-2 and the skeleton void type bc-3 are selected to carry out the indoor performance evaluation and tracking observation of the test section. Firstly, the high and low temperature performances of the three mixtures are evaluated through rutting tests and small-beam low-temperature crack resistance tests, respectively. Secondly, the freeze-thaw splitting and four-point bending fatigue tests are used to assess the durability. Finally, the technical condition index data of the pavement of three mixtures in the past five years are analyzed to evaluate their actual pavement effects. The results show that the dynamic stability of bc-1 is 9041 times/mm, and the high temperature stability is improved by 15.25% and 12.16% compared to bc-2 and bc-3, respectively. The low temperature bending strain of bc-1 is 2 948, improved by 9.92% and 15.88% compared to bc-2 and bc-3, respectively. The fatigue life test results of the three thin-layer materials are bc-1 > bc-3 > bc-2. From the perspective of technical condition indicators of pavement, all three mixtures are rated as excellent after five years of application, and the annual average attenuation rates of road condition indexes are 0.42%, 1.10%, and 1.16%, respectively.