沥青路面就地热再生施工参数优化与效益评估

Optimization of construction parameters and benefit evaluation for hot in-place recycling of asphalt pavement

为优化就地热再生施工参数,降低再生施工费用,分析了压实度与碾压温度、再生剂用量、温拌剂用量之间的关系,建立了就地热再生沥青路面压实度的预测模型。构建了沥青路面就地热再生施工的费用模型,并据此形成了施工参数的多目标优化模型。选择施工时路表温度为38℃、60℃,通过遗传算法揭示了目标压实度与施工费用的内在关系,探明了最优施工参数,评估了参数效益。最后依托泉南高速石吉段养护工程对模型进行了验证,结果表明:再生沥青混合料压实度与碾压温度、再生剂用量、温拌剂用量正相关;最低施工费用随压实度的增大而增大,呈非线性关系,60℃路表温度较38℃路表温度可降低最低施工费用19.0%~22.5%;压实度每增加0.1%,38℃与60℃路表温度对应的最低施工费用分别平均升高7.62%、7.95%;提出了施工参数优化模型,将计算结果与实际施工结果进行对比,发现该模型可以有效计算不同压实度的最优施工参数,且优化施工参数可提高压实均匀性,较未优化参数可在路表温度为38℃、60℃时分别降低单位面积施工费用8.7%、24.2%。

In order to optimize the construction parameters of hot in-place recycling(HIR)and reduce recycling construction costs,the relationships between compaction degree and rolling temperature,the amount of rejuvenator,and warm mixing agent dosage were analyzed,and the prediction model for the compactness of HIR asphalt pavement was established.The cost model of construction of HIR was constructed,and a multi-objective optimization model of construction parameters was formed accordingly.On this basis,the internal relationship between target compactness and construction cost was revealed by genetic algorithm when the typical initial pavement temperature was 38℃ and 60℃,respectively.The optimal construction parameters were ascertained,and the parameter benefits were assessed.Finally,the model was verified based on the maintenance project of the Shiji Section of Quanzhou-Nanning Expressway.The result shows that the compactness of recycled asphalt mixture is positively correlated with the rolling temperature,the amount of rejuvenator,and the amount of warm mixing agent.The minimum construction cost increases with the increase of compaction degree in a nonlinear relationship,and the minimum construction cost can be reduced by 19.0%—22.5%at 60℃ compared with 38℃.The minimum construction cost corresponding to the pavement temperature of 38℃ and 60℃ increases by 7.62%and 7.95%as the compactness increases by 0.1%on average.Compared with the actual construction results,it is found that the optimization model can effectively calculate the optimal construction parameters of different compaction degrees.Moreover,the optimized construction parameters can improve the compaction uniformity,and the construction cost per unit area can be reduced by 8.7%and 24.2%at the 38℃ and 60℃ road surface temperature,respectively,compared with that of the non-optimized parameters.