沥青路面结构层间接触状况诊断新方法

A novel technique for asphalt pavement interlayer contact condition diagnosis

沥青路面结构层间接触状况的诊断对路面养护、罩面等维修决策具有重要意义,但目前尚缺乏定量的方法对沥青层和基层间的黏结状况进行准确判定.本文针对沥青层-基层黏结问题,依托京哈线实际工程数据和案例,基于结构行为方程、桥渡原理以及力学仿真等理论方法和技术模型,建立了沥青路面结构层间接触状况的无损诊断方法和诊断标准,并进行了案例分析.

Asphalt pavement is a multi-layer continuous structure with an interlayer bonding condition that can greatly influence its bearing capacity and must be monitored over the whole service length.Hence,proper maintenance and rehabilitation measures are taken and better feedback can be made for the design.Nevertheless,asphalt pavement interlayer bonding condition plays a hidden role and is difficult to quantify unless applying damage discovery techniques like drilling core process.The original structure is destroyed by the damage detection approaches,the results also suffer from low coverage rate and high dispersion,therefore,actual engineering demands are not satisfied.Here,some recent methods are briefly presented based on asphalt pavement interlayer bonding condition non-destructive diagnosis and their restrictions are discussed.Moreover,a new technique is provided with the merits of utilizing only mechanical simulation and overall superficial distresses condition evaluation index with high accuracy.This simulation procedure adopts bridging principles to build a connection between asphalt pavement superficial distresses and asphalt pavement micro mechanic parameters.It uses a structure behavior equation capable of identifying four typical deterioration modes and has specific physical meaning parameters to predict asphalt pavement overall superficial distresses.The established model allows the asphalt pavement interlayer bonding acting as a hypothetical input variable.The known input variables include easily obtainable design parameters of the asphalt pavement structure,historical superficial distresses,surface deflection,traffic load,and environmental factors,however,the output is the predicted asphalt pavement overall superficial distresses condition.The asphalt pavement interlayer bonding condition is defined by contrasting the theoretical asphalt pavement overall superficial distresses conditions between its complete bonding condition and discontinuous bonding condition to a certain degree.Examples in parts of the Jingha highway show that great discrepancies exist between theoretical asphalt pavement overall superficial distress in the condition of complete interlayer bonding and actual asphalt pavement overall superficial distress.The actual asphalt pavement sections in overall superficial conditions are deteriorated much faster than normal ones.By setting the asphalt pavement interlayer bonding continuations as 75%and 90%for K315–K316 section and K316–K317 section,respectively,the revised and predicted overall superficial distresses of the theoretical asphalt pavement are consistent with the real ones.The hypothetical values are then chosen as the diagnosed quantitative asphalt pavement interlayer bonding continuations and are proven to be correct through drilling core sample results.The analyses in other sections show that middle traffic volume asphalt pavement structure is quite weak when its interlayer bonding continuation is 70%,and under this value,its bearing capacity is almost equivalent to the situation when its interlayer bonding continuation is 0%;when its interlayer bonding continuation is 85%or more,its bearing capacity is almost equivalent to the situation where its interlayer bonding continuation is 100%.This proposed non-destructive diagnosis method for asphalt pavement interlayer bonding condition is effective and shows good application prospects in road engineering.