Mechanical response of asphalt pavement under driving conditions by fiber bragg grating optical sensing technology
Pan Qinxue1,3 Zheng Jianlong1,3 Yang Bo2,3 Liu Hongfu1,3
1. School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha Hunan 410004, China
2. Chongqing Jiaotong University, Chongqing 400074, China
3. National Engineering Laboratory of Highway Maintenance Technology, Changsha 410114, China
Abstract：To reveal real mechanical response law in semi-rigid base asphalt pavement and provide references for the design of durable pavement, the strains of asphalt pavement under realistic cases of vehicle speeds and axle loads were tested by fiber bragg grating optical sensors. Test results show that the most unfavorable load position on asphalt surface layer is the center of wheel load where the largest tensile strain in this layer can be observed| viscoelasticity is manifested obviously in the duration curve of static strain, conforming with the Bugers model by a fitting coefficient of 0.98| An obvious compression-tension-compression waveform is shown in the dynamic strain curve. The most unfavorable load position of cement stabilized macadam base layer is the gap center of two wheels where the largest tensile strain in this layer can be observed| The elastic behavior is manifested in the duration curve of static strain and the tension waveform with a peak is mainly presented in the dynamic strain curve. Theoretical function models were established for the strain at the bottom of pavement layers changing with axle load and vehicle speed, and the law for the ratio of compressive peak to tensile peak of the longitudinal dynamic strain changing with vehicle speed was obtained. The research results can be referred in the design of durable asphalt pavement and fatigue tests in laboratory.
