Study on influencing factors of synergistic deformation between built-in strain sensor and asphalt mixture

Strain sensor play an irreplaceable role in monitoring the structural response of asphalt pavements. The effective synergistic deformation of sensor and pavement structure is a key foundation to ensure accurate sensor measurements. The differences between sensor and pavement material lead to complex synergistic deformation between them. Therefore, this study intends to investigate the factors that influence the synergistic deformation of the sensor and the asphalt mixture under different operating conditions. The aim is to reveal the working mechanism of sensor and asphalt mixture synergistic deformation and improve the application value of the measured sensor data. Firstly, by using digital image correlation (DIC) technology and direct tensile beam test, a new test method was designed for the synergistic deformation evaluation of sensor and asphalt mixture. Then, the strain response test was carried out on the asphalt mixture specimens with built-in strain sensor under different stress modes such as multi-stress tension axial compression, tension-compression alternation and sinusoidal cycle. Finally, the numerical value monitored by DIC technology was used as strain reference value to calculate the measurement error of the sensor, and then to analyze the evolution of the synergistic deformation of strain sensor and asphalt mixture. The results show that loading mode and magnitude, temperature and sensor position deviation are the key factors that affect the deformation compatibility between the sensor and the asphalt mixture. The loading frequency has less influence on deformation compatibility. The average absolute error E̅a of the sensor measurement increases as the load increases. The measured strain response shows the opposite measurement deviations under multi-stress tension and axial compression. The strain response accuracy of the sensor drops sharply at high temperatures of 30 °C∼50 °C. At this time, the average absolute error of measurement E̅a and the relative error E̅r can be increased by 3.49–11.79 times and 2.01–2.91 times, respectively. The working environment temperature of the high modulus strain sensor in collaboration with the asphalt pavement should be below 30 °C. Deflection of the position of the embedded sensor will cause the measured value to be smaller. When the deflection angle is 12°, the measurement error of the sensor can be increased by 2.43–5.46 times under the same load. The results provide an important reference for solving the technical problems of incompatibility between built-in strain sensor and asphalt pavement, and promoting the sensor technology to deeply enable traditional asphalt pavement structures.