Use of Seismic Pavement Analyzer To Monitor Degradation of Flexible Pavements Under Texas Mobile Load Simulator

The seismic pavement analyzer (SPA) combines several wave propagation techniques in a single unit and can rapidly perform nondestructive tests to determine the condition of pavement. The modulus of each layer of pavements is a major parameter estimated with the SPA. The SPA and its portable version, the PSPA, have been used with the field operation of the Texas mobile load simulator (TxMLS) to detect the variation in properties of different layers with the number of axle loads applied to the pavement. The theoretical background related to the methods used with the SPA and PSPA is discussed. Results from tests of the SPA and PSPA at a TxMLS testing site are presented. The variation in moduli as a function of the deterioration of pavement is detected. The results have been compared with those obtained from direct seismic measurements made on the top of each layer to evaluate the accuracy of the devices. In general, a good agreement was achieved.