The modulus of asphalt concrete determined from laboratory complex modulus tests are compared with the modulus from in situ nondestructive tests using the portable seismic pavement analyzer (PSPA). The PSPA consists of two receivers and a source packaged into a hand-portable system, capable of performing high frequency seismic tests. The laboratory complex modulus tests were conducted on laboratory compacted specimens prepared from loose mixtures obtained at the time of construction. These tests were performed at a range of frequencies and temperatures. Multiple PSPA tests were conducted in situ at two different pavement sites. Measurements were conducted in the direction of traffic as well as perpendicular to traffic direction. In general, similar grand average seismic modulus values were observed at different locations. No significant difference was observed between seismic modulus values obtained in the longitudinal and transverse directions. Neither did the modulus vary significantly from one location to the other. Pavement surface temperatures were also recorded during PSPA tests. Elastic moduli obtained from laboratory tests and in situ PSPA tests were compared at the same temperature and loading frequency. Comparisons indicate that the laboratory modulus is approximately 30 per cent higher than the modulus from PSPA. (a) For the covering entry of this conference, please see ITRD abstract no. E217099.
Samenvatting