Multiple Impact Surface Waves (MISW)—Improved Accuracy for Pavement System Thicknesses and Moduli vs. Spectral Analysis of Surface Waves (SASW)

Abstract

This paper includes a comparison and discussion of the surface wave test results, as well as backgrounds of the MISW and SASW methods. The older Spectral Analysis of Surface Waves (SASW) and newer Multiple Impact of Surface Waves (MISW) test methods were performed at the same forensic investigation project on a concrete pavement underlain by a cement treated base, for comparison purposes. The older SASW and newer MISW methods differ only slightly from one another in the equipment used and method of data collection, but involve significantly different data processing. The SASW method greatly overestimates Young’s moduli of less stiff base materials immediately below the much stiffer asphalt or concrete pavement layer. In contrast the MISW method is able to estimate the properties of these less stiff base materials immediately below the much stiffer pavement layers by accounting for higher order wave modes during the inversion process.