| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 93 === The study is aimed to evaluate the feasibility of using the impact-echo method to replace the conventional destructive core test for estimating the thickness of the plate-like structure in asphalt concrete pavement. Since promising results were found for asphalt concrete pavement with coarse aggregate substrate, the impact-echo method has a great potential in practical application for nondestructive measurement of pavement thickness. In the result, highly inhomogeneous characteristic of asphalt concrete is presented because large variance in P-wave speed is measured for tests performing at different location of the same section. Some obviations were found between the measured thickness and the coring thickness. It is largely caused by variation between the P-wave speed measured on the surface and the average P-wave speed through the thickness, since the pavement was placed and compacted in two layers. Secondly, gluing the coarse aggregate of the substrate level and separating the coarse aggregate at the bottom of the asphalt concrete during compacting process also lead to errors in thickness measurement. Thus, a possible range of error in thickness measurement is plus one maximum coarse aggregate size in substrate or minus one coarse aggregate size in asphalt concrete. More researches for improving the test method should be proceeded.
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