Research of Grouting Quality in Prestressed Duct Through Impact-echo Method

Abstract

The paper presents the method of quantitative detection and evaluation of the corrugated pipes' grouting density. To this purpose many tests were carried out by using the impact-echo method. In the paper, we got the stress propagation paths of impact-echo in the corrugated pipes and established an internal cavity estimation model based on the time curve of the impact-echo. In the experimental model, the defects of the corrugated pipes were set up by artificial means which were divided into 5 levels: the full density, 3/4 density, 1/2 density, 1/4 density and all empty, then using the impact-echo tested the corrugated pipes' grouting densities. The results show that the estimation model of internal cavity estimation model can be used to quantitatively evaluate the degree of density of the corrugated pipes, the curves' correlation of the theoretical value of the model calculation and the experimental data is R=0.9426 which indicate that the two curves fit well.