The Testing Technology Of Ducts Grouting Compactness Based On The Impact-Echo Method

In recent years,along with strengthening national investment in transportation engineering, the construction of highway and railway bridges is booming.Among them, as a result of the method of post-tensioned prestressed concrete beam is superior performance in the field of large span, and it has resulted in a widely used in highway and bridge construction. However, the quality control of concrete beam pipe grouting generally adopts the process control, so there will be a negligence or improper use of technology will lead to grouting is not dense, it will directly affect the bearing capacity and durability of structure.So,we must assess the duct grouting quality.This article will adopt the impact-echo method to the duct grouting quality detection technology for the theoretical analysis and experimental research, The study is summarized as follow:1.Refer to a large number of related literature at home and abroad,summarizes the characteristics of the prestressed duct and the current problems need to be solved, elaborated the background and significance of selected topic, and introduces the development of related fields at home and abroad.Introduced the basic theory of stress wave,elaborated on the stress wave propagation law in the medium and the law of reflection and transmission in different interface of impedance,and described the basic principle and operation method of impact-echo.2.Combining with the domestic common quality defects of grouting and testing environment,we design four groups of test model beam,according to the different defects and different test methods for testing,comparative test data respectively and record the key of the spectrum characteristics,Inductive and selection test scheme which can be used in actual engineering.The testing data can be in conformity with the preset defect data, combined with the data, summarizes the testing experience,combined with the data and summarizes the testing experience.3.The advanced multifunction portable impact-echo system was employed,combining with the conclusion of model beam test to help make the impact-echo method detection of grouting quality technology is applied to practical engineering,good results had been achieved.It concludes that:Through the analysis of testing data based on the impact-echo method,it could detect grouted、ungrouted and part-grouted duct.4.A comprehensive summary of theoretical and experimental study of the impact-echo method was conducted, and a preliminary suggestions was made for the future study.