Nondestructive Testing Technology Test And Engineering Application Based On The Impact-echo Method

Impact-echo is a new method for nodestructive test,which is a invented and checked comprehensive technology by Cornell University and the NIST(National Institute of Standards and Technology). The impact-echo method only needs to test the single side of the element and is a very convenient method.It overcomes the defect of ultrasonic method,the ultrasonic method needs to penetrate by placing sensors on both sides of the element.Currently the Impact-echo method is widely used to detect the thickness of concrete structure and the defects of the structures. Based on the impact-echo method, in this paper,the research on the evaluation of grouting duct density has been investigated by theoretical experimental.Combined with the engineering application research,feasibility study of evaluation of grouting density used the impact echo method is discussed in pratical projects.Especially internal grout density of tendon ducts in civil engineering is a very solemn problem.In2001,poorly grouted tendon duct was classified as one of the top ten quality defects in Road and Bridge construction by Ministry of Comunications in China.T, so focused on testing on test and field engineering application research will have the profound significantce. Based on the Impact-echo method has been applied in the above aspects,this paper focus as following:1. The characteristics of several main nondestructive testing method and the present situation foreign development in civil were introduced.2. The propagation characteristics through medium, technical parameters and the basic detection principles of impact-echo were introduced in this paper.It would provide theoretical basises for futher study.3. As a new type of non-destructive testing technology,impact-echo method was applied in non-destructive evaluation of grouting condition.Portable Impact-Echo System(PIES) was used in this paper for experimental and the applied engineering research on grouting situation in prestressed pipe.Thus grouting situration can be estimated. Profound research of the modal influence analysis of the cross section rectangular beam has been carried out.Influential factors of the impact-echo method in the evaluation of prestressed pipe were studied.The main researched factors include height width ratio of the section of the element and the reinforecement.4. Further improve instruction meaning of the impact-echo method used in prestressed grouting pipe of practical engineering is through the field engineering application research.