On the Effects of Mechanical Impedance Test Methods
By T. Tamai
Concrete Journal, Vol.59, No.2, Feb. 2021
- Synopsis
- In recent years, methods for estimating the compressive strength of concrete by nondestructive testing using a hammer with a built-in accelerometer to measure mechanical impedance have been proposed, and in 2017, these methods were standardized by the Japanese Society for Non-Destructive Inspection (NDIS 3434-1, 3434-2, 3434-3). However, few studies have been conducted on influencing factors affecting such tests, and few proposals have been made regarding the degree of influence of such factors and methods to correct for such factors. This paper introduces experimental results regarding factors thought to affect test results. The findings include the facts that load strength and the recording trigger value of acceleration are influencing factors, whereas carbonation and tester skill are not, and also the fact that accurate measurement may be achievable using only nine measuring points. It is hoped that this paper will inspire many researchers to clarify the effects of other factors and propose methods for calculating mechanical impedance values to be used as reference values as well as strength estimation methods.
- Keywords:
- Mechanical impedance method, Load strength, Measuring points, Carbonation, Skill of the tester, Hammer weight
