Proposal of a correction factor for rebound hammer testing of concrete strength in the Mao Khe shaft project

Abstract

In underground mining construction, concrete is widely used for structural support. The rebound hammer method has recently been applied more frequently to assess in-situ concrete strength; however, its results often differ from those obtained by standard compression testing. This study aims to establish a correction factor to align rebound hammer results with compressive strength values. Experimental investigations were carried out on a limited number of M200 concrete specimens designed for roadways in the vertical shaft project of Mao Khe Coal Company. Based on systematic analysis, a correction factor “kc” was developed, ensuring both scientific reliability and practical relevance. The proposed factor is recommended for application in evaluating the compressive strength of M200 concrete used in the Mao Khe vertical shaft project, with suggestions for further research to enable broader application.