Development of correlation graph between concrete compressive strength and rebound hammer number/ Mohd Harif Mohd Zin

Nondestructive Test (NDT) is a test that does not impair the intended
performance of the element or member under investigation and the NDT that
have been used is Schmidt Rebound Hammer. The main purpose of this study
is to develop a separate correlation graph between concrete grades 30, 35, and
40 vs. Rebound Hammer Number at 28 days. The material used in this study
was a normal concrete and the laboratory process have been conducted at
Civil Engineering Laboratory, University of Technology Mara (UiTM),
Penang. The cube mould used was 150mm x 150mm x 150mm and cured in
ordinary water under room temperature. The number of samples that have
been prepared was 81 cubes. The test was done by using Rebound Hammer
Apparatus and Compression Machine at 7, 14 and 28 days after the grid line
on cube was drawn. The average value for Rebound Number and
Compressive Strength was calculated. From the calculated result, the separate
correlation graph between Rebound Number and Compressive strength was
developed. It is concluded, the graph that was developed is able to use in
finding the target mean strength of concrete after Rebound Hammer Test.