Application of Rebound Hammer Method for Estimating Compressive Strength of Bricks

摘要

The Rebound Hammer strength test, being a non-destructive test, has its advantages of preserving integrity of sample. Besides, the test is relative simple, economical and versatile compared to conventional crushing tests. The method is widely used for testing concretes manufacturers of such rebound hammers usually provide calibrated curves showing the relation of compressive strength and rebound number concrete only. But these hammers can conveniently be used to test stones and bricks also. This paper presents some models for correlation between rebound number and compressive strength of bricks. 10 different samples of brick were collected from different manufacturers and rebound numbers was taken 20 times for each brick, 10 times for horizontal hammer position and 10 times for vertical. The samples were then tested in a universal testing machine to obtain their actual compressive strength. Linear and exponential correlations between average rebound number and compressive strength were established using least square parabola method. Regression coefficients for the proposed models were found to vary from 0.87 to 0.96. The proposed linear model for horizontal hammer position was found to be the better one with a regression coefficient of 0.96 which indicates the acceptability of this model for predicting compressive strength of bricks.