Schmidt Rebound Hammer
The Schmidt rebound hammer is one of the oldest and best-known methods of comparing concrete in various parts of a concrete structure and indirectly assessing concrete strength.
The Schmidt rebound hammer is a form of live non-destructive test carried out in-situ enabling an instant result whilst on-site. It is actually a measure of surface hardness. The rebound hammer should be considered as a means of determining variations of strength within a structure rather than an accurate means of assessing strength.
Surface Preparation
The surface under test should be clean and smooth. The area must first be prepared by hand grinding/sanding the area using a silicon carbide stone. Rebound testing cannot be completed on rough surfaces as this can lead to unreliable results. No part of the preparation or actual testing carried out using Schmidt hammer will leave damage, only a minor dent in places due to the strike action of the internal rod.
We can test the hardened concrete both on the ground and also vertical walls enabling you to get a reading wherever your concrete has been placed. Each section is tested in 9 points formed in a grid array.
Testing is carried out in accordance to British Standards BS EN 12504-2.
Is there a more accurate and widely accepted way of testing the actual concrete strength? Yes, through a destructive testing process known as Diamond drilling and concrete coring where the section is drilled, core samples removed and compression tested in our laboratory.
This article forms part of our investigation services.