A Schmidt hammer, also known as a Swiss hammer or a rebound hammer or concrete hammer test, is a device to measure the elastic properties or strength of concrete or rock, mainly surface hardness and penetration resistance. It was invented by Ernst Schmidt, a Swiss engineer.
How do you use a concrete hammer test?
When the plunger of rebound hammer is pressed against the surface of concrete, a spring controlled mass with a constant energy is made to hit concrete surface to rebound back. The extent of rebound, which is a measure of surface hardness, is measured on a graduated scale.17 באוק׳ 2014
What is the Schmidt Hammer Test?
1. A non-destructive technique used to determine the compressive strength, surface hardness and penetration resistance of reinforced concrete and masonry structures by measuring the rebound of a spring-loaded mass impacting against the surface of the sample.
How do you do a Schmidt hammer test?
Prior to testing, the Schmidt hammer should be calibrated using a calibration test anvil supplied by the manufacturer. Twelve readings should be taken, dropping the highest and lowest, and then taking the average of the ten remaining.
How does hammer test work?
Pushing the test hammer's piston against the surface of hardened concrete loads a spring mechanism until it trips and releases a hammer mass. The mass strikes the piston, which impacts the concrete with a defined amount of energy.
What is the procedure of rebound hammer test?
Procedure: The instrument firmly held perpendicular to the test surface and gradually pushed toward the test surface until the hammer impact. After impact, the pressure is maintained on the instrument. The rebound number is read on the scale to the nearest whole number and recorded.
How do you read rebound hammer results?
Keep the Rebound Hammer firmly pressed against the concrete surface and read the rebound number on the scale. As long as you hold the Rebound Hammer firmly against the concrete, the rebound number will remain on the scale. Record your reading.
What is the use of rebound hammer test?
The Rebound Hammer has been around since the late 1940's and today is a commonly used method for estimating the compressive strength of in-place concrete. Developed in 1948 by a Swiss engineer named Ernst Schmidt, the device measures the hardness of concrete surfaces using the rebound principle.