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A Guide to the Rebound Hammer Test

What is Rebound Hammer Test

Concrete, a fundamental building material, serves as the backbone for structures worldwide. Ensuring its strength and durability is crucial in construction projects. One simple yet effective method to assess the integrity of concrete is the Rebound Hammer Test. In this blog, we’ll provide a quick refresher on the test and guide you through the process of conducting it.

Understanding the Rebound Hammer Test:

The Rebound Hammer Test, also known as the Schmidt Hammer Test, is a non-destructive method used to estimate the compressive strength of concrete. It involves striking the surface of the concrete with a spring-loaded hammer and measuring the rebound distance. This rebound distance correlates with the concrete’s hardness and, by extension, its compressive strength.

Equipment Needed:

  1. Rebound Hammer: The instrument itself, equipped with a plunger, a spring, and a mass that strikes the concrete surface.
  2. Grinding Stone: Used to prepare the concrete surface by removing loose particles and obtaining a flat and smooth test area.
  3. Measuring Tape: To measure the rebound distance accurately.
  4. Safety Gear: Personal protective equipment, including safety glasses and gloves.

Step-by-Step Guide:

  1. Surface Preparation: Before starting the test, prepare the concrete surface by using the grinding stone to remove any loose particles or contaminants. This ensures a clean and flat test area.
  2. Calibration: Calibrate the rebound hammer according to the manufacturer’s instructions. This is a crucial step to ensure accurate and reliable test results.
  3. Test Points Selection: Identify the locations for testing. These points should be representative of the overall concrete structure. Typically, a grid pattern is used to ensure comprehensive coverage.
  4. Testing Procedure:
    • Hold the rebound hammer perpendicular to the concrete surface.
    • Align the instrument’s plunger with the test point.
    • Press the instrument against the concrete surface, ensuring good contact.
    • Release the spring-loaded mass to strike the concrete surface.
  5. Rebound Distance Measurement:
    • Use the measuring tape to measure the rebound distance. Measure from the point of impact to the point where the hammer returns.
  6. Recording and Analysis:
    • Record the rebound values for each test point.
    • Use a correlation chart provided by the instrument’s manufacturer to convert rebound values into an estimated compressive strength.
  7. Interpretation:
    • Higher rebound values indicate higher concrete compressive strength.
    • Compare the results with project specifications and industry standards to assess the concrete’s quality.


The Rebound Hammer Test offers a quick and straightforward method for evaluating concrete strength without causing damage. Regular testing can help monitor the structural integrity of concrete over time, allowing for timely maintenance and ensuring the longevity of construction projects. By following these simple steps, engineers and construction professionals can harness the power of the rebound hammer to make informed decisions about the quality of their concrete structures.