The Schmidt Rebound Hammer (Swiss Hammer) is an increasingly popular strength assessment apparatus due to its simple operation and portability. A plunger rod is pressed against the concrete surface until a spring-loaded mass releases causing an impact. The rebound of the mass is registered as the "rebound number" which provides estimated strength of concrete.
Click the Schmidt Hammers Comparison Table above to enlarge, print, or download. The table compares compressive strength and impact energy between Original Schmidt Hammer, Silver Schmidt, Schmidt Live, and Rock Rebound Test Hammers.
Most versions are divided into two concrete rebound hammer types based on the impact energy they produce. Schmidt Concrete Test Hammers are available in Type N or Type B model. Both are effective on concrete mixes with a similar range of compressive strengths.
- Schmidt Type N Test Hammers are often considered as the “standard” models and have a higher energy output to test a wide range of concrete structures. Used when testing structures 4in (100mm) or more in thickness.
- Schmidt Type L Test Hammers have lower impact energy and provide more repeatable values when testing items less than 4in (100mm) in thickness. Ideal for thinner sections like precast pipe or early-age concrete for form removal or post-tensioning operations, Type L concrete hammers also reduce both cosmetic and structural damage to concrete with thin cross sections.
- Rock Schmidt Hammers are designed with specific geological and geotechnical capabilities. These hammers are frequently used to assess the workability, boreability, and excavatability of rocks, as well as estimating the uniaxial compressive strength of discontinuity walls.