What is a Rebound Hammer / Schmidt Hammer / Concrete Strength?

A rebound hammer (Schmidt hammer) is a non-destructive testing device used to measure the surface hardness of concrete and estimate its strength. It is primarily used in construction and civil engineering sites to quickly assess the compressive strength of concrete. The measurement principle involves a spring-driven hammer that strikes the concrete surface, and the rebound value is recorded. This rebound value is then converted into compressive strength (N/mm² or MPa) using a standardized conversion chart. Rebound hammers are ideal for quick and easy assessments over large areas; however, results can be influenced by surface conditions and concrete density. Therefore, it is recommended to use them in combination with other testing methods for accurate strength evaluation. They are commonly used for quality control in new construction, diagnosing deterioration in existing structures, and assessing strength before seismic retrofitting. With proper measurement procedures and conversion charts, rebound hammers provide reliable data and serve as essential tools for safety and maintenance management.

Application of Rebound Hammer / Schmidt Hammer / Concrete Strength

✅ Quality Control at New Construction Sites
After pouring concrete, a rebound hammer (Schmidt hammer) is used to quickly measure compressive strength and verify that the quality meets design specifications.
✅ Deterioration Diagnosis of Existing Structures
For aging infrastructure such as elevated highways or roads, a Schmidt hammer is used to measure surface strength and assess the deterioration of the concrete.
✅ Pre-Evaluation Before Seismic Retrofitting
Before seismic retrofitting, the Schmidt hammer is used to measure the strength of concrete in existing buildings, providing reference data for reinforcement planning.
✅ Quality Inspection After Construction
After the concrete hardens, a Schmidt hammer is used on-site to check the curing and strength, ensuring the quality after construction.

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