The concrete rebound hammer provides a highly efficient, completely non-destructive testing method for evaluating structural integrity without requiring noisy, heavy-duty hydraulic crushing equipment. Operating strictly as a Type N testing instrument, the Concrete Rebound Hammer QualiCRH™-2000A calculates an immediate, indirect estimate of in-place compressive strength by measuring the physical bounce-back of an internal spring-loaded metal weight.
When an inspector firmly presses the 25mm radius spherical tip against a prepared testing surface, the internal spring mechanism, which features a precisely calibrated 75mm stretch length, fires the inner mass forward. This specific mechanical action delivers a highly regulated impact energy of 2.207 Joules (0.225Kgf.m). The mass then bounces backward off the concrete face. A pointer slider, governed by a tightly controlled static friction of exactly 0.65N, ensures the physical rebound distance translates accurately into a highly readable hardness score on the aluminum casing.
| Feature | Practical Operational Method |
|---|
| Core Principle | The internal spring-loaded mass strikes the structural wall; the resulting bounce-back distance physically indicates the surface hardness. |
| Operating Range | Calculates a highly reliable estimate of crushing strength, specifically engineered to evaluate concrete mixes measuring strictly between 10 to 70 MPa. |
| Testing Depth | Physically assesses the structural condition of the top 30 to 50 millimeters of the concrete layer, requiring appropriate abrasive surface preparation to bypass the outer crust. |
| Standard Compliance | Meets highly stringent international testing protocols, explicitly satisfying ASTM C805, EN 12 504-2, DIN 1048, and BS1881 Part 202. |
| Calibration Method | Factory calibration requires verifying the instrument against a standard steel testing anvil (rated at 60 HRC), requiring an average rebound confirmation value of 80±2. |
| Orientation Corrections | Because gravity physically alters the mechanical rebound, shooting at different angles requires manual mathematical calculation adjustments to ensure accurate data. |
Field Testing Protocol
To achieve highly consistent accuracy with the 1kg, Ф54×280mm QualiCRH™-2000A, operators must follow specific empirical testing protocols. Because the rebound score reacts strongly to physical surface variables, inspectors must aggressively grind away loose debris or carbonated crusts using an abrasive stone before recording any readings.
The testing method requires keeping the cylindrical housing perfectly perpendicular to the test face, performing a cluster of distinct strikes across a localized grid, and mathematically averaging the collected numbers. If an operator tests the top face versus the bottom face of a poured slab, the readings will systematically differ because heavier gravel aggregates physically settle downward during the curing phase. Furthermore, operators must strictly avoid deploying the instrument on fresh, partially cured concrete; striking highly soft material can physically damage the localized area by up to 10.5 MPa and produce completely distorted strength estimates.
For the absolute highest level of structural precision, inspectors must pair the raw rebound numbers with physically drilled core samples to create a highly accurate, site-specific calculation curve that accounts for local aggregate variations and moisture levels.
