Testing Principle
The device is loaded by gently pressing the tip of the impact plunger against a solid surface, it then slides out of the housing until it is fully extended. The plunger is then pressed against the surface to be tested which fires a percussion weight against the rear of the plunger and rebounds.
The rebound is dependent upon the hardness of the surface under test, the harder the surface the higher the rebound and vice versa. The maximum height of rebound is recorded on a scale which represents the rebound as a percentage of the forward movement of the percussion weight. The rebound number obtained with the HT 225A can be converted to a compressive strength value via conversion tables contained in the user manual. The conversion varies with the angle of test therefore values must be corrected for those other than the standard horizontal direction. The various angular corrections are also shown in a table in the user manual.
Technical Specifications
Part Number
Description
HT 225A
HT225A Portable Concrete Test Hammer
Measuring range
10-70MPa
Accuracy
± 1R
Normal Kinetic Energy
2.207J (0.225kgf.m)
Flip tension spring rigidity
7.84N (0.80kgf)/cm
Punch advance for impact hammer
75mm
Impact surface hardness value between impact hammer and rod
HRC59-63
Maximum breakout friction of pointer system
0.49 – 0.78N (50-80g)
Mean value of steel-anvil rating of concrete test hammer
80+-2
Dimension
60x280mm
Weight
1kg
Packing List
HT225A Concrete Test Hammer
Carborundum Stone
Conversion Tables
Protective Wooden Box
Operating Instructions
