END Especial - Rebound Hammer

The rebound hammer test is done to find out the compressive strength of the concrete by using a rebound hammer and the underlying principle of the rebound is:

O teste de resonancia com o martelo é usado para se determinar a força do concreto usando um martelo especial de resonancia e o seu princípio basico é:

The rebound of an elastic mass depends on the hardness of the surface against which its mass strikes. When the plunger of the rebound hammer is pressed against the surface of the concrete, the pring-controlled mass rebounds and the extent of such a rebound depends upon the surface hardness of the concrete. the surface hardness and therefore the rebound is taken to be related to the compressive strength of the concrete. The rebound value is read from a graduated scale and is designated as the rebound number or rebound index. The compressive strength can be read directly from the graph provide on the body of the hammer

A resonancia de uma massa elástica depende da dureza da superficie contrária a que se aplica o impacto. Quando o embolo do martelo é pressionado contra a superfície do concreto

Before commencement of the test, the hammer should be tested against a test anvil, to get reliable results, for which the manufacturer of the hammer indicates the range of readings on anvil suitable for different types of rebound hammer

The plunger is pressed against the surface of the concrete, keeping the instrument perpendicular to the test surface. A gradual increase in pressure is applied until the hammer impacts. (don`t touch the button while depressing the plunger. Press the button after impact, in case it ins`t convenient to note the rebound reading position).