The Mechanical Concrete Test Hammer (Schmidt Hammer) test is the quickest, simplest and least expensive method for non destructive evaluation of concrete and other masonry materials. It is most ideally suited to the measurement of material uniformity over large areas of structure. It provides a measure of relative material surface hardness and is used extensively for the testing of concrete and rock.
The hammer consists of a spring loaded plunger which when released, strikes the surface. During the rebound stroke, the mass moves a pointer that indicates the maximum point of return and at the same time indicates a reference value on the scale called the redound number. This number, when converted based on correlation table, gives the compression resistance value in respect of the impact angle.