Implementation of Non-Destructive Impact Hammer Testing Methods in Determination of Brick Strength

In the building industry, non-destructive testing methods are mostly used to determine parameters of concrete structures and concrete of its own; as to other materials, these methods serve semi-occasionally and, as a rule, testing procedures and evaluation are not codified in technical standards. One of non-destructive testing field of applications is testing of piece bricks. This paper deals with findings concerning non-destructive testing of clay solid bricks, honeycomb bricks and lime sand bricks by means of Schmidt Impact Hammers types LB/L. Described here are testing method, procedures of test finding evaluation as well as calibration correlations between impact hammer rebound number and compression strength or flexural strength (lime sand bricks only). Evaluated calibration correlations between impact hammer rebound number and brick strength feature close correlation; its coefficient varies between 0.95 and 0.98, therefore these values are usable in practice. When testing honeycomb bricks varying in hole arrangement and wall thickness, it is necessary to take both these factors into account through specification of calibration correlation of non-destructive/destructive tests of limited number of bricks.