Penetration Resistance Test ( Or windsor Probe Test )

Principle of The test : THe penetration resistance depends on the strength of the concrete mass .

Method : Fire a standard probe into the concrete with a standard cartridge .

Theory : Exposed probe is longer , compressive strength is higher .

The depth of penetration , which will usually lie between 20 and 40mm , is measured & the mean of three readings is related emprirically to compressive strength by calibration charts .

THe strength is assessed by the length of probe which remains upstanding on the concrete surface .

The results are not influenced by surface conditions , moisture content or ambient temperature but by the hardness of aggregates used .

Some damage in the form of cracking may be caused . Reinforcment must be avoided & simple safety precautions should be taken .