Trade Journals for the Concrete Industry

The concrete test hammer introduced by Ernst O. Schmidt at the beginning of the 1950’s is without any doubt the most widely used NDT measuring instrument for a rapid assessment of the condition of a concrete structure. Despite this fact, the validity of the method remains a hotly debated topic amongst experts in the NDT field. This is largely due to two factors. Firstly, the mechanical Schmidt hammer has long since established itself as a “commodity”. This has led to the market being saturated with cheap copies of varying quality. This is confusing for the customer and too often the decision is made on price alone. The unreliability of the cheap copies damages the method generally. Secondly, the incorrect usage of the hammer for estimating compressive strength (blind reliance on the manufacturer’s conversion curves) is a major cause for concern amongst NDT experts.