engleski

Two Stage Methods of Concrete Strength in Structures

When the compressive strength of a given concrete structure is not known or questionable, several test methods could be applied for subsequent tests. The questions arising during subsequent estimation of concrete strength have mostly been dealt with in reference literature (1, 5, 6). Subsequent concrete quality testing is done in the structure by determining compressive strength by destructive or by non-destructive methods. These methods are of different confidence, but also different costs. In this paper we deal with reliability of test methods, the number of test specimens or spots and criteria for compressive strength evaluation. Contractors and Purchasers risks are also taken into account. Non-destructive tests are not fully reliable and they are used always in combination with drilled cores. Efforts are made to decrease the number of cores to the reasonable amount. For economic reasons and simplicity of testing, two stage concrete quality control has been introduced by combination of destructive and non-destructive method. It is well known that the strength of concrete in a structure is approximately 15% lower than in specimens made of identical concrete. The criteria for evaluating concrete quality in a structure is the same as the criteria for evaluating concrete quality during control testing on cubes.

concrete; concrete; quality; criteria

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