Models for Estimation of Concrete Compressive Strength Based on Experimental Research with Destructive and Non-destructive Methods

This article presents experimental studies for assessing the concrete compressive strength in existing reinforced concrete members with destructive and non-destructive methods. For the destructive tests, 12 cube test specimens and 12 reinforced concrete beams (from which, 11 cores were drilled) were prepared in one day with the same recipe composition of the concrete. For two years, the reinforced concrete members were indoors, and in the following years, they were left outdoors exposed to external atmospheric influences. The research is aimed at the combined use (SonReb method) of two non-destructive methods: the method of elastic rebound (Schmidt rebound hammer) and ultrasonic pulse velocity method (UPVM) in order to achieve greater accuracy in assessing the compressive strength of concrete. Models have been developed describing the correlation between the determined compressive strength in the destructive test of cubes and cores with themeasured rebound number and ultrasonic pulse velocity for the age of the concrete 1126th and 1926th day. The analysis was performed in Microsoft Excel environment.