Built-in Concretes Made with Gypsum Free Cements: Compression Strength Determination Using Nondestructive Testing Methods

conference paper

English

Gypsum free cement (GFC) concretes feature high initial strength within 1 to 3 days; whereas such strength is comparable to common concrete strength after 28-days-hardening. To determine concrete strength nondestructively, ball thrust hardness tests are most frequent, in particular by Schmidt Impact Hammers, manufacturer PROCEQ Co., Switzerland. Nevertheless, ultrasonic pulse method is usable as well. To determine compression strength by means of impact hammers and to derive strength from nondestructive test-ing parameters, calibration correlations are described here for concretes after at least 14-days-hardening (e.g. calibration correlations of impact hammer by manufacturer or according to ČSN 731373). However, when us-ing GFC concrete, it is important to know its strength during initial hardening (1 to 3 days). This paper de-scribes calibration correlations for GFC concretes relating to Schmidt Impact Hammers, types N and L, as compared with calibration correlations defined by ČSN 731373 and calibration correlations indicated by im-pact hammer manufacturer in question. Furthermore, another calibration correlation for compression strength determination is indicated herein on the basis of ultrasonic pulse velocity, though its practicability is rather limited, as ultrasonic pulse velocity is affected by concrete components.

gypsum free cement, concrete, strength, nondestructive testing, impact hammer, ultrasonic pulse method

BROŽOVSKÝ, J.; FOJTÍK, T.; BROŽOVSKÝ, J.

2007

1. 9. 2007

Millpress Science Publishers

Rotterdam, Holandsko

978-90-5966-054-0

Recent Developments in Streuctural Engineering, Mechanics and Computation

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