GYPSUM FREE CEMENTS AND CONCRETES MADE WITH THEM: STRENGTH DETERMINATION USING NONDESTRUCTIVE TESTING METHODS

článek v časopise - ostatní, Jost

angličtina

Gypsum free cement (GFC) is based on Portland clinker. Gypsum as an initial setting time regulation additive is replaced by a system based on lignosulfonane of alkali metal and carbonate of alkali metal. This binder features high initial strength and short initial setting time; subsequently, these properties continue in concretes made with this binding material. Concrete with gypsum-free cement is characterized with short setting time and high initial strength. Concrete with gypsum-free cement has comparable strength after 3 days of curing with a 28 days strength of common concrete with Portland cement containing gypsum. Our paper describes methodology and calibration relations for both - GFC strength determination through ultrasonic pulse velocity and strength determination of types of concrete made with GFC using ball thrust hardness test. The last-named method is applicable for GFC compression strength determination; and also for types concrete based on GFC, commendable are impact hammers (Schmidt Impact Hammers type N and/or L respectively - made by PROCEQ Co., Switzerland). These methods enable testing of concretes based on GFC after their casting without any harm to materials built into construction in contrast to destructive strength tests on cores. Presented testing methodology along with test results take into account specificity of particular materials and products. As analyzed above, this methodology is usable in technical practice. The methodology constitutes essential precondition of measurement reproducibility and repeatability.

Non-destructive testing, Cement, Concrete, Compression strength, Impact Hammer, Ultrasonic pulse velocity

BROŽOVSKÝ, J.; ZACH, J.; BROŽOVSKÝ, J.

1. 11. 2007

Informatics India Ltd 2007

Indická republika

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