CHANGES OF CONCRETE CHEMICAL COMPOSITION DUE TO THERMAL LOADING DETECTED BY DTA ANALYSIS

článek ve sborníku ve WoS nebo Scopus

angličtina

The new types of concrete for example high performance concrete (HPC) have higher compressive strength and durability thanks to their lower porosity and denser microstructure. In case of fire the low amount of pores may cause explosive spalling, which can lead to collapse of the entire construction. Besides porosity, there are several other factors and effects which contribute to the formation of explosive spalling. The determining effect seems to be the evaporation of chemically or physically bound water, which is accompanied by volume changes of the CSH phases and gel particles. One of the methods used to gather knowledge concerning changes of chemical components of concrete is the differential thermal analysis (DTA). In this study basic information about chemical changes and liberation respectively desorption of water in the microstructure of high strength concrete is given. The obtained knowledge leads to better understanding of the basics of explosive spalling and crack formation in the microstructure at certain temperatures. In the experiments a series of specimens was exposed to temperatures of 150, 250, 350 and 450°C and then analysed. The DTA, TG and DTG measurements have shown that in some specimens the changes of the components are not that dramatic and therefore the deterioration of the microstructure and risk of explosive spalling would not to be feared.

High performance concrete (HPC), porous system, differential thermal analysis (DTA), explosive spalling and high temperatures.

NOVÁKOVÁ, I.; BODNÁROVÁ, L.; HELA, R.; DIEDERICHS, U.

2015

8. 10. 2015

MFPA Leipzig GmbH

Leipzig, Germany

978-3-9814523-6-5

4th International Workshop on Concrete Spalling due to Fire Exposure

32

40

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