Special Concretes: Enhancement of Resistance to Aggressive Media Using Fly Ash and Admixtures Featuring Pozzuolana Characteristics

Special Concretes: Enhancement of Resistance to Aggressive Media Using Fly Ash and Admixtures Featuring Pozzuolana Characteristics

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This paper presents findings of testing focused on resistance enhancement of special concretes (SCC, HPC, RPC) as well as common concrete (C) through application of secondary raw material (fly ash) and admixtures featuring pozzolana characteristics (meta kaolin). The tests were aimed at examination, comparison, analyzing and evaluation of admixture of fly ash and/or meta kaolin respectively as to their influence on above mentioned special concretes exposed to various chemical aggressive media. Analyzed concretes were stored in aggressive liquid media (SO42-, Cl-, engine lubrication oil), gaseous media (simulated concentration of CO2, SO2 under various relative humidity), along with reference samples in aqueous media as specified by appropriate standards. After 3, 6, 9 and 12 months, particular concretes passed through physico-mechanical and physico-chemical analyses i.e. tested were their physico-mechanical and physico-chemical properties, appearance, and condition after their exposure to particular aggressive media. After 12 months of such treatment, no physico-mechanical parameters of special concretes modified by fly ash and meta kaolin were deteriorated. Surprisingly, SCC concrete modified by fly ash and HPC concrete modified by meta kaolin achieved markedly better parameters as compared with identical concretes with no application of fly ash and meta kaolin. RPC concrete modified by fly ash, as compared with unmodified RPC concrete, featured inferior to a certain extent nevertheless, these properties did not reduce resistance of these concretes to particular chemical aggressive media. However, common concretes made with fly ash admixture, achieved markedly in-ferior physico-mechanical parameters that demonstrated themselves through diminished resistance to tested chemical aggressive media.

This paper presents findings of testing focused on resistance enhancement of special concretes (SCC, HPC, RPC) as well as common concrete (C) through application of secondary raw material (fly ash) and admixtures featuring pozzolana characteristics (meta kaolin). The tests were aimed at examination, comparison, analyzing and evaluation of admixture of fly ash and/or meta kaolin respectively as to their influence on above mentioned special concretes exposed to various chemical aggressive media. Analyzed concretes were stored in aggressive liquid media (SO42-, Cl-, engine lubrication oil), gaseous media (simulated concentration of CO2, SO2 under various relative humidity), along with reference samples in aqueous media as specified by appropriate standards. After 3, 6, 9 and 12 months, particular concretes passed through physico-mechanical and physico-chemical analyses i.e. tested were their physico-mechanical and physico-chemical properties, appearance, and condition after their exposure to particular aggressive media. After 12 months of such treatment, no physico-mechanical parameters of special concretes modified by fly ash and meta kaolin were deteriorated. Surprisingly, SCC concrete modified by fly ash and HPC concrete modified by meta kaolin achieved markedly better parameters as compared with identical concretes with no application of fly ash and meta kaolin. RPC concrete modified by fly ash, as compared with unmodified RPC concrete, featured inferior to a certain extent nevertheless, these properties did not reduce resistance of these concretes to particular chemical aggressive media. However, common concretes made with fly ash admixture, achieved markedly in-ferior physico-mechanical parameters that demonstrated themselves through diminished resistance to tested chemical aggressive media.

concrete, admixture, fly ash, pozzolana characteristic, resistance, aggressive media, meta kaolin

concrete, admixture, fly ash, pozzolana characteristic, resistance, aggressive media, meta kaolin

BROŽOVSKÝ, J.; FOJTÍK, T.

01.09.2007

Millpress Science Publishers

Rotterdam The Netherlands

978-90-5966-057-1

Recent developments in Structrural Enginnering, Mechnics and Computation

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