Vedalakshmi, R. and Rajagopal, K. and Palanisamy, N. (2008) Enhanced corrosion resistance of rebar embedded in fly ash added concrete: Role of "k" factor. Indian Journal of Chcmical Tcchnology, 15 (4). pp. 375-382.

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Abstract

In Indin, the abundnnt availability of fly ash necessitates the increase in the addition of lly ash in pozzolana ceinent from 25 to 35%. Higher rcplacemcnt level of tly ash reduced the development of eorly oge strength of concretc. By adopting the cemcnt cfficicncy factor (k) when dcsigning the fly ash added concrctc, eithcr equal or more compressive stl'ength has becn attaincd. In the prescnt study, by adopting this factor, the concretes having strength of20 and 35 MPa were designcd at 40% replaccmcnt of tly ash. Thc enhanced COITosion resistance of rebm was evaluated by conducting chloride migration test, potcntial-timc studics and 90 days chloride ponding test. Results were compared with Ordinary Portli1l1d cement (OPC) and Fly ash addcd concrete (FAC) without k factor. The studies reveal that the diffusion co-efficient of chloride is Icss in FAC-with k than that of ope ,md FAC without k eoncretcs. 1n 1% chloride contaminated concretc, the rebar in FAC-with k shows more passivc potential than the other two concretes. Under 90 days chloride ponding test, the corrosion resistance ofrebar in FAC is 3-7 times more than that of the rebar in OPC concrete. The reduced chloride ion penetration inneascd the cOITOsion resistance of rcbar. The 40% I'eplacement of fly ash reduced the alkalinity of FAC-without k whereas the 01-1 ions concentration increases in FAC-with-k and maintained the passivity of rebnr in presence of chloride. Hence in addition to early strength development, the enhanced corrosion resistance of rebar in FAC-with k is mainly because of reduced chloride ions penctration and increased OW ions concentration.

Item Type:	Article
Uncontrolled Keywords:	Fly ash; Pozzolana cement; Efficiency factor; Chloride diffusion; Corrosion rate
Subjects:	Corrosion Protection Corrosion Science and Engineering
Divisions:	UNSPECIFIED
Depositing User:	ttbdu cecri
Date Deposited:	17 Jan 2012 09:50
Last Modified:	17 Jan 2012 09:50
URI:	http://cecri.csircentral.net/id/eprint/165

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