Effect of Curing Temperature on the Chloride Ion Diffusion of Superplasticized Cement and Fly Ash pastes

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Title: Effect of Curing Temperature on the Chloride Ion Diffusion of Superplasticized Cement and Fly Ash pastes

Author(s): J. G. Cabrera, T. A. H. Dodd, and S. O. Nwaubani

Publication: Special Publication

Volume: 139

Issue:

Appears on pages(s): 61-76

Keywords: admixtures; cement pastes; chloride ions; compressive strength; curing; diffusion; fly ash; porosity; superplasticizer; temperature; water-cement ratio; water-reducing agents; Materials Research

Date: 9/1/1993

Abstract:
Presents an evaluation of the effects of temperature and type of superplasticizer--high-range water-reducing admixture) (HWRA)--on there rate of chloride-ion diffusion through hydrated superplasticized ordinary portland cement (OPC) pastes and opc + fly ash (PFA) pastes. OPC pastes and OPC/PFA pastes with a water-cementitious materials ratio of 0.31 containing a HRWRA were prepared in the laboratory and cured at 21, 30, and 45 C for different lengths of time, so as to obtain approximately identical compressive strengths. Five different types of HRWRA were used in the study. At the end of the curing period, the specimens were placed in diffusion cells maintained at 30 C and the amount of chloride passing through the pastes was measured. Measurements of total porosity and pore-size distribution were made using helium pycnometry and mercury-intrusion porosimetry. The variations of chloride diffusion coefficients arising from changes in the temperature of curing and type of HRWRA are presented and discussed.