Title:
Effect of Curing Conditions on High-Volume Fly Ash Concrete Made With ASTM Type I and III Cements and Silica Fume
Author(s):
V. Sivasundaram, A. Bilodeau, and V. M. Malhotra
Publication:
Symposium Paper
Volume:
154
Issue:
Appears on pages(s):
509-530
Keywords:
cements; chlorides; compressive strength; curing; fly ash; freeze thaw durability; silica fume; superplasticizer; Materials Research
DOI:
10.14359/967
Date:
5/1/1995
Abstract:
Presents the results of a study on the effect of curing conditions on the air-entrained, superplasticized high-volume fly ash concrete made with ASTM Types I and III cements and silica fume. For the four concrete mixtures made, the total cementitious materials content was about 370 kg/m 3, and the water- cementitious materials ratio was kept at 0.310.01. The proportion of ASTM Class F fly ash in all the mixtures was 58 percent by weight of the (cement + fly ash) content. Two mixtures incorporated silica fume at the dosage rate of 8.5 percent of the total cementitious materials content. The properties of fresh concrete including the time-of-set and autogenous temperature rise were determined. Specimens were cast and moist cured for the determination of compressive and flexural strengths, resistance to chloride ion penetration, and freezing and thawing cycling at various ages. Compressive strength and chloride ion penetration measurements were also performed at various ages on the specimens that were subjected to laboratory air curing after three days of moist curing. The use of ASTM Type III cement instead of Type I increased the early age strength significantly without affecting the long term strength development under moist curing conditions. Under air curing conditions, the concretes incorporating the Type III cement achieved significantly higher strengths at every test age up to one year. The use of silica fume resulted in only marginal improvement in the strength properties under the two curing regimes. The air curing resulted in a significantly lower resistance to chloride ion penetration (RCP) of all the concretes, but the drop in RCP was greater for those made with ASTM Type I cement. The use of silica fume increased the resistance to chloride ion penetration of concretes significantly under both curing conditions.