Title: Effects of Admixtures on Portland Cement Concretes Incorporating Blast Furnace Slag and Fly Ash

Author(s): Noel P. Mailvaganam, R.S. Bhagrath, and K.L. Shaw

Publication: Symposium Paper

Volume: 79

Issue:

Appears on pages(s): 519-538

Keywords: accelerating agents; admixtures; blast furnace slag; calcium chlorides; compressive strength; concretes; fly ash; plasticizers; portland cement; portland pozzolan cements; portland slag cements; setting (hardening); temperature.

DOI: 10.14359/6710

Date: 5/1/1983

Abstract:
The effect of chloride, chloride free accelerators and superplasticizer admixtures on the physio-chemical properties of two types of concrete were determined. Fly ash and slag at 30% cement replacement by weight were compared to a reference mix with 100% normal Portland cement. Two series of mixes utilizing different admixture dosages and cured at two temp-eratures (22°C and 5°C) were investigated. The compressive strength results and temperature time curves indicate that at 22°C all three admixtures were effect-ive in offsetting the early strength reduction due to cement replacement. With the exception of fly ash mixes, 28 day strengths were close to and in some instance exceeded the strength of the 100% Portland cement mixes. At lower temperatures (5°C) the performance of conventional accelerating admixtures was marginal in comparison with the superplasticizer. In general the order of admixture effectiveness observed in both series of mixes was in the order: superplasticizer>chloride>non-chloride.