Evaluation of Pre-Early Age Strength of Super Fine Ggbs Mortars
K. Chaaruchandra, M. Cruickshank, R.P. West, J. Reddy
Abstract. This paper reports on a study exploring the use of a super-fine ground granulated blast-furnace slag (SF GGBS) for the precast industry wherein pre-early age strength becomes prominent for de-shuttering of formwork and optimizing productivity. The results will be discussed for research undertaken to study the effect of temperature curing methods, accelerating admixtures and SFGGBS on the compressive and flexural strength of standard mortars to establish the efficacy of the cement fineness and the new accelerator in very early age strength attainment. In this study a rapid hardening cement (RHC) is compared to a 50% SFGGBS to examine the effect of curing temperature (at 20 and 35 oC) and two new types of accelerating admixture on strengths at 6 different age of testing (16hr, 1, 2, 3 ,7 , 28 days). In comparison to pure RHC at 16 hrs, the SFGGBS mortars without admixture achieved only 35 % of flexural strength and about 30% of compressive strength at low temperature; whereas nearly 96 % of flexural strength and 100% of compressive strength at high temperature. With the addition of admixture 1, a new more effective admixture developed to activate SFGGBS, mortars achieved over 70 % of flexural strength and 60% of compressive strength at low temperature whereas over 128 % of flexural strength and 120% of compressive strength at high temperature. At 24 hrs the results are nearly similar to 100% RHC and with further increase in the age of the testing the results are found to broadly equate; thus demonstrating the effective performance of admixture 1 and higher temperature in activating SFGGBS for achieving better pre-early age strength.
Accelerating Admixture, Mortar, Pre-Early Age, Strength, Super-Fine GGBS
Published online , 9 pages
Copyright © 2018 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: K. Chaaruchandra, M. Cruickshank, R.P. West, J. Reddy, ‘Evaluation of Pre-Early Age Strength of Super Fine Ggbs Mortars’, Materials Research Proceedings, Vol. 7, pp 676-684, 2018
The article was published as article 65 of the book Non-Conventional Materials and Technologies
 Clear C. A., 2011, “Cement type/ early age properties”, Concrete Today, BRMCA British Ready-Mixed Concrete Association brmca.org.uk, pg. 12-14.
 Cakir O. & Akoz F., 2008, “Effect of curing conditions on the mortars with and without GGBFS”, Construction and Building Materials, 22, 308-314. https://doi.org/10.1016/j.conbuildmat.2006.08.013
 NSAI, IS EN 196-1:2005, “Methods of testing cement – Part 1: Determination of strength”, Dublin.
 Soutsos M., Hatzitheodorou A., Kanavaris F. and Kwasny J., 2014, “Effect of temperature on the strength development of mortar mixes with GGBS and fly ash”, Magazine of Concrete Research; Dec2014, Vol. 66 Issue 24, p1277-1285, 9p.
 National Ready Mixed Concrete Association (NRMCA), 2012, “Concrete CO2 fact sheet”, NRMCA Publication Number 2PCO2.
 J.I. Escalante-Garcı´a, J.H. Sharp, 2001, “The microstructure and mechanical properties of blended cements hydrated at various temperatures”, Cement Concrete Research, 31, 695– 702. https://doi.org/10.1016/S0008-8846(01)00471-9
 J.I. Escalante, L.Y. Go´mez, K.K. Johal, G. Mendoza, H. Mancha, J. Me´ndez, 2001, “Reactivity of blast-furnace slag in portland cement blends hydrated under different conditions”, Cement Concrete Research ,31, 1403– 1409. https://doi.org/10.1016/S0008-8846(01)00587-7
 D.M. Roy, G.M. Idorn, 1982, “Hydration, structure and properties of blast furnace slag cements, mortars and concrete”, ACI Journal, 79 (6), 444– 457.