The rate of strength development of mortar mixes with SCMs at elevated curing temperatures

Author(s):Marios Soutsos, Gidion Turu'allo
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference
Materials, Systems and Structures in Civil Engineering 2016
Segment on Concrete with Supplementary Cementitious Materials
Editor(s): Ole M. Jensen, Konstantin Kovler and Nele De Belie
ISBN:978-2-35158-178-0
e-ISBN: 978-2-35158-179-7
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 296 - 305
Total Pages: 10
Language : English

Abstract: The early age strength development of mortars containing ground granulated blast furnace slag (ggbs) at levels of up to 70% of the total binder have been investigated to give (1) guidance as to their early age strength development and (2) how this is affected by curing temperature. 28-day target mean strength for all concrete specimens was 55 MPa. Supplementary cementitious materials (SCMs) such as ggbs were used to give similar 28-day compressive strengths to those with neat Portland cement (PC). However, their early age strengths are shown to be significantly lower than PC when cured at 200 C. High curing temperatures benefit ggbs mixes much more than Portland cement mixes. Measurements of temperature rise under adiabatic conditions have shown that high levels of cement replacement by ggbs, e.g. 70% are required to obtain a significant reduction in the peak temperature rise. Even though the temperature rise using ground granulated blast furnace slag (ggbs) is lower than from using Portland cement, it is shown that it still influences significantly the early age strength contribution of ggbs. Maturity measurements are needed to take advantage of such enhanced early age strengths. Precast concrete factories, for example, should confirm that the actual compressive strength of the concrete in the structural element at the time of lifting operations exceeds the required strength. Maturity functions like the Nurse-Saul and Arrhenius based one proposed by Freiesleben Hansen and Pedersen (FHP) have been examined for their applicability to ggbs mortars. Activation energies, required as input for the FHP equation, have been determined according to ASTM C1074-98. The inaccuracies in the strength predictions of both maturity functions have been quantified and the reasons identified to enable future improvements.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00