Revisiting the effect of slag in reducing heat of hydration in concrete in comparison to other supplementary cementitious materials

Hoon Moon, Sivakumar Ramanathan, Prannoy Suraneni, Chang Seon Shon, Chang Joon Lee, Chul Woo Chung

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Blast furnace slag (SL) is an amorphous calcium aluminosilicate material that exhibits both pozzolanic and latent hydraulic activities. It has been successfully used to reduce the heat of hydration in mass concrete. However, SL currently available in the market generally experiences pre-treatment to increase its reactivity to be closer to that of portland cement. Therefore, using such pre-treated SL may not be applicable for reducing the heat of hydration in mass concrete. In this work, the adiabatic and semi-adiabatic temperature rise of concretes with 20% and 40% SL (mass replacement of cement) containing calcium sulfate were investigated. Isothermal calorimetry and thermal analysis (TGA) were used to study the hydration kinetics of cement paste at 23 and 50 °C. Results were compared with those with control cement and 20% replacements of silica fume, fly ash, and metakaolin. Results obtained from adiabatic calorimetry and isothermal calorimetry testing showed that the concrete with SL had somewhat higher maximum temperature rise and heat release compared to other materials, regardless of SL replacement levels. However, there was a delay in time to reach maximum temperature with increasing SL replacement level. At 50 °C, a significant acceleration was observed for SL, which is more likely related to the pozzolanic reaction than the hydraulic reaction. Semi-adiabatic calorimetry did not show a greater temperature rise for the SL compared to other materials; the differences in results between semi-adiabatic and adiabatic calorimetry are important and should be noted. Based on these results, it is concluded that the use of blast furnace slag should be carefully considered if used for mass concrete applications.

Original languageEnglish (US)
Article number1847
JournalMaterials
Volume11
Issue number10
DOIs
StatePublished - Sep 27 2018

Keywords

  • Adiabatic calorimeter
  • Blast furnace slag
  • Calcium sulfate
  • Heat of hydration
  • Isothermal calorimeter
  • Maximum temperature rise
  • Semi-adiabatic calorimeter

ASJC Scopus subject areas

  • Materials Science(all)

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