The Effect of Elevated Curing Temperatures on High Ye'elimite Calcium Sulfoaluminate Cement Mortars.

Yeonung Jeong,Sung-Chul Chun,Hyunuk Kang,Juhyuk Moon,Craig W Hargis

doi:10.3390/ma12071072

Yeonung Jeong, Sung-Chul Chun + Show 3 more

Open Access

https://doi.org/10.3390/ma12071072

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Abstract

This study investigated the material properties and hydration characteristics of calcium sulfoaluminate cement (CSA) based mortars cured under 3 different initial curing temperatures. Two CSA cements with different M-values were selected. Obtained experimental results of mechanical properties, dimensional stability, and heat release were explained by hydration characteristics from X-ray diffraction, thermal gravimetric analysis, porosimetry, and thermodynamic modeling. Decomposition of ettringite decreased compressive strength but re-formation of ettringite after additional curing at 30 °C helped to recover the strength in CSA cement with a high amount of calcium sulfate. CSA cement with a low amount of calcium sulfate which was designed to predominantly have monosulfate as the main hydration product, showed increased 1-day strength after higher temperature curing but this occurred was at the expense of decreased 28-day strength.

Highlights

Calcium sulfoaluminate (CSA) cement was initially developed as an expansive additive for concrete [1,2]
The compressive strengths of CSA1 mortars were higher than CSA2 mortars at any given age or curing temperature, except CSA1-90 which had a lower strength than CSA2-90 at 1 day. (Figure 3)
The strength of CSA mortars cured at 90 ◦ C was lower than those cured at 30 ◦ C and 60 ◦ C

Summary

Introduction

Calcium sulfoaluminate (CSA) cement was initially developed as an expansive additive for concrete [1,2]. CSA cement has been considered as a sustainable alternative to replace ordinary Portland cement (OPC), since the production of the CSA cement requires less limestone and a lower calcination temperature compared to OPC [3,4,5,6]. This implies that the CSA cement is a more sustainable cement than OPC due to creating less CO2 emissions during its production process. CSA cement can reduce energy consumption during clinker grinding due to its more friable nature [7,8].

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