Research on the Hydration Properties of C4A3S-CSH2 Cement System at Different Temperatures.

Min Li,Suping Cui,Yali Wang,Mingzhang Lan,Zhifeng Chen,Jianfeng Wang

doi:10.3390/ma13184000

Min Li, Suping Cui + Show 4 more

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https://doi.org/10.3390/ma13184000

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Journal: Materials	Publication Date: Sep 9, 2020
Citations: 7	License type: CC BY 4.0

Affiliation: Beijing University of Technology, Tangshan College

Abstract

Sulphoaluminate cement has the advantage of low-temperature application performance, but its hydration mechanism at low temperatures is not yet clear. Anhydrous calcium sulfoaluminate (C4A3S) is the main mineral in the composition of sulfoaluminate cement clinkers. In this paper, C4A3S mixed with gypsum (CaSO4∙2H2O) to form a C4A3S-CSH2 cement system; X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG), scanning electron microscopy (SEM) and mercury intrusion analysis (MIP) to clarify the effect of temperatures on the hydration properties of C4A3S-CSH2 cement system. The results showed that hydration of the C4A3S-CSH2 cement system could carry on at low temperatures, even at −15 °C. The main hydration product was ettringite. Low temperatures did not change the types of the hydration products, but the low temperature of 0 °C was more favorable for the formation of ettringite. The early hydration of the C4A3S-CSH2 cement system was inhibited by the decrease in temperature. However, hydration of the cement at 0 °C continued at a high rate after one day. Morphologies of the ettringite for the C4A3S-CSH2 cement system at −15 °C were needle-like structures, while they were of columnar structure at 0 °C. The compressive strength of samples at 0 °C reached 82 MPa, which is significantly higher than that at 20 °C.

Highlights

Calcium sulphoaluminate cements (CSA) are promoted as one of the most promising cementitious materials due to their outstanding properties such as lower CO2 emissions [1], fast setting and hardening, high early strength [2], impermeability [3] and good durability [4]
C4 A3 S is the main mineral in the composition of sulphoaluminate cements clinkers
It has the advantages of high hydration activity, strong low temperature adaptability and high early strength

Summary

Introduction

Calcium sulphoaluminate cements (CSA) are promoted as one of the most promising cementitious materials due to their outstanding properties such as lower CO2 emissions [1], fast setting and hardening, high early strength [2], impermeability [3] and good durability [4]. C4 A3 S is the main mineral in the composition of sulphoaluminate cements clinkers. It has the advantages of high hydration activity, strong low temperature adaptability and high early strength. It is widely used in winter construction, emergency repairs, marine engineering, etc.

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