Role of Tartaric Acid in Chemical, Mechanical and Self-Healing Behaviors of a Calcium-Aluminate Cement Blend with Fly Ash F under Steam and Alkali Carbonate Environments at 270 °C.

Tatiana Pyatina,Toshifumi Sugama

doi:10.3390/ma10040342

Abstract

Tartaric acid (TA) changes short-term mechanical behavior and phase composition of sodium-metasilicate activated calcium-aluminate cement blend with fly ash, type F, when used as a set control additive to allow sufficient pumping time for underground well placement. The present work focuses on TA effect on self-healing properties of the blend under steam or alkali carbonate environments at 270 °C applicable to geothermal wells. Compressive strength recoveries and cracks sealing were examined to evaluate self-healing of the cement after repeated crush tests followed by two consecutive healing periods of 10 and 5 days at 270 °C. Optical and scanning electron microscopes, X-ray diffraction, Fourier Transform infrared and EDX measurements along with thermal gravimetric analyses were used to identify phases participating in the healing processes. Samples with 1% mass fraction of TA by weight of blend demonstrated improved strength recoveries and crack plugging properties, especially in alkali carbonate environment. This effect was attributed to silicon-rich (C,N)-A-S-H amorphous phase predominant in TA-modified samples, high-temperature stable zeolite phases along with the formation of tobermorite-type crystals in the presence of tartaric acid.

Highlights

Self‐healing of cementitious materials has been explored in civil engineering during the last twenty years [1, 2]
The present paper evaluates the effect of tartaric acid (TA) on Thermal Shock Resistant Cement (TSRC)’s healing efficiency under alkali carbonate and steam environments at 270oC
The original compressive strength of Tartaric acid (TA)‐modified and control cement samples was measured after curing in water or alkali carbonate for 24 h at 270°C

Summary

Introduction

Self‐healing of cementitious materials has been explored in civil engineering during the last twenty years [1, 2]. Research on self‐healing cementitious materials evaluates various innovative venues, such as encapsulation and utilization of hollow fibers [5,6,7,8,9], intrinsic self‐healing stays to be more economical and robust compared to other technologies [10]. Such self‐healing was observed in civil structures long time ago [11]

Methods

Results

Discussion

Conclusion