Accelerated sulfate corrosion of limestone powder cement-based materials in a high geothermal environment by electrical pulse

Abstract

A high geothermal environment influences the durability of cement-based materials. In this work, the effects of various erosion temperatures on the performance of limestone powder cement-based materials (LCBM) subjected to sulfate attack were comparatively investigated, and the service life of samples exposed to sulfate attack under the action of an electrical pulse was predicted by establishing a Wiener-based stochastic process model. Specifically, the LCBM exhibited temperature increases in the immersion and electrical test, more severely damaging the samples. Meanwhile, the electrical pulse accelerated the sulfate ion penetration into the samples at different erosion temperatures compared with the samples subjected to immersion. In addition, ettringite, gypsum and thaumasite formation were observed in the samples at a low-temperature (5 °C), whereas high temperatures (20 °C and 40 °C) led to ettringite and gypsum formation only. The degradation analysis of the reliability of life-based on the Wiener stochastic process demonstrated that the service life of samples at 5 °C, 20 °C and 40 °C in the electrical test were 190, 85, and 45 days, respectively. In summary, the study findings indicated that limestone powder or machine-made sand made of limestone are not suitable as the constituent material of cement-based materials to resist sulfate erosion in a high geothermal environment.