Sulphuric Acid Resistance of Cementitious Materials: Multiscale Approach to Assessing the Degradation

Abstract

The deterioration of conventional cement (CC) and alkali-activated (AA) cementitious materials when exposed to sulphuric acid is influenced by the scale, both in terms of scale of manufacture (paste, mortar, and concrete) and level of observation (microscopic to macroscopic). The degradation of samples at the microscale was examined using scanning electron microscopy, energy dispersive x-ray, x-ray diffraction, Fourier transform infrared spectroscopy, and microcomputed tomography. Macroscopic measurements were used to establish the cross-section change, mass loss, and compressive strength. In addition, the ion change in the reservoir solution was examined using inductively coupled plasma mass spectroscopy. Microscale and macroscale measurements highlight the fundamental difference in the degradation of CC and AA materials, and therefore current simple indicator tests are inadequate for comparing the performance of materials.