Field Performance of Portland Limestone Cement Concretes Exposed to Cold-Temperature Sulphate Solutions

摘要

This paper presents data from a field test program to evaluate the sulphate resistance of concrete produced with varying limestone contents (0-15%) and supplementary cementitious materials (SCM) contents in order to evaluate the risk of thaumasite formation, which is expedited at cold temperatures (0-10 °C). Concrete specimens were placed in one of three sulphate solutions (Na2SO4, MgSO4, CaSO4), which were buried approximately 2 m below ground (temperature varying from 4 to 13 °C). Specimens were retrieved annually to measure expansion, resonant frequency, mass loss and to conduct visual rating. Following six years of exposure, concrete with higher w/cm exhibited an increased level of expansion; however, minimal differences were found between varying limestone contents. The addition of fly ash or silica fume to Portland limestone cement produced concretes with better sulphate resistance than Type MS (moderate sulphate) cement concretes and mirrored the performance of ordinary Portland cement with fly ash and silica fume.