Strength development and micro-mechanism of magnesium oxychloride cement concrete

Abstract

This paper presents the feature of magnesium oxychloride cement and its particle. Water-resistant admixture and other inorganic materials (silica fume, fly ash and slag) with mix proportion were added to the mix proportion to improve the mechanical properties of magnesium oxychloride cement concrete. By recording the uniaxial compressive strength of concrete at 7–128 days, the influences on the early and late strength of magnesium oxychloride cement caused by different inorganic materials and varied consumption of magnesium chloride solution were analysed. It is shown that the early strength development is fast and the strength with fly ash performs the highest strength; the late strength of concrete reduces because of the scumming of magnesium oxychloride cement, but the strength resumes. Using X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscope to investigate the micro-mechanism, the dense gel phase is found in magnesium oxychloride cement concrete with fly ash, which led to the advantage in compressive strength over other samples.