Cold Sintering of Calcium Carbonate for Construction Material Applications

An alternative to traditional binder-based construction materials using "cold sintering", a hydrothermal mechanism that involves subjecting the sample to simultaneous pressure and comparatively low temperatures, was explored. Ground and precipitate calcium carbonates (GCC and PCC) were used as the primary starting materials. Ordinary portland cement (OPC) and zinc oxide were studied for comparison. Compressive strength tests showed promising results from the OPC mortars with the cement mostly replaced by GCC. Scanning electron microscopy showed sintering of calcium carbonate and zinc oxide with the selection of suitable solutions. Porosity of sintered samples measured by nitrogen adsorption-desorption improved considerably. These data support the feasibility of cold sintering as an alternative method for production of conventional precast construction materials.