Development of micro and macro fracture properties of cementitious materials exposed to freeze-thaw environment at early ages

Abstract

The freeze–thaw cycles can affect the fracture properties of early age cementitious materials significantly. Considering the multiscale and multiphase nature of cementitious materials, it is of significance to study the fracture properties of cementitious materials across scales. This study investigates the development of fracture properties of cement paste subject to freeze–thaw cycles at the age of 1, 3, and 7 days at both macro and micro scales by using the three-point bending test method and the nano scratch technique, respectively. At micro scale, the fracture properties of the unreacted clinker, the hydrates and the interfacial transition zone (ITZ) between the clinker and the hydrates phases were measured. The developments of micro fracture properties of the three phases and the macro fracture properties of paste beams are evaluated and compared for both frozen and unfrozen samples. For the first time the nano-scratching technique was used to study the effect of the early age frost attack on the fracture properties of individual phase in cement paste. The findings in this study provide an insight into the fracture properties of cementitious materials from the microscopic point of view, and will benefit the further understanding of the mechanism of freeze–thaw damage to cementitious materials.