Coagulation of cement particles is an inevitable phenomenon of fresh cement-based materials undergoing solidification. Coagulation can be classified into two types, reversible flocculation and irreversible coagulation, wherein microstructural change affects the rheological properties, including shear thinning and thixotropy, and the hydration process. This paper attempts to measure the mechanical property and the coagulation of cement particles according to the mix proportions of cement paste. Experimental setups were proposed for two different types of coagulations using a laser backscattering instrument. Volume fraction and size distribution of coagulated particles were obtained, and their variations were discussed. From the obtained results the microstructural buildup of freshly mixed cement pastes can be divided into three categories: permanent coagulation and strong and weak flocculation.
Keywords: cement paste; coagulation; flocculation; laser backscattering; particle size.