Experimental investigation and modeling of hydration and performance evolution of fly ash cement

A systematic study on several mix designs has been carried out to correlate the microstructural properties, i.e. degree of hydration, C–S–H composition, capillary porosity to the mechanical properties, such as compressive strength and elastic modulus. For this purpose, thermodynamic modeling was used to calculate the type and amount of hydrates formed during ongoing hydration of ordinary Portland and blended fly ash cements. Obtained results of the phase development over the hydration time agree well with the measured amount of the phases. Additionally, by plotting the measured compressive strength versus the modeled porosity, a quasi-unique relationship for both, OPC and OPC blended systems, is obtained. This new finding gives further insights allowing us to develop a micromechanical model linking the mineralogical composition of anhydrous systems to corresponding mechanical properties. On the other hand, it provides a possibility to improve the composition of cementitious systems to improve their properties and performance.