Graduate Assistant: Prasanth Tanikella Faculty Advisor: Jan Olek

1. Incorporation of physical and chemical properties of fly ash in modeling hydration of blended cements Graduate Assistant: Prasanth Tanikella Faculty Advisor: Jan Olek Introduction Modeling of fly ash in concrete Estimation of Synergic Action • Hydration properties of concrete modeled using CEMHYD3D • Steps in hydration modeling • Creation of a 3D microstructure • Simulation of hydration and microstructure development (this includes hydration kinetics and chemistry, temperature and curing conditions • Virtual testing of resultant microstructure • Scope of the project • CEMHYD3D is equipped with modeling of low percentages of limestone in cement • Prediction of properties with fly ash in cement is possible • The variations in hydration is due to the difference in the PSD, composition, activation energies, hydration products • Microstructure of the input 2D SEM image is different when fly ash is included in cement • Phase volume, surface fractions and hydration stoichiometry vary • Correlation structures to be executed for fly ash phases as well • Explore the utility of CEMHYD3D to predict the synergistic effects of blended fly ashes. • Traditional products of hydration of cement are calcium silicate hydrate, calcium hydroxide, AFm and Aft phases, hydrogarnet • When hydrated by itself, class C fly ash predominantly yields calcium aluminosilicate hydrate, stratlingite and monosulphate • Introduction of fly ash in cement concrete alters both the kinetics and the products of hydration • Efficiency factors • Efficiency factors for compressive strengths • Efficiency factors to determine the pozzolanic effect of the admixtures • Quantification of Synergic action • Synergic Action (SA) • Strength gain • ` • Synergic action is known to be affected by curing time and temperature in the form of the constant ‘a’ Research Objectives • The focus of the present research is on studying and modeling of synergistic effects of ternary mixes of fly ash • To modify CEMHYD3D so as to incorporate the influence of fly ash in binary and ternary cement mixes and model the hydration characteristics Properties of available fly ashes • All the following experiments were performed on the fly ashes from 20 different sources across Indiana which include both class F and class C ashes • Total Chemical Analysis • Particle Size Distribution • Magnetic particle content • X-Ray diffraction analysis • Scanning electron microscopy • Strength activity index Conclusions • Synergistic effects due to other properties of fly ash which are already measured (from the set of fly ashes available) are unknown and can be estimated • Modeling of fly ash in concrete and the incremental effects can be found out by modifying the original CEMHYD3D model