Rheology and Hydration of Cementitious Slurries

Predicting temperature effects on rheology and hydration of cementitious slurries considered for oil-well cement applications is important as temperature can vary significantly in a bore-well. During the plastic stage the fluid properties (yield and plastic viscosity) are investigated using a rheometer, while isothermal calorimetry is used to evaluate setting characteristics and early-age (0–7 days) heat of hydration. In this paper, experimental results at 3 different temperatures show that a 50/50 blend of Type I portland cement and slag cement at a 0.45 water-cementitious ratio has similar rheological and hydration properties as the reference system (Type I portland cement paste). The rheological properties were found to follow a two-parameter Bingham model, and temperature effects can be accounted for by an Arrhenius model. The effect of temperature on hydration rate can be predicted by a maturity function, which also is based on the Arrhenius rate model, where the apparent activation energy is a measure of temperature sensitivity.