Prediction of Elastic Moduli Development of Cement Mortars Using Early Age Measurements

This paper presents an investigation of the time development of dynamic and static elastic moduli of eight mortars made using CEM I cements with contrasting properties. Mixing and the preparation of dynamic testing prism specimens conformed to European standards. A nonstandard specimen and bending test setup was devised for measuring the development of a static Young's modulus. It was determined that dynamic Young's moduli determined using an ultrasonic pulse velocity test are often, but not always, greater than those determined using a resonant frequency test. The ratio of a static Young's modulus to a dynamic Young's modulus for a particular cement mortar increased nearly linearly with increasing static modulus after 3 days, and this increase can be predicted using the measured 3-day static modulus. In addition, methods for predicting the increase in the static and dynamic modulus and decrease in Poisson's ratio of mortars, from age 3 to 56 days, using measured 3-day elastic moduli, are presented. Predicted 56-day values of static Young's modulus, dynamic modulus, the ratio of these, and Poisson's ratio for the eight different mortars were within 5% of the measured values. The observed relations among different elastic properties may be useful for verification of prediction models. (C) 2014 American Society of Civil Engineers.