A Study of the Correlation Between Static and Dynamic Modulus of Elasticity on Different Concrete Mixes

This study is to determine the relationship between the Static Modulus of Elasticity and the Dynamic Modulus of Elasticity in various concrete mixes. The Static Loading Test was used to measure the strains associated with applied stresses on cylindrical concrete specimens to determine the Static Modulus. An Ultrasonic Pulse Wave Velocity (UPV) technique was utilized to measure the travel time of pulse waves propagating through rectangular prism specimens. The travel times were used to compute the Dynamic Modulus of Elasticity. An Impact Hammer measuring device was also used to measure resonance frequencies of vibrations in rectangular prisms, which also correlate to the Dynamic Modulus.;Four different concrete mixes were cast and each underwent the testing at 1, 3, 7, 14, and 28 days. The four concrete mixes were a 50% Slag mix, a 30% Flyash mix, an Ordinary Portland Cement (OPC) mix, and a Self-Consolidating Concrete (SCC) mix. The relationships between different calculated moduli values were plotted against each other to determine the correlation between them. Empirical relationships based on these values were then determined. The Static Modulus values were also computed using ACI 318 equations, and were compared to the measured Static Modulus values.;The results show that the Dynamic Modulus of Elasticity is higher than the Static Modulus of Elasticity for each concrete mix. The Dynamic Modulus obtained from UPV resulted in the highest values, while the Static Modulus was the lowest at all ages. The relationship between the Static and Dynamic Modulus is linear. The Dynamic Modulus from UPV and Vibration methods also exhibits a linear relationship. Empirical equations were developed to estimate the Modulus of Elasticity at different ages.;SCC had a much higher compressive strength compared to other concrete mixes. The use of ACI 318 equations to estimate Young's Modulus from 28-day compressive strength yielded conservative values as compared to the measured Static Modulus values.