Strain Measurement Methods: ASTM C520 and non-standard method

The current method to measure creep and shrinkage as stated by ASTM C512 utilizes a minimum of four concrete cylinders, and a Whittmore strain gauge to measure deflections. Research being conducted at the University of Wyoming uses a new measurement technique that utilizes one cylinder measuring 4 inches in diameter and 45 inches in height. This technique also uses a Long Gauge High Range Extensometer (LGHRE). Research presented in this paper conducts tests to determine the validity of the technique. This is done by measuring the dispersion of the two techniques and comparing the results. The results of this research suggests that the technique using the tall cylinders and LGHRE meets and exceeds the coefficient of variation from ASTM C512, while taking less than half the time to measure. Additionally, the results of this research are compared to various mathematical models used to predict modulus of elasticity. Most models predicted a reasonable modulus of elasticity. Future research is suggested into comparing the results of the two techniques when measuring creep of concrete.