Combined Stress Wave Techniques to Estimate Concrete Strength

摘要

An experimental program was carried out to evaluate the use of combined stress wave testing to estimate concrete strength. Concrete test samples with water/cement ratios of 0.4 to 0.6 and aggregate/cement ratios of 3.9 to 6.3 were prepared and tested. The concrete cylinders were monitored for 28 days after casting. After carrying out the stress wave testing, the standard compressive strength of each cylinder (f'_c) was determined. The stress wave testing results were analyzed using a velocity model and a model combining velocity and attenuation indices. Subsequently, results were correlated with the corresponding f'_c, using least squares regression analysis. The validity of the equations developed from the regression analysis was further corroborated by casting new concrete cylinders and monitoring them over a period of 87 days. This paper discusses the issues related to the use of stress wave testing in estimating concrete strength.