Non-destructive ultrasound and sclerometry tests to estimate the optimization resistance of concrete

ABSTRACT

Concrete compressive strength (fck) is generally estimated by the axial compression test, with non-destructive methods considered as a second option. The objective of the study is to evaluate the quality of concrete through ultrasonic and sclerometric tests, correlating them with the axial compression method. 60 concrete specimens aged 7, 14 and 28 days were made. The results of the ultrasound tests showed greater dispersion for 7 days of age, possibly due to its initial stage of healing. As healing progressed, the accuracy of the ultrasound assay improved significantly, especially at 28 days. It can be stated, with 95% confidence, that for wave propagation speed results above 4550 m/s, they represent characteristic compressive strength greater than 25 MPa and average resistance greater than 30 MPa. In the sclerometry test, the results indicated higher characteristic resistances than those obtained in the axial compression test. For sclerometric compression strength results greater than 38 MPa, the expected fck results are 25 MPa, with 95% confidence. It was concluded that the results of this study point to the existence of an effective correlation between the compressive strength obtained in the different tests.

Keywords
compressive strength; ultrasound; sclerometry; non-destructive testing