Rebound Hammer Test: An Investigation into Its Reliability in Applications on Concrete Structures

Figure 7

Calibration curve for different stress states. Average compressive stress: dashed line: 5 MPa; dash-dotted line: 10 MPa; continuous line: 0 MPa; dotted bold: Schmidt curve. Calibration curve: R_c = e^aRI; RI = rebound index; a∈[0.088, 0.096]; R² ≅ 0.67. Inside any dataset, C.o.V. ≤ 9% for vanishing stress; C.o.V. ≤ 6% for compressed prisms (5 and 10 MPa).