BOND STRENGTH BETWEEN SHOTCRETE OVERLAY AND REINFORCED CONCRETE BASE

摘要

1. The tensile bond strength was essentially the same for both hydroblasted and mechanically blasted methods of surface preparation: 142.0 psi (0.98 MPa) and 139.8 psi (0.96 MPa), respectively. 2. The shear bond strength was similar for both hydroblasted and mechanically blasted methods of surface preparation: 1047.7 psi (7.22 MPa) and 972.7 psi (6.71 MPa), respectively. 3. The ratios of shear to tensile bond strengths were similar for both hydroblasted and mechanically blasted surfaces: 7.38 and 6.96, respectively. 4. The average shear strength for the overlay and base was 992.6 psi (6.84 MPa) and the average shear bond strength was 1016.8 psi (7.01 MPa). Bond strengths are as high as can be expected based on the shear strengths of the overlay and base. 5. There is not a good correlation between tensile and shear bond strength tests. 6. The ratio between shear and tensile bond strength is about 3 to 4 for surfaces with a macro texture of 0.06 in. (1.5 mm) and increases as the macro texture increases to a ratio as high as 7. 7. Shear bond strength increases as the shear strength of the base concrete increases but the correlation is not good. 8. The guillotine shear bond test has potential to be a standard.