Investigating the Effect of Repeated High Water Pressure on the Compressive and Bond Strength of Concrete with/without Steel Bar

Abstract

The application of reinforced concrete for permanent and temporary deep ocean structures has recently become more prevalent; however, the static and dynamic effects of high water pressure on concrete remain unexplored. This paper investigates the influence of high water pressure (60 MPa) on four series of concrete cylinders with and without an embedded steel bar under sustained and cyclic loading conditions. The residual compressive strength, bond strength, and associated evolution of surface and internal damage are evaluated after exposing concrete cylinders to a water pressure of 60 MPa. The first series is exposed to sustained water pressure for 7 and 60 days, while the other series is tested under repeated water pressure for 10, 20, 30, 60, and 150 cycles. The results reveal that residual compressive strength falls immediately by 16% within 7 days of sustained high water pressure, but the strength then remains stable up to 60 days. Under repeated high water pressure, residual compressive strength gradually reduces by up to 40% until 60 cycles, after which it remains reasonably stable until 150 cycles as crack propagation is arrested at a certain depth within the concrete cylinders. The bond strength between the steel bar and matrix is observed to decrease considerably under repeated cycles of 60 MPa water pressure up to 26%. The damage gradually propagates at the matrix/steel bar interface under the repeated water pressure, resulting in a reduction in residual pullout capacity.

Evolution characteristics and mechanism of concrete performance under water pressure environment: A comprehensive review

“…Wegen et al 20 conducted uniaxial compression tests on concrete at different hydrostatic pressures and found that water pressure did not adversely affect strength. Muhaimin et al 29 applied a high water pressure of 60 MPa to concrete and found that residual compressive strength decreased significantly. This was a result of the hydraulic gradient caused by the huge difference in internal and external water pressure.…”

“…References [7, 8, 11, 12, 17, 18, 20–22, 29, 39–41] were studied on the static strength of concrete after exposure to water pressure. In terms of dynamic strength, Zhou et al 11 used the SHPB device to conduct dynamic mechanical tests on concrete after exposure to different water pressures.…”

“…However, concrete in practical engineering is usually affected by circulating water pressure. Muhaimin et al 29 conducted repeated high water pressure tests on reinforced concrete and found that surface cracks gradually expanded as the number of water pressure cycles increased, resulting in a decrease in bond strength between steel bars and concrete matrix, as well as a decrease in residual uniaxial compressive strength.…”

“…Other researchers, Peng et al, 27 and Wang et al 28 carried out dynamic triaxial compression tests considering the effect of loading rate on hydraulic concrete. Muhaimin et al 29 and Peng et al 30 considered the effect of cyclic water pressure on concrete and carried out mechanical tests on concrete under cyclic water pressure. In addition, some researchers 31,32 focused on the influence of water pressure on concrete permeability and found that penetration depth increased with the increase of water pressure.…”

Nonlinear Mechanical Effect of Free Water on the Dynamic Compressive Strength and Fracture of High-Strength Concrete

“…Water or an aqueous solution in the pore space has a significant effect on the mechanical properties of concrete. The pore fluid is reported to be responsible for numerous phenomena of premature fracture of various brittle materials (including concretes) under loads significantly lower than permissible for these materials in a dry state [ 6 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ].…”