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.
Production of tires in Indonesia increase steadily, however, utilization of waste tires is very limited. Thus, it is necessary to look for an alternative using waste tires for concrete construction. The objectives focus on using crumb rubber as a waste tire with variations in substitution of crumb rubber to fine aggregate in the concrete of 0%, 10%, 20%, and 30%. In addition, to improve crumb rubber bonding to the concrete mixture, 10% NaOH solution was used. This research is true experimental by making a concrete mixture with a target strength of 20 MPa. The compressive strength testing was conducted at 3, 14, and 28 days, while for splitting test and modulus of elasticity at 28 days. The result showed that each addition 10% of crumb rubber, the weight of concrete volume decreased by 3 %. Compressive strength and splitting strength also decreased with increasing crumb rubber volume. Every 20% addition of crumb rubber, the compressive strength decreased of 26%, while the splitting strength decreased by 10%. The substitution of crumb rubber more than 20% of the volume of fine aggregate is not recommended.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.