The life of a concrete bridge exposed to deicing salt or seawater has often been limited by corrosion of the steel reinforcement. The service life of a concrete structure, degraded by corrosion, is considered to be the sum of the initiation and propagation periods. The initiation phase is the time required for sufficient accumulation of aggressive species at the rebar surface to initiate corros...

The synthesis of rebar graphene on Cu substrates is described using functionalized boron nitride nanotubes (BNNTs) that were annealed or subjected to chemical vapor deposition (CVD) growth of graphene. Characterization shows that the BNNTs partially unzip and form a reinforcing bar (rebar) network within the graphene layer that enhances the mechanical strength through covalent bonds. The rebar ...

Micro cracks occurring in concrete around tensile rebar is well known latent damage phenomenon. These micro cracks develop, and can be detected after reaching the surface of the concrete. Detection of these cracks before they are fully formed is preferable, but observing the whole crack structure is difficult. Another problem is repairing micro cracks under the concrete surface. The autogenous ...

As the cylindrical sp(2)-bonded carbon allotrope, carbon nanotubes (CNTs) have been widely used to reinforce bulk materials such as polymers, ceramics, and metals. However, both the concept demonstration and the fundamental understanding on how 1D CNTs reinforce atomically thin 2D layered materials, such as graphene, are still absent. Here, we demonstrate the successful synthesis of CNT-toughen...

This paper studied the effects of reinforcement corrosion on bond performance between rebar and concrete. Tests were carried out to evaluate the degradation of bond between reinforcing steel and concrete for different corrosion levels of reinforcing steel. A series of 20 specimens of different concrete strength with various reinforcing steel corrosion levels were designed and manufactured. Each...

The deterioration of bond strength between reinforcing steel and concrete as a result of impressed cathodic current with respect to the exposure time was investigated. A current in the magnitude of 3ma/ft2 (based on reinforcing rebar area) was used for a period of five years. Chemical analyses for sodium (Na+), potassium (K+) and chloride (Cl-) ions in concrete cylinders were performed as a fun...

Modeling of reinforced concrete structures through the use of 3D detailed models derives significant numerical issues especially when dealing with large-scale meshes that incorporate large numbers of reinforcement bars embedded in the hexahedral mesh. In 3D detailed reinforced concrete simulations, mapping the reinforcement grid inside the concrete hexahedral finite elements is performed using ...

OBJECTIVE Excelsior XT-27 (Stryker Neurovascular, Fremont, CA, USA) or Rebar 27 (eV3 Covidien, Irvine, CA, USA) microcatheters have recently been used to overcome the limitations of the Renegade Hi-Flo microcatheter such as interference between two microcatheters (one for stent delivery and the other for cerebral aneurysm coiling) during the jailing technique. We evaluated differences and influ...

Severe corrosion of epoxy coated rebar in the substructure of 5 major marine bridges in the Florida Keys was detected after only a few years of construction. Corrosion occurred underneath the coating and was preceded by loss of adherence between the steel and the coating. Damage surveys of the bridges, which were built around 1980, were conducted from 1986 to 2000. Corrosion resulted in delamin...

This study focused on the residual strengths of reinforced concrete beams with heavy deterioration. This work is based on experimental investigation of reinforced concrete beams naturally corroded over 30 years. Visual inspection was firstly conducted and the concrete cracking, spalling of concrete cover, corrosion of rebar were recorded. Material tests on concrete and corroded rebar were also ...