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Rebar (short for reinforcement bar or reinforcing bar), known when massed as reinforcing steel or steel reinforcement, [1] is a tension device added to concrete to form reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension.
When the tensile strength of concrete is exceeded in the concrete cover above the rebar, concrete starts to spall. Cracks appear in the concrete cover protecting the rebar against corrosion and constitute preferential pathways for CO 2 direct ingress towards the rebar. This accelerates the carbonation reaction and in turn the corrosion process ...
Conventionally the term concrete refers only to concrete that is reinforced with iron or steel. However, other materials are often used to reinforce concrete e.g. organic and inorganic fibres, composites in different forms. While compared to its compressive strength, concrete is weak in tension. Thus adding reinforcement increases the strength ...
The initiation time is related to the rate at which carbonation propagates in the concrete cover thickness.Once that carbonation reaches the steel surface, altering the local pH value of the environment, the protective thin film of oxides on the steel surface becomes instable, and corrosion initiates involving an extended portion of the steel surface.
Concrete spalling from the ceiling of an office unit (interior) in Singapore, possibly due to rebar corrosion. Reinforced concrete can fail due to inadequate strength, leading to mechanical failure, or due to a reduction in its durability. Corrosion and freeze/thaw cycles may damage poorly designed or constructed reinforced concrete.
The rebar-based formative skeletal structure can also act as a core on which printable concrete is shotcreted in a new method developed at TU Braunschweig. [11] The rebar cages can also be installed inside printed concrete formworks in non-structural members, and the holes are filled with grout.
The early strength of the concrete can be increased if it is kept damp during the curing process. Minimizing stress prior to curing minimizes cracking. High-early-strength concrete is designed to hydrate faster, often by increased use of cement that increases shrinkage and cracking. The strength of concrete changes (increases) for up to three ...
The purpose of concrete cover is to protect the reinforcement from corrosion, fire, and other potential damage. The required concrete cover depends on several factors, including the environmental conditions to which the structure will be exposed, the size of the reinforcing steel, the concrete strength, and the type of structure being constructed.