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A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving ( see below ).
If rebars have been improperly installed or have inadequate concrete cover at surfaces exposed to the elements, oxide jacking and spalling can occur during the structure's lifetime: flat fragments of concrete are detached from the concrete mass as a result of the rebar's corrosion. Concrete, like most consolidated hard rocks, is a material very ...
Concrete, which must be free of trash, wood, paper and other such materials, is collected from demolition sites and put through a crushing machine, often along with asphalt, bricks and rocks. Reinforced concrete contains rebar and other metallic reinforcements, which are removed with magnets and recycled elsewhere. The remaining aggregate ...
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.
Normal concrete contains 19 mm (0.75 in) equivalent diameter aggregate which is 35-45% of concrete, fibers longer than 20 mm (0.79 in) are more effective. However, fibers that are too long and not properly treated at time of processing tend to "ball" in the mix and create work-ability problems.
Concrete roadway in San Jose, California A concrete road in Ewing, New Jersey. Concrete surfaces (specifically, Portland cement concrete) are created using a concrete mix of Portland cement, coarse aggregate, sand, and water. In virtually all modern mixes there will also be various admixtures added to increase workability, reduce the required ...
Rebar (short for 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. Concrete is strong under compression, but has low tensile strength.