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The durability design of reinforced concrete structures has been recently introduced in national and international regulations. It is required that structures are designed to preserve their characteristics during the service life, avoiding premature failure and the need of extraordinary maintenance and restoration works.
Example of flat piece of concrete having dislodged with corroded rebar underneath, Welland River bridge across Queen Elizabeth Way in Niagara Falls, Ontario. The expansion of the corrosion products (iron oxides) of carbon steel reinforcement structures may induce internal mechanical stress (tensile stress) that cause the formation of cracks and disrupt the concrete structure.
Frost damage of early-age concrete is particularly harmful for the concrete mechanical resistance because the ice volume expansion causes micro-cracks in the concrete structures, and as a consequence it lowers the compressive strength of concrete. [4]
The improvement of concrete durability using controlled permeability formwork. Proceedings of the 5th International Conference “Structural Faults Repairs, Vol 2, 1993, pp. 233–238. Price, W.F.
Concrete tests can measure the "plastic" (unhydrated) properties of concrete prior to, and during placement. As these properties affect the hardened compressive strength and durability of concrete (resistance to freeze-thaw), the properties of workability (slump/flow), temperature, density and age are monitored to ensure the production and ...
Self-consolidating concrete or self-compacting concrete (SCC) [1] is a concrete mix which has a low yield stress, high deformability, good segregation resistance (prevents separation of particles in the mix), and moderate viscosity (necessary to ensure uniform suspension of solid particles during transportation, placement (without external compaction), and thereafter until the concrete sets).
Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [1] and is the most widely used building material. [2] Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. [3]
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 ...