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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.
Structural concrete can also be used for flat roof constructions. There are three main categories, precast/prestressed, cast-in-place and shell. There are many types of precast/prestressed concrete roofing. The following are the most common types. [8] Double tees are the most common products for short spans up to 60 feet (18 m)
Fretting refers to wear and sometimes corrosion damage of loaded surfaces in contact while they encounter small oscillatory movements tangential to the surface. Fretting is caused by adhesion of contact surface asperities, which are subsequently broken again by the small movement. This breaking causes wear debris to be formed.
To attempt to simplify and to stylize a very complex set of various reactions, the whole ASR reaction, after its complete evolution (ageing process) in the presence of sufficient Ca 2+ cations available in solution, could be compared to the pozzolanic reaction which would be catalysed by the undesirable presence of excessive concentrations of alkali hydroxides (NaOH and KOH) in the concrete.
The individual gaps are sealed by watertight elastomeric profiles, and surface beam movements are regulated by an elastic control system. The drainage of the joint is via the drainage system of the bridge deck. Certain joints feature so-called “sinus plates” on their surface, which reduce noise from over-passing traffic by up to 80%. [2]
Because the masonry veneer is non-structural, it must be tied back to the building structure to prevent movement under wind and earthquake loads. Brick ties are used for this purpose, and may take the form of corrugated metal straps nailed or screwed to the structural framing, or as wire extensions to horizontal joint reinforcement in a fully masonry veneer or cavity wall.
Highly decorative wood-shingle siding on a house in Clatskanie, Oregon, U.S. Siding or wall cladding is the protective material attached to the exterior side of a wall of a house or other building. Along with the roof, it forms the first line of defense against the elements, most importantly sun, rain/snow, heat and cold, thus creating a stable ...
In 19th-century shipbuilding, composite construction was the use of an iron hull framework which was covered in timber planking to provide the water-tight skin of the hull. If properly insulated fastenings were used on the timber, the underwater hull could be covered with copper sheathing without the problem of galvanic corrosion.