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Shaped like a “U” or channel to catch water (e.g., where the edge of a tile roof meets a wall). Through wall flashing Spans the thickness of the wall and directs water to weep holes. Cap flashing (drip cap) Often used above windows and doors. Drip edge A metal used at the edges of a roof. Step flashing (soaker, base flashing)
Concrete sealers are applied to concrete to protect it from surface damage, corrosion, and staining. They either block the pores in the concrete to reduce absorption of water and salts or form an impermeable layer which prevents such materials from passing.
Cathodic protection (CP; / k æ ˈ θ ɒ d ɪ k / ⓘ) is a technique used to control the corrosion of a metal surface by making it the cathode of an electrochemical cell. [1] A simple method of protection connects the metal to be protected to a more easily corroded " sacrificial metal " to act as the anode .
Concrete cover, in reinforced concrete, is the least distance between the surface of embedded reinforcement and the outer surface of the concrete (ACI 130). The concrete cover depth can be measured with a cover meter. The purpose of concrete cover is to protect the reinforcement from corrosion, fire, and other potential damage.
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.
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]
The Republican president-elect has threatened to impose a 25% tax on all products entering the U.S. from Canada and Mexico as one of his first executive orders when he takes office in January.
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.