The concrete cover is the distance from the outer edge of the outermost reinforcement to the concrete surface. In the durability design, this protective layer shall be the layer of the outermost steel bar when there is no specification.
The role of concrete protective layer
1. In the concrete structure, reinforced concrete is a composite material composed of two different materials of steel and concrete. The good bonding properties of the two materials are the basis of their joint work. The requirements from the angle of reinforcement bonding of steel bars to the concrete protection layer are obtained in order to ensure that the steel bars work together with the surrounding concrete, and the steel bars can fully exert the strength required for calculation.
2. The steel bars are exposed to the atmosphere or other media are easily corroded and rusted, which reduces the effective cross-section of the steel bars and affects the structural stress. Therefore, it is necessary to specify the minimum thickness of the concrete protective layer for different use environments according to the durability requirements to ensure that the components does not occur the corrosion of structural reinforcement in the design life of the steel.
3. Fire protection requirements for reinforced concrete beams, slabs, prestressed members and the concrete protective layer are use to ensure the components are in the fire during the fire resistance limit determined by the fire resistance of the building and make sure the components will not loss support. The concrete protective layer should meet the requirements of relevant national standards.
GB50010-2010 (2015 edition) "Code for design of concrete structures" stipulates:
Concrete protective layer regulations
The thickness of the concrete protective layer of ordinary steel bars and prestressed tendons in the components shall meet the following requirements:
The thickness of the protective layer of the stressed steel bar in the component shall not be less than the nominal diameter of the steel bar.
The concrete structure with a design life of 50 years shall be designed. The thickness of the protective layer of the outermost steel bar shall comply with the following tables; for the concrete structure with a design life of 100 years, the thickness of the protective layer of the outermost steel bar shall not be less than 1.4 times.
1. When the concrete strength grade cannot more than C25, the thickness of the protective layer in the table should be increased by 5mm;
2. The reinforced concrete foundation should be provided with a concrete cushion. The thickness of the concrete protective layer of the reinforcement in the foundation should be calculated from the top surface of the cushion and should not be less than 40mm.
Concrete protection layer inspection basis
GB50010-2010 "Code for design of concrete structures" (2015 edition)
GB 50204-2015 “Code for acceptance of constructional quality of concrete structures”
GB/T50344-2004 “Technical standard for inspection of building structure”
JGJ/T152-2008 “Technical specification for test of reinforcing steel bar in concrete”
DB11/T365-2016 “Technical specification for inspection of the depth of coverage and the diameter of reinforcing bars in concrete by electromagnetic method”
GBT 50784-2013 "Technical standard for in-site inspection of concrete structure"
JJF1224-2009 “Calibration Specification for reinforced concrete covermeter and floorslab thickness tester”
Concrete protective layer detection technology
Concrete cover measuring instrument
The concrete cover gauge can be used to detect the spacing of the steel bars in the concrete structure and the thickness of the concrete cover.
Detection principle: The method of detecting the spacing of steel bars, the thickness of concrete protective layer, the nominal diameter of concrete structures and components by electromagnetic induction principle.
The Profometer 630AI is an advanced protective layer measuring instrument based on the new generation Profometer touch screen with universal probes and scanning carts. The enhanced correction factor provides maximum protection layer accuracy for dense rebar layout areas. Specific features are used to map the concrete cover and report any 2D rectangular bar layout.
Single line mode
Area scan mode (displays the first layer of steel protection layer)
Rooting civil engineering, reducing engineering costs, reducing engineering risks... Earth Products China Limited have been firmly committed for 32 years.
PM-630AI concrete cover measuring instrument
In order to thank your help and support, we are now giving you a special discount to the PROCEQ products.
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PM-630AI concrete cover measuring instrument
Original price: $65,000
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32 years anniversary, we offer 32 sets with breakdown price as a feedback
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● The sixth generation of the Profometer system
● Based on AI algorithm, it can measure the protective layer under dense double-row steel bar configuration
● High precision and high reliability for single line, multi-line, area scan measurement and analysis
● Upgradeable half-cell potential measurement module, combining steel bar detection and rust analysis to achieve dual-use
For more information, please contact Earth Products China Limited.
Service hotline: 400-700-9998
Official website: en.epccn.com