Corrosion of Buried Steel at New and In-Service Infrastructure (2023) / Chapter Skim
Currently Skimming:
2 Fundamentals of Steel Corrosion, Industry Applications and Approaches, and Sources of Corrosion Data
2 Fundamentals of Steel Corrosion, Industry Applications and Approaches, and Sources of Corrosion Data
Pages 17-28
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 17... ...
However, the spatial and temporal variations of materials found under Earth's surface in which steel is buried are even more complex and difficult to understand, and the steel more difficult to protect. Before presenting information about the complexities of corrosion and corrosion prediction in later chapters, this chapter presents some fundamentals regarding steel corrosion at the electrochemical level, describes different types of buried-steel applications, discusses general industry approaches to protection of steel from corrosion, and highlights sources of data regarding corrosion of buried steel.
|
From page 18... ...
More details of steel Box 2.1 provides a description of corrosion corrosion potential.are providedMore in Chapter 4.steel corrosion are provided in Chapter 4. Soil and rock serve twodetails primary BURIED ofbut STEELfunctions distinct APPLICATIONS in infrastructure construction: first, they can Soilbeandusedrock serve two as building primarytobut materials distinct construct functions geotechnical BURIED STEEL inassets infrastructure construction:dams, (e.g., embankments, APPLICATIONS first,slopes, they can and some be used types as building Soilof and materials rock serve retaining to construct walls)
|
From page 19... ...
The spatial separation of the ions and the alignment of water dipoles results in a potential drop from the metal surface into the solution, which is associated with the corrosion potential.
|
From page 20... ...
The committee calls this the "corrosion allowance approach" and calls those industries in which this approach is applied the "geo-civil industries." The geo-civil industries attempt to predict corrosion rates by characterizing the corrosivity of the earth materials in which the steel is placed. The steel components are then designed with sufficient volumes of steel to compensate for expected steel loss due to corrosion over the design lifetime of the component, the application of protective coatings (e.g., galvanized zinccoated steel reinforcing strips used in mechanically stabilized earth [MSE]
|
From page 21... ...
In all cases and industries, the corrosion of buried steel is caused by the same mechanisms, and the subsurface characterization techniques used by the different industries might be combined to inform both modeling of corrosion rates and design of protective measures. MICROORGANISMS The presence of microorganisms and microbial activity can be anticipated on most buried steel infrastructure.
|
From page 22... ...
Steel casing will be in direct contact with the soil, making corrosivity a significant design consideration that can be addressed with thicker steel casing cross sections or protective coating of steel. The reinforcement may corrode if the grout cracks.
|
From page 23... ...
Areas with grade changes that selected, and thicker steel cross sections are used must be controlled for infrastructure (e.g., with protective coatings (e.g., galvanized steels)
|
From page 24... ...
Ground Anchors Soil nails What are they? Closely spaced tension-carrying Solid-bar soil nails: Constructed by drilling a hole, steel bars grouted into soil.
|
From page 25... ...
The steel Corrosion implications? When the steel corrodes rods mitigate slip by resisting shear through their in a section under tension, it cannot stabilize the cross section but do not undergo tension that would mass and the rock face or slope will move (or fail)
|
From page 26... ...
Corrosion can result and leakage, depending on the type of liquid, can result in environmental contamination including groundwater. Underground Storage Tank SOURCE: Diagrams of piles, drilled shafts, MSE walls, sheet piles, ground anchors, soil nails, and rock bolts from Keller Management Services, LLC (2022)
|
From page 27... ...
It is reasonable to conclude that the high level of uncertainty associated with the experimental data could lead to either costly overconservative design or unsafe underconservative design. Since completion of the NBS studies, others have studied the performance of buried steels and archived data from specific applications (e.g., related to MSE walls, piles, ground anchors, rock bolts, and culverts)
|
From page 28... ...
The effects of a number of different parameters were investigated, including pipe size, slope, and corrugation type; soil temperature, resistivity, pH, and abrasiveness; and water temperature, resistivity, pH, chemistry, and flow rate. • Studies on the corrosion of ground anchors, rock bolts, and soil nails are reported by the National Cooperative Highway Research Program (Withiam et al., 2002)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.