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Steel-reinforced concrete characteristics
Published in Brian Cherry, Green Warren, Corrosion and Protection of Reinforced Concrete, 2021
The durability, strength, shrinkage, wear resistance, and other mechanical properties of concrete will be influenced by aggregate characteristics such as particle size, shape, and surface texture, hardness, strength, elastic modulus, porosity, contamination, and chemical reactivity with the cement paste. Aggregates do not normally influence the chemistry of cement unless they participate in alkali-aggregate reactions (AAR), as will be elaborated later. Therefore, the chemistry of concrete is usually the chemistry of cement. Use of chloride contaminated aggregates such as sea sand or other materials from saline origins can have dire consequences with respect to reinforcement corrosion, as will be elaborated later. Organic matter may interfere with the hydration of the cement and reduce the final strength of the concrete. Clay and other fine material should be avoided wherever possible as it may coat the aggregate, be chemically reactive, and/or form soft inclusions in the concrete. It may also increase the water demand of the concrete.
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Published in J. Russell Boulding, Epa Environmental Engineering Sourcebook, 2019
The presence of large inclusions in the area to be treated can limit the use of the ISV process. Inclusions are highly concentrated contaminant layers, void volumes, containers, metal scrap, general refuse, demolition debris, rock, or other heterogeneous materials within the treatment volume. Figure 14-1 gives limits for inclusions within the treatment volume [7, p. 17]. If massive void spaces exist, a large subsidence could result in a very short time period. These problems, as well as those caused by other large inclusions, may be detected by ground penetrometry or other geologic investigations. Some inclusions such as void volumes, containers, and solid combustible refuse can potentially generate gases. However, the oversized hooding is intended to control and mitigate any release. If large volumes of off-gases are generated during a short time period, the off-gas treatment system may overload. Vitrification of flammable or explosive objects can result in spattering of the molten glass. Underground storage tanks can be treated only if they are filled with soil prior to the vitrification process.
Soil Mechanics
Published in P.K. Jayasree, K Balan, V Rani, Practical Civil Engineering, 2021
P.K. Jayasree, K Balan, V Rani
Inclusion: Inclusion is a generic term that encompasses all man-made elements incorporated in the soil to improve its behavior. Examples of inclusions are steel strips, geotextile sheets, steel or polymeric grids, steel nails, and steel tendons between anchorage elements. The term reinforcement is used only for those inclusions where soil-inclusion stress transfer occurs continuously along the inclusion.
Influence of rare earth metals on inclusion modification of dual phase steel
Published in Canadian Metallurgical Quarterly, 2023
Ammasi Ayyandurai, Mohd Uzair Ul Haque
The demand for higher-performance steel and its quality requirements has increased yearly. The automobile industry is one of the significant steel-consuming industries for which the quality of the steel used in automobile applications should be of inclusion free. The formability of steel matters as much as the strength of the components in automobile industries. The cleanliness of the steel mainly depends on the content and type of inclusion present in the steel. Steel quality can be increased by controlling or modifying the non-metallic inclusions because it significantly affects steel properties [1]. Inclusions are chemical compounds combining a metallic element (e.g. Fe, Mn, Al, Si and Ca) and a non-metallic element (O, S, N, C and H). The most common inclusions include oxides, sulphides, oxy-sulphides, phosphates, etc. Inclusions phases are different from the steel matrix, which is the main cause of the failure of the materials. Thus, many efforts have been devoted to controlling the composition, size and amount of inclusions. There are several ways of removing or modifying inclusions based on density, magnetic stirring, calcium and synthetic slag treatment. However, calcium treatment is the method that many industries adopt because it is very effective and economical to modify the Al-Mg-rich inclusions (spinels) to large, isotropic, and spherical calcium aluminates and calcium sulphides with low melting points. Though, it also has issues when the size of the inclusions increases or gets trapped in the steel. Therefore, steelmakers have been finding different elements instead of calcium, which can modify the inclusions very well. Also, if it remains trapped in liquid steel, it should have a significantly less or null harmful effect on the steel properties. In recent years, steelmakers have started using rare earth metals (REM) because they can modify the shape of sulphide inclusions and improve the hot workability of steel and also reduces the degree of undercooling, refines the as-cast structure and limit solidification segregation in steel. REM has a greater affinity towards oxygen and sulphur [2]. It also promotes steel properties such as impact toughness, magnetic properties and corrosion resistance [1]. One of the rapidly growing steels in the world is advanced high strength steel (AHSS), mainly Dual Phase (DP) steel is much more useful than any other AHSS grade steel in the automobile industry. However, DP steel has several drawbacks, such as poor stretch-flange-ability and formability. The failure of the material due to inclusions present in the steel at rolling or metal forming processes should be avoided. Moreover, one of the prominent inclusions in the steel, which need to be modified to improve the formability of DP steels, is MnS. This study adds RE into dual-phase (DP) steel to control and modify the secondary inclusions. The severity of the inclusion and global cleanliness index of steel has been measured using the inclusion classifier and ISO 4967 standard method.