Applications of Portland Cement

Portland cement is widely used in the construction industry for the manufacture of concrete with admixtures. such as gravel, sand and expanded materials, with steel reinforcement as reinforced concrete and as a binder between bricks and other building blocks. 

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Risch A, Pollmann H, Ecker M (1997) Application of Portland cement and high alumina cement for immobilization/solidification of a waste model composition. Proceedings of the 10th ICCC, Goteborg, Sweden, vol. 4,4iv044,8 pp... 

These bricks find relatively frequent use in Kraft mills because of the amount of alkaline media encountered. They are used in the liquor regeneration systems, the smelt tank, the lime slaker, the causticizer, the liquor storage tanks, and the caustic storage tanks. They, of course, can be used in any industry having corrosive alkaline conditions. As with any corrosion resistant material of construction, proper care must be exercised to insure the proper application of Portland cement brick. 

It is refreshing that a momentum is gathering toward an appreciation for authentic American masonry materials and practices. Many decades of inappropriate restorations have been suffered with the application of Portland cement-based repair materials softened with hydrated Ume. The recent interest in hydrauhc hmes as a restoration alternative represents a quantum leap in sophistication. Where natural cement beds are present, hmes are much more physically compatible than portland cement mortars and further deterioration will likely be avoided through their application. However, where true replacement-in-kind is desired, limes are as inaccurate as portland cement when natural cements are present in the construction. Foremost in a determination of an appropriate repair material is an identification of the original binders and their proportions. It is hoped this paper will spark further interest in the forensic aspects of American masonry construction and that the scientific data will keep pace with the increasing desire among preservation professionals for accurate analysis of existing materials. 

There are less exotic ways of increasing the strength of cement and concrete. One is to impregnate it with a polymer, which fills the pores and increases the fracture toughness a little. Another is by fibre reinforcement (Chapter 25). Steel-reinforced concrete is a sort of fibre-reinforced composite the reinforcement carries tensile loads and, if prestressed, keeps the concrete in compression. Cement can be reinforced with fine steel wire, or with glass fibres. But these refinements, though simple, greatly increase the cost and mean that they are only viable in special applications. Plain Portland cement is probably the world s cheapest and most successful material. 

Other Types of Portland Cements. White Portland cement is standard Type I or III Pordand cement with raw materials selected and controlled to have negligible amounts of iron and manganese oxides, which impart the gray color. The white Pordand cement is used in decorative and architectural applications like precast curtain walls, terrazzo surfaces, stucco, tile grout, and decorative concrete. 

Geothermal cements are also employed to fix the steel wellbore casing in place and tie it to the surrounding rock (8). These are prepared as slurries of Portland cement (qv) in water and pumped into place. Additional components such as silica flour, perlite, and bentonite clay are often added to modify the flow properties and stability of the cement, and a retarder is usually added to the mixture to assure that the cement does not set up prematurely. Cements must bond well to both steel and rock, be noncorrosive, and water impermeable after setting. In hydrothermal applications, temperature stability is critical. Temperature cycling of wellbores as a result of an intermittent production schedule can cause rupture of the cement, leading to movement and, ultimately, failure of the wellbore casing. 

In recent years use of the oxide as a constituent of cement has been advocated,1 especially in Sweden. Thus, a mixture of Portland cement (60 to 70 per cent.) and white arsenic (40 to 30 per cent.) heated to 200° to 250° C. affords a hydraulic cement of normal setting time and of less solubility than ordinary cement, so that lime liberation is inhibited and the resistance to water improved. Wooden structures exposed to the action of sea water may be protected by spraying with a concrete composed of white arsenic, cement and sand in the proportions 1 3 12. The arsenic makes the mixture elastic and helps the cement to adhere to the wood. There is, however, danger in the too widespread application of arsenic in the directions described above. 

Because of the large supply of sulfur, there is increased interest in its possible use in the construction industry (7-13). This chapter reviews research at The University of Calgary concerned with sulfur in civil engineering applications. Large volumes of materials are required for construction. The amount of sulfur which is available may be compared with the consumption of some of the principal construction materials (Table I). In Canada the annual production of sulfur is already a sizeable fraction of the yearly consumption of some of these materials. For example the annual sulfur production is about half that of raw steel and about three quarters that of portland cement. Elsewhere sulfur production is much smaller than that of presently used construction materials, but there are indications that sulfur production will be increasingly important. 

Blast-furnace slag cements with high slag contents have lower heats of hydration than pure Portland cement, which is advantageous for large scale concrete structures (e.g. dams). The lower calcium hydroxide content results in their being somewhat more chemically stable than Portland cement. Blast-furnace slag cements are used in similar applications to Portland cement. 

Polyesters and expoxies have been used to seal cracks in rock formations and to anchor rock reinforcement members in drilled holes. The mechanical properties of these materials are much better than those of Portland cement. However, the chemicals are (relative to other grouts) very expensive and very viscous. Rendering them less viscous by using diluents so that they will penetrate sands makes them even more expensive. Because of their limited application as grouts, polyesters and epoxies are not detailed further. 

CACs were developed in response to the need for cements resistant to groundwater and seawater attack and are the only cements, other than Portland cement, that are in continuous long-term production [2], The property of CAC that was most important in their commercial development is the resistance to sulfate attack, which contrasted with the poor-sulfate resistance of contemporary Portland cements [2], and CAC was first patented in 1908 [2], Most early applications, in construction projects following the First World War, were in structures exposed to seawater, such as harbor pilings. Because CAC hardens rapidly, it was adopted for prestressed concrete beams in the post World War II construction boom, with some unfortunate results. Poor understanding of the material properties of CAC and incorrect water to cement ratios led to the collapse of several buildings, and the use of Portland cements, which are cheaper, has replaced CAC in prestressed concrete beams[2]. 

One very important niche application for calcium aluminate (cements) is as refractory castables. Key to the success of calcium aluminates in this application are their refractory properties that contrast with those of Portland cements. Although Portland cement maintains good strength when heated, reactive components (CaO) are liberated and can absorb moisture from the atmosphere when cooled, causing expansion and deterioration of, for example, kiln linings. CACs are not much susceptible and can be used to form monolithic castables and refractory cements [28, 29],... 

In concrete, triethanolamine accelerates set time and increases early set strength (41—43). These are often formulated as admixtures (44), for later addition to the concrete mixtures. Compared to calcium chloride, another common set accelerator, triethanolamine is less corrosive to steel-reinforcing materials, and gives a concrete that is more resistant to creep under stress (45). Triethanolamine can also neutralize any acid in the concrete and forms a salt with chlorides. Improvement of mechanical properties, whiteness, and more even distribution of iron impurities in the mixture of portland cements, can be effected by addition of 2% triethanolamine (46). Triethanolamine bottoms and alkanolamine soaps can also be used in these type applications. Waterproofing or sealing concrete can be accomplished by using formulations containing triethanolamine (47,48). 

Portland limestone cements are a relatively recent development. They consist of intimate blends of Portland cement and limestone, in which the limestone acts as an extender [9.2, 9.3]. About 1 million tonnes of limestone was used in 1990 in this application in the European Union [9.1], and, following the publication of a European Prestandard for the product in 1992 [9.2], the amount is likely to grow rapidly. 

Foundry sand (FS) - In typical foundry processes, sand from collapsed molds or cores can be reclaimed and reused - Little information is available regarding the amount of FS that is used for purposes other than in-plant reclamation, but spent FS has been used as a fine aggregate substitute in construction applications and as kiln feed in the manufacture of Portland cement - Most of the spent FS from green sand operations is land filled, sometimes being used as a supplemental cover material at landfill sites 81-87... 

Cariou, B. Ranc, R. and Sorrentino, F., "Industrial Application of Quantitative Study of Portland Cement Clinker Through Reflected Light Microscopy," Proceedings of the 10th International Conference on Cement Microscopy, International Cement Microscopy Association,SanAntonio,Texas, 1988, pp. 277-284. 

Bensted J, Varna SP. Some applications of IR and Raman. Spectroscopy in cement chemistry, Part 111 Hydration of Portland cement and its constituents. Cement Technology, (5) 440-450, 1974. 

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