Tag Archive for Tag: cement

Tag: cement Note on Cement-Lime Mortars versus Masonry-Cement Mortars

At times in the past, and to some extent even to this day, controversy has existed within the masonry technical community over the comparative performance of cement-lime mortar and masonry-cement mortar. Each cementitious system has advantages and disadvantages. Each has demonstrated general suitability for use and also general cost-effectiveness for suppliers and users. Masonry cement complies with the physical property

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Tag: cement Cement composites Terminology

A number of subject specific terms are useful in order to discuss concisely frc structure and behaviour. The term frc itself can refer to either fibre-reinforced cement or fibre-reinforced concrete. There are a number of distinctions between the two. The first normally refers to thin-sheet material produced with high cement content (often 1:1 by weight with fine aggregate but occasionally

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Tag: cement Use of supplementary cementing materials (SCMs)

Supplementary cementing materials (SCMs) are materials that contribute to the properties of concrete through either pozzolanic reaction (e.g., low-calcium fly ash, silica fume, or calcined clay), or hydraulic reaction (e.g., ground granulated blastfurnace slag, hereinafter called slag), or both (high-calcium fly ash). These materials are generally used to partially replace the Portland cement component, the level of replacement varying widely

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Tag: cement Alkalis in Portland cement

The predominant source of alkalis in concrete is the Portland cement. As noted in Chapter 2, Portland cement contains relatively minor amounts of both sodium (Na) and potassium (K) and these are usually expressed as oxides, Na2O and K2O, in a typical chemical analysis. Since these alkalis tend to behave fairly similarly in Portland cement concrete, it is common practice

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Tag: cement Carbonation and its effects

As noted previously, the reactions between atmospheric CO2 and alkaline components of concrete produce a carbonated surface layer in which the pore solution pH value is depressed to near-neutral levels. A secondary effect of carbonation, also significant in terms of its influence on corrosion, is that it can cause the release of bound chloride ions into the pore solution phase

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Tag: cement Physical and chemical characteristics of cement composites

The aim of this chapter is to provide information on aspects of the internal characteristics of concrete that relate to concrete durability. Pertinent chemical and physical characteristics, particularly those involving pore solutions and pore structures, are discussed in some detail, as these most closely affect most durability concerns. Concrete is an unusual engineering material. Unlike most engineering materials it is

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Tag: cement Steep-Slope Roof Coverings

These differ from low-slope roof coverings in that on steep-slope roofs water flows rapidly over exposed units to eaves. Many of the low-slope roof coverings described in Art. 12.4 can be successfully used on steep slopes. Many of the low-slope materials, however, become slick when wet. This should be taken into account before they are specified for steep slopes. Asphalt Shingles These are composed

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Tag: cement Portland-Cement Concrete

Portland-cement concrete is a mixture of portland cement, water, coarse and fine aggregates, and admixtures proportioned to form a plastic mass capable of being cast, placed, or molded into forms that will harden to a solid mass. The desirable properties of plastic concrete are that it be workable, placeable and nonsegregating, and that it set in the desired time. The hardened concrete should provide the

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Tag: cement Oxychloride Cements

Lightly calcined magnesium oxide mixed with a solution of magnesium chloride forms a cement known as magnesium oxychloride cement, or Sorel cement. It is particularly useful in making flooring compositions in which it is mixed with colored aggregates. Floors made of oxychloride cement are sparkproof and are more resilient than floors of concrete. Oxychloride cement has very strong bonding power

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Tag: cement Natural Cements

Natural cements are formed by calcining a naturally occurring mixture of calcareous and argillaceous substances at a temperature below that at which sintering takes place. The ‘‘Specification for Natural Cement,’’ ASTM C10, requires that the temperature be no higher than necessary to drive off the carbonic acid gas. Since natural cements are derived from naturally occurring materials and no particular

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