Concrete mineral admixtures

Fukudome, K., Shintani, T., Kita, T., and Sasaki, H., Utilization of Coal Ash Produced from Pressurized Fluidized Combustion Power Plant as a Concrete Mineral Admixture, CANMET/ACI Int. Conf. on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concr., (V. M. Malhotra, ed.), SP-178 522-544 (1998)... 

For special high strength appHcations, ie, up to 69 MPa (10,000 psi), special formulations of Pordand cement concretes have been developed. These ate based on the use of chemical and mineral admixtures. The typical mineral admixtures ate fumed siUca and other po22olanics. The chemical admixtures ate generally chemicals termed supetplastici2ets that allow very low water to cement ratios, ie, between 0.4 and 0.25, and reduce the amount of water needed to provide plasticity or dow to the concrete. PubHc works appHcations take just under 32% of the total Pordand cement market streets and highways represent 68% of this usage, and water and waste account for 23%. 

Modem concretes often incorporate a mixture of chemical and mineral admixtures, each of which may interact with the various constituents of cements and influence cement hydration reactions. The admixture-cement interactions may in fact be viewed as the reaction between two complex chemical systems - the multicomponent, multiphasic inorganic materials in the cement and the organic compounds of multicomponent admixture systems. For example, lignosulfonate water-reducers are intrinsically complex mixtures of chemical compounds derived from the chemical degradation of lignin, while synthetic admixtures such as superplasticizers contain species with a broad distribution of molecular weights, reaction products, or other chemicals added for a specific purpose [125]. The performance of an admixture in concrete is highly dependent on many... 

ASTM 1994. ASTM C618 Standard Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete. ASTM International. World Wide Web Address http// www.astm.org. 

McCarthy, G. J., Solem, J. K., Manz, O. E. Hassett, D. J. 1990. Use of a database of chemical, mineralogical and physical properties of North American fly ash to study the nature of fly ash and its utilization as a mineral admixture in concrete. Materials Research Society Symposium Proceedings, 178, 3-34. 

One of the most significant uses of fly ash is as a mineral admixture in Portland cement concrete. This use alone accounted for over 56 wt% of the fly ash utilized in the USA in 2001 (American Coal Ash Association 2002). Fly ash is particularly well suited to this application because of its... 

Water-reducing admixtures and set controlling admixtures Finely divided mineral admixtures Admixtures for no-slump concretes... 

GBFS is used as a mineral admixture for Portland cement concrete... 

ASTM (1994) Standard specification for fly ash and raw or calcined natural pozzolan for use as mineral admixture in Portland cement concrete. American Society for Testing and Materials, Annual Book of ASTM Standards, C618-92a, vol 04.02, West Conshohocken, PA, p 194... 

In addition to low chloride permeability, mineral admixtures impart other properties to the concrete depending on the admixture selected such as ... 

An FHWA study by Thompson and Lankard (19, 20) reviewed the effect on the corrosion of steel in the concrete of several variables, including cement type, mineral admixtures, water-to-cement ratio, and aggregate type. This study showed silica fume to be the most effective mineral admixture in the mitigation of corrosion of steel rebar. It also suggested that careful selection of the concrete mix components could extend the life of a concrete bridge member. It is estimated that use of a silica fume admixture provides an increase of expected life of 10 years beyond that provided by black steel rebar in conventional concrete. 

I. Turkmena and M. Gavgalib, Influence of mineral admixtures on the some properties and corrosion of steel embedded in sodium sulfate solution of concrete, in Journal of Materials Letters, Vol. 57, 2003, pp. 3222-3233. 

Cochet, G., and Sonentino, F. (1993) Limestone filler cement properties and uses, in Mineral Admixtures in Cement and Concrete (ed. S.N.Ghosh), ABI Books, New Delhi, pp. 212-295. 

Rosenberg, A.M., and Gaidis, J.M. (1989) New mineral admixture for high strength concrete. Concrete International Design and Construction 11,31-35. 

Mineral admixtures can be used to reduce concrete permeability. These are typically fly ash, microsilica, or blast furnace slag and are also addressed by TRB [42], and by ASTM Committee C09 on Concrete. 

E.F. Irassar, A. Di Maio, O.R. Batic, Sulfate attack on concrete with mineral admixtures,... 

The large group of cements and concretes covers many traditionally used materials that have for some 20 years been the subject of rapid development and innovation. Also, their variety has been extended, mainly due to use of various polymer additions and chemical and mineral admixtures. In this chapter the main kinds of cements and concretes are introduced briefly. 

Application of pozzolanic mineral admixtures is considered beneficial for ordinary concrete and indispensable for high strength concrete. 

Bui, D. D. (2001) Rice Husk Ash as a Mineral Admixture for High Performance Concrete. Delft, Netherlands Delft University Press. 

From Malhotra, V.M., Mineral admixtures, in Concrete Construction Engineering Handbook, Nawy, E.G., Ed., CRC Press, Boca Raton, FL, 1998, p. 2-38. Originally from Zhang, M.H. and Malhotra, V.M. 1995. Characteristics of a thermally activated alumina-silicate pozzolanic material and its use in concrete. Cement Concrete Res. 25(8) 1713-1725. 

Concrete, made from cement, aggregates, chemical admixtures, mineral admixtures, and water, comprises in quantity the largest of all synthesized materials. The active constituent of concrete is cement paste and the performance of concrete is largely determined by the nature of the cement paste. Admixtures are chemicals that are added to concrete for obtaining some beneficial effects such as better workability, strength, durability, acceleration, retardation, air entrainment, water reduction, plasticity, etc. Mineral admixtures, such as blast furnace slag, fly ash, silica fume, and others, are also incorporated into concrete to improve its quality. 

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