CONCRETE IN HOT ENVIRONMENTS - CHAPTER 4 docx

... pp. 66–87. 4. 24. Tipler, T.J., Handling. In Proc. Intern. Seminar on Concrete in Hot Countries. Helsingor, 1981, Skanska, Malmo, Sweden, pp. 71–9. 4. 25. Anon., Keeping it cool with liquid nitrogen. Concrete ... the setting of the concrete (ASTM C4 94) . Accordingly, a water-reducing and retarding admixture combines the effects of both water-reducing and retarding admixtures, a...

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... Classification 4. 3.2.2 Water-reducing admixtures 4. 3.2.3 Retarding admixtures 4. 3.2 .4 Superplasticisers 4. 3.3 Fly-ash 4. 3 .4 Long mixing and delivery times 4. 4 Control of workability 4. 4.1 Increasing initial ... slump 4. 4.2 Lowering concrete temperature 4. 4.2.1 Use of cold water 4. 4.2.2 Use of ice 4. 4.2.3 Use of cooled aggregate 4. 4.3 Retempering 4. 4.3.1 Retempe...

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... heterogeneous material made up of several fine-grained minerals which are formed during the clinkering process. Four minerals, namely Alite, Belite, Celite and a calcium-aluminate phase, make up some 90% ... added during the grinding of the cement clinker (section 1.1). The gypsum combines with the C 3 A to give a high-sulphate calcium sulphoaluminate, known as ettringite (3CaO·Al 2 O 3 ·3CaS...

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... length of time in which cement mixes, including concrete, remain plastic and workable, and can be handled and used on the building site. Accordingly, a minimum of 45 min is specified in most standards for ... ‘hardening’. These stages of setting and hardening are schematically described in Fig. 2.1. The initial and final setting times are of practical importance. The initial setting t...

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... rise measured in mass concrete. Control mix contained 40 0 kg/m 3 ordinary Portland cement (OPC). In the fly-ash concrete 30% of the OPC was replaced by fly-ash and in the slag concrete 75% of ... grains and, thereby, reduce the spacing between the solids. Hence, on subsequent hydration, the resulting capillary pores in the silica-fume- containing paste are much finer than the...

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... cement), and 2 and 6 (10 min mixing time, 340 kg/m 3 cement). In fact, the effect of fly-ash was quite significant, increasing, in the case of 10 min mixing, plastic shrinkage by approximately ... mainly on the building site, and the latter mainly in the production of glass-fibre-reinforced concrete products, commonly known as GRC products. A detailed discussion of fibre-reinforced...

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... accessible, since the forms can be up to 16 ft (4. 88 m) high and 44 ft (13 .41 m) long. Openings/Inserts Jumps forms are best suited to building designs in which the open- ings are regularly occurring ... tie rods used in forming concrete columns and walls. Load- carrying capacity for ties ranges from 1,000 to 70,000 lb (45 0 to 31,750 kg). Figure 6.3 Wall form ties. 1 84 Chapter 6...

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... corresponding increase in the modulus of elasticity. (3) Joints should be provided in concrete members in order to reduce the restraining effect of the structure on shrinkage. It is self-evident ... presented in Chapter 5. 7 .4. 2. Concrete Composition and Properties 7 .4. 2.1. Aggregate Concentration In considering shrinkage, concrete may be regarded as a two-phase material...

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... not indicated by the data of Fig. 8.13 implying, in turn, that some other mechanisms may be involved. 8 .4. 2 .4. Mineral Admixtures In discussing the effect of mineral admixtures on drying shrinkage ... load, shrinkage occurs simultaneously. Accordingly, creep is the increase in deformation with time under a sustained load excluding drying shrinkage. This is demonstrated in Fig. 8.1...

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... 9.12 in which the intensity of the reaction is measured by the resulting expansion. Indeed, this effect is utilised in determining the potential alkali reactivity of cement-aggregate combinations ... containing Santorin earth. Cement Concrete Res., 11 (4) (1981), 507–18. 9.19. Dunstan, E.R., Performance of lignite and sub-bituminous fly ash in concrete A progress report. Report REC-...

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