CONCRETE IN HOT ENVIRONMENTS - CHAPTER 6 pdf

... jump forms are braced from the outside, no or minimum inside bracing is needed, thus eliminating interference with interior shoring. 164 Chapter 6 3. Tie holes are then drilled from both sides ... (Figure 6. 9). Stripping Stripping begins by removing all form ties and anchor-positioning bolts. The form panel with its strongbacks is then pulled away from the wall by tilting or rolling (F...

Ngày tải lên: 08/08/2014, 10:22

... concentration 6. 4.5 Summary 6. 5 Strength-W/C ratio relationship 6. 6 Effect of temperature 6. 6.1 Internal cracking 6. 6.2 Heterogeneity of the gel 6. 6.3 Type of cement 6. 7 Summary and concluding remarks References 7 ... and S.Mindess Concrete in the Marine Environment P.K.Mehta Concrete in Hot Environments I.Soroka Durability of Concrete in Cold Climates M.Pigeon a...

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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% ... water, hydration takes place bringing about setting and subsequent hardening in a few hours. If not allowed to dry, the resulting solid gains strength with time mainly during the first...

Ngày tải lên: 08/08/2014, 10:22

... ‘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 time determines ... 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...

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... fume concrete using ASTM test C 666 , procedures A and B. Proc. Sec. Intern. Conf. on Fly Ash, Silica Fume, Slag and Natural Pozzolans in Concrete (ACI Spec. Publ. SP-91), Madrid, Spain 19 86. ed. ... rise measured in mass concrete. Control mix contained 400 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 c...

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... Observation in testing and use of water-reducing retarders. In Symp. on Effect of Water-Reducing Admixtures and Set Retarding Admixtures on Properties of Concrete (ASTM Spec. Tech. Publ. No. 266 ). ASTM, ... (1982), 429–32. 4.20. Ravina, D., Slump loss of fly ash concrete. Concrete Int., 6( 4) (1984) 35–9. 4.21. ACI Committee 305, Hot- weather concreting (ACI 305R-89). In ACI Man...

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... 2, and 3 and 6) . This increased shrinkage is attributable to the grinding effect of the mixing operation which, on prolonged mixing, increases the fines content in the concrete mix. Finally, the ... shrinkage is expected in the former than in the latter concrete. It is also evident from Fig. 5.8 that plastic shrinkage increases significantly with an increase in mixing time from...

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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 ... replacing OPC with natural pozzolan (Santorin earth) on drying shrinkage of concrete. (Adapted from Ref. 7.19.) Fig. 7.15. Effect of replacing OPC with high-calcium fly-ash on drying shri...

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... 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 (see section 7.4.2 .6) , it was pointed ... 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 fo...

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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 ... Toronto Press, Toronto, Canada, 1 968 , pp. 113–24. 9.15. Brown G.E. & Oates, D.B., Air entrainment in sulfate-resistant concrete. Concrete Int., 5(1) (1983), 36 9. 9. 16. Cabrera, J...

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