Precast concrete materials, manufacture, properties and usage - Chapter 4 pot

... 1982 Fig. 4. 4. Freeze-thaw % weight loss versus carbon/cement in wet-pressed kerbs. TABLE 4. 7 DETAILS OF WET-PRESSED PAVING SLAB MIXES Copyright Applied Science Publishers Ltd 1982 in Table 4. 4 and ... 0·32 0· 34 0·36 0·38 0 40 Observed and cost-corrected-relative-to-control failing loads (flexure) are shown in Table 4. 13. It can be seen that F/C over 0·37 detrimentally affects...

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... concrete I. Title 691′·3 TA683·7 ISBN 0-2 0 3 -4 905 7-6 Master e-book ISBN ISBN 0-2 0 3-7 988 1-3 (Adobe eReader Format) ISBN 0-8 533 4- 9 9 4- 0 (Print Edition) WITH 40 TABLES AND 109 ILLUSTRATIONS © APPLIED ... Publishers Ltd 1982 PRECAST CONCRETE Materials, Manufacture, Properties and Usage M.LEVITT ARCS, BSc, DIC, PhD Head—Materials Scie...

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... CONTROL STRENGTH FOR 24 HOUR OLD 4/ 1 MORTAR CYLINDERS TABLE 2.2 24 HOUR AND LATER AGE COMPARATIVE STRENGTH FOR 4/ 1, 0.5 W/C MORTARS Copyright Applied Science Publishers Ltd 1982 2 .4 WATER REPELLENTS These ... properties of the fresh and/ or the hardened material. The chapter excludes additives such as ground blast furnace slag and pulverised fuel ash (fly ash), the latter be...

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... relevant to precast concrete manufacture leaving mix design to Chapters 5 and 6. 1.5.1 Cement types The most common cements used are ordinary and rapid-hardening Portland (including white), sulphate-resisting ... characteristic strengths above 40 N/mm 2 , nor some sandstones above 50 N/mm 2 . (f) Aggregate variations affect physical, chemical and architectural properties and ve...

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... concrete colour Both the desk-top 100mm square sample and the 300mm square hand- portable samples are misleading in the case of unpigmented materials, and for coloured concretes and mortars they seldom ... agents should be water-in-oil emulsion creams or chemical release agents. Ordinary mineral mould oils and oil-in- water emulsions promote streaking and staining. (c) Pan-type...

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... off up to a 240 V or three-phase supply under closely supervised nominally dry conditions. 13. Re-vibration of concrete is beneficial if the concrete is re-vibratable and the cost of double handling ... accurate and consistent quantity of concrete into the mould. In some precast processes tilting tables are used both to cast the concrete and lift the mould and concrete int...

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... 1 4 Sand 1 54 5 –3·0 Cement 100 Water 40 +1 4 3·0=38 4 = Added water 40 = Effective or free water 40 +1 4+ 1·5 =42 ·9 = Total water Admittedly one would not work to such accurate batch weights in a precast ... process a 4- or 8-drop would take place about every 15 seconds. 6.6.3 Wet and earth-moist mix presses In the production of floor tiles the wet and earth-moist mix mentioned...

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... normal-cured concrete. Flexural strength at 4 24 hours old is the practical consideration as concrete is subject to bending during demoulding and handling. If, for example, one aimed at and achieved ... up and gains strength slowly; a warm-starting concrete, say 25°C, warms up and gains strength more quickly; and a concrete starting at, say 40 °C, can be handled within a f...

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... Concrete and plastics: U (sandwich)=0 44 On an area proportionality U (panel)=0 44 ×0·8+3·08×0·2=0·97 W/m2 ° C. It may be seen that it is quite easy to undertake one’s own calculations, and ... days before cleaning and scrubbing the surface. 8 .4 SITE HANDLING AND USAGE With a good deal of sense 90% of the site problems that occur with precast products could be avoided, an...

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... all procedures in the manufacture and/ or testing (Assessors and Company). 4. Keeping Record Cards on all machinery, equipment, etc. (Company and Assessors). (See Chapter 5.) 5. Calibration of all ... knowledge, ‘know-how’ and ‘alchemy’, and if one does not know what the variables are doing at any one time control is lost. One can list the factors and control variables one would...

Ngày tải lên: 08/08/2014, 10:23