Precast concrete materials, manufacture, properties and usage - Chapter 5 ppt
Precast concrete materials, manufacture, properties and usage - Chapter 5 ppt
... 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 into the near-vertical ... 240V 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 ha...
Precast concrete materials, manufacture, properties and usage - Chapter 6 pptx
... cycle
would be about 25 seconds with about 10– 15 seconds in the pressing
stage.
In the brick process a 4- or 8-drop would take place about every 15
seconds.
6.6.3 Wet and earth-moist mix presses
In ... to 15 N/
mm
2
) and eject. The backing is the earth-moist mix, and the facing the
wet mix, and the two are interdiffused by interface cement and water
migration. The backing m...
Precast concrete materials, manufacture, properties and usage - Chapter 7 pptx
... 10–20°C/hour, and temperature gradients
should be 50 – 150 °C/metre. In rapid cooling of a Jespersen precast unit
with an A/C of 6 5, a centre temperature of 90°C, and a surface
temperature of 35 C, cracking ... 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...
Precast concrete materials, manufacture, properties and usage - Chapter 9 ppt
... standard
deviation
Day no. Average of 10 Standard 0·9×7·0 Accept/
deviation (
σ
) +0·62
σ
reject
51 7·4 0 5 6·61 A
52 7·3 0·6 6·67 A
53 7·1 0·8 6·80 A
54 7·0 1·0 6·92 A
55 6·9 1·0 6·92 R
56 ... 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. Calibra...
Precast concrete materials, manufacture, properties and usage - Chapter 0 pot
... concrete
I. Title
691′·3 TA683·7
ISBN 0-2 0 3-4 9 05 7-6 Master e-book ISBN
ISBN 0-2 0 3-7 988 1-3 (Adobe eReader Format)
ISBN 0-8 53 3 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 S...
Precast concrete materials, manufacture, properties and usage - Chapter 1 pdf
... 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 ... strengths above 40 N/mm
2
, nor some
sandstones above 50 N/mm
2
.
(f) Aggregate variations affect physical, chemical and architectural
properties and very few prec...
Precast concrete materials, manufacture, properties and usage - Chapter 2 pot
... Table 2 .5 illustrates this effect.
TABLE 2 .5
TYPICAL EFFECT OF PLASTICISING ADMIXTURE ON
PROPERTIES OF A VIBRATED CONCRETE PRODUCT
The dosage rates vary from 100 to 1000 ml /50 kg cement and each
type ...
ADMIXTURES
This chapter covers the range of admixtures used in precast concrete
products and mortars used with precast masonry. They are all used at
relatively low con...
Precast concrete materials, manufacture, properties and usage - Chapter 3 ppsx
... 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...
Precast concrete materials, manufacture, properties and usage - Chapter 4 pot
... following F/C ratios and approximate total water contents were
used:
F/C 0 0· 25 0·37 0 50 0·63 0· 75
Total water 0·28 0·32 0·34 0·36 0·38 0·40
Observed and cost-corrected-relative-to-control failing ... one fly ash and F2 was selected. The
works mix was a 3/1 by weight sand/ordinary Portland cement mix with
a sand grading:
Sieve No. Passing %
1·18 mm 100
600 µm 95
300 µm 50
150 µ...
Precast concrete materials, manufacture, properties and usage - Chapter 8 pdf
... resistance.
Example 4
Part sandwich cladding panel 150 mm thick with 50 mm cast-in
expanded plastics panel taking up 80% of area. k=1·0 for concrete,
0·0 25 for expanded plastics.
Solid section: ... 1h
Non-air-entrained 0 50 0·30 0·20
Air-entrained 0·40 0· 05 0·01
Fig. 8.18. Defective kerbs with only partial replacement.
Copyright Applied Science Publishers Ltd 1982
8 .5. 3 Corrosion...