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1、Construction Building Envelope and Interior Finishes Databook Sidney M. Levy McGraw-Hill New York San Francisco Washington, D.C. Auckland Bogot Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto 1 Section Concrete Contents 1 1.1.0History 1.1.1Ge
2、neral properties 1.2.0Portland cement as a major compo- nent 1.2.1High early cement 1.2.2How cement content affects shrink- age 1.2.2.1Effect of cement/water content on shrinkage 1.3.0Control joints 1.3.0.1Maximum spacing of control joints 1.3.0.2Dowel spacing 1.3.0.3Keyed construction joint detail
3、#2 1.3.0.4Doweled construction joint detail 1.3.0.5Typical isolation joint detail #1 1.4.0Admixtures 1.5.0Chloride content in the mixing water 1.6.0Guidelines for mixing small batches of concrete 1.7.0Recommended slumps 1.7.1The slump test 1.7.1.1The slump cone 1.8.0Forms for cast-in-place concrete
4、1.8.1Maximum allowable tolerances for form work 1.8.2Release agents for forms 1.8.3Principal types of commercially available form ties 1.9.0Curing of concrete 1.9.1Curing procedures 1.9.2Curing times at 50 and 70F 1.10.0Concrete-reinforcing bar size/weight chart 1.10.1ASTM Standards including Soft M
5、et- ric 1.10.2Recommended end hooksall grades 1.10.3Stirrup and tie hooksall grades general 1.10.3.1Stirrup and tie hooksall grades seismic 1.10.4Welded wire fabric (WWF) weights and sizes 1.10.4.1Common types of welded wire fabric 1.10.5Typical one-way concrete slab rein- forcing detail 1.10.6Typic
6、al two-way concrete slab rein- forcing detail 1.10.7Typical concrete wall form schematicone side in place 1.10.7.1Typical concrete wall form sche- matic with walkway bracket in- stalledone side in place 1.10.7.2Typical concrete wall form sche- maticrebar in placeready to be buttoned up 1.10.7.3Typic
7、al waler and walkway bracket attachment 1.10.8Typical concrete wall form 1.10.8.1Typical pilaster, 45 corner, 90 in- side and outside corner form details 1.10.8.2Typical attachment of form to plate and long key installation 1.10.9Form installation accessories 1.10.10Proper key and wedge connections
8、and installation diagrams 1.11.0 Notes on the metrifi cation of rein- forcing steel 1.11.1Drawing scales 1.12.0Tilt-up construction 1.12.1Panel construction 1.12.2Lifting stresses and concrete design 1.12.3During the lift 1.12.4Insert capacity theory 1.12.5Brace length and safe working loads 1.12.6R
9、igging and the crane 1.12.7Problem areas 1.12.8Safety notes and product applica- tion 1.13.0Prestressed concrete 1.13.1Posttensioned concrete 1.13.2Typical tendon layout 1.13.3Tendon layout to avoid small open- ings 1.13.4Tendon coupler 1.13.5Typical jack and pump details with manual seating valve o
10、r sequencing valve 1.13.6Some posttensioning Dos and Donts 1.13.7Glossary of terms 1.14.0Precast concrete 1.14.1Precast welded tieback connections 1.14.2Precastcolumn-to-beam connec- tions 1.14.3Precastplank-to-precast, plank-to- steel beam connections 1.14.3.1Precastplank-to-CMU wall con- nections
11、1.14.3.2Eccentric bearing details 1.14.3.3Beam-to-wall connections 1.14.3.4Column-to-footing connections 1.14.3.5Tie forces and typical tie arrange- ments 1.14.3.6Hanger connections 1.14.3.7Column base connections 1.14.3.8Corbel design 1.14.3.9Corbel force diagrams and typical reinforcement 1.15.0Ke
12、yed joint connections 1.15.1Special exposure requirements for concrete 1.16.0Weathering regions and weathering index 1.17.0Seismic map of the United States 1.18.0Minimum cover for reinforcement in cast-in-place concrete 1.18.1Minimum cover for reinforcement in precast concrete 1.18.2Minimum cover fo
13、r reinforcement in prestressed concrete 1.19.0ConcreteQuality Control checklist 1.20.0Concrete reinforcementQuality Control checklist 1.21.0Concrete form removalQuality Control checklist 2Section 1 1.0.0 History Concrete is an ancient material of construction, fi rst used during the Roman Empire, wh
14、ich extended from about 20 B.C. to 200 A.D. The word concrete is derived from the Roman concretus, meaning to grow together. Although this early mixture was made with lime, cement, and a volcanic ash material called pozzolana, concrete today is a sophisticated material to which exotic constitutents
15、can be added and, with computer-controlled batching, can produce a product capable of achieving 50,000 psi compressive strength. The factors contributing to a successful batch of concrete are Precise measurement of water content; Type, size, and amount of cement and aggregate; Type, size, and locati
16、on of reinforcement within the concrete pour to compensate for the lack of tensile strength basic in concrete; Proper curing procedures during normal hot or cold weather conditions. 1.1.1 General Properties With some exceptions, the two most widely used concrete mixtures are Normal-weight (stone) co
17、ncrete with a dry weight of 145 psf (6.93 kPa); Lightweight concrete (LWC) with a weight of approximately 120 psf (5.74 kPa). Extra light con- crete, with weights as low as 80 psf (3.82 kPa), an be achieved with the use of special aggregates. Other Types of Concrete Lightweight InsulatingContaining
18、perlite, vermiculite, and expanded polystyrene, which is used as fi ll over metal roof decks, in partitions, and in panel walls. CellularContains air or gas bubbles suspended in mortar and either no coarse aggregates or very limited quantities are included in the mixture. Use where high insulating p
19、roperties are re- quired. Shot-crete or GuniteThe method of placement characterizes this type of concrete, which is ap- plied via pneumatic equipment. Typical uses are swimming pools, shells, or domes, where form- work would be complicated because of the shape of the structure. FerrocementBasically
20、a mortar mixture with large amounts of light-gauge wire reinforcing. Typ- ical uses include bins, boat hulls, and other thin, complex shapes. 1.2.0 Portland Cement as a Major Component Different types of portland cement are manufactured to meet specifi c purposes and job conditions. Type I is a gene
21、ral-purpose cement used in pavements, slabs, and miscellaneous concrete pads and structures. Type IA is used for normal concrete, to which an air-entraining admixture is added. Type II creates a moderate sulfur-resistant product that is used where concrete might be exposed to groundwater that contai
22、ns sulfates. Type IIA is the same as Type II, but is suited for an air-entrainment admixture. Type III is known as high early strength and generates high strength in a week or less. Type IIIA is high early, to which an air-entrainment admixture is added. Type IV cement produces low heat of hydration
23、 and is often used in mass pours, such as dam con- struction or thick mat slabs. Type V is a high sulfate-resistant cement that fi nds application in concrete structures exposed to high sulfate-containing soils or groundwater. White Portland cement is generally available in Type I or Type III only a
24、nd gains its white color from the selection of raw materials containing negligible amounts of iron and magnesium oxide. White cement is mainly used as a constituent in architectural concrete. Concrete3 1.2.1 High Early Cement High early cement does exactly what its name implies: it provides higher c
25、ompressive strength at an earlier age. Although Type III or Type IIIA cement can produce high early strength, there are other ways to achieve the same end result: Add more cement to the mixture 600 lb (272 kg) to 1000 lb (454 kg); Lower the water content (0.2 to 0.45) by weight; Raise the curing tem
26、perature after consultation with the design engineer; Introduce an admixture into the design mix; Introduce microsilica, also known as silica fume, to the design mix; Cure the cast-in-place concrete by autoclaving (steam curing); Provide insulation around the formed, cast-in-place concrete to retain
27、 heat of hydration. 1.2.2 How Cement Content Affects Shrinkage When low slumps, created in conjunction with minimum water requirements, are used with correct placement procedures, the shrinkage of concrete will be held to a minimum. Conversely, high water content and high slumps will increase shrink
28、age. A study at the Massachusetts Institute of Technol- ogy, as reported by the Portland Cement Association, indicated that for every 1% increase in mixing water, shrinkage of concrete increased by 2%. This study produced the following chart, showing the correlation of water and cement content to sh
29、rinkage. 1.2.2.1 Effect of Cement/Water Content on Shrinkage Cement Content Bags/cubic Concrete compositionWater cementSlumpShrinkage yardCementWaterAirAggregateWater ? airratio by weight(inches)(av. 3 ? 3 ? 10* prism) 4.990.0890.2020.0170.6920.2190.723.30.0330 5.990.1070.2070.0160.6700.2230.623.60.
30、3300 6.980.1240.2100.0140.6520.2240.543.80.0289 8.020.1430.2070.0150.6350.2230.463.80.0300 1.3.0 Control Joints Thermal shrinkage will occur and the object of control joints, sometimes referred to as construction joints is to avoid the random cracking that often comes about when a concrete slab drie
31、s and pro- duces excess tensile stress. Control joint spacing depends upon the slab thickness, aggregate size, and water content, as reported by the Portland Cement Association in their articles “Concrete Floors on Concrete,” second edition, 1983. 1.3.0.1 Maximum Spacing of Control Joints Slump of 4
32、6 inches (101.6 mm152.4 mm) Max. size aggregate lessMax. size aggregateSlump less than 4 inches Slab Thicknessthan 34inches (19.05 mm)larger than 34inches(101.6 mm) 4“ (101.6 mm)8 (2.4 m)10 (3.05 m)12 (3.66 m) 5“ (126.9 mm)10 (3.05 m)13 (3.96 m)15 (4.57 m) 6“ (152.4 mm)12 (3.66 m)15 (4.57 m)18 (5.49
33、 m) 7“ (177.8 mm)14 (4.27 m)18 (5.49 m)21 (6.4 m) 8“ (203.1 mm)16 (4.88 m)20 (6.1 m)24 (7.32 m) 9“ (228.6 mm)18 (5.49 m)23 (7.01 m)27 (8.23 m) 10“ (253.9 mm)20 (6.1 mm)25 (7.62 m)30 (9.14 m) 4Section 1 The term control joint is often used as being synonymous with construction joint, however, there i
34、s a difference between the two. A control joint is created to provide for movement in the slab and induce cracking at that point, whereas a construction joint is a bulkhead that ends that days slab pour. When control joints are created by bulkheading off a slab pour, rather than saw-cutting after th
35、e slab has been poured, steel dowels are often inserted in the bulkhead to increase load transfer at this joint. 1.3.0.2 Dowel spacing. Slab Depth in. (mm)Diameter (bar number)Total length in. (mm)Spacing in. (mm) center to center 5“ (126.9 mm)#512 in. (304.8 mm)12 in. (304.8 mm) 6“ (152.4 mm)#614 i
36、n. (355.6 mm)12 in. (304.8 mm) 7“ (177.8 mm)#714 in. (355.6 mm)12 in. (304.8 mm) 8“ (203.1 mm)#814 in. (355.6 mm)12 in. (304.8 mm) 9“ (228.6 mm)#916 in. (406.4 mm)12 in. (304.8 mm) 10“ (253.9 mm)#1016 in. (406.4 mm)12 in. (304.8 mm) Concrete5 (By permission from The McGraw-Hill Co., Structural Detai
37、ls Manual, David R. Williams.) 1.3.0.3 Keyed Construction Joint 6Section 1 (By permission from The McGraw-Hill Co., Structural Details Manual, David R. Williams.) 1.3.0.4 Doweled Construction Joint Detail (By permission from The McGraw-Hill Co., Structural Details Manual, David R. Williams.) 7 1.3.0
38、.5 Typical Column Isolation Joint Detail #1 1.4.0 Admixtures Although concrete is an extremely durable product, it faces deterioration from various sources: chemical attack, permeation by water and/or gases from external sources, cracking because of the chemical reaction (known as heat of hydration)
39、, corrosion of steel reinforcement, freeze/thaw cy- cles, and abrasion. Much of the deterioration caused by these internal and external factors can be drastically delayed by the addition of a chemical admixture to the ready-mix concrete. Admixtures are chemicals developed to make it easier for a con
40、tractor to produce a high-quality concrete product. Some admixtures retard curing, some accelerate it; some create millions of mi- croscopic bubbles in the mixture; others allow a substantial reduction in water content, but still per- mit the concrete to fl ow like thick pea soup. Water-reducing adm
41、ixturesImprove strength, durability, workability of concrete. Available in normal range and high range. High-range water-reducing admixtureAlso known as superplasticizer, it allows up to 30% re- duction in water content with no loss of ultimate strength, but it creates increased fl owability. It is
42、often required where reinforcing steel is placed very close together in intricate forms. Accelerating admixturesThey accelerate the set time of concrete, thereby reducing the pro- tection time in cold weather, allowing for earlier stripping of forms. Accelerating admixtures are available in both chl
43、oride- and nonchloride-containing forms. Nonchloride is required if concrete is to be in contact with metal and corrosion is to be avoided. Retarder admixturesRetards the setting time, a desirable quality during very hot weather. Air-entraining admixturesCreates millions of microscopic bubbles in th
44、e cured concrete, al- lowing for expansion of permeated water, which freezes and is allowed to expand into these tiny bubbles, thereby resisting hydraulic pressures caused by the formation of ice. Fly ashWhen added to the concrete mixture, it creates a more dense end product, making the concrete ext
45、remely impermeable to water, which affords more protection to steel reinforcement contained in the pour. The addition of fl y ash can increase ultimate strength to as much as 6500 psi (44.8 MPa), in the process, making the concrete more resistant to abrasion. Silica fumeAlso known as microsilica, it
46、 consists of 90 to 97% silicon dioxide, containing vari- ous amounts of carbon that are spherical in size and average about 0.15 microns in size. These ex- tremely fi ne particles disperse into the spaces around the cement grains and create a uniform dense microstructure that produces concrete with
47、ultra-high compressive strengths, in the nature of 12,000 (82.73 MPa) to 17,000 psi (117.20 MPa). Multifi lament or fi brillated fi bersThis material is not a chemical admixture per se, but several manufacturers of concrete chemical additives also sell containers of fi nely chopped synthetic fi bers
48、, generally polypropylene, which, when added to the ready-mix concrete, serve as secondary reinforcement and prevent cracks. 1.5.0 Chloride Content in the Mixing Water Excessive chloride ions in mixing water can contribute to accelerated reinforcing-steel corrosion and should be a concern when evalu
49、ating a mix design. Maximum water-soluble chloride ions, in various forms of concrete (as a percentage), should not exceed the following: Prestressed concrete0.06% Reinforced concrete exposed to chloride in service (e.g., garbage slab)0.15% Reinforced concrete that will be dry and/or protected from moisture infi ltration1.00% Other reinforced concrete0.30% 8Section 1 1.6.0 Guidelines for Mixing Small Batches of Concrete (by Weight) Max. size aggregateCement (lb/kg