Plasticizers
• Water reducers
• Organic, or combination of organic and inorganic substances
• Dosage 0.1 to 0.4 % by weight of cement
• Entrained air which is not more than 1 to 2 %
• Anionic surfactants such as lignosulphates and their modifications and derivatives, salts of sulphonates, hydrocarbons.
• Nonionic surfactants such as polyglycol esters, acid of hydroxylated carboxylic acid and their modification and derivatives.
• Other products such as carbohydrates etc.
• Calcium, Sodium, Ammonium lignosulphonates are mostly used.
Superplasticizers
• High range water reducers
• Dose varies from 0.5 to 3 % by weight of cement
• They do not entrain air
• Reduction of water up to 15 to 30 %
• Sulphonated malanie form aldehyde condensates (SMF)
• Sulphonated naphthalene formaldehyde (SNF)
• Modified lignosulphonates (MLS)
• Other types
Factors affecting the workability of concrete in case of use of Plasticizer or Super plasticizer
• Type of Plasticizer or Super plasticizer
• Dosage
• Mix composition
• Variability in cement composition
• Mixing procedure
• Equipment
• Others
Site problems in the use of Superplasticizer
• Slump loss- Initial high slump, Using Retarders, By repetitive dose, By dosing at final point, By keeping temperature low, By using compatible Superplasticizer
• Problem with crushed sand
• Sequence of addition of Superplasticizer
• Type of mixer
• Importance of shape and grading of aggregates
• Casting the cubes
• Excessive segregation, Retardation
Retarders
Applications
1. Hot weather concreting
2. Grouting oil wells
3. RMC Plants
4. To exposed the aggregates
5. Concreting for joints
Material
• Most commonly used Calcium sulphate (Gypsum)
• Starches, cellulose material, sugars, acids or salts of acids
• Common sugar- 0.2 %
• Lignosulphonic acid and their salts, hydroxylated carboxylic acid and their salts, Mucic acid, calcium acetate.
Accelerators
Application
• Permit early removal of formwork.
• Reduced the required period of curing.
• Advanced the time that which structure can be placed in service.
• Cold weather concreting
• In emergency repair work
• Under water concreting
Material
• Calcium chloride- not more than 0.4 %
• Soluble carbonates, silicates, fluosilicates and some of the organic compounds.
Air entraining agents
• Natural wood resin.
• Animal and vegetable fat oils such as tallow, olive oil and their fatty acids such as stearic and oleic acid.
• Various wetting agents such as alkali salts or sulphated and Sulphonated organic compounds.
• Water soluble soaps of resin acids and animal and vegetable fatty acids.
• Miscellaneous materials such as sodium salts of petroleum, sulphonic acids, hydrogen peroxide and aluminium powder etc.
Factors affecting amount of air entrainment
• Type and quantity of air entraining agent
• W/C ratio of the mix
• Type and grading of aggregate
• Mixing time
• Temperature
• Type of cement
• Influence of compaction
• Admixtures other than air entraining agent
Effect of air entrainment on properties of concrete
• Increased resistance to freezing and thawing
• Improvement in workability
• Reduction in strength
• Reduces segregation and bleeding.
• Reduces permeability
• Reduces alkali aggregate reaction
• Increases resistance to chemical attack
• Reduces sand content, cost and heat of hydration
• Reduces unit weight of concrete
• Improves abrasion resistance
Optimum air content in concrete
• Depends upon purpose for which concrete is used, its location and climatic conditions, maximum size of aggregates, and richness of mix.
• Usually ranges from 3 to 6 %
• lower air content for floors
• For surfaces exposed to atmosphere 3 to 4 %
• For mass concrete 3%
• Gravimetric method
• Volumetric method
• Pressure method
Chemical requirements of fly ash as per IS 3812 part I 2003
Physical requirements
Sr. No.
|
Characteristics
|
Requirement values
|
1
|
Fineness Specific surface in m2/Kg
|
320
|
2
|
Compressive strength at 28 days in N/mm2, Min
|
Not less than 80 % of corresponding plain cement mortar cubes
|
3
|
Lime reactivity – Avg compressive strength in N/mm2
|
4.5
|
4
|
Soundness by autoclave test expansion of specimens % Max
|
0.8
|
Oxide composition of cement clinker, fly ash and GGBS
Sr. No.
|
Constituents
|
Percentage content
| ||
Cement clinker
|
Blast furnace slag (IS 12089- 1987)
|
Fly ash
| ||
1
|
Lime CaO
|
60-67
|
30-45
|
1.0-3.0
|
2
|
Silica SiO2
|
17-25
|
30-38
|
35-60
|
3
|
Alumina Al2O3
|
3.0-8.0
|
15-25
|
10-30
|
4
|
Iron Oxide Fe2O3
|
0.5-6.0
|
0.5-2.0
|
4-10
|
5
|
MgO
|
0.1-4.0
|
4.0-17.0
|
0.2-5.0
|
6
|
MnO2
|
-----
|
1.0-5.0
|
---------
|
7
|
Glass
|
------
|
85-98
|
20-30
|
8
|
Sp. gravity
|
3.15
|
2.9
|
2.1-2.6
|
Silica fume
• Undensified form with bulk density 200 - 300 Kg/m3
• Densified form with bulk density 500- 600 Kg/m3
• Micro palletized form with bulk density 600 -800 Kg/m3
• Slurry form with bulk density 1400 Kg/m3
• It must confirm the requirements of IS 15388 –2003 or ASTM C 1240 -2000
• At least 85% of silicon dioxide in non crystalline form.
• Particle size with diameter in between 0.1 to 0.2 micron
• Min specific surface area is 15000 m2/kg
• Spherical particle shape
• Sp. Gravity 2.2
In India marketed by Elkem metallurgy Ltd. Vashi Navi Mumbai, M/s Mc-Bauchemie Pvt Ltd under the trade name Centrilit fumes (Slurry form)
Rice husk ash
• Silica 85 % min
• Moisture content 2 % max
• Particle size 25 micron
• Colour grey
• Ph value 8
•
Characteristics
|
Supplementary Cementitious materials
| ||
Silica fume
|
Metakaolin
|
RHA
| |
Silica
|
90-94
|
48-55
|
92
|
Alumina
|
1-3
|
40-45
|
0.5
|
Iron oxide
|
1.5-2.5
|
1-2
|
0.2
|
Lime
|
0.5
|
2-4
|
0.5
|
MgO
|
1-3
|
0.12-1
|
0.5
|
Alkalies
|
< 2
|
< 0.5
|
2-4
|
Fineness m2/g
|
25-27
|
15-20
|
20-25
|
Metakaolin
Characteristic
|
Value
|
Silica (Wt %)
|
48-55
|
Alumina
|
40-45
|
Iron oxide
|
1-2
|
Lime
|
2-4
|
MgO
|
0.12-1
|
Na2O
|
< 0.5
|
K2O
|
< 2
|
Loss of ignition
|
15-20
|
Fineness m2/g
|
48-55
|
Surkhi / Calcined clay pozzolana
IS 1344 1981 For use in mortar/ concrete
IS 1727 1967 Testing of material
Construction chemicals for water proofing
• Integral water proofing compounds
• Acrylic based polymer coatings
• Mineral based polymer modified coating (Slurry coating)
• Chemical DPC for rising dampness
• Water proofing adhesives for tiles, marble and granite
• Silicon based water repellent material
• Injection grout for the cracks
• Protective and decorative coatings
• Joint sealants
Integral water proofing compound
• These compounds are added in the concrete during mixing as like admixtures.
• These are basically pore fillers, water repellent and reduce the water cement ratio of the concrete which will make concrete dense.
• Main materials in the pore filling class are Silicate of soda, Aluminum and zinc sulphates and Aluminum and Calcium chloride. Chemically inactive pore filling materials are Chalk, Talc.
• Materials like Soda, Potash soaps, Calcium soaps, Resin, Vegetable oils, fats, waxes are water repelling materials.
• They are quite economical for the structure which is continuously wet or under damp conditions.
• Mc-Bauchemie (Ind) Pvt ltd.
1. Mc- special DM
2. Dichtament DM
3. Putz- Dichtament
• Fosroc chemicals Pvt ltd
1. Conplast prolapin 421 IC
2. Conplast prolapin I-P
Performance requirement are covered in IS 2645-1975
Acrylic based polymer coating
• Temperature changes causes expansion and contraction of concrete which causes cracking
• Concrete cracks due to drying shrinkage
• Inadequate design i.e. less reinforcement
• Unequal settlement
• Available under the trade name Roofex 2000 which is produced by Mc-Bauchemie (Ind) Pvt ltd.
• White in colour and mainly applied by brush or spray
Mineral based polymer modified coating
• Slurry coatings is formed by mixing hydraulically setting powder and liquid polymer component.
• This coating requires curing one week or so.
• Used mainly for terrace gardens, parking places, basements, swimming pools and sanitary area.
• Mc-Bauchemie (Ind) Pvt ltd
1. Dichtament DS
2. Dichtament DS-flex
3. Zentrifix
• Fosroc chemicals Pvt ltd
1. Brush bond
2. Xypex
Protective and decorative coating
• Used in case of very thin members like roof tiles, Chajjas, sunshades etc.
• Mainly used as protective and decorative coating
• Acrylic based polymer product
• Mc-Bauchemie (Ind) Pvt ltd
1. Emcecolour flex
• Fosroc chemicals Pvt ltd
1. Dekguard S
Chemical DPC for rising dampness
• Control the capillary rise in the external walls of the building.
• Chemicals are injected at some interval which will control the capillary action of water
• Mc-Bauchemie (Ind) Pvt ltd
1. Samafit VK1
2. Samafit VK2
Water proofing adhesives for tiles, marble and granite
• Used as adhesives for tiles
• These materials are having very good adhesion or bond strength, water proofing qualities and strength and durability.
• They are mostly used for exterior tiling works.
• Mc-Bauchemie (Ind) Pvt ltd
1. Zentrival PL – for glazed and ceramic tiles
2. Zentrival HS- For marble and granite
• Fosroc chemicals Pvt ltd
1. Nitobond EP
2. Nitobond PVA
3. Nitotile SP
Silicon based water repellant Materials
• They are mainly used to maintain the architectural beauty of the structures.
• They will form a thin water repellant transparent film on th surface.
• The treatment may have to be repeated at closer intervals say 3 to 4 years.
• It is not that much costly material.
• Material is covered in IS 12027- 1987.
• NISIWA SH by Mc-Bauchemie (Ind) Pvt ltd
Injection grout for cracks
• Expansive cement
• Used for repair, remove the leakages and water proofing
• Suitable for gravity as well as pressure grouting
• Centicrete and Conbex 100 produced by Mc-Bauchemie (Ind) Pvt ltd , Fosroc chemicals Pvt ltd respectively
Joint sealants
• Any contraction or expansion joint
• Joints of doors and window openings
• Joints of sanitary appliances
• Fosroc chemicals Pvt ltd
1. Nitoseal 215
• Sika chemicals
1. Sikalastic
2. Sika-S11A
3. Sikacryl GP
• Roff chemicals
1. Qualcrete
2. Saniseal
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