An over all view of Ready mix concrete scenario in Tamil Nadu : Sustainability construction

Arivusudar Nagarajan Arivusudar Nagarajan

Ready mix concrete plant layout

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RMC Means

• Organizing.• Planning .• Scheduling. • implementing .

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Type of Batching plants

• Model name CP 18 – 16cum/hr . • Model name CP 30 – 30cum/hr . • Model name M1 - 56cum/hr . • Model name M3 - 64cum/hr

As per BIS 4926-2003

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Departments in RMC

• Quality control.• Sales & Marketing. • Plant & machinery . • Transport & maintenances.• Accounts .

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PLANT LAYOUTPLANT LAYOUT

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CONVEYOR BELT

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Type of Mixer 1) Non-tilting reversible drum concrete mixer, 2) Double conical tilting mixer, 3) Pan mixer, 4) Turbo pan mixer, and 5) Single shaft compulsory mixer/pug mill.

Ready Mixed Concrete Plants Ready mixed concrete (RMC) plants shall be equipped with computer (containing minimum 15 recipes), monitor and printer. Delivery slips of RMC plants shall contain the following information

1.Name of RMC plant supplier with logo and address2. Delivery note No.3. Name of receiving party 4.Ordered quantity in m ,5. Recipe number, 6.Number of batches, 7.Batch size in m3,

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8.Date, 9.Starting time, 10.Moisture percentage of each material at the time of batching, 11. Weighing chart for each type of component with total for each component independently, 12.Total quantity delivered in m3,13. Remarks column, 14.Transit mixer number and capacity, 15.Transit mixer driver’s name,16. Representative of RMC plant (signature column), and Representative of customer (signature column).

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DOUBLE SHAFT MIXER

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BATCHING PLANTBATCHING PLANT

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CONCRETE PUMPS

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Transit Miller with 6cum capacity

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TRUCK MOUNTED BOOM PUMPS

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RMC PLACEMENT THROUGH BOOM PUMPS

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Planning

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Problems in RMC 1. Traffic obstructions public , festival , Government , natural

calamities .2. Concrete delivery timing with 2hours maximum. 3. Skilled persons required for all the departments .4. Raw materials scarcity in metro’s 5. Demand of customers .6. Outstanding of customers 7. Transit Miller – inside blade functioning . 8. RPM in Transit miller . 9. Temperature problems .

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10. On time delivery as per code suggested .11. Dosage of concrete as per code suggested .12. Raining time batching will gets very slow.13.Batching timing per vehicles 30Min. 14. Vehicles' arrangements . 15. Tracking using GPS modeling . 16. Cold joint problems .17.Ball pass issues .18.Delay in concrete – debited amount . 19. No of vehicles . 20 Quality Accept – Slump min 80mm +/-10mm , Avg

Compressive strength 3 days – 45% , 7 days -65 % , 28 days – 100% . 21. If any case in failure in cube – Customer will go the illegal or

NDT Testing . 19

22. Air voids in concrete . 23. Usage of cement materials. 24. Mix design or any problems .

Etc ………………………….

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RMC pricing for Dec15

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Global Market • The Ready Mix Concrete (RMC) industry is growing due to the

superior technical properties over normal concrete, but the potential is still huge.

• The Ready Mix Concrete (RMC) industry in India is in its early stages with cement consumption of just 2-3 per cent of total production.

• The cement companies are able to leverage the RMC market in a better way since cement is one of the essential ingredients in the manufacture of RMC. Of course, acquiring and operating suitable aggregate quarries in India is a difficult task, but since cement companies possess sufficient experience in limestone quarrying will have technical competency of running such captive operations too.

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The industry• The construction has industry benefited from Ready mix

Concrete right from its inception during the late 40’s. This technology has since grown in a big way in Europe and USA, consuming more than 60% of the cement produced.

• Ready mix Concrete industry in India is likely to consume more than 5% of the cement produced from the current levels of around 3%.

• The plant is capable of programming 99 different types of mixes for producing different grades of concrete both automatically and manually.

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RMC & GGBS POTENTIAL IN TAMIL NADU

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Advantages of Ready mix Vs Site mix,

• Several quality and time required is among the most prominent.

• Besides, labour and space requirements on site for the latter add to the cost.

• A typical 1500 sq ft of area will take around 6-8 hours for concreting if site mix is used which if compared to Ready mix, will take only 2-3 hours.

• Ready mix is also environment friendly and any grade of concrete is available at a given point of time.

• A wide range of computer-controlled concrete batching plants, transit mixers for transporting the RMC to the construction sites, pumps and concrete placing are manufactured in India.

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Cont… • The use of RMC is growing due to its superior technical

properties than normal concrete. The difference between normal concrete and RMC lies in the technology used for production.

• In the case of RMC, all the ingredients are proportioned in accordance with the standard codes of practice to get the targeted strength and durability.

• The quality of concrete depends on the way it is mixed, placed, compacted, finished, cured and protected. RMC used in construction makes it possible to achieve speed with quality.

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Green concrete –slag

Development of GGBS Production in India:

• India has witnessed a rapid growing rate in slag grinding and the production of quality GGBS has been seen literally across the country since the mid-2007s.

• Central government for the steel industry and the increased awareness and recognition of the benefits on the use of quality GGBS not only by cement manufacturers and ready-mixed concrete players, but also by real estate developers, architects and designers and the public. With the establishment of the national standard IS 455-1989, market demand for quality GGBS has been given a big boost.

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• The number of slag grinding plants set up in India over recent years 12 projected between 2010 to 2015, VRM and press mill. Major players in Manufacturing GGBS are JSW & Tata Cement the number of operating slag grinding plants has increased from one to a projected.

• Cement the number of operating slag grinding plants has increased from one to a projected 12. Out of the 12 GGBS plants, about 5 plants were set up over the 5-year period. From 2013 to 2015.

• The total GGBS production has gone from a zero position to an amazing projected 31.2Mt per year by end of 2007.

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Green market by-products potential in India

• The fine particles of fly ash by virtue of their lightness can become air borne, if not managed well.

• At present nearly 65,000 acres of land is occupied by ash ponds. The fly ash generated in India is likely to reach 145 million tons mark by 2008 and 200 Million tons mark by 2015.

• About 70% of hot slag is granulated and incorporated in to cement. Hot slag production is projected to rise to more than 10 million tons in the next few years.

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• Granulated slag (ggbs) is the glassy grannular material that is formed in the process of producing iron in a blast furnace and is formed by rapidly chilling the molten material and subsequently grinding it in to a fine powder.

• India is also a prime rice producing country in the world. Nearly 100 million tons of paddy produces 20 million tons of rice husks which in turn can produce about 4 million tons of rice husk ash.

• Good quality rice husk ash can become a substitute for silica fume.

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Working with Ground Granulated Blast furnace Slag (GGBS) Concrete

Water Demand - GGBS allows for water reduction of 3 to 5% in concrete without any loss in workability.

Water should not be added to GGBS concrete after dispatch from the concrete plant as it reduces strength and durability of the concrete.

Engineering Benefits:

• Concrete made with GGBS continues to gain strength over time, and has been shown to double its 28-day strength over periods of 10 to 12 years.

• GGBS cement prevents the occurrence of efflorescence, the staining of concrete surfaces by calcium carbonate deposits. Due to its much lower lime content and lower permeability, GGBS is effective in preventing efflorescence when used at replacement levels of 50% to 60%.

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Durable concrete requires high percentage mixture of GGBS: • Lower temperature rise in concrete, reducing the risk of

thermal cracking in massive concrete structures.• Elimination of the risk of damage caused by alkali-silica

reaction (ASR).• High resistance to chloride ingress, reducing the risk of

reinforcement corrosions .• High resistance to attacks by sulphate and other chemicals

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Setting Times • Concrete with up to 30% GGBS will exhibit similar initial

setting as concrete with Portland cement only.• At replacement levels of 40 to 50% the initial set is likely to be

extended by one to two hours and for concrete containing more than 50% GGBS setting time maybe extended past three hours.

• Longer setting times can have the advantage of allowing concrete to be worked for longer periods meaning time delays, including delays in transport, between mixing and using concrete are less critical.

• They also reduce the risk of cold joints in larger concrete pours.

Strength development

GGBS concrete has slightly slower strength development at early ages, but will have equal if not greater strength at 28 days compared to non GGBS concrete.

At 7 days GGBS concretes will have 50 to 60% of its characteristic strength compared to 70 to 80% for Portland cement only concrete at the same time.

At 28 days GGBS concrete will have fully developed its characteristic strength and will continue to develop strength past 90 days.

It is good practice to make 56 day cubes when using GGBS concrete at 50% and above should there be any concern over later strength development.

Bleeding

• Concrete with up to 40% GGBS replacement does not exhibit different bleeding characteristics from that of concrete made with Portland cement.

• For higher percentages of GGBS there is a longer period of bleeding due to the increase in setting times of these mixes. Concrete should be allowed to bleed fully before finishing.

Strength results: GGBS Vs Fly Ash Mix

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Mix Cost comparison – Grade wise

Mix Cost comparison – Grade wise

Grade M50

OPC + PFA mix OPC + GGBS mix

Material Qty Cost Material Qty CostOPC 440 2259.84OPC 230 1181.28Flyash 30 33GGBS 230 598           

Cementecious cost 2292.8 Cementecious cost 1779.28

Mix TypeMix cost 7 DAYS %

28 DAYS %

OPC + PFA mix 3780 44.45 Mpa 88  49.15 99.67 

OPC + GGBS mix 3266 31.85 Mpa 64 43.89   87.76  SAVING = 514/Cum

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Grade M25

OPC + PFA mix (MAHA)

OPC + PFA mix (Bharathi) OPC + GGBS mix (MAHA)

OPC + GGBS mix (Bharathi) Triple blend (MAHA) Triple blend (bharathi)

Material Qty CostMateri

al Qty Cost Material Qty CostMateri

al Qty Cost Material Qty Cost Material Qty Cost

OPC 290 1489.44OPC 350 1855OPC 238 1222.368OPC 238 1261.4OPC 175 899OPC 175 928

Flyash 70 77Flyash 0 0GGBS 102 265.2GGBS 102 265.2Flyash 52 57Flyash 52 57

                        GGBS 123 320GGBS 123 320

Cementecious cost 1566.44

Cementecious cost 1855

Cementecious cost 1487.568

Cementecious cost 1526.6Cementecious cost 1276

Cementecious cost 1305

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Mix Type Mix cost 7 DAYS % 28 DAYS %

OPC + PFA mix (MAHA) 3053 18.37 MPA 73   

OPC + PFA mix (Bharathi)) 3342 20.59 MPA 82   

OPC + GGBS mix (MAHA) 2975        

OPC + GGBS mix (Bharathi) 3014        

Triple blend (MAHA) 2763        

Triple blend (Bharathi) 2792        

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ALCOFINE MIX & COST DETAILS

Grade M25

OPC + PFA mix (MAHA)OPC + PFA mix

(HEMADRI)OPC + PFA mix

(BHAVYA)OPC + PFA + A.F mix

(MAHA)OPC + PFA + A.F mix

(HEMADRI)OPC + PFA + A.F mix

(BHAVYA)

Material Qty CostMateria

l Qty Cost Material Qty Cost Material Qty Cost Material Qty Cost Material Qty Cost

OPC 290 1489.44OPC 350 1855OPC 280 1484OPC 266 1366.6OPC 266 1410OPC 266 1410

Flyash 70 77Flyash 0 0FLY ASH 60 1.38

FLY ASH 60 66

FLY ASH 60 66

FLY ASH 60 66

                 ALCOFINE 14 0.322

ALCOFINE 14 0

ALCOFINE 14 0

Cementecious cost 1566.44Cementecious

cost 1855Cementecious

cost 1485.38Cementecious

cost 1432.498Cementecious

cost 1476Cementecious

cost 1476

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Mix Type Mix cost 7 DAYS %

OPC + PFA mix (MAHA) 3053 18.37 MPA 73

OPC + PFA mix Bharathi 3342 20.59 MPA 82

OPC + PFA mix (BHAVY) 2972 16.15 MPA 65

OPC + PFA+A.F mix (MAHA) 2919 19.25 MPA 77

OPC + PFA+A.F mix bharathi 2963 18.07 MPA 72

OPC + PFA+A.F mix (BHAVYA) 2963 23.40 MPA 93

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CEMENT REPLACEMENT MATERIALS

FLY ASH It is finely divided residue resulting from the

combustion of powdered coal and transported by the flue gases and collected by electrostatic precipitator ( Thermal Power plants)

Mostly used pozzolonic material Reference IS-3812. Replacement up to 35 percentage .

Contd…

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Savings in cement Reducing heat of hydration Reducing water demand Spherical shape and smooth surface of flyash

helps to reduce the inter-particle friction and thus facilitates mobility.

Reduce Bleeding and drying shrinkage. Fly ash particles plasticize cement paste and

improves flowability and rheology of the mix. Contributes to strength

Contd…

ADVANTAGES OF FLY ASH

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CEMENT + C-S-H Gel + Ca(OH)2

WATER FLYASH C-S-H Gel

SECONDARY HYDRATION OF FLY ASH

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PETROGRAPHIC VIEW OF FLY ASH

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FLYASH-PARTICLE PACKING EFFECT

FLYASH

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Cement Flyash

BALL BEARING EFFECT

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Trapped Water

DISPERSION OF CEMENT PARTICLES WITH FLY ASH

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Fly ash is called as coal ash materials. Ready mix concrete using waste materials as

cost saving . Customers preferred to site mix . % of replacement involved in concrete mix.

Contd…

Customer Awareness

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Condensed Silica Fume is a by product of ferro-Silicon alloy industry and it is the dust which is collected from furnace exhaust system

Fineness of silica fume is @ 15000 m2/kg as against 280 to 290 m2/kg of Cement

Contributes significantly to compressive strength due to micro-filler effect and excellent pozzolanic properties

Leads to increase in density and reduction of permeability in concrete

It’s use is must for manufacturing of concrete above M50 Contd…

SILICA FUME (Micro Silica)

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Condensed Alco Fume is a by product of ferro-Silicon alloy industry and it is the dust which is collected from furnace exhaust system

Contributes significantly to compressive strength due to micro-filler effect and excellent pozzolanic properties

Leads to increase in density and reduction of permeability in concrete

It’s use is must for manufacturing of concrete above M45

Contd…

Alco fine

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SILICA FUME

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Admixtures are materials mostly chemicals that are added in small quantities during the preparation of concrete to impart certain specific properties to it.The requirements may be

Improving the workability of concrete during placing Retarding or accelerating setting Improving the impermeability and water tightness of the

cast concrete. Imparting corrosion inhibition etc Entraining air in concrete

Chemical Admixtures

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Compatibility test by Marsh Cone Apparatus

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DEFLOCCULATION OF CEMENT PARTICLES

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DISPERSION OF MECHANISM

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EFFECT OF SUPER PLASTICISERON WORKABILITY

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SLUMP : Collapse

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EFFECT OF SUPER PLASTICISERON WORKABILITY

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PUMPABLE CONCRETE

1. Air entrainers :

TYPES OF ADMIXTURES

They entrain air in the form of micro air bubbles which helps in improving the durability of concrete in freezing environment, sulphate and alkali attack.

2. Water reducers

To reduce the water-cement ratio and yet retain workability. It is possible to reduce water upto 12%. The only precaution is that it should be mixed thoroughly

3. Accelerating admixtures :

To accelerate setting of cement in cold environment or where early setting is desired.It assists in early removal of form work

4. Retarding admixtures :

To delay the setting time of concrete, for RMC supplied to far off sites.Prolongs setting time, giving higher strength at later stages, also results in reduction in micro cracks.

5. Super plasticisers :To make flowing concrete for concreting in heavily reinforced sections, tremie concrete, for pumping concrete.(when added to normal concrete with 75mm slump upto 250mm can be achieved)

6. High range water reducers :

PC based admixturesWater reduction capacity of about 25-40%High performanceEarly strength and early setting

7. Bonding agents :

To increase bond strength, old and new concrete(in repair and rehabilitation works), they are usually modified latex or polymer compounds

8. Corrosion inhibitors :

To inhibit corrosion

• Aggregate is the word used to describe any inert material .

• Usually rock derivative generally between 50mm down to 75 micron used to produce concrete .

• It is divided into coarse aggregate and fine aggregate

• Those which are 4.75mm to 50mm are classified as coarse aggregates

• Those below 4.75mm to 75 micron as fine aggregates

• Except for mass concrete in dams etc. which may contain upto 150mm size aggregate, the maximum size of aggregate is normally 20mm in most cases

• But it may be 40mm for plain concrete or massive works.

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AGGREGATES

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Specific gravity: it should have good crushing strength and density

Surface texture: it should be smooth,slightly rough but not honeycombed

Particle shape : it should not be flaky or elongated.

Porosity : it should have very low water absorption

Should not be Reactive

PROPERTIES OF COARSE AGGREGATES

Water demand, Workability Cohesion of concrete in plastic state Strength, Density, Durability Porosity of hardened concrete Stability : it should be chemically inert.

Impurities: it should be free from impurities (like silt, clay)

Compactness: it should be graded, as then only the voids can be less.

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PROPERTIES OF AGGREGATE EFFECT

• Specific gravity implies the absolute weight per unit volume of aggregates

• A low specific gravity may indicate

high porosity

poor durability

low strength.

• Specific gravity of aggregates is used in arriving at mix design

• Generally the specific gravity of good aggregates is greater than 2.5 g/cm3

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SPECIFIC GRAVITY

• Surface texture reveals how grainy or smooth the surface of the aggregate is.

• It indicates bonding strength and porosity. • Higher the smoothness of the particle, lesser is the

bonding between aggregate and cement matrix. • rough textured aggregates develop higher bond strength

than smooth textured aggregates,• This property is especially considered while producing

high strength concretes.

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SURFACE TEXTURE

Particle shapes are classified as Irregular Rounded Flaky Angular Aggregates should be as much cubical as possible in shape

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PARTICLE SHAPE

• Grading of aggregates means particle size distribution of the aggregates.

• Principle of grading is that smaller size particles fill up the voids left in larger size particles.

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GRADING

IS sieve Designatio

n

Percentage passing for single size aggregate of nominal size by weight

63 mm 40mm 20 mm 16 mm 12.5 mm

10 mm Remarks

80 mm 100 - - -63 mm 85-100 100 - -40 mm 0-30 85-100 100 -20 mm 0-5 0-20 85-100 10016 mm - - 85-100 100

12.5 mm - - - 85-100 10010 mm 0-5 0-5 0-20 0-30 0-45 85-100

4.75 mm 0-5 0-5 0-10 0-202.26 mm - - - 0-5

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GRADING OF COARSE AGGREGATE

• Indian standards divides the sand into four zones

• zone-I to zone-IV based on the sieve analysis• Sand falling in zone-I is coarse and that falling in

zone-IV is fine. • Sand falling in zone IV shall not be used for

reinforced concrete work.• Fineness modulus for sand : ranges from 2.2 to

3.2, higher value indicates coarser grading

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SAND

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IS sieve designation

Percentage passingZone-I Zone-II Zone-III Zone-IV

10 mm 100 100 100 1004.75 mm 90-100 90-100 90-100 90-1002.36 mm 60-95 75-100 85-100 95-1001.18 mm 36-70 55-90 75-100 90-100

600 microns 15-34 35-59 60-79 80-100300 microns 5-20 8-30 12-40 15-50150 microns 0-10 0-10 0-10 0-15

Remarks Very coarse Coarse Medium Fine

REQUIREMENT OF FINE AGGREGATES

• Water helps in dispersing the cement evenly

• Quality of water for making concrete and for curing

• Water should be free from salts, oils, acids, alkalis, sugar and organic materials

• pH value shall not be less than 6

• Sea water is not suitable for making concrete

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WATER

SL. No.

Description Tested as per Permissible limit (max) mg/l

1 Organic IS-3025(part-18) 2002 Inorganic IS-3025(part-18) 30003 Sulphates (as SO3)

Sulphates (as SO4)IS-3025(part-24) IS-3025(part-24)

400500

4 Chlorides (as Cl) IS-3025(part-32) 2000 mg/l for concrete not containing embedded steel

1000 mg/l for RCC work

5 Suspended matter IS-3025(part-17) 2000

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PERMISSIBLE LIMITS FOR SOLIDS IN WATER

FRESH CONCRETE Fresh concrete is a freshly mixed material which

can be moulded into any shape. Workability: is the ease with which fresh

concrete can be mixed, transported, placed and compacted in the moulds or forms

Apart from water-cement ratio the concrete has to be compacted well to get the required strength

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UNDERSTANDING CONCRETE

TESTS ON FRESH CONCRETE

WORKABILITY 1. Slump Test 2. Compaction Factor Test 3. Flow Test. Yield Test

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• It is the science of the deformation and flow of materials and is concerned with relationships between stress, strain, rate of strain and time.

• The term Rheology deals with the materials whose flow properties are more complicated than those of fluids (liquids or gases)

RHEOLOGY OF CONCRETE

Factors affecting workability:• Water content

• Mix proportions

• Size of aggregates

• Shape of aggregates

• Surface texture of aggregate

• Grading of aggregate

• Use of admixture

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Segregation: Segregation can be defined as the separation of the

constituent materials of concrete.

Bleeding: Sometimes referred as water gain It’s a particular form of segregation due to

highly wet mix If water cement ratio is more than 0.7 Badly proportioned and insufficiently mixed

concrete

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BLEEDING

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While traversing from bottom to top Bleeding channels responsible for

permeability It may be interrupted by aggregates

(flaky) It may be interrupted by reinforcement Reduces bond between reinforcement,

aggregate and paste Remedy— re-vibration, delayed finishing

Cement – 3.15Coarse aggregate – 2.70Sand – 2.60Water – 1.00Fly ash – 2.15Silica Fume - 2.20

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SPECIFIC GRAVITY

Compaction of concrete is the process adopted for expelling the entrapped air from the concrete.

The entrapped air in the form of voids reduces the strength of concrete.

For every 1% of entrapped air, the strength of concrete falls about 5% to 6%.

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COMPACTION

Hand compaction Tamping Ramming : generally permitted for

unreinforced foundation concrete RCC should never be rammed Compaction by vibration: common needle

vibrator dia is 25mm to 40mm External vibrators Surface vibrators

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METHODS OF COMPACTION

Contd…

When inserting a needle vibrator, allow it to penetrate the bottom of the layer as quickly as possible.

If it is done slowly, the upper part of the concrete will get compacted and prevent the air in the bottom layer from escaping.

The vibrator should be left in the concrete for about 10 sec. and then withdrawn slowly. If it is withdrawn fast, a hole will be left in the concrete.

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PRECAUTIONS

Contd…

The vibrator should be inserted again at a distance of not more than 50 cm from its last position.

The vibrator should not be allowed to touch the face of the form work or the reinforcement to prevent the reinforcement from losing bond with concrete

Do not stop the vibrator when the needle is in the concrete.

Do not over vibrate or under vibrate

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• The rate of levelling should not be less than the rate placing of concrete

FINISHING OF CONCRETE

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Effect of Water-Cement ratio Effect of maximum size of aggregate on

strength Grades of concrete: Concrete in construction is specified by

grade like M20,M25 etc. Usually increments of five.

M20 means the specified crushing strength is 20 N/mm2

STRENGTH OF CONCRETE

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CURING Why Curing ? To prevent loss of moisture from the Concrete

due to combined effect of hot sun and drying wind

Creation of conditions for promotion of uninterrupted and progressive hydration of cement during the period immediately after placing

Curing does not mean only application of water

HARDENED CONCRETE

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1. WATER CURING2. MEMBRANE CURING3. APPLICATION OF HEAT (Steam Curing)4. ACCELERATED CURING

CURING METHODS

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• Sampling Criteria• Cube Testing• Acceptance Criteria• Non Destructive Testing of Concrete

1. Rebound Hammer Test 2. Ultra sonic pulse velocity testing • Core Test

COMPRESSIVE STRENGTH

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OTHER CONCRETES :• High strength concrete

• High performance concrete

• Mass Concrete

• Light-weight concrete

• High-density concrete

• No-fines concrete

• Roller compacted concrete

• Ferrocement

• Self compacting concrete.

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HIGH STRENGTH CONCRETE

CONCRETE GRADE FROM M60 ONWARDS REGARDED AS HIGH STRENGTH CONCRETE

FOR HIGH STRENGTH CONCRETE DESIGN STANDARDS GIVEN IN THE CODE IS-456-2000 MAY NOT BE APPLICABLE

THEY HAVE TO BE OBTAINED FROM SPECIFIED LITERATURES OR BY EXPERIMENTAL RESULTS

SPECIAL CONCRETES

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POSSESSING1. HIGH WORKABILITY2. HIGH STRENGTH3. HIGH DENSITY4. HIGH DIMENSIONAL STABILITY5. LOW PERMEABILITY6. RESISTANCE TO CHEMICAL ATTACK

HIGH PERFORMANCE CONCRETE

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NORMAL CONCRETE HEAVY SELF WEIGHT

(DENSITY 2200 to 2600 KG/M3)

LIGHT WEIGHT CONCRETE DENSITY (300 to 1850 KG/M3) LOW THERMAL CONDUCTIVITY

LIGHT WEIGHT CONCRETE

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DENSITY 3360 TO 3840 KG/M3 EVEN 5280 KG/M3 USING IRON AS BOTH F.A. AND C.A

DENSITY 50% HIGHER THAN THE CONVENTIONAL CONCRETE

USED AS A SHIELDING MATERIAL FOR PROTECTION FROM RADIATION

HIGH DENSITY CONCRETE

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• It is made by introducing air or gas into the slurry composed of cement and finely crushed sand by alluminium powder.

• Uniformly cellular structure is formed.• Also called as gas concrete, foam concrete,

cellular concrete

AERATED CONCRETE

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By Omitting fine aggregate fraction Made by cement, water and single sized coarse

aggregates Having large voids and hence light in weight Applications

Temporary structures In external walls for Thermal insulation Rough texture gives good base for plastering Free from dampness because of low capillary action

on account of large voids

NO-FINES CONCRETE

ROLLER COMPACTING CONCRETE

• Recent development particularly in the field of Dam construction.

• Lean mix• No slump concrete• High volume fly ash to the extent of 60 to 65%• Compacted by Rollers.• Compressive strength of about 7 Mpa to 30

Mpa

FERRO CEMENT It is a relatively new material consisting of

wire meshes and cement morar. Thickness of elements is 2 to 3 cm Water –cement ratio 0.4 to 0.45 Cement -sand ratio 1:2 External cover to reinforcement is 2 to 3mm

APPLICATIONS OF FERROCEMNT

FOR CASTING DOMESTIC OVER-HEAD WATER TANKS

FOR TANKS USED AS GRAIN SILOS IN VILLAGES FOR CONTAINER USED AS GAS HOLDER UNIT

IN “GOBBAR GAS” PLANTS. IDEAL MATERIAL FOR BOAT BUILDING FOR MANHOLE COVER

SELF COMPACTING CONCRETE

• Self levelling concrete• With Super plasticizer (Glenium )• Fines• Should not be vibrated• Applications Precast units.

MASS CONCRETE• It’s is a concrete having considerable

dimensions that may get affected by thermal behavior of Concrete. Ex-Concrete Dam

• Members with minimum cross sectional dimension of a solid concrete member approaches or exceeds 2 to 3 ft

• Cement contents above 364 kg/m3

• It is a latest development in the construction industry

• Concrete is batched and mixed in a centralised Plant and transported to the sites far-away from the plant through Transit-Mixers and placed through pumps to the required height and distances.

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RMC (READY MIX CONCRETE)

ANY QUESTIONS ?

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THANK YOU

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