Concrete

CONCRETE CONSTRUCTION: NEW TECHNIQUES AND METHODS

Presented by:05 Eesha Jain

13 Pareshram Mistry15 Alisha Nisar

28 Sumitra Patel42 Kanan Gala

Concrete is a composite construction material composed primarily of aggregate, cement and water.Various chemical admixtures are also added to achieve varied properties

Concrete has relatively high compressive strength, but much lower tensile strength. For this reason it is usually reinforced with materials that are strong in tension

ADDITIVES: In history adding volcanic ash to the mix allowed it to set under water. Adding horse hair made concrete less liable to crack while it hardened and adding blood made it more frost-resistant. In modern times, researchers have experimented with the addition of other materials to create concrete with improved properties, such as higher strength or electrical conductivity

What is concrete….???

PROPERTIES:

Concrete Overlay

1938

1891

3000 BC

Egyptian Pyramid

300 BC- 476 AD

Roman Architecture

1913

1908

19031889

1824

1836

Portland Cement

Cement Testing

Alvord Lake Bridge

Ingalls Bldg

Ready Mix

Concrete Street

Concrete Homes

1915

19671936

Coloured Concrete

Hoover Dam

19701950

1980

1930

Air EntrainingAgent

1992

1990 1999

Concrete Sports Dome

Concrete Countertops

Tallest Bldg

DecorativeConcrete

Fiber Reinforcement

Concrete Engraving

Polished Concrete

INNOVATION CAUSED BY ….

CHANGING METHODS OF CONSTRUCTION – • Shotcrete

CHANGE IN CORE INGREDIENTS – • Concrete Canvas• Engineered Cementitious Composite (ECC)

ADMIXTURES – • Cellular Fibro Concrete• Light Transmitting Concrete• Recycled Aggregate

•The dry mixture Cellular Fibro Concrete is a specially selected and calibrated multi-component mixture based on cement that has undergone certain stages of processing. •An outstanding advantage is that one of the components in the mixture can be fly ash or

metallurgical slag, which contributes to solving the problem with utilization of these waste products.

CELLULAR FIBRO CONCRETE

•This technology allows to set upfront the density of the cellular concrete in the range from 250 to 1400 kg/m3 when applied in monolithic construction.

•Water-resistant

Type Of Cellular Concrete Produced From A Prefabricated Dry Mixture.

PROPERTIES

• Frost-resistant

• Nature-friendly• Excellent Thermal And Sound Insulation

• Fire-resistant

APPLICATION•Roads

•Pipelines

•Tunnels

•Sea and river ports •Oil and gas fields •Roofs

•Floors

•Low level buildings

•Individuals can solve many construction tasks quite inexpensively such as embankment and alley repairs, insulation of roofs and floors, new construction, specific architectural designs, etc.

•Bridges

Form: prefabricated blocksIngredients: 96% concrete, 4% optical fibreDensity: 2100 - 2400 kg/mMaximum block size: 1200 x 400 mmThickness: 25 - 500 mmStandardcolours: grey, black, whiteFinish: polishedCompressivestrength: 50 N/mmBending tensilestrenght: 7 N/mmSpecial requests: custom-made products (different block sizes,thickness, colour) available on request

TRANSLUCENT CONCRETE is a combination of optical fibres and fine concrete. Strands of optical fibers are cast by the thousands into concrete to transmit light, either natural or artificial, into all spaces surrounding the resulting translucent panels.

prefabricated blocksIngredients:96% concrete4% optical fibreDensity: 2100-2400 kg/m³Compressive strength: 50 N/mm²Bending tensile strength: 7 N/mm²Finish:polished

BLOCK SIZESMaximum block size:1200 x 400 mmThickness:25-500mmOther (smaller) block sizes are available on request

RECYCLED AGGREGATES IN NEW CONCRETE

SUSTAINABILITY:•Recycled aggregates can be obtained from the disintegration of the concrete matrix (called recycling). •During the crushing process, constituents of the concrete matrix have the tendency to return to their most stable form with only strong particles can survive and weaker particles would be reduced to some more stable but smaller size particles which still can be reused.• Using recycled aggregates can regain the embodied energies, conserve natural resources and also preserve our precious landfill space.

SECONDARY RECYCLED MATERIALS USED AS AGGREGATE IN CONCRETE- Glass- Blast Furnace Slag- Steel Slag- Mining and Quarrying Wastes- By-products from Power Plants- Incinerator Bottom Ash Aggregate (IBAA)- Rubber- Polystyrene Concrete- Wood Chip Concrete

APPLICATION AND PERFORMANCEBased on overseas and local experience, recycled aggregates can be used in:

•Production of concrete•Road sub-base•Rock infill for gabion and stone column•Drainage filter•Pipe surround/ haunching•Production of recycled concrete paving blocks•Parapet wall and planters International Wetland Park Phase II, Hong Kong.

Concrete Canvas is a flexible, cement impregnated fabricthat hardens when hydrated to form a thin, durable, water andfire proof concrete layer.CC allows concrete construction without the need for plant ormixing equipment. Simply position the Cloth and just addwater.Once hydrated, CC remains workable for 2 hours andhardens to 80% strength within 24 hours. Accelerated orretarded formulations can be produced to meet specificcustomer requirements.CC is available in 1.1m wide rolls in 3 thicknesses: CC4, CC8 and CC13, which are 4, 8 and 13mm thick respectively.

RECYCLED AGGREGATES IN NEW CONCRETE

RAPID:Once hydrated, CC remains workable for 2 hours andhardens to 80% strength within 24 hours. Accelerated orretarded formulations can be produced to meet specificcustomer requirements.FLEXIBLE:CC has good drape characteristics allowing it to take up theshape of complex surfaces including those with a doublecurvature.STRONG:The fibre reinforcement prevents cracking, absorbs energyfrom impacts and provides a stable failure mode.DURABLE:CC is chemically resistant, has good weathering performanceand will not degrade in UV.WATER PROOF:The PVC backing on one surface ensures that the material iscompletely water proof and chemically resistant.FIRE PROOF:CC is a ceramic and will not burn.

PROPERTIES OF CONCRETE CANVAS

Engineered Cementitious Composite (ECC), also called bendable concrete, is an easily molded mortar-based composite reinforced with specially selected short random fibers, usually polymer fibers. Unlike regular concrete, ECC has a strain capacity in the range of 3–7%, compared to 0.1% for ordinary Portland cement (OPC).

UNIQUE PROPERTIES•Tensile properties superior to other fiber-reinforced composites•Ease of processing on par with conventional cement•The use of only a small volume fraction of fibers (~ 2 %),•Tight crack width•superior corrosion resistance •self-healing In the presence of water unreacted cement particles recently exposed due to cracking hydrate and form a number of products (Calcium Silicate Hydrate, calcite, etc.) that expand and fill in the crack. This self-healing behaviour not only seals the crack to prevent transport of fluids, but mechanical properties are regained.

ENGINEERED CEMENTITIOUS COMPOSITE (ECC)

TYPES OF ECC:•Lightweight (i.e. low density) ECC•Self compacting concrete•Sprayable ECC•An extrudable ECC

FIELD APPLICATIONS:ECC have found use in a number of large-scale applications in Japan, Korea, Switzerland, Australia and the U.S. These include:

•A 225-mm thick ECC bridge deck on interstate 94 in Michigan was completed in 2005.

•The 95 m (312 ft.) Glorio Roppongi high-rise apartment building in Tokyo contains a total of 54 ECC coupling beams (2 per story) intended to mitigate earthquake.

•The 1 km (0.62 mi) long Mihara Bridge in Hokkaido, Japan was opened to traffic in 2005.The steel-reinforced road bed contains nearly 800 m3 of ECC material. The tensile ductility and tight crack control behaviour of ECC led to a 40 % reduction in material used during construction.

Glorio Roppongi

Bridge deck in Michigan repaired using ECC link slab method.

Mihara Bridge

PROPERTIES AND ADVANTAGES:•Low Water/Cement Ratio•High Strengths with Rapid Strength Gain•High Density/Low Permeability•Enhanced Adhesion and Bond Strength•High Speed High Output•Reduction in Formwork Costs•Ease of Access

Shotcrete is mortar or small-aggregate concrete that is pneumatically projected onto a surface at high velocity. Also known as “gunite” and “sprayed concrete,”•Shotcrete was developed in 1911 and its concept is essentially unchanged even in today’s use. •Shotcrete is applied by a dry or wet process.

The “dry spray” Process The “wet spray” Process

SHOTCRETE

New Construction•Shell roofs and domes•Retaining walls• Free form structuresUnderground Construction• Tunnel linings• New Austrian tunnelling method•Storage reservoirsWater Retaining Structures• Sea and river walls• Reservoirs and dams•Swimming pools

Protective Coatings•Fire protection to structural steelwork•Pipeline encasement•Rock and soil stabilisationStrengthening and Repair•Concrete damaged byreinforcement corrosion•Fire damaged structures•Housing

Comparison ChartMaterial Attribute GrancreteTM Portland Cement

Typical Strength (psi) 6000-8000 2000-4000

Fire-proof (>2000 F) Yes No Burns<1000 F

Water-proof Yes No

pH 3-11 Tolerance Yes No

Hardening Time < 30 min 2-4 hours

Functional Cure Time < 30 min 1-28 days

Can apply at < 32 F Yes No

Expansion or contraction Not hardly Yes

Temperature related No Yes cracking

Self Leveling Yes No

Bonds to itself Yes No

Green Materials Yes No

Tolerant to salt water Yes No