Eco-Friendly Concrete

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Transcript of Eco-Friendly Concrete

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ECO-FRIENDLY CONCRETE

GREEN CONCRETE

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Presentation Overview

What is Eco-Friendly Concrete?

Set-backs of Traditional Concrete

Where Does CO2 come from in Concrete?

Need of Eco-friendly Concrete

Features of Eco-Friendly Concrete

Strategies for Eco-Friendly Concrete

Materials for Eco-Friendly Concrete

Green Concrete Mix Design Objectives

Sustainable/Green Construction with Green Concrete

Advantages of Eco-friendly Concrete

Conclusions

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What Is Eco-Friendly Concrete

Concrete that uses less energy in its production & produces less

carbon dioxide than normal concrete is referred to as Eco-

friendly or Green Concrete.

Environment friendly.

Considered to be cheap to produce.

Less energy consumption & greater durability.

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Set-Back of Traditional Concrete

Traditional concrete is made from a mixture of cement, sand,

gravel and water.

Cement is an environmentally hazardous material for the

following reasons:

Cement production is extremely energy intensive, making it third

producer of CO2 emission.

Cement production is increasing approximately 5% a year, making it

one of the most environmental destructive material.

Aggregate materials like sand and stone that are mixed with cement

are mined from quarries, further taxing our natural resources.

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Where Does CO2 Come From In

Concrete Two main sources:

i. Cement: Most of CO2 in concrete is from the cement manufacturing process. A typical cubic meter of concrete

contains about 10% cement by weight. The reaction in the

process of Cement manufacture is:

ii. Aggregates: Use of virgin aggregates contributes about 1% of all

CO2 emissions from a typical cubic meter of concrete. Therefore,

the use of alternate aggregate is desirable. The use of local and

recycled aggregates is desirable as it can reduce transportation

and fuel cost and support sustainable development.

CaCO3 = CaO + CO2

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Need Of Eco-Friendly Concrete

Need of green concrete for better environment and sustainable

construction can be characterized by the following factors;

Consumption of Natural Resources: More than 5 cubic billion yard concrete is produced globally, requiring huge natural resources

for producing cement and aggregates.

Global Warming: One ton of cement releases one ton of CO2 into

the atmosphere (greenhouse gas) contributes to the global

warming.

Water Consumption: Concrete industry uses over one trillion

gallon of water each year globally.

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Features Of Eco-Friendly Concrete

Optimize Use of Available Materials

Better Performance

Enhanced Cohesion Workability / Consistency

Reduced Carbon Footprint

No Increase in cost

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Strategies For Eco-Friendly

Concrete

Increased Dependence on Recycled Materials.

Effective use of Supplementary Cementitious Materials.

Improved Mechanical Properties.

Use Of Grey Water.

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Materials Selection Criteria

Locally available

Salvaged, re-furnished or re-manufactured

Reusable or recyclable

Resource & Energy efficiency

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Materials For Eco-Friendly Concrete

Cement Replacements:

GGBS Fly Ash

Recycled Glass Silica Fume

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Materials For Eco-Friendly Concrete

Aggregates Replacement:

Recycled Concrete Material Waste

Plastic

Demolition Waste Recycled Glass Aggregates

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Materials For Eco-Friendly Concrete

1. Cement Replacement

The reduction in the use of Portland cement can be achieved with partial replacement of cement by the various cementitious

materials, such as:

Fly Ash

Ground Granulated Blast Furnace Slag

Silica Fume

Wood Ash etc.

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Materials For Eco-Friendly Concrete

A. FLY-ASH:

Fly-ash usually refers to the ash produced during the combustion of coal.

Less expensive than OPC and improves the strength of concrete.

Generates less heat of hydration, thus preferable for mass concrete

applications.

Fly ash use in concrete improves the workability of plastic concrete, and the

strength and durability of hardened concrete.

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Materials For Eco-Friendly ConcreteAdvantages of Fly-Ash:

Utilization of fly ash as a part replacement of cement or as a mineral admixture in concrete saves on cement and hence the emission of CO2.

Use of good quality fly ash in concrete has shown remarkable improvement in durability of concrete, especially in aggressive environment.

Some of the technical benefits of the use of fly ash in Green Concrete are:

Higher ultimate strength

Increased durability

Improved workability

Reduced bleeding

Increased resistance to alkali-silica reactivity.

Reduced shrinkage.

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Materials For Eco-Friendly Concrete

B. GROUND GRANUALTED BLAST-FURNACE SLAG:

Excellent cementitious material.

Obtained by quenching of molten iron slag form blast furnace into

water/steam, to produce glassy granular product, dried and grounded

to fine powder.

Optimum cement replacement level is about 70 to 80 %.

Produces less heat of hydration and improves the durability of

concrete.

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Materials For Eco-Friendly Concrete

Comparison of GGBFS with Portland Cement Concrete:

Concretes with higher dosages of GGBFS will have lower heat of

hydration.

Concerts containing slag may show longer time of setting than

PCC for moderate and higher dosages and at lower ambient

temperatures.

Concrete with GGBFS gains strength more slowly, will have lower

strength at early ages and equal or higher strength at later ages.

Increasing slag dosage is associated with lower permeability in

concrete.

Concrete containing GGBFS dosage greater than 35% by mass of

cementitious material, have shown improvement in resistance to

sulphate attack as well as to alakli-aggregate expansion.

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Materials For Eco-Friendly Concrete

c. SILICA FUMES:

Also known as “micro silica”

Ultra fine powder obtained as a by-product of silicon

and ferrosilicon alloy production, from the condensation of Silicon dioxide gas.

Consists of spherical particles of 150nm dia.

Silica fume is typically used in quantities ranging from 7

to 12% of the mass of the cementitious material

Improves the durability and increases the ultimate

compressive strength.

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Materials For Eco-Friendly Concrete

Advantages of using Silica Fume (SF)

It is generally specified for specialized applications such as

structures exposed to aggressive chemicals.

It increases durability by making concrete less permeable.

Increase compressive strength as well.

Due to its smaller size it decreases the void space in the cement

matrix, phenomenon is known as packing.

Properly proportioned silica fume concrete can achieve very high early and ultimate compressive strength.

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Materials For Eco-Friendly Concrete

D. WOOD ASH:

Wood ash is the residue powder left after the combustion of

wood.

Wood ash has a huge capability for use as mineral admixture

and activator in cementitious material.

Improves the compressive strength, appropriate for the many

structural application.

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Materials For Eco-Friendly Concrete

2. Aggregate Replacement

Green concrete can be produced by the use of recycled material,

few of these are as follows:

Concrete Debris

Post Consumer Glass

Foundry Sand

Waste Plastic

Stone Crusher Wastes

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Materials For Eco-Friendly Concrete

A. CONCRETE DEBRIS:

Most important replacement for reuse as aggregate in new concrete.

Use of concrete debris to produce new concrete conserves

natural resources, reduces valuable landfill capacity and

reducing the use of virgin material.

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Materials For Eco-Friendly Concrete

There are 7 steps in construction waste recycling

1. feeding and preliminary crushing

2. sorting systems,

3. high-pressure washing system,

4. secondary and tertiary crushing system.

5. wastewater recycling system,

6. dust purification system, and the last step is the

7. automatic control system

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Materials For Eco-Friendly Concrete

B. POST CONSUMER GLASS:

Glass is a unique inert material that could be recycled many

times without changing its chemical properties.

Suitable aggregate for the concrete.

Substantially reduces consumer landfill waste.

Increases the durability of concrete.

Waste Glass ConcreteRecycled Glass Aggregates

Waste Glass Concrete

Pavement

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Materials For Eco-Friendly Concrete

c. FOUNDARY SAND:

Commonly known as metal casting sand having high quality

silica sand.

Sand is typically recycled and reused through many production

cycles.

Foundry sand full fills the ASTM requirements for compressive strength, absorption, and bulk density.

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Materials For Eco-Friendly ConcreteD. WASTE PLASTIC

Plastic is cheap, flexible and strong material and

can be recycled to produce many new products.

Industrial wastes from poly-ethylene-terephthalate

(PET) plastic waste were studied as the alternative replacement of a part of the conventional aggregates.

5 to 50 % replacement levels may be used.

The modified concrete mix, with addition of plastic

aggregate replacing conventional aggregate up

to certain 20% gives strength with in permissible limit.

Flakes of waste Plastic

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Waste Plastic Waste Plastic Concrete

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Materials For Eco-Friendly Concrete

E. STONE CRUSHER WASTES:

Quarry Rock Dust can be defined as residue, after the

extraction and processing of rocks to form fine particles.

It can be used as an alternative replacement for sand in the

concrete.

It has sharp and angular particles, thus because of such causes

a gain in strength due to better interlocking.

Quarry rock dust concrete experiences better sulfate and acid

resistance.

Its permeability is less as compared to that of conventional

concrete.

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Stone Crusher Wastes Waste Stones for Green Conc.

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Green Concrete Mix Design

Objectives

Objectives

Optimizes void spaces

Improved Engineered Properties

Less heat of hydration

higher slump & flow

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Sustainable/Green Construction

with Green Concrete

Affordability & Durability

Efficiency

Occupant Health

Waste & Pollution

Reduction

• Sustainable buildings refers to both a structure

and the operational processes that

are environmentally responsible and resource-

efficient

• Minimized environmental impact &

optimized economical capability.

• The main focus of Eco-

friendly concrete is on:

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Advantages of Green Concrete

Environmental Advantages:

Reduction of CO2 emission by concrete.

Reducing waste disposal problems.

Financial Advantages:

Reduced dead weight, allowing easy handling &lifting .

Less maintenance & repair required.

Economical.

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Advantages of Green Concrete

Improved Engineered Properties:

Protection against concrete deterioration.

Higher Strength & Durability

Lowered permeability.

Higher Modulus of elasticity.

Lower heat of hydration of concrete.

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Conclusion

Green concrete technology is one of the major steps that a construction industry can implement to achieve a better

environment to live.

Green concrete Technology can save the construction cost &

natural materials for future use or the generations to come and

sustain it for good amount of time.

The usage of Eco-friendly concrete ensures sustainable

development with greater efficiency and productivity.

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