Eco-Friendly Concrete
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Transcript of Eco-Friendly Concrete
ECO-FRIENDLY CONCRETE
GREEN CONCRETE
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
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.
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.
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
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.
Features Of Eco-Friendly Concrete
Optimize Use of Available Materials
Better Performance
Enhanced Cohesion Workability / Consistency
Reduced Carbon Footprint
No Increase in cost
Strategies For Eco-Friendly
Concrete
Increased Dependence on Recycled Materials.
Effective use of Supplementary Cementitious Materials.
Improved Mechanical Properties.
Use Of Grey Water.
Materials Selection Criteria
Locally available
Salvaged, re-furnished or re-manufactured
Reusable or recyclable
Resource & Energy efficiency
Materials For Eco-Friendly Concrete
Cement Replacements:
GGBS Fly Ash
Recycled Glass Silica Fume
Materials For Eco-Friendly Concrete
Aggregates Replacement:
Recycled Concrete Material Waste
Plastic
Demolition Waste Recycled Glass Aggregates
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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
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
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.
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
Waste Plastic Waste Plastic Concrete
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.
Stone Crusher Wastes Waste Stones for Green Conc.
Green Concrete Mix Design
Objectives
Objectives
Optimizes void spaces
Improved Engineered Properties
Less heat of hydration
higher slump & flow
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:
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.
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.
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.