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Construction Industry Construction Industry and its Impact to Built and its Impact to Built

EnvironmentEnvironment

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Construction Industry account for one-sixth of the world's fresh water withdrawals, one-quarter of its wood harvest. 

The cement sector alone accounts for 5 % of global man made CO2 emissions

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Construction & Demolition (C&D) generate between 10% and 40% of the solid waste stream in most countries (Kibert et al, 2000). C&D wastes can generally be used for low-priority works like footpaths, drains, pavements etc.

Most bonding & drying agents in carpets, veneers, particle board, plywood and paint emit volatile organic compounds (VOC’s) which contribute to greenhouse gases and global warming.

Pollution and Waste

Environmental

impacts

Resource

depletion Physical

disruption Chemical

pollution Other effects; Social

disruption,

undesirable

visual impact.

Social impacts

Loss of open space & biodiversity Social Isolation Increased car dependency Decreased air quality Unhealthy indoor environment

Economic impacts

To Builders: Increased compliance costs & waste disposal costs

To Owners: Increased utility & maintenance costs

To Occupiers: Loss of well being & productivity

To Society: Decreased environmental quality

• According to the World Watch Institute about 40% of the world's total energy usage is dedicated to the construction and operation of buildings.

• The building industry consumes 3 billion tons of raw materials annually, 40% of the total material flow in the global economy.

• Only about 0.003 % of earth's water is readily available as fresh water for human use (Miller, 1992). Building materials manufacturing, construction and operations consumes 16% of available fresh water annually

• In 1990 the building industry consumed 31% of Global energy and emitted 1900 Megaton's of Carbon.

Towards an innovative & eco-friendly

Construction Industry

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‘Continued ability of a society, an ecosystem, or any such interactive system to function without exhausting key resources and without adversely

affecting the Environment’

Principles:

1.Maximizing the use of renewable and natural resources;

2.Minimizing the use of energy and water;

GREEN BuildingGREEN Building

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Green building materials offer specific benefits to the building owner and building occupants:

Reduced maintenance/replacement costs over the life of the building;

Energy conservation and reduce harmful emissions;

Improved occupant health and productivity;

Lower costs associated with changing space configurations;

Do not exhaust the existing supplies of finite materials;

Green Buildings MaterialsGreen Buildings Materials

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Underlining Principle:

Assuming that all stages in the life of a material right from extraction, manufacture, transportation to the installation, operation, maintenance and the recycling and waste management cause some degree of Environmental impact which needs to be evaluated.- This is called Life Cycle Analysis (LCA) for any material/product.

Choosing Building MaterialsChoosing Building Materials

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1. CEMENT CONCRETE

Energy Intensive industry Depletion of natural resources Green house gas emissions

Characteristics of Sustainable Characteristics of Sustainable Managed AlternativesManaged Alternatives

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Recommended Alternatives:

1.Blast furnace Slag Concrete

Using Ground Granulated Blast Furnace slag with Cement (from steel plants) in mixes

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Recommended Alternatives:

2.Using Recycled Aggregates

Crushed Concrete, Bricks and other masonry waste

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3. Mortars and Plasters:

Basic Mortar used: 1 : 6 (Cement : Sand)

1.Cement : Lime : Sand (1 : 1 : 6)

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2. Lime : rha : Sand (1 : 1 : 1)rha: Rice husk ash - hard protecting coverings of grains of rice (burnt)

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Our predecessors knew it better…….

We were much less resource dependent in the past

Looking back to think ahead……………..

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RAMMED EARTH AND MUD BLOCKS RAMMED EARTH AND MUD BLOCKS

CONSTRUCTION IN BHUTANCONSTRUCTION IN BHUTAN

Earthen Construction TechnologyA brief History

Tabo Monastery , HP – India , 996 AD Shey Monastery, Ladakh

17th Century

Ramasseum, EgyptAround 1300BCOur Very Own

Auroville-Earth Institute

Aman, Gangtey

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Innovative Building Technologies:

Hollow Interlocking-Compressed Stabilized Earth Block(HI-CSEB)

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Innovative Building Technologies:

Machine that produces HI-CSEB, developed by Auroville Earth Institute, Tamil Nadu, India

Aurum Press 3000

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HI-CSEB

Economical/affordable, environmentally friendly, easily available, stronger, energy saving and simple to

manufacture

Better Thermal Insulation

Warm in winter and cool in summer

Technical /Engineering Aspects

Block ProductionMaterial selection

Soil Identification – Top soil and soil with organic matter should not be used. Grain size distribution - more of sandy is preferred.

Gravel (mm) Sand(mm) Silt(mm) Clay(mm)

20 to 2mm 2 – 0.02 0.02 – 0.002 0.002 - 0

Some basic test for identifying the suitability of soil

Proportions

• Cement : Soil (1 : 6)• Water content = 25 liters for one bag of

cement• Varying the ratio esp. the cement has the

proportionate cost involved • The ratio can go up to 1 cement to 10 soil

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Same basic data on CSEB

Properties Values

Dry Compressive Strength @28days3 – 6Mpa (N/sqmm) ( +10% after 1 year,

20% after 2years)

Wet compressive strength @28days (3days immersion)

2 – 3 Mpa

Dry bending Strength @28days 0.5 – 1 Mps

Dry Shear Strength @28days 0.4 – 0.6Mpa

Density 1700 to 2000kg/cum

Water absorption @ 28days after 3 days immersion 8 to 12 % by weight

Energy Consumption 110MJ ( Kiln fired bricks = 539MJ)

Comparison with other building blocksProperties CSEB (HI - 245) Ordinary class III

brickConcrete hollow

blocks

Size 245x 245 x 95 195 x 95 x 75 390 x 190 x 190

Weight 8kg 3kg 16kg

Compressive strength (28days)

30 – 60kg/cmsq 35kg/cmsq 45kg/cmsq(approx)

Cost (Nu.) 13 per block ( 1:6 mix ratio)

11 per brick @ Thimphu

38.00 per block @ Thimphu

For a 250mm thick 1msq wall in a load bearing building @ Thimphu

Block Numbers Cost(Nu)

HI - CSEB 40(Approx) 520

Ordinary second class brick 166(approx) 1496.00

Hollow concrete Block 19.5(approx) 741

Block production machinesTwo Machines in the market

1)HI – CSEB Block machine – Habitech centre, Thailand

2) AURUM PRESS 3000 – Auroville,India Designer/ manufacturer Auroville Earth institute/ Aureka,

Cost of Press Rs 69,800.00

Cost of Mould ( 1 set) Rs 41,500.00

Max Blocks size 245 x 245 x 95

Compression force 150KN( 15 tones)

Production capacity per day with 7 workers

500 Blocks (average)

Designer/ manufacturer Habitat centre , Bangkok

Cost of Press 73,500.00 (Nu) 2008 rate

Cost of Mould ( 1 set) -

Max Blocks size 300 x 150 x 95

Production capacity per day ( 6- 7 workers)

500 average

Pilot House Construction – SQCA using HI – CSEB 245

• Two storied load bearing structures - serve as model for the earthquake resistant design features

• Sample Blocks test results

Soil sample source Average Compressive Strength Proposed construction site (1:8 mix

ratio

22 kg/cmsq

Buddha Dodema site ( 1: 8) 33 kg/cmsq

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SQCA – Pilot Project

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Hollow Interlocking –Compressed Stabilized Earth Block (HI-CSEB)

Pilot house using HI-CSEB

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Some other buildings using HI-CSEB

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Advantages

1. Use of cheap & locally available materials2. Job opportunity for local people3. Biodegradable materials4. Energy efficiency and eco friendliness 5 – 15 times

less energy consumed than fired brick and around 3 – 8 times less emission

5. Transferable technology6. Import Reduction

Advantages

7. Cost effectiveness8. Minimum mortar required9. Keys that interlock with each other provides better

integrity10. Hollow provisions for laying vertical and horizontal

reinforcements to improve the lateral load resisting capacity

11. Ease and Fastness in construction12. Fire resistant

Limitations• Only for low rise structures: maximum 2 storey

• Strength very much dependant on the properties of soil

• Too much stabilization(cement) will make no economic sense

• Interlocking features do not provide air tightness. Minimum gap is formed due to which termite/air current can pass.

Limitations

• Requires minimum mortar between the blocks to maintain horizontal construction level

• Too much mortar between the blocks jeopardizes the interlocking feature

• For frame structures, HI-CSEB can be used as filler materials but the structural members sizes increases due to increase in the block weight

HI-CSEB in Bhutan

• No of private individuals who procured the machine-2

• Commercial basis- Established in Jemina by 2 firms

Way forward

1. Conference on GREEN Construction – Awareness and exchange of knowledge;

2. Sensitization w/shops & trainings in Green building practices;

3. Standards and regulations;

R & D required

Formulation of standards and guidelines

Conclusion• Sustainable /economical/eco friendly building

material • Easy and simple technology• Creates employment opportunities • Reduce dependency on import of bricks• Making housing affordable

Therefore, production and construction with HCSEB is relevant and it is to be adopted where ever possible.

Thank youand

Tashi Delek

www. sqca.gov.bt