Khush Bakht

7/31/2019 Khush Bakht

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Report title

Ecology and sustainability of building materials

Select 5 most commonly used building materials and analyze them on account of:

a) Energy consumption in production processing and transportation

b) Pollution in production, use and demolition

c) Renewable or non renewable sources

d) Potential for re-use/recycling

e) Health hazards in production and use

f) Cost of maintenance

Suggest alternate choices for non-environment friendly materials


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1. INTRODUCTION AND OBJECTIVE OF STUDY

2. METHODOLOGY FOR FIELD RESEARCH

It has been given in the assignment to select 5 most commonly used building materials and toanalyze them on the account of sustainability and their environmental impacts on the

surroundings. The five materials which I have selected are:

1. Brick

2. Concrete

3. Glass

4. Steel

5. Wood

These materials have been analyzed on the account of:

a) Energy consumption in production processing and transportation

b) Pollution in production, use and demolition

c) Renewable or non renewable sources

d) Potential for re-use/recycling

e) Health hazards in production and use

f) Cost of maintenance

Suggestion for environmental friendly materials have also been given in the end of the report.

3. REVIEW OF LITERATURE

Building material is anymaterialwhich is used for aconstructionpurpose.

Unlike all other living creatures, man has always to protect himself against nature by means of

clothing and buildings. Apart from animal hides, building materials are the oldest category of

materials used by man to maintain his existence, followed soon by weapons.

The traditional materials used in the developing world were by their nature more sustainable thanmost modern materials. Renewable or very widely available raw materials were used without

elaborate or energy consuming processes, though frequent labour intensive maintenance was

required. Modern materials often imply greater environmental impact, without necessarily

assuring of better environmental quality. This rises the problems of comparing and assessing

different types of variables.
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The construction industry is a huge and increasing consumer of materials. Total materials take

by all industries currently runs over 10 billion tons per annum, with construction responsible for

around 80% of that amount. Construction uses a wider range of materials than almost any other

industry, including metals, ceramics, plastics, natural materials such as timber and natural stones,

etc.

Construction materials are not particularly high-technology types, neither are they expensive.

Compared with other industries, the materials for construction are, in general, among the

cheapest. They are not high embodied-energy materials.

There are several aspects that must be taken into consideration when choosing building materials

with regard to the sustainability:

Limit use and reuse of building materials;

The environmental impact of building materials;

Use of residual products;

The possibilities for recycling of the chosen materials;

The durability of buildings and materials;

The quantity of energy required for the production and the use of the materials.

Sustain means to support or to keep a process going, and the goal of sustainability is that life on

the planet can be sustained for the foreseeable future. There are three components of

sustainability: environment, economy, and society. To meet its goal, sustainable developmentmust provide that these three components remain healthy and balanced. Furthermore, it must do

so simultaneously and throughout the entire planet, both now and in the future. At the moment,the environment is probably the most important component, and an engineer or architect uses

sustainability to mean having no net negative impact on the environment. Thus the termsustainable has come to be synonymous with environmentally sound or friendly and green.

Despite the critical importance of all three components (environmental, economic, and social) insustainable development, this report focuses on the environmental impact of most commonly

used building materials.


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In the manufacture and use of construction materials, the critical elements of environmentalimpact are the utilization of resources, the embodied energy, and the generation of waste

materials. These are the issues that engineers and architects must consider when planning and

building a structure.

In order to estimate the environmental impact of a building material, it is necessary to consider

all stages in the life of the material. Each construction material is manufactured from some

combination of raw materials, with some expenditure of energy, and with associated wastes.Therefore manufacture is an essential element in computing the environmental impact, and

manufacture is probably the element most widely cited when considering the environmental

impact of construction materials. Are the raw materials renewable? Are they scarce? Are theyimportant to the global environment? How much energy is required in the manufacture? How

much waste is produced during the manufacture? What impact do these wastes have on the

environment? These questions are very important and in order to achieve sustainability, these

points must be considered.


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1. CONCRETE

Concrete is a high-volume, low-cost building material produced by mixing cement, water and coarse and

fine aggregates. Its use is nearly universal in modern construction, as it is an essential component ofroads, foundations, high-rises, dams and other staples of the developed landscape.

Energy consumption is production, processing and transportation:

Concrete is manufactured from aggregates (rock and sand), hydraulic cement, and water. It

usually contains a small amount of some chemical admixture, and it often contains a mineraladmixture replacing some portion of the cement. A typical concrete formulation contains a large

amount of coarse and fine aggregate, a moderate amount of cement and water, and a small

amount of admixture.

The aggregates are usually obtained by mining. The coarse and fine aggregates are usually mined

separately. Occasionally aggregate is obtained as a by-product of some other process (e.g., slagor recycled concrete). Aggregates may be crushed and may be washed. They are usually

separated into various size fractions and reconstituted so as to satisfy the grading requirements.

A modest amount of energy is involved in all these processes.

The hydraulic cement may be straight Portland cement or a mixture of Portland cement and some

proportion of a supplemental cementing material such as fly ash or slag. Portland cement is

usually manufactured by heating a mixture of limestone and shale in a kiln to a high temperature(approximately 1500C), then intergrinding the resulting clinker with gypsum to form a fine

powder. Thus it is not surprising that the Portland cement has a rather high embodied energy.

Energy consumption is the biggest environmental concern with cement and concrete production.

Cement production is one of the most energy intensive of all industrial manufacturing processes.

Including direct fuel use for mining and transporting raw materials, cement production takes

about six million Btus for every ton of cement (Table 2). In some Third World countries, cement

production accounts for as much as two-thirds of total energy use, according to the Worldwatch

Institute.

Supplemental cementing materials, as noted above, may also be used as mineral admixtures in

concrete. These are byproducts of other manufacturing processes and as such are taken to haveminimal embodied energy.

The water in concrete is normally ordinary tap water with no further processing. Thus it has verylittle embodied energy and no waste.

Concrete is usually manufactured by combining and mixing these constituents in large batches in

a ready-mixed concrete plant and hauling the mixture to the construction site in a truck. These


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processes (moving materials, mixing them, and hauling the concrete) require modest amounts of

energy and produce small amounts of waste. Including energy for hauling, sand and crushedstone have embodied energy values of about 40,000 and 100,000 Btus per ton, respectively.

Concrete used in structural applications normally includes some amount of reinforcing steel, and

in some applications this steel is prestressed. Prestressed concrete is often precast. Precastconcrete is manufactured at a plant and heated to accelerate the early hydration reactions and

allow rapid removal from formwork.

The environmental impact of using concrete at a construction site is basically similar to the

impact of manufacturing concrete in a ready-mixed concrete plant. The concrete is moved to its

desired location, consolidated into the formwork, and finished. After the concrete has set andgained some strength, the formwork is typically removed. These are all low-energy operations.

The impact of concrete on sustainability during the lifetime of the structure is primarily a

function of its role in energy transmittance (i.e., its insulating properties) and its role in energy

storage. Concrete is not an especially good heat conductor, not as good as steel, for example. It isalso not an especially good insulator, not as good as wood, for example. A very high porosity is

necessary to provide good insulating properties, and concrete has less porosity than wood. On theother hand, concrete provides a large thermal mass so it can store energy and release it later.

Embodied Energy for Cement and Concrete Production

Notes:

Calculations of energy requirements for cement production based on figures supplied by the

Portland Cement Association, 1990 data. Aggregate and hauling energy requirements based on

data supplied by PCA and based on the following assumptions:

Cement hauled 50 miles to ready-mix plant

Aggregate hauled 10 miles to plant
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Concrete mix hauled 5 miles to building site

Concrete mix: 500 lbs. cement, 1,400 lbs. sand, 2,000 lbs. crushed stone, 260 lbs.

water/yard.

Energy requirements for transportation of concrete are low because it is produced locally from

local resources, typically manufactured within 100 kilometers of the job site.

The overall embodied energy of concrete is therefore lower than for most structural materialsother than wood.

Pollution in production, use and demolition

Pollution caused by cement production:

There are two very different sources of carbon dioxide emissions during cement production. Thereaction between limestone and shale to produce clinker produces CO2. Furthermore, the fuel

used in the kiln and the electricity in the grinding mills themselves produces some amount of

gaseous waste, principally CO2 and CO. These gases are non toxic and are released to theatmosphere, where they contribute to global warming.

Combustion of fossil fuels to operate the rotary kiln is the largest source: approximately34 tons

of CO 2 per ton of cement. But the chemical process of calcining limestone into lime in thecement kiln also produces CO 2:

CaCO 3 CaO+ CO 2 limestone lime + carbon dioxide

This chemical process is responsible for roughly 1/2 ton of CO 2 per ton of cement, according to

researchers at Oak Ridge National Laboratory. Combining these two sources, for every ton of
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cement produced, 1.25 tons of CO 2 is released into the atmosphere (Table 4). In the United

States, cement production accounts for approximately 100 million tons of CO 2 emissions, or just

under 2% of our total human-generated CO 2. Worldwide, cement production now accounts for

more than 1.6 billion tons of CO 2over 8% of total CO 2 emissions from all human activities.

Suggestion:

The most significant way to reduce CO 2 emissions is improving the energy efficiency of the

cement kiln operation. Indeed, dramatic reductions in energy use have been realized in recent

decades, as discussed above. Switching to lower-CO 2 fuels such as natural gas and agricultural

waste (peanut hulls, etc.) can also reduce emissions. Another strategy, which addresses the CO 2

emissions from calcining limestone, is to use waste lime from other industries in the kiln.

Substitution of fly ash for some of the cement in concrete can have a very large effect.

The U.S. EPA (cited by UBC researchers) estimates total particulate (dust) emissions of 360

pounds per ton of cement produced, the majority of which is from the cement kiln. Other sources

of dust from cement production are handling raw materials, grinding cement clinker, and

packaging or loading finished cement, which is ground to a very fine powderparticles as small

as125,000 of an inch.

Pollution caused by concrete manufacturing:

During the concrete manufacturing, dust, unused concrete, and wash water contaminated withconcrete are the principal waste, and the latter two wastes may be at least partially reclaimed and

reused.

Common sources of dust are sand and aggregate mining, material transfer, storage (wind erosion

from piles), mixer loading, and concrete delivery (dust from unpaved roads). Dust emissions canbe controlled through water sprays, enclosures, hoods, curtains, and covered chutes.

Other air pollution emissions from cement and concrete production result from fossil fuelburning for process and transportation uses. Air pollutants commonly emitted from cement

manufacturing plants include sulfur dioxide (SO 2) and nitrous oxides (NO X). SO 2 emissions

(and to a lesser extent SO 3, sulfuric acid, and hydrogen sulfide) result from sulfur content of

both the raw materials and the fuel (especially coal).


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Waste during the use of precast concrete includes unused concrete, contaminated wash water,and used formwork. Formwork may be wood, which must be disposed in a landfill, but

sometimes it is steel and can be reused.

Water Pollution

Another environmental issue with cement and concrete production is water pollution. The

concern is the greatest at the concrete production phase. Wash-out water with high pH is the

number one environmental issue for the ready mix concrete industry, according to Richard

Morris of the National Ready Mix Concrete Association.

At the batch plant, washwater from equipment cleaning is often discharged into settling ponds

where the solids can settle out.

Potential for re-use/recycling

At the end of its service life, a concrete structure can be demolished and disposed. The

demolition process is done by brute force -- depending on the size of the structure, it may involve

controlled blasting or some type of hammer. These processes use modest amounts of energy.

Concrete, which must be free of trash, wood, paper and other such materials, is collected fromdemolition sites and put through acrushing machine, often along with asphalt, bricks and rocks.

Reinforced concrete contains rebarand other metallic reinforcements, which are removed withmagnets and recycled elsewhere. The remaining aggregate chunks are sorted by size. Largerchunks may go through the crusher again. Smaller pieces of concrete are used as gravel for new

construction projects.Aggregate basegravel is laid down as the lowest layer in a road, with fresh

concrete or asphalt placed over it. Crushed recycled concrete can sometimes be used as the dryaggregate for brand new concrete if it is free of contaminants, though the use of recycled

concrete limits strength and is not allowed in many jurisdictions.
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Recycled crushed concrete being loaded into a semi-dump truck to be used as granular

fill.

The waste produced by demolition of a concrete structure includes dust, powder, and fragments

of concrete. These are typically land filled.

Renewable or non renewable sources

Use of water in concrete is only an environmental issue in locations where the water is already

not sufficient for basic needs.

conclusion

Cement and concrete are vital components in building construction today. Concrete has many

environmental advantages, including durability, longevity, heat storage capability, and (in

general) chemical inertness. For passive solar applications, concretes ability to function as a

structural element while also providing thermal mass makes it a valuable material. In many

situations concrete is superior to other materials such as wood and steel. But cement production

is very energy intensivecement is among the most energy-intensive materials used in the

construction industry and a major contributor to CO 2 in the atmosphere. To minimize

environmental impact, therefore, we should try to reduce the quantity of concrete used in

buildings, use alternative types of concrete (with fly ash, for example), and use that concrete

wisely.

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Environmental-Considerations/

Health Concerns in production and use

Working with wet concrete requires a number of precautions, primarily to protect your skin from

the high alkalinity. Rubber gloves and boots are typically all that is required to provide

protection. Cement dermatitis, though relatively uncommon, occasionally occurs among workers

in the concrete industry who fail to wear the proper protective clothing.

Once it has hardened, concrete is generally very safe. Traditionally, it has been one of the most

inert of our building materials and, thus, very appropriate for chemically sensitive individuals.
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As concrete production has become higher-tech, however, that is changing. A number of

chemicals are now commonly added to concrete to control setting time, plasticity, pumpability,

water content, freeze-thaw resistance, strength, and color. Most concrete retarders are relatively

innocuous sucrose- (sugar-) based chemicals, added in proportions of .03% to .15%. Workability

agents or superplasticizers can include such chemicals as sulfonated melamine-formaldehyde and

sulphonated napthalene formaldehyde condensates. Air-entraining admixtures function by

incorporating air into the concrete to provide resistance to damage from freeze-thaw cycles and

to improve workability. These are usually added to the cement and identified with the letter A

after the type (Type IA). These materials can include various types of inorganic salts (salts of

wood resins and salts of sulphonated lignin, for example), along with more questionable

chemicals such as alkyl benzene sulphonates and methyl-ester-derived cocamide diethanolamine.

Fungicides, germicides, and insecticides are also added to some concrete.

Because of these chemical admixtures, todays concrete could conceivably offgas small

quantities of formaldehydes and other chemicals into the indoor air. Unfortunately, it is difficult

to find out from the manufacturers the actual chemicals in these admixtures. For chemically

sensitive clients, it may be advisable to specify concrete with a bare minimum of admixtures, or

use a sealer on the finished concrete to minimize offgassing. Asphalt-impregnated expansion

joint filler, curing agents that are sometimes applied to the surface of concrete slabs to reduce

water evaporation, special oils used on concrete forms, and certain sealants used for treating

finished concrete slabs and walls can also cause health problems with some chemically sensitive

individuals.

Finally, concrete floors and walls can cause moisture problems and lead to mold and mildewgrowth, which cause significant health problems in certain individuals. There are two commonsources of moisture: moisture wicking through concrete from the surrounding soil; and moisture

from the house that may condense on the cold surface of concrete.

Cost of maintenance

SUGGESTIONS

Cement Substitutes

Replacing energy-consuming Portland cement with recyclable materials and minerals offers two

distinct benefits to the environmentit significantly reduces the amount of CO2 released intothe atmosphere and it minimizes massive landfill disposal.

A promising green concrete being heralded for sustainability is high-volume fly ash

concrete. Fly ash is a by-product of coal-burning power plants, and in the past, almost 75% offly ash produced made its way to landfills.


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Recycled fly ash, when mixed with lime and water, forms a compound similar to Portland

cement and is extremely strong and durable.

High-volume fly ash concrete displaces more than 25% of the cement used in traditional

concrete, reducing the amount of emissions needed to make the concrete mix.

Fly ash concrete was somewhat difficult to source in the past. Due to a significantincrease in demand, there are more producers and distributors working to steadily

increase the fly ash supply.

AshCrete is a concrete substitute that relies heavily on the use of recycled fly ash. Made up of

97% recycled materials, AshCrete is made from fly ash, bottom ash, borate, and a chemical from

the chlorine family. (Note: The use of such a chemical is not environmentally friendly because

chlorine, used in this way, is suspected to cause a number of environmental and human healthproblems. The inventor of AshCrete is currently seeking a natural substitute for this

chemical.) As a building product AshCrete is known for its extreme strength, approximately

twice the strength of Portland cement.

Similar to fly ash, blast furnace slag is another by-product that can be recycled and used as a

cement substitute for concrete. It is produced from blast furnaces used to make iron and, like flyash, creates a very strong cement when mixed with lime and water. Commonly referred to as

slag, it can be easier to find than fly ash.

The newest cement substitute being introduced into green building is carbon concrete, a

thermoplastic. To make this material, an oil refinery by-product (a heavy residual substance that

is typically very difficult to dispose of) is turned into a binder material to replace the use ofcement.

Unlike fly ash and slag, carbon concrete cannot be used for tall buildings or towers

because there is some degree of creep over time. This material is recommended

primarily for use in flooring and paved roads because of its tendency to settle.

Shell and The University of Delft have developed this technology and it is being

promoted and distributed by a company called C-Fix. At this time it only is used in

Europe, but C-Fix is looking to expand their operations very soon

Concrete Alternatives

In addition to cement substitutes, there are other ways of making concrete more sustainable,based on two core environmental principlesrecycle and reduce. These alternatives include:

The use of recycled aggregate materials and preparations that results in reduced

amounts of concrete needed to complete the job. Conventionally, cement was mixed

with virgin materials, such as sand or gravel, to make durable, workable concrete. Theuse of recycled materials has gained credibility and momentum in the concrete industry


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and aggregate is now mined from various solid wastes, including: fiberglass waste

materials, discarded glass, granulated plastics, wood products, old tires, and more.

Papercrete or fibercrete/fibrous concrete that is made by using waste paper as an

aggregate material. These concrete mixtures still rely on the use of cement, but the

amount of cement used represents a fairly small percentage of the cured material byvolume, so one can argue that it is a greener alternative than traditional concrete.

Other alternatives, such as foam crete, ceramicrete, glass fiber reinforced concrete

(GFRC), and grasscrete, which reduce the overall amount of concrete in use, resulting

in decreased emissions and energy expenditures.

o Foam crete is a lighter, aerated, foam-based concrete that requires less energy to

produce.

o Ceramicrete and glass fiber reinforced concrete are twice as strong as traditional

concrete, so builders use less of it.

o Grasscrete is a method of laying concrete in a checkered, cellular pattern that

allows grass to grow between the concrete blocks. The result? Less concreteused and improved drainage and storm run-off.

Another green alternative is concrete produced in a dry-process kiln. These kilns are

much more thermally efficient than wet-process kilns and drastically reduce energyconsumption.

2.CLAY BRICK

A brick is a block ofceramicmaterial used inmasonryconstruction, usually laid using various kinds of

mortar.[1]

It has been regarded as one of the longest lasting and strongest building materials usedthroughout history.

PRODUCTION PROCESS

After extraction from quarries, the clay raw material is laid out in order to obtain a homogeneous

mixture. Several stages are involved in preparing the clay. It is stockpiled, then crushed to attainthe required grain size and then stockpiled again for several days or even months.

Before processing, the moisture content is controlled and it may be necessary to add water toobtain the right consistency for forming. Materials such as sawdust or residue of paper industry

can be added to increase the porosity of the final product. For bricks, the clay is extruded ormolded to obtain the shape required and then cut to size. In roof tile making, the clay can

undergo a two-stage process, the second of which may occur after extrusion, depending on theroof tile being manufactured. For example, for interlocking tiles, the extruded clay is pressed

between two moulds.
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The formed clay is dried in order to reduce its moisture content and then loaded into kilns for

firing. When this is completed and the products have cooled, they are packed ready for dispatch.Throughout all stages of production, the process is subject to rigorous quality control.

ENERGY CONSUMPTION

The energy consumed during the manufacture of clay products is primarily that used in forming,drying and firing.

As in the cement and lime industry, most of the energy used in brick manufacture is required to fire the

bricks - typically more than 95 per cent of all energy use. There are considerable differences between

the energy requirements for different types of brick kilns, depending on whether the firing is continuous

or intermittent, on the size and heat-transfer efficiency of the kiln and on whether the brick-earth used

contains combustible materials.

Energy consumption in brick-making technologies

Technology Scale ofproduction

(No. of bricks)

Labour required

(man-hr for 1000

solid bricks)

Over-all energy

consumption

(MJ/1000 solid

bricks)

Small-scale production, all manualmethods, clamps, stoves, scotch kilns

2,000 20 to 30 7,000 to 10,000

Small-scale production, all manual

methods, up draught and down draught

kilns

2,000 30 to 40 10,000 to 15,000

Medium-scale production, all manual

methods, Bulls kilns

20,000 30 to 40 4,000

Medium-scale production, semi-

mechanized method, Hoftmann on zig-zag kiln

30,000 30 to 35 3,000 to 3,500

Large-scale production, full mechanized

tunnel kiln

150,000 10 to 15 3000 to 4000

In addition to the size of kilns, the actual amount of fuel required to burn a given amount of

bricks would depend, among others, on the following factors:

(a)characteristics of raw material (clay);(b) porosity of bricks;(c) volume of water (moisture) to be evaporated;

(d) quality of the carbonaceous matters in the bricks;

(e) temperature to be attained;

(f) reuse of hot air generated in the kiln;(g) quality of fuel


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Typical fuel requirements of kilns

Type of KilnHeat Requirement

(MJ/1000 Bricks)Quantity of Fuel Requirement

(Tons/1000 Bricks)

Wood Coal Oil

Intermittent 7,000 to 15.000 0.50-1.0 0.25-0.6 0.15-0.35

Continuous 2,000 to 5,000 0.15-0.3 0.10-0.2 0.05-0.1

POLLTUION

Atmospheric emissions are associated with all phases of the manufacturing process.

Three main kinds of gaseous emission occur:

Emissions coming from ceramic conversion of the raw material in the kiln. The emissionsare HCl (hydrochloric acid), HF (hydrofluoric acid), SOx (sulphuric acid) and C02.

Exhaust gas emissions from combustion processes (from drying and firing plants). Theemissions are CO (carbon monoxide), CO2 (carbon dioxide), NOx (nitrogen oxides) and

particles. Emissions due to the use of organic substances (additives). The emissions are VOCs

(volatile organic compounds).

Fired clay bricks are responsible for the greater of environmental impacts amongst bricks. The firing of

clay consumes large amounts of energy produced largely from fossil fuels causing release of CO2. The

primary source of air pollution is the firing kiln. Emissions are from the combustion of fuel and gaseous

emissions driven off as the clay is fired, including sulfur dioxide, hydrogen fluoride and hydrogen

chloride. Factors that may affect emissions include raw material composition and moisture content, kiln

fuel type, kiln operating parameters, and plant design.

Reusable if used with lime mortar

Downcyclable into low-grade fill / aggregate

Durable

Large reserves

Un-reclaimable if used with Portland cement mortar


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High embodied energy

High output of CO2

The firing of bricks can produce a bag of pollutants including fluorides, chlorides and oxides

of nitrogen and sulphur. Strict limits are placed on emissions in the UK.

Clay extraction has a long-term environmental impact on the landscape

Transportation can add considerably to the embodied energy

Transp[oprtation cost

In normal brickwork,brick represents approxiamately 70 percent of the volume-the rest is

mortar.brick is heavy material manufactured at one factory. brick is normally used in large

quantities,meaning that transport over large distances can have enviroenmntal impact.

The production of brick seriously pollutes the environment and is very energy consuming but

bricks have low maintenance leveland are very durable,in the majority of cases outlasting allother materials in buildings

In comleted buildings,brick is considered a healthy material.the potential of problem can arise

when radioactive byproducts are used in the manufacture of the bricks e.g slag from the blastfurnaces.other wise brick has positive effect on the indoor climate,especially birkcs have many

pores which will regulate humidity.

Recycling

Cleaning bricks is time consuming, difficult and dusty work that, if mechanised, israrely successful. New techniques should be applied to tackle such problems.

Cement rich mortars are difficult to remove. In countries like Greece, where mortar

from ancient constructions is a full ceramic material, it does not need to be removed.

Excess mortar dust can inhibit the adhesion between mortar and bricks and lead to

weaker masonry, depending on the mortar composition.

Bricks from demolished buildings may vary in quality. It is therefore difficult to assessthe strength and load-bearing capacity of masonry made from recycled bricks.

European and national standards are very strict and it is extremely difficult to be sure

that recycled bricks used in new structures will be durable.

Due to the difficult nature and high labour costs associated with the process, the use ofrecycled bricks may be more expensive than the use of new bricks.

The stability and porosity of recycled brick renders it suitable for use as a fill or surfacing material in

roads and trenches.recycled bricks are maily usable in smaller structure such as party walls and

external walls where there is no heavy horizontal loading.

Bricks that cannot be dismantled can be gound and in certain cases used as an equivalent to

pozzolana in cemnt.larger pices can be used as aggregate in concrete.


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Sugeestions

The ideal building material would be borrowed from the environment and replaced after use.

There would be little or no processing of the raw material and all the energy inputs would bedirectly, or indirectly, from the sun. This ideal material would also be cheap. Mud bricks cancome close to this ideal.

Steel

Steel is a metal alloy whose major component is iron, and is the usual choice for metal structural

building materials. It is strong, flexible, and if refined well and/or treated lasts a long time.

Steel buildings are primarily known for their strength and functionality. These steel buildings can be

employed as functional offices, host households, while some serve as storage areas. They provide

shelter to people and have evolved according to the specific requirements of men and women. Steel

frames are lightweight, less difficult to work with and less expensive to ship and store. It is also easier

to carry and move around a jobsite, so they have much less strain to put on construction workers who

are putting together steel buildings.

Steel, which is an alloy of iron and carbon, is the most versatile and important engineering and

construction material in the world. Its use influences every aspect of our lives and the built

environment, from automotive manufacture to construction products, from steel toecaps for

protective footwear to refrigerators and washing machines and from cargo ships to the finest scalpel

for hospital surgery. Created of high quality and aesthetic Demands a lower maintenance priceNon-

combustible to fire Steel is environmentally friendly Components can be employed again and once

more. Steel frame construction is rigid in structure and is dimensionally stable.

RECYCCLING

11. Steel can be re-used and recycled without having effecting the environment.

ENERGY COMSUMPTION

12. Construction with steel components is really quick when compared to other materials.

COST OF MAINTEENCE

13. Steel construction with steel components is resistant to termites and other destructiveinsects.

14. Steel construction is cheaper than any other construction techniques.

You can also get the old steel buildings recycled that are no longer in use into new
http://en.wikipedia.org/wiki/Steelhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Corrosion#Surface_treatmentshttp://en.wikipedia.org/wiki/Corrosion#Surface_treatmentshttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Alloyhttp://en.wikipedia.org/wiki/Steel


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constructing materials. If you are thinking to get building supplies that do not harm the

environment whilst offering a safe and secure place for your company or loved ones then steelbuilding is one of the best alternatives to opt for.

Steel is one of the most sustainable building materials in the world. The industry has

embraced the common sense approach that reducing its impact on the environment is not onlythe right thing to do, but it makes economic sense.

Since the early 1990s, the steel industry has reduced its energy use to produce a ton of

steel by approximately 1/3.

More than 95% of the water used in the steel making process is recycled and returned -often cleaner than when it was taken from the source.

Every piece of steel used in construction contains recycled content. Further, all steel

can be recovered and recycled again and again into new high quality products.

Steel is durable, safe, and strong. It is not susceptible to rot, termites, or mold. Steelused for framing will last from hundreds to over a thousand years due to its zinc

coating, a natural element. Steel structures require less material (both reduced weightand reduced volume) to carry the same loads as concrete or masonry or woodstructures.

Steel is dimensionally stable: it will not warp, split, or creep - making it durable and

built to last. Dont waste time and dollars on costly call backs. Minimize cracking and

pops in drywall and other finishes with CFS framing.

Steel to build faster

The speed and accuracy of construction is critical to the creation of building and stakeholder

value. Earlier occupancy means an office owner can begin renting space sooner, a factory

owner can start producing products faster and the store operator can bring in sales poundsquicker. Fast construction also lowers financing costs and overhead expenses for construction

management services.

Because structural steel is lighter than other framing materials, it needs a smaller and simpler

foundation. This reduces both cost and the time spent on construction.

Easily disassembled for repairs/alterations/relocation Vandal resistant.

Produces less scrap and waste (2% for steel vs. 15-20% for wood).

Scrap is 100% recyclable.

Slower aging process with less maintenance.

Enhanced resale value.

Every ton of steel recycled saves 2,500 pound of iron ore, 1,400 pounds of steel, and

120 pounds of limestone.

All steel framing contains a minimum of 25% recycled steel .


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As far as the environmental issues are concerned; whenever we can reuse a material instead ofproducing a new one by using raw materials, even these raw material are also recycled; we can

save on resources and energy which are the real gains for the conservation of nature.

When we consider the importance of this fact, it is quite obvious that constructional use ofsteel offers great advantages concerning the refurbishment and reusability properties.

Refurbishment projects which are used in many applications in many countries are especiallypreferred for being a dry construction creating a clean and waste free working environment. In

most of the cases, this type of construction also allows refurbished buildings to be operational

during the construction work which is also a very big advantage. Steel is % 100 recyclablematerial without degradation and its recycling rate can go up to beyond % 60 for the

constructional steel in some countries. Magnetic separation utility gives an advantage to steel

for the removal of material from the other surrounding solid wastes. It is also very important to

note that, promoting steel as the alternative way of building system against wood is a verypositive and effective environmental approach in considering the destruction of trees and thus

the scarcity of our forests. While it is predicted that the iron ore resources will last 7 millionyears with todays mining activities; it is not easy to renew the diminished forests especiallywithin a short period of time. It is also important for our environmental values to note that; the

energy need to produce 1 ton of scrap- based steel is about one fifth of the ore-based steel.

From life-cycle perspective, materials may have down-cycling property which produces lower

grade materials. Actually steel is the only material with a closed material loop which is animportant advantage when compared to many down-cycled materials. It can be % 100 recycled

to the same product, function and quality as before. It is also possible to convert the recycled

steel into another metal product easily depending upon the industrial needs and marketdemands. More than 435 million tonnes of steel are recycled each year. On the other hand,

steel industry is spending a great effort to bring the emission levels much more down the upper

limits. Almost all the constructional steel products contain recycled steel. In general a newsteel framing material contains % 28 minimum recycled steel.[4] So, it must be realised thatthe constructional steel which becomes a post-consumer recycled material in the future also

supply us an important advantage in saving landfill spaces and contributing to the conservation

of our nature.

https://docs.google.com/viewer?a=v&q=cache:b3JAWm6iQToJ:www.arch1design.com/advste

elgreenbuilding.pdf+&hl=en&gl=pk&pid=bl&srcid=ADGEESjZkD2WL5zMZuSCm3wZ7e40JCfEbH1XsJH0UruipxHpBg8Qj-FVfmXYdiKOwBfrss9reGz5O2KklUYOvC6qpiYo_v-

C_SsYqIR-caoiWpR4JIvFoe26DIon-

sAReu67qY8otFG5&sig=AHIEtbT95TK7Pnl41IaizjpcqJwVsR3REw

GLASS

Glass is anamorphous(non-crystalline) solid material. Glasses are typicallybrittleand optically

transparent.
http://en.wikipedia.org/wiki/Amorphous_solidhttp://en.wikipedia.org/wiki/Amorphous_solidhttp://en.wikipedia.org/wiki/Amorphous_solidhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Transparency_and_translucencyhttp://en.wikipedia.org/wiki/Brittlehttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Amorphous_solid


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Glassmakingis considered an art form as well as an industrial process or material.

Clearwindowshave been used since the invention of glass to cover small openings in a

building. They provided humans with the ability to both let light into rooms while at the same

time keeping inclement weather outside. Glass is generally made from mixtures of sand andsilicates, in a very hot fire stove called akilnand is very brittle. Very often additives are added

to the mixture when making to produce glass with shades of colors or various characteristics(such asbulletproof glass, orlight emittance).

The use of glass in architectural buildings has become very popular in the modern culture.

Glass "curtain walls" can be used to cover the entire facade of a building, or it can be used to

span over a wide roof structure in a "space frame". These uses though require some sort of

frame to hold sections of glass together, as glass by itself is too brittle and would require anoveGlass is made out sand rich in silica and could be reused indefinitely. The process of

making glass is energy intensive. One ton of virgin glass requires four GigaJoule of energy. rly

large kiln to be used to span such large areas by itself.

Glass is the dominating material in modern day architecture which places optical emphases

and provides for numerous technical functions.

The glass industry primarily uses energy to supply heat to the glass melting furnaces in which

the raw materials are melted and refined, with downstream processing used to ultimately formand finish glass.

This guideline describes the manufacture of flat glass, and pressed and blown glass. Flat glass includesplate and architectural glass, automotive windscreens and mirrors. Pressed and blown glass includes

containers, machine and hand-blown glassware, lamps and television tubing. In both categories a glassmelt is prepared from silica sand, other raw materials such as lime, dolomite, and soda, and cullet(broken glass). The use of recycled glass is increasing and this requires extensive sorting and cleaningprior to batch treatment to remove impurities. The use of recycled glass reduces the consumption ofboth raw materials and energy.

For the manufacture of special and technical glass, lead oxide (up to 32 wt. %), potash, zinc oxide,and other metal oxides are added. Refining agents include arsenic trioxide, antimony oxide, nitrates,and sulfates. Metal oxides and sulfides are used as (de-) coloring agents.

The most common furnace used to manufacture glass melt is the continuous regenerative type witheither side or end ports connecting brick checkers to the inside of the melter. Checkers conserve fuel byacting as a heat exchanger--the fuel combustion products heat incoming combustion air. The moltenglass is refined (heat conditioning) and then is either pressed, blown, drawn, rolled or floated,depending on the final product. Damaged/broken product (cullet) is returned to the process.

The most important fuels for glass melting furnaces are natural gas, light and heavy fuel oil andliquefied petroleum gas. Electricity is also

used (frequently installed as supplementary heating). Energy requirements range 3.7-6.0 kiloJoulesper metric ton (kJ/t) glass produced.

Waste Characteristics

Two types of air emissions are generated, those from the combustion of fuel to operate the glassmelting furnaces and fine particulates from the vaporization and recrystallization of materials in the
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melt. The major emissions are sulfur oxides (SOx), nitrogen oxides (NOx) and particulates which cancontain heavy metals such as arsenic and lead. Note: particulates from lead crystal manufacture canhave a lead content of 20-60 percent and an arsenic content of 0.5-2 percent. Certain specialty glassescan produce releases of hydrogen chloride (HCl), hydrogen fluoride (HF), arsenic, boron and lead fromraw materials. Container, press and blow making operations produce a periodic mist when the hot gobcomes into contact with the release agent used on the molds.

Cold top electric furnaces that operate with coverage of the melt surface by raw material feedrelease very little particulate matter as the blanket acts as a filter to prevent the release of particulatematter. Some releases of particulates will take place when tapping but furnace releases should be in theorder of 0.1 kg/t when operated this way.

Lead glass manufacture may result in lead emissions of the order of 2-5 kg/t.In all cases, the concentration of heavy metals and other pollutants in the raw flue gas mainly

depends on the type of fuel used, the composition of the feed material, and the portion of recycledglass. High input of sulfates

or potassium nitrate may increase emissions of SO2 and NOx respectively. Where nitrate is used, in

excess of two-thirds of the introduced nitrogen may be emitted as NOx. Heavy metals used as

(de)colorizing agents will increase emissions of these metals.The grinding and polishing of flat glass to produce plate glass has become obsolete since the

development of the float glass process. The chemical make-up of detergents that may be used by floatglass manufacturing could vary significantlysome could contain phosphorous in hand blown andpressed glass, pollutants in effluents are generated by finishing processes such as cutting, grinding,polishing and etching and include suspended solids, fluorides, lead, and variations in pH.

Liquid effluents also result from forming, finishing, coating, and electroplating operations. Heavymetal concentrations in effluents occur where silvering and copper plating processes are in use.

http://www.miga.org/documents/GlassManufacturing.pdf

Local impacts

As with all highly concentrated industries, glassworks suffer from moderately high localenvironmental impacts. Compounding this is that because they are mature market businessesthey often have been located on the same site for a long time and this has resulted in

residential encroachment. The main impacts on residential housing and cities are noise, fresh

water use, water pollution,NOxand SOx air pollution, and dust.

Noise is created by the forming machines. Operated by compressed air, they can produce noise

levels of up to 106dBA. How this noise is carried into the local neighborhood depends heavilyon the layout of the factory. Another factor in noise production is truck movements. A typical

factory will process 600T of material a day. This means that some 600T of raw material has to

come onto the site and the same off the site again as finished product.

Water is used to cool the furnace, compressor and unused molten glass. Water use in factories

varies widely, it can be as little as one tonne water used per melted tonne of glass. Of the one

tonne roughly half is evaporated to provide cooling, the rest forms a wastewater stream.

Most factories use water containing anemulsifiedoil to cool and lubricate the gob cuttingshear blades. This oil laden water mixes with the water outflow stream thus polluting it.

Factories usually have some kind ofwater processingequipment that removes this emulsified
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oil to various degrees of effectiveness.

The oxides of nitrogen are a natural product of the burning of gas in air and are produced in

large quantities by gas fired furnaces. Some factories in cities with particular air pollution

problems will mitigate this by usingliquid oxygen, however the logic of this given the cost in

carbon of (1) not using regenerators and (2) having to liquefy and transport oxygen is highlyquestionable. The oxides of sulfur are produced as a result of the glass melting process.

Manipulating the batch formula can effect some limited mitigation of this; alternativelyexhaust plume scrubbing can be used.

The raw materials for glass making are all dusty material and are delivered either as a powderor as a fine-grained material. Systems for controlling dusty materials tend to be difficult to

maintain, and given the large amounts of material moved each day, only a small amount has to

escape for there to be a dust problem. Culletis also moved about in a glass factory and tends to

produce fine glass particles when shovelled or broken.

[edit] Global environmental impact

The main global impact factor is the production ofCO2due to the burning of fossil fuels in the

heating of the furnace and production of electricity to supply the compressors. Typically a tonof glass packed will liberate between 500 and 900 kg of CO2, assuming a gas-fired furnace and

coal-fired electricity usage. In areas with predominantly renewable or nuclear energy, the CO2

released comes only from the conversion of carbonates to oxides in the ingredients of the glass

itself.

http://en.wikipedia.org/wiki/Glass_production

recycling of glass

Glass is made from quartzite (or quartz) sand. Quartz is a mineral that the earth is not making

more of, so in that sense, sand can be considered non-renewable mineral. But, the supply of

quartz sand is plentiful and glass can be recycled

Glass and aluminum are examples of recyclable resources. The bottles and cans made from them can

be re-processed into new products. There is no limit to the number of times these products can be

recycled.

Read more:Difference Between a Renewable & Recyclable Resource | eHow.comhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-

resource.html#ixzz1rGajBevQ
http://en.wikipedia.org/wiki/Liquid_oxygenhttp://en.wikipedia.org/wiki/Liquid_oxygenhttp://en.wikipedia.org/wiki/Liquid_oxygenhttp://en.wikipedia.org/w/index.php?title=Glass_production&action=edit&section=21http://en.wikipedia.org/w/index.php?title=Glass_production&action=edit&section=21http://en.wikipedia.org/w/index.php?title=Glass_production&action=edit&section=21http://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Glass_productionhttp://en.wikipedia.org/wiki/Glass_productionhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://www.ehow.com/facts_5904510_difference-between-renewable-recyclable-resource.html#ixzz1rGajBevQhttp://en.wikipedia.org/wiki/Glass_productionhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/w/index.php?title=Glass_production&action=edit&section=21http://en.wikipedia.org/wiki/Liquid_oxygen


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TIMBER

Wood is the only building material on the planet which is naturally renewable,

recyclable and leaves a lighter footprint than any other. In its production theembodied energy in wood is a fraction of the energy required to produce almostany other building material. Wood is carbon negative, as a result of carbonsequestration, or in other words storage. To grow a kilo of it takes 1.47 Kgof carbon dioxide on average and gives off 1.07 Kg of oxygen. So, using woodfrom sustainably managed forests minimises CO2 omissions. The thermalinsulation properties of wood save energy and therefore save emissionsthroughout the life of a building.

http://www.apptimber.com/environment/WhyUsingTimber.pdf

When comparing the embodied energy of timber to that of other building materials one also needs to

take into consideration the comparative embodied energy in the differing types of timber product,and assess this along with other environmental impacts. Timber products range from air dried sawn

hardwood, with the lowest embodied energy (of around 0.5 MJ/kg), to kiln dried softwood (at around

3.4 MJ/kg), to engineered timber products such as plywood (at around 10.4 MJ/kg) and Glulam (for

example laminated beams, at 11 MJ/kg). By way of comparison to other types of building material,

clay bricks have an embodied energy of approx. 2.5 MJ/kg, cement 5.6, mild steel 34 and aluminium

170 MJ/kg. A large component of embodied energy is transport, and timber performs favourably

when comparing the environmental cost of transport to other materials due to timber products

generally being light and easy to handle with high strength to weight ratios.

The Embodied Energy of a material needs to be considered along with factors such as the effect on

the carbon cycle and other environmental impacts. In terms of renewability, plantation timber is

renewable and can be regrown in a relatively short time (15-25years). Other environmental impacts

that need to be considered are those of pollution impacts during the manufacturing process and solid

waste generation. The waste produced during the processing of a raw material into a product, while

not necessarily having an economic cost, has an environmental cost, and as such must be considered

when comparing materials in terms of sustainability. In comparing a timber frame wall to a steel

frame wall in terms of total pollutants emitted, it is estimated that the environmental cost of a timber

wall is 30% of that of a steel frame wall. While the manufacture of timber products is associated with

low levels of emissions, and the forests where the timber is grown act as a store of CO2, the

manufacture of cement, for example, involves emissions of sulphur dioxide, carbon dioxide and

nitrogen oxides.

The carbon cycle of timber as a building material is very different to that of other building materials.

As part of the process of photosynthesis, trees give off oxygen and absorb carbon from the air, which

is stored in the tissue of the tree. When a tree is burnt as fuel or left to decay the same amount of

carbon is again released into the atmosphere. In this cycle a tree can be said to be carbon neutral, or

a temporary store of carbon. If, however, the tree is harvested for use as a building material, the

timber utilised remains a store of carbon for the duration of the life of the building, therefore

reducing the amount returned to the atmosphere.
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The specification of locally grown plantation timber further reduces energy costs when compared to

the environmental impact of transporting important timber.

Timber is a truly renewable building material, it is easy to work with and provides endless alternatives

in design. It is a store of carbon and has a low embodied energy. Timber Frame is a time honoured,energy-efficient, environmentally sound, versatile, structurally safe and above all aesthetically

pleasing method of building. Given a increasing global trend of sustainable forest management, an

increasing desire to make the correct environmental choices, and the re-discovery of the comfort of

living in a timber home and the natural beauty of timber as a material, the growing trend of building

timber homes could be just the startand the right thing to do.

http://jacquescronje.wordpress.com/2010/05/09/timber-a-sustainable-building-material-14-october-2008/

http://makeitwood.org/documents/doc-692-timber-as-a-sustainable-material.pdf
http://jacquescronje.wordpress.com/2010/05/09/timber-a-sustainable-building-material-14-october-2008/http://jacquescronje.wordpress.com/2010/05/09/timber-a-sustainable-building-material-14-october-2008/http://jacquescronje.wordpress.com/2010/05/09/timber-a-sustainable-building-material-14-october-2008/


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Adobe

Basic mud bricks are made by mixing earthwith water, placing the mixture into moulds anddrying the bricks in the open air. Straw or otherfibres that are strong in tension are often addedto the bricks to help reduce cracking. Mudbricks are joined with a mud mortar and can beused to build walls, vaults and domes.

Mud bricks have the potential to provide thelowest impact of all construction materials.Adobe should not contain any organic matter the bricks should be made from clays andsands and not include living soil. They requirevery little generated energy to manufacture, butlarge amounts of water. The embodied energycontent of mud bricks is potentially the lowestof all building materials but additives, excessivetransport and other mechanical energy use canincrease the delivered embodied energy of all earth construction. [See: 5.2 Embodied Energy]

In a similar way, the greenhouse gas emissionsassociated with unfired mud bricks can (andshould) be very low. To keep emissions toan absolute minimum, the consumption offossil fuel and other combustion processeshave to be avoided. [See: 5.1 Material UseIntroduction]The materials for making mud bricks arereadily available in most areas and may besourced directly from the site of the building insome cases.

DATA ANALYSIS WITH STATISTICS AND GRAPHICAL REPRESENTATAIONS


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CONCLUSIONS/SUGGESTIONS

BIBLOGRAPHY AND APPENDICS

REFRENCE

http://www.rsc.org/images/Construction_tcm18-114530.pdf
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