Looking At The Materials Used In Construction Construction Essay

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During construction the choice of materials to be used has always and will always be the first priority of a competent and excellent engineer.

These choices have to be made based on the properties of the available material. These properties must suit the taste of the engineer, the owner and the normal environmental requirements.

Having visited a specific site (case study) located in the Pajam area of Negeri Sembilan Malaysia. As a visiting engineer the choice of wood, steel and cement as a focus material aroused from the fact that these are the basic materials needed in high quantity and quality for building a good and solid building. This site is a mosque owned by the Negeri Sembilan government, therefore it's a public place and needs extra attention because it will experience very high rate of usage from members of the public. C:\Users\user\Desktop\site pics\IMG_1146.JPG

Fig 1.0 front view of case study.

CASE STUDY/ SITE VISIT

On visiting site the main materials that were used for different components that I chose are as follows:

Cement for beam, column, wall and floor

Wood for roof and wall

And steel for beam, column e.t.c.

CEMENT

Finely grained particle made from limestone, calcium carbonate, iron oxide and other raw materials. When mixed with water a chemical reaction occurs or takes place, this is known as HYDRATION. It makes it able for cement to serve its role as a binding agent.

Basically there are different types of cement but the most popular one used all over the world and also used in my case study is Portland cement. The various other types of cement include

Slag cement

Pozzolanic cement

High-alumina cement.

PORTLAND CEMENT

Discovered in the nineteenth century from the heating of a mixture of clay and chalk to derive an hydraulic substance meant for binding purposes.

This would develop excellent strength and durability in a reasonable short time without any atmospheric action. Though its setting ability may be hydrophobic

C:\Users\user\Desktop\site pics\IMG_1128.JPGC:\Users\user\Desktop\site pics\DSCF1459.JPG

Fig 2.0 Portland cement

PROPERTIES & CHARASTERISTICS OF PORTLAND CEMENT

The various characteristics of cement shall be elaborated into main properties as follows:

Hydration

Soundness

Fineness

elasticity

Strength

HYDRATION

The reaction that occurs during the mixture of water and cement is chemically known as hydration. This reaction causes its hardening and setting. Each one of the reaction with every chemical consistuent occurs at different times and rates. So the final time and rate will determine the duration of hardening and setting.

SOUNDNESS

Soundness of cement after setting could be said to be undesirable if there is an excessive change in volume, particularly when expansion occurs. The effect of using unsound cement may not be apparent for some little period of time but later it results into cracking and disintegration of the surface of the concrete. Le chatelier out of his many principles derived a way of testing the soundness of the Portland cement.

FINENESS

Reaction between water and cement starts from the surface of the cement, under the rate of reaction of substances, ones with finer particle tends to have faster rate of reaction to those with wider and coarse surface. Fine cement also improve the cohesiveness of fresh concrete and can be effective in reducing in reducing the risk of bleeding.

In terms of economical inclination, the fine particle is costlier than the coarse particle because there is need for the use of more machineries to grind the coarse aggregate and this machineries goes for quite a huge amount of money due to the sophistication.

ELASTICITY

The modulus of elasticity of cement is relatively linear at low stress levels but becomes increasingly non-linear as matrix cracking develops. The elastic modulus of the hardened paste may be in the order of 10-30 GPa and aggregates about 45 to 85 GPa. The concrete composite is then in the range of 30 to 50 GPa. (www.indiastudychannel.com)

STRENGHT

Generally this is the most important property being the main thing needed in binding like binding of bricks. Strength at times depends on the cement consistuent. The British standard requirement for strength in Portland cement entails 32.5n of cement under of 28 days which could be greater than 32.5Nmm-2 but must be less than 52.5Nmm-2 of mortar prisms. This shows relatively how much strength is required and gotten in the use of Portland cement for building.

STEEL

This is an alloy of metal mostly gotten from the melting of pig iron; this takes in a blast furnace and makes coke one of its byproduct. This actually is the most common manufacturing method of steel others include:C:\Users\user\Desktop\site pics\DSCF1488.JPG fig 3.0 type of steel used in my case study. (Produced with the use of blast furnace)

Cementation process

Crucible process

Open hearth process

Electric melting process

Duplex process

L.D. processes

Regarding my case study the blast furnace is used so this report shall be restricted to this method of production. Steel has its own peculiar characteristics which include:

Ductility

Malleability

Weld ability

Brittleness

Ductility of steel

Ductility is the extent to which materials can be deformed without fracture. In other words ductility is the materials ability to deform under tensile stress. This property is mostly desired at the stage of fixing the steel in buildings.

Malleability of steel

Almost same with ductility but it has the ability to go back to its starting shape, position or form i.e. it at time could refer to the elasticity of the material and could play a major role in rail construction that expansion and shrinkages really affect the rail lines that are mostly steel material.

Weld ability

This makes any steel to be able to change shape, helps in the sustainability and the recyclability because if its not more useful in a particular state it can be easily changed to another shape by welding to another size and shape for use.

Difficult to harden:

It is so because if you want to harden it, you would have to go through its real manufacturing process and other processes to make it become what you want. Of which there is no guarantee of deriving the desired specie of steel, also if this is attempted it loses its properties such as its ductility and brittleness.

Brittleness

Brittleness implies the inability of the metal to absorb energy by impact (shock loading). Steels which are able to absorb energy in this way would be described as 'tough'. Brittleness depends on:

Grain size

Carbon content

Ambient service temperature

Euro standards for structural steel contain a number of toughness categories, the tougher steels being more suitable for service in colder climates or where severe effect may be possible. (G.D. Taylor, 2000)

WOOD

Wood is an organic material, natural composite of cellulose fiber embedded in a matrix of lignin which resists compression. Woods are very vital in construction in the sense that they are used both in the building as a foundation material and also in the beautification of the building. Woods have been categorized according to their parent tree and texture; primarily they can be classified as:

HardwoodC:\Users\user\Desktop\site pics\IMG_1149.JPG

Softwood fig 4.0 some species of woods used in my site

C:\Users\user\Desktop\site pics\DSCF1393.JPGfig 5.0 sample of hardwood in the site.

The following are the properties and characteristics of wood mostly desirable fo excellent building.

DENSITY

Basically known as the ratio of mass to volume of all voids, this could be said to be a principal factor of wood because the following sub-factor such as strength, hardness and suitability which folds up from this density.

The mean density for softwoods used for load-bearing purposes lies between 450 & 600 kg/m3 also this can reach 700kg/m3 among some European hardwoods and even 1000kg/m3 for hardwoods imported from overseas.

MOISTURE CONTENT

Wood can absorb little water content on its cellular structure, though much water content is always detrimental to its workability and sustainability.

In reference to my case study most of the woods used were inform of decoration i.e. not really used in construction so the woods have been well refined such that it has no space for retaining water. Even the ones used for logging and facial board were also treated the same way. Mostly only unrefined wood usually have high water retaining capacity and this ability helps in maintaining the inner climate of the wood

STRENGHT

The strength of a construction material could also be said to be its resistance to failure.

It exhibits a broad range of elastomechanical properties, though this depend on the specie of parent tree, when subjected to tension timber (wood) generally exhibits a brittle behavior. The strength of wood increases under the following conditions:

Reduction in moisture content

Reduction in temperature

Reduction in grain-load angle

Increasing density. E.t.c.

THERMAL PROPERTIES

In terms of thermal insulation wood porosity plays a very vital role and also gives it pleasant surface temperature. It thermal conductivity depends on direction of grain, density and moisture content. In contrast with any other building material the co efficient of thermal expansion is extremely low therefore it is not 'so' necessary to check changes in length due to temperature fluctuation.

C:\Users\user\Desktop\site pics\IMG_1151.JPG fig 6.0 illustration of some properties.

PERFORMANCE CRITERIA

This is an extent to which all the materials perform to in order to suite the taste of the building. Various engineers have various criteria's in choosing building materials for an excellent performance of the building.

Regarding my case study the criteria in which the materials were used were based on the sustainability of the materials and others below:

FIRE

Being a public place this was taken very much into consideration in order to make sure that the building is going to be fire free. The choice of the material was taken to high esteem to avoid fire outbreak coming up as a result of conductivity by the material. Such materials like cement and steel had this criterion making them very high in the preferential listing of materials though they are very important in most building. But wood is like a boost to fire but the ones with high thermal insulation were chosen.

DURABILITY

Meaning ability of something to last long without sustaining much wear & tear, using durable materials gives rest of mind in terms of when renovation and replacement of materials would be. most durable materials last as long as the building exist. This is a very important criterion to look upon to as far as the selection of material is concerned.

HEALTH SAFETY

Materials should not be a threat to health safety, they are not supposed to have any effect on human health, so both the physical and chemical consistuent of materials should not pose any danger to the safety of the building. This is another essential criterion to onto which materials in my case study were chosen. If materials and their properties are not health inclined, they are to be avoided in all possible ways.

COMFORT

Materials should make buildings comfortable, make itself easy to use, brings comforts in all its actions to the building. Comfortability technically could also refer to sustainability of the material

STRUCTURAL SAFETY

The building should also be free from structural vices i.e. it should be able to withstand stress and displacement from gravity, wind, thermal or moisture movement. This factor does destroy buildings with inferior and low quality materials. I think criteria should be taken as a priority according to the environment where the building is situated. i.e. when you are constructing a building in quake and tornado prone areas, then the materials to be used must be able to stand all these possible threats.

. Some other criteria in which choice of materials are made is

Resistance to weathering

Serviceability

Appearance. E.t.c.

MANUFACTURING PROCESS AND EFFECT OF MATERIALS

CEMENT:

To produce cement with consistent high quality, careful controls of application of raw material has to be taken in place. The major consistuent of cement include chalk or limestone mostly gotten from rocks and clay (a type of soil which its properties include plasticity, shrinkage under firing) firing of the grain due to its fineness brings about the real cement color. Clay's ingredient also includes:

SiO2 (silica)

Al2O3 (alumunia)

Fe2O3 (ferrite)

All these ingredients with the chalk or lime stone usually don`t have fast reaction between themselves until well heated to around 1500â-¦c, then slow chemical reaction occurs.

So after mixing all the ingredients, two products are formed at that high temperature and they are:

Dicalcium silicate C2S

Tricalcium silicate C3S surrounded by matrix containing Tricalcium aluminate C3A and tetra calcium alumino ferrite C4AF

Although it is important to control relative quantity of compounds produced e.g. the ratio of C3S to C2S which will affect the rate of hardening and heat output can simply be regulated by adjusting the limestone : clay ratio, more of lime stone tends to produce more C3S which contains more calcium oxide, Whereas too much lime becomes uncombined and produces unsoundness.

There are two main aspects of the manufacturing process, firstly is to produce a finely divided mixture of raw materials i.e. limestone & clay.

The second is to heat this mixture to produce chemical combination.

To achieve these two main aspects, there is need to dry and there are only two methods of drying, they are the wet and dry process.

The wet process involves quite a long process because it entails adding of water and after the heating it later entails evaporation to get the rid of the moisture content while the dry process entails simple drying of the compounds which are mixed into desired compositions and dried up straight away in the kiln and at the final stage of production of both process i.e. whichever used, gypsum is added to the already gotten fine grain. This gypsum is added to prevent flash setting if water is added. The final step is now bagging for easy transportation and easy workability.

ENVIROMENTAL EFFECT

Portland cement manufacture can cause environmental impacts at all stages of the process. These include emissions of airborne pollution in the form of dust, gases, noise and vibration when operating machinery and during blasting in quarries, consumption of large quantities of fuel during manufacture, release of CO2 from the raw materials during manufacture, and damage to countryside from quarrying. Equipment to reduce dust emissions during quarrying and manufacture of cement is widely used, and equipment to trap and separate exhaust gases are coming into increased use. Environmental protection also includes the re-integration of quarries into the countryside after they have been closed down by returning them to nature or re-cultivating them.

MANUFACTURING PROCESS OF STEEL AND ITS ENVINROMENTAL EFFECT

Iron is first smelted into ore, since the carbon content would be too high therefore making it less desired, so to become steel it would be melted and reprocessed then the internal process of casting into ingots. Ingots are then heated in a soaking pit and hot rolled into slabs, blooms and billets. Blooms are hot or cold rolled into structural steels. But in modern times it is done in an assembly way forcing the principle of ore going and steel coming out of a blast furnace. Though after this steel are usually heat treated for strength.

p.s. slag is the waste product released from the blast furnace during steel production.

Though steel does not have much environmental effect than gases released from the blast furnace during its production which are known as slag. These are very harmful emissions such as carbon monoxide. Then another process in the blast furnace is coke making.

Coke is a major source of VOC`s and also carbon monoxide emissions; blast furnace steel making generate a large quantity of sulphur, nitrogen oxides and carbon monoxides.

Downstream processes such as casting and rolling account for significant amount of sulphur oxides being released to the environment. As sulphur is liberated from the metal surface, waste water from coke making has high contaminant levels. Requires quite extensive removal and treatment before disposal

Waste water generation from iron making, steel making and downstream processes, much of which results from cooling water from wet scrubbers is somewhat mitigated by significant rates of reuse and recycling.

Solid wastes from industries present problems due more to the volume of the wastes generated than to the hazard presents therefore causing havoc in the environment.

The sector is a very large consumer of energy and as such is a major contributor to green house gas emissions.

WOOD

MANUFACTURING PROCESS AND ENVINROMENTAL EFFECTS

Wood occurs naturally i.e. it is sourced from timber and timber are gotten from trees. Detailed production of wood starts from felling of trees in the forest, Trees like mahogany, obeche e.t.c. they are characterized with fat stems which are then cut off, the lumberperson takes them to the saw mill where the bark is pulled off and its sliced into suitable sizes and shapes. There the woods is like refined, these woods are then sold for construction mostly used for roofing and other aspects of constructions such as decking and lintel.

Major effects of wood production comes from the tree falling aspect (deforestation)

Only few occurs at the saw mill like environment pollution caused by noise from the milling machineries and dirt's e.t.c but in deforestation it could cause so many problems e.g.

Threat to global warming.

Aids depletion of ozone layer

Discourages green area initiatives

Threat to nourishment of soil nutrients due to direct contact from the sun after the tress forming shields have been felled and used in wood production.

MAIN MATERIALS USED FOR DIFFERENT COMPONENTS IN MY CASE STUDY.

Roof and walls are very important components or parts of a building. Without these components no structure has being built especially in the case of wall, though there are different materials that could be used for this components but regarding my case study the materials that were used are as follows

ROOFS: arch and wood

WALL: brick and concrete

ROOF

Roof is a cover for the whole building that prevents it from sun, rain and other natural factor, regarding my case study the roof was made of wood and arch pan.

C:\Users\user\Desktop\site pics\IMG_1153.JPG

Fig 7.0 showing the arch pan

JUSTIFICATION

ARCH

Arch pan is a type of roofing sheet that was moulded and fired. It is very thick that nothing can penetrate it. Mortar is used in binding them together. This arch is mostly used in ancient houses, religious places and royal places. Though it's not common nowadays, aluminum roofing sheets has taken its place. Though quite expensive but durable, In reference to my case study being a religious and public place it is much needed because of its durability, sustainability, uniqueness and long life span.

C:\Users\user\Desktop\site pics\IMG_1154.JPG

Fig 8.0 showing the wood used for facial board

WOOD

Wood in roofing in my case study was used for 2 purposes, first is for skeletal roofing and the second is for the frame work and facial boarding, facial boarding is placed around the roof, this supports the pan and outer ceiling. This woods are normal refined woods treated with antipests and other chemicals that prevent insects such as termites invasion.

Skeletal roofing is very important because it is on it the pan or roofing sheets sit on and also serve as a link between the pan and the ceilings. Also wirings are done through and around the skeletal frames, whereas facial board is used to support the pan and links the outer ceiling with the pan outside, it could be decorative but it posses vital uses such as prevention of pest and insects from entering to go and destroy the frame work inside.

WALL

Wall is a solid structure that is mostly used to demarcate or separate particular area. Wall supports a buildings super-structure. It consists of blocks put together and joined by mortar making it to stand straight and rigid and could be of any height, it basic material components are bricks and concrete in respect to my case study because different other materials could be used. C:\Users\user\Desktop\site pics\IMG_1110.JPG Fig 9.0 showing walls with bricks and concrete.

JUSTIFICATION

BRICKS:

Is an artificial stone made by forming clay into rectangular shapes, its consistuents also contain aggregates and cement, they are mixed into required proportions and moulded into rectangular shapes and fired if needed. It is this bricks that are arranged on each other vertically erect and shocked with mortars to form walls. C:\Users\user\Desktop\site pics\DSCF1463.JPGfig 10.0 showing some excess bricks in the site that were not later used.

CONCRETE

Mixture of aggregates, cement and water. When made into paste for shocking blocks, its known as mortar at that state, also this mortar can be used for plastering of walls when required. It also aids the uprightness of the wall, at times it is used in decorating the walls itself. According to my case study, the walls were painted after plastering for some beautification and also aids sustainability.

C:\Users\user\Desktop\site pics\IMG_1130.JPGC:\Users\user\Desktop\site pics\DSCF1424.JPGFig 11.0 showing the mixing of concrete with diagram A being mixed manually and B is concrete discharge from a motor mixer.

BENEFIT OF RECYCLABILITY AND SUSTAINABILITY OF MATERIAL TO REDUCE ENVIROMENTAL AND HEALTH IMPACTS IN THE SURROUNDING.

Recyclability can be described as the further use of materials to prevents it wastage due to its potentiality of been useful. So it could also be defined as processing or making a material into another material.

Sustainability in its own way is the ability to endure all natural and artificial Set-back the building may encounter during its life time. Also it is the ability to withold all forces that may be a threat to the buildings life span.

Benefit of recyclability and sustainability:

When most buildings become delapidated and starts to suffer extincsion, this is mostly caused when the materials used are not sustainable and also they cant be recycled, it will keep on deroriating bit by bit and become hide out for hoodlums and criminals which would be hazardous to the community.

Another is the availability of aggregate, because most of aggregates are produced from the blasting of used and demolished buildings made with materials that can be recycled.

Recycling helps in the conservation of limited resources. Instead of allowing all available raw material to go in the production of new ones, old ones are being used which helps in the conserving of the limited available raw materials.

These materials that can be recycled helps in the promotion of efficient energy, technically helps in job creation and could be financially rewarding.

Regarding my case study sustainability of the materials would help the building

To retain its beauty

Last long

To be efficient i.e. serve its purpose excellently

Enviromentally friendly

Safe and healthy

Serve as a landmark in the area where it is situated.

VISIBLE DEFECTS IN THE BUILDING MATERIAL USED

After checking all the material used in the building (my case study), fourtunately for the site engineer and unfortunately for me we couldn`t find much defects on the materials used but after thorough checking I was able to notice some defects.

The first I noticed was moulds on the bricks ussually caused by fungi. This fungal attack does happen when blocks have been fired and ready to be used are now deposited, if not covered then it will open to fungi which will cause moulds on this bricks.

If the moulds are not too much the brick could be used but must be painted or treated with some anti-fungal chemicals but in my case study some where condnmed because after they attacked the block while it was still on the floor the engineers had it in mind that after painting it will have been avoided but after mounting by the next day they got to site to countinue mounting others they found out that it had been fully attacked so they had to demolish that part and got new bricks to fill in that space. C:\Users\user\Desktop\New Folder\SAM_0059.JPGfig 12.0 showing some bricks defect in my case study.

The second that I noticed happened to be a wood pest, which affected the woods that were supposed to be used for logging and skeletal roofing, it's a parasitic attack whereby termite happen to be the parasite while the wood is the victim. The wood is eaten up but not completely and not concentrated in what area but in different parts of the wood. These woods had to be thrown away, though only 15 logs were affected in my site according to my site engineer and before they spread to the others they were disposed and others were treated with different chemicals by applying the chemicals on them with the aid of brush. One of the chemicals used is gamaline 20, also I was also made to believe that there are species of wood that are mostly affected and there is another specie that is almost immuned to the infection, these species were used in my case study. Image showing one of the woods affected is in the following page. C:\Users\user\Desktop\site pics\DSCF1452.JPGC:\Users\user\Desktop\site pics\DSCF1454.JPG

Fig 13.0 showing some defects noticed in the wods in my case study and also illustrations by one of my group members on how it attacks.

CODE OF PRACTICE FOR TIMBER PRESERVATION IN RESPECT TO MY CASE STUDY

The preservative of timber is listed in the BS 1282 i.e for the safe handling and preserving timber, there are different preservatives of timber but they are only chosen based on different criterias which include:

The ease of inspection of the components to impact or know the effects of the preservative.

The risk, in that situation, of damp or insect attack.

The ease with which maintanance and repair work can be carried out.

The consequences of attack e.g. if the preservative fail and the component gets infected, the kind of outcome it might bring as in can it lead to the destruction of the building.

The required lifetime of the component.

Property or charasteristics of the material(timber)to be preserved.

All the previous requirements were among the priorities of choosing preservatives by my site engineer for the preservation for the timber used. He told us they made use of organic solvents preservatives and they applied by brushing.

ORGANIC SOLVENT PRESERVATIVES {BS 5707}

Examples are chloronaphthalenes, metallic naphtalenes and penta chlorophenol. Penetration is excelent provided the timber is dry, hence they are often preffered where only brush or spray application are feasible. They are non-creeping, non-staining, non-corrosive to metals, non-swelling and quick drying. Painting is ussually possible once drying is complete which ussually takes a few days. They are widely used for remedial treatment, though many organic solvents are highly flammable and present a fire risk until dried, especially when used in confined areas such as roof spaces. When used for new work the moisture content of the timber at the time of treatment should be that required for end use, since the preservatives does not increase the moisture content. They are often used to preserve new joinery, though it Is important that all machining / drilling, e.t.c., be carried out prior to application if maximum protection is to be achieved. They are more expensive than the other types and release solvents into the atmosphere- a procces which is increasingly being regarded as environmentally unacceptable. (G.D. Taylor, 2000)

It is applied by brushing in my case study, because this give only limited penetration of timber, although they may be the only feasible method for in-situ remedial work which was carried out in my case study. If several coats are applied and the treatment is repeated periodically, a useful degree of protection is achieved.

FINANCIAL AND ENVIROMENTAL COST AWARENESS

After a thourough 1 hour interview with the engineer in charge in name Engr. Abdulhafiz ibn Mohammed. I was made to believe that the allocated amount for the project estimated and budgeted by the clients ( Negeri Sembilan Government in Malaysia) is 3.5 million malaysian ringitt but the total amount already spent just before furnishing sums up to 3.2 million Rm. Mere looking at the building, the cost sounds expensive and outrageous but after seeing a summarised price breakdown which states as follows

Building : 2.3 million

Tax : 300, 000 Rm

Fittings :300, 000 Rm

Environmental awareness cost: 5000 Rm

Workmanship : 495,000 RM

Miscallenous expenses : 300, 000 Rm

The above was the summarised cost given by the engineer that was released to the government.

C:\Users\user\Desktop\site pics\DSCF1456.JPGfig 14.0 show discussion between us and the engineer.

CONCLUSION & RECOMMENDATION

Lastly, after hectic times in site, I have been aable to give a detailed report to solve some common site problems. Having a general overview of on what a malaysian site project looks like. I have understood the applicatio, behaviour, qualities, worth and so many other things on building material.

At first when I started visiting sites with my group members, the problems faced arised from hostility showned by some construction workers, language barriers and at times the unpredictable weather. Fortunately after combating various set-backs we met our case study. A very much suitable one I must say, it gave us something more than encouragement, thanks to the competent engineer and the tirelessly working labourers. At this point this project is hereby pronounced a freat success.

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