Concrete in the Sydney opera house

Concrete used for construction purposes is a hard structural material comprising of sand and gravel placed strongly together with cement and water. The strength of water is needful for simply ensuring that all particles of the aggregate are surrounded by the paste of cement completely, aggregate spaces are filled and the concrete achieves the desired viscosity which enables it to be poured and spread efficiently and effectively.

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Introduction
Concrete in the Sydney opera house
Sydney house is a center of performing arts located in Sydney of the New South Wales. The
building holds numerous venues for performing hosting 1500 performances yearly. The building
occupies 1.8 hectares of land space and is 600 ft. tall and 394 ft. at widest point. Sydney house
contains shells of precast concrete composing of 75.2 meters radius sphere mainly used to form
the structure roof supported by ribs of precast concrete. In addition to shells of tiles and walls of
glass, the exterior of the building is covered with granite quarried panels. The treatments of the
interior is too conducted with concrete. The building hosts recording studio, restaurant and cafes,
bars, concert halls and theatre for drama.
Concrete used for construction purposes is a hard structural material comprising of sand
and gravel placed strongly together with cement and water. Sand and gravel are chemically inert
particles commonly known as aggregate. Previously, clay was the main substance that was being
used as a bonding material. Lime and gypsum were used as binders in developing a substance
that closely resembled the today’s modern concrete (Adalberth, 2014). Lime which is the
chemical calcium oxide, derived from limestone, chalk and oyster shells continued to be used as
the main agent for forming cement till the 1800s. A few years later, a mixture of limestone and
clay were burned and grounded together by Joseph Aspdin and the mixture was named Portland
cement which dominantly existed as the main agent of cementing applied in the production of
concrete.
Aggregates are commonly grouped in relation to their sizes generally as either fine which
possesses sizes ranging between 0.025mm to 6.5mm or course ranging between 6.5mm to

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38mm. aggregate materials must be free from unwanted mixtures such as soft particles and
vegetable matter since even slight contents of organic compounds of soil usually encourage
chemical reactions eventually affecting the concrete strength.
Methods of aggregate or cement production and the manifested qualities of the aggregate
or cement that is utilized in making concrete usually defines the characteristics of the concrete.
For example, the ratio of water to cement usually determines the character of an ordinary
structural concrete (Allen & Iano, 2011). The concrete is stronger when the content of water ratio
is equal or lower to that of cement. Presence of water is needful for simply ensuring that all
particles of the aggregate are surrounded by the paste of cement completely, aggregate spaces are
filled and the concrete achieves the desired viscosity which enables it to be poured and spread
efficiently and effectively. Another factor of concrete durability is also the cement amount in
comparison to the aggregate which is usually expressed three-part ration – cement to fine
aggregate to coarse aggregate. Relatively less aggregate is considered where a stronger concrete
is desired.
Concrete strength is usually measured in either pound per square inch or kilograms per
square centimeter of force required to crush a given sample of hardness or age. Environmental
factors possess great impacts on concrete particularly moisture and temperature. Unequal stresses
of the tensile are observed whenever a concrete is exposed to premature drying which can never
be resisted in an imperfect state of hardness (Zhang et al, 2014). Concrete is normally kept damp
for a while immediately upon pouring through a process called curing to slower the shrinkage
process which frequently occurs as it hardens. The strength of concrete is also affected by
adverse temperatures. With an aim of reducing the impacts resulting from this, calcium chloride
and related additives are added to the cement mixture. These additives accelerate the process of

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setting thereby, in turn, generating sufficient heat which counteracts low temperatures. Concretes
that are large and its proper coverage cannot be achieved are usually not poured in temperatures
of freezing.
Concrete hardened onto embedded metal commonly steel often referred to as either
reinforced concrete or ferroconcrete. The steel metal offers contribution to improving the tensile
strength of the concrete. Stresses such as the action of wind, earthquakes, strong vibrations or
forces triggering bending are not normally withstood by plain concretes hence making it not
suitable for most applications. The tensile strength of steel and the compressional strength of
concrete enables such reinforced concrete to withstand heavy stresses for a good duration of time
(Bergsdal et al, 2015). The ease of positioning steel closer to or exactly at the point where strong
stresses are expected is made possible through the fluidity of the concrete mix.
Prestressed concrete forms another innovation in the construction field. This type of
concrete is obtained through processes of pre-tensioning and post-tensioning. Lengths of steel
wire, cables and ropes are placed in an empty mold then stretched and anchored. After pouring of
the concrete and its settlement, anchors are released and as the steel is adjusting to its original
length, the concrete is compressed whereas, in the post-tensioning process, the steel is made to
run through ducts created in the concrete. After hardening of the concrete, anchoring of the steel
is done on the exterior of the member by use of a gripping device (Binici et al, 2012). The
transmitted intensity of compression is regulated through the application of a measured quantity
of stretching force to the steel.

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Discussion
Types of concrete
The following are the common types of concrete:
 High strength concrete. It is a type of concrete that contains the most strength of
approximately 40Mpa.
 High-performance concrete. It is a modern way of referring to the modern and developed
concrete of nowadays. This type of concrete outperforms the normal type of concrete in
very many aspects such as lifespan mostly under corrosive environmental conditions,
permeability, density and placement flexibility.
 Lightweight concrete. This type of concrete is obtained through using small, lightweight
aggregates for example balls of Styrofoam or through the addition of foaming agents to
the concrete mixture. Lightweight concretes are used in non-structural elements since
they have low structural. The most suitable example is the aerated autoclaved concrete
blocks which are frequently used in making walls (Van et al, 2010). It is also called
cellular concrete.
 Self-consolidating concrete also known as self-compacting concrete
 Shot Crete or sprayed concrete. A thick or uneven coating is formed through spraying of
concrete onto a surface. The main difference existing between this type of concrete and
other types is that sprayed concrete is not poured into a form or mold but directly sprayed
on a surface. It is commonly used in infrastructure projects and repairing old or cracked
surfaces of concrete. It is at times also called hunting.

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 Water resistant concrete. Most common concretes are usually permeable to water in that
they allow water to pass through them. Water resistant concretes are developed to possess
replacement of fine cement particles that resists the passage of water through them. They
are very useful in the underground construction of structures such as basements and water
storage structures or at times roofs.
 Micro reinforced concretes. These are newest and most complicated type of concrete.
They are accompanied by small amounts of steel, fiberglass and fibers made of plastics
that are meant to alter the concrete properties to meet the desired objectives (Cole, 2009).
Factors influencing consideration of concrete
 High compressive strength but a lower strength of tensile. Minus compensating, concrete
would be failing from stresses from tensile even in situations of loading in compression.
Instead, concrete elements exposed to stresses from tensile must be subjected to
reinforcement s from materials such as steel which is stronger in handling tension.at low
stresses, the elasticity of concrete is usually constant and begins to reduce at stresses
which are of higher levels as matrix cracking develops (Tay & Show, 2014). Concretes
usually possess very low thermal expansion coefficients and it eventually shrinks as it
matures. As a result of shrinkage and tension, all structures of concrete cracks to some
extent. Creeping, in turn, occurs to concretes that are exposed to the long duration of
forces. The density of concretes usually varies but is generally approximately
2400kgs/m3. The most common concrete is usually the reinforced concrete which
commonly utilizes steel as the main reinforcement material. With all factors constant and
equal, lower water content concrete against cement usually forms the strongest concrete
than that with a higher ratio (De et al, 2013). The resultant quantity of cement materials

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to influences the strength of the concrete, demand for water, shrinkage, resistance to
abrasion and eventually density of the concrete. All concretes must crack regardless of
the availability of enough or reliable compressive strength. In addition, high hydration
rate makes high Portland cement content mixtures to crack more readily. Shrinkage
usually occurs during the concrete transformation from plastic state to solid through
hydration process. This often occurs during finishing operations whenever the rate of
evaporation is high though, during normal environmental conditions, plastic shrinkage
cracks happens almost immediately after placement.
 Elasticity (Sheety, 2013). The concrete elasticity modulus is normally a function
modulus of aggregates elasticity modulus and the matrix of the cement and its
proportions. At low stress, the elasticity modulus of concrete is almost constant but
progressively begin at higher levels of stress accompanied with crack development. A
hardened paste elasticity modulus is usually in the order 10-30 GPa and aggregates
ranging between 45 to 85 GPa whereas that of concrete composite falling between 30- 50
GPa.
Thermal properties
 Shrinkage and expansion (Sharma et al, 2011). Concrete possess a low thermal
expansion coefficient. In addition, whenever limited provisions are availed for
expansion, large forces are created resulting to cracks in some parts of the structure that
are not in apposition of either sustaining the force or the repeating contraction and
expansion cycles.
 Thermal conductivity concrete possesses almost average thermal conductivity which is
way lower than those of metals but greatly higher than those of other materials used in

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building or construction for example wood which is a poor insulator. Fireproofing of
structures made in steel is normally achieved through the erection of a concrete layer. In
contradiction, fireproof forms a wrong term to prefer to insulators mostly in situations
where fires possess very high temperature which might trigger chemical changes in
concretes which eventually causes very significant damages to the concrete (Dimoudi &
Tompa, 2008).
 Cracking. Shrinking of concretes is a continuous process as it matures. This due to the
continuous ongoing chemical reactions within the concrete material. In addition, the
shrinkage rate rapidly falls over a time duration. Generally, concretes are considered not
to shrink past the age of 30 years as a result of hydration. Concretes normally cracks due
to either stress from tensile facilitated by shrinkage or usage or setting stress. Different
mechanisms have been developed or adopted with an aim of overcoming this (Roodman
et al, 2009). These mechanisms include: limitation cracks and its size is facilitated
through fiber reinforcement concretes which uses fine fibers widely distributed all over
the mixture or larger metals and other elements of reinforcement. In most big structures,
joints or concealed saw-cuts are enabled within the concrete with an aim of making
inevitable cracks to be experienced in places where they can be easily and efficiently be
handled.
 Shrinkage cracking. Cracks of shrinkage are experienced whenever members of concrete
undergo controlled volumetric changes or shrinkage due to processes of drying,
autogenous shrinkage and effects of thermal conductivity. Regulations are either
provided internally exhibited through an ununiformed drying process, shrinkage and
reinforcements or externally through supports, walls and various conditions of the

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boundary (Raut et al, 2011). Upon surpassing of tensile strength, a crack normally
develops. The amount of occurring shrinkage frequently influences the number and
width of crack shrinkage which develops. In addition to this factor of influence are the
reinforcement amount and its spacing provisions. In 2-3 days of placement, plastic
cracks are observed or visible as shrinkage resulting from drying develops over a longer
time duration. When the concrete is in young age, autogenous shrinking also occurs
resulting from a reduction in volume which concurrently originates from chemical
reactions present in the Portland cement.
 Tension cracking. Concrete members are usually exposed to tension by the loads applied
to it.
 Creep. This is a resultant deformation or permanent movement of a certain material with
an aim of overcoming stress exposed to it. Creep is usually observed on concretes that
are exposed to long duration forces. Creep is rarely caused by the short-term forces such
as earthquakes and wind. Concrete structure or element may sometimes experience
limited cracking as a result of creep existence but must rather be controlled. Shrinkage,
creep and cracking are all reduced or regulated through by the quantity of primary and
secondary concrete structures reinforcing.
 Water retention (Eguchi et al, 2010). Mote water is held by the Portland cement concrete.
Other types of concretes usually allow more water to pass through them such as previous
concretes hence provide the most suitable option or alternatives to Macadam roads since
they do not demand storm drains fittings.

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The current types of concrete are better than the older versions or types of concrete since
the today concrete possess better and improved characteristics features which favors the
objectives of building construction projects as discussed above.
Advantages of concrete
 Concrete ingredients are easily obtained and available
 It is not affected by defects and flaws unlike natural stones as it is free from them
 Are easily manufactured to desired strength with economy (Pacheco & Jalali, 2012).
 It possesses high durability properties
 Easily cast to any desired shape in the working site making it economical
 It exhibits limited to cost of maintenance
 Can efficiently withstand high temperatures
 Facilitates safety of the fire safe building as it is noncombustible
 Resistivity to wind and water hence resourceful in storm shelters
Disadvantages
 It contains a lower tensile strength when compared to other materials of binding
 It possesses limited ductility features (Okamara et al, 2011).
 It entails high weight compared to its visible strength
 Some concretes usually entails soluble salts causing efflorescence

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Alternative material
Concrete possess several advantages as it is strong, durable and affordable but besides
these many advantages, there stands a very significant limitation caused by the same concrete.
This is its carbon-intensive process of production. Most of the elements of concrete such as sand,
water, and gravel are natural apart from cement which possesses a very significant implication to
the environment.
Its industrial process of extraction, development, and generation of increased
temperatures during and in the process of production results to the emission of a very large
amount of CO2 to the atmosphere of roughly 1 ton in every ton of produced cement (Naik,
2008). This limitation has led to the development of other most suitable alternatives which more
environment-friendly in the placement of concrete hence Hempcrete is considered a better
alternative.
Hempcrete as an alternative
Hempcrete as an alternative to concrete is a cost-effective and environmentally friendly
alternative hence the most suitable alternative for housing and construction of large projects. It is
developed from mixtures containing water, hemp a binder based lime. Concurrently blocks of
hempcrete are capable of absorbing large quantities of CO2 forming the main environmental
feature making the material most suitable house construction for human dwellings and
commercial purposes.

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Advantages
There exist very many reasons and advantages triggering consideration of hempcrete as a
construction material over other building materials such as concrete (Flower & Sanjayan, 2016).
These advantages include the following:
 Friendliness to the environment
 The low footprint of carbon
 High resistance to wind
 It Is a very good insulator
 Possess limited risks and hazards during handling
 Has got low thermal conductivity properties
 It can be recycled completely or wholly
 High durability properties
 It possesses high resistance to pests
In addition to the advantages exhibited by the hempcrete as an alternative option to concrete, it
also possesses the following disadvantages:
 It withstands limited load amounts (Morel et al, 2016). The loads are usually carried by a
frame hence the frame is very essential. This challenge is widely minimized through the
filling of earthbags with either hempcrete or a mixture similar to it. Wide walls of
earthbags avail the desired thickness which supports single loads on small and simple
structures.

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 In order to comfortable build, raising o forms are required. Earthbags get rids of the need
of form and formwork. In addition, vetiver grass should be used in place of hemp which
is also an insect resistor and rot resistant simultaneously.
 It is accompanied by increased costs, expenses and environmental footprints which
originates from illegalizing of hempcrete in most places hence encouraging transportation
of this material under long distance (Gonzalez & Navaro, 2014).
Most housing buildings usually possess 30-40 tons of embodied carbon which is
absorbed by hemp as the plant grows hence saving buildings a larger part of CO2 creating a
negative carbon footprint. It is thus very essential for the replacement of embodied energy with a
negative embodied energy in almost zero homes of carbon.
Walls nature of being lightweight implies limited supports and existence of lighter
foundations thus saving time and cost. Timber and permeable hemp blocks are used in the
structural frame construction.
A lime of hemp is a product of low energy. Costs of construction can be lower compared
to the prevailing traditional building materials (Khudhair & Farid, 2009). Transportation and
handling of products are made easier since they are of lightweight together with shallower
foundation requirements. Hemp lime being ductile too aids in avoiding costly movements of
joints.
Reduced heating and cooling requirements lead to reducing the operational cost which is
generally achieved by the enhanced insulation and the characteristics of the low U value of
hemp-lime. The permeability to vapor of the products from hemp lime too helps in forced
ventilation requirements reduction and de-humidification via installations of air conditioners.

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Concurrently, the continuous maintenance is reduced through utilization of durable lime binders
(Guggemos & Horvath, 2010).
The warmth within a building is facilitated by the high thermal insulation of the hemp-
lime products. Condensation of the trapped moisture within the building is avoided through the
high permeability to vapor facilitating the through the transfer of humidity. This eventually
assists in maintaining and improving the quality of the air within the building while controlling
humidity together with limiting or discouraging the growth of molds and fungi that could
interfere with human health.
Hemp blocks usually hold back absorbed heat during sunny periods which the heat is not
needed by the internal living but utilized later when its need arises for example during nights and
overcast periods hence saving on other related costs.

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Conclusion
Calculation of embodied energy of building materials
This is an energy required to construct and maintain a construction project premise i.e.
with a wall of brick or even concrete and other materials hence it is the required energy in
making bricks, transportation to site, bricklaying, plastering and maybe even painting of the
same material (Harris, 2011). The most preferred practice that is encouraged is to include
demolition and recycling energy requirements. The figure below provides a summary in form of
a flowchart elaborating the essential elements for estimating embodied energy:
The below formulae and steps are applied in calculating embodied energy of building materials
including concrete and hempcrete:

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Constituent materials establishment.
Calculation of weights of the constituent materials in m2 of the wall of cavity
Application of embodied carbon factors
Addition of constituent materials embodied carbon aimed at establishing the total
embodied carbon

Building and Construction 17
In conclusion, hempcrete is generally a better building material to applied during
construction of housing projects in comparison to other building materials such as
concrete since it possess several advantages as mentioned above with environmental
protection being the main through emission of low carbon footprint.

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References
Adalberth, K., 2014. Energy use during the life cycle of buildings: a method. Building and
Environment, 32(4), pp.317-320.
Allen, E. and Iano, J., 2011. Fundamentals of building construction: materials and methods.
John Wiley & Sons.
Bergsdal, H., Brattebø, H., Bohne, R.A. and Müller, D.B., 2015. Dynamic material flow analysis
for Norway's dwelling stock. Building Research & Information, 35(5), pp.557-570.
Binici, H., Aksogan, O. and Shah, T., 2012. Investigation of fibre reinforced mud brick as a
building material. Construction and Building Materials, 19(4), pp.313-318.
Cole, R.J., 2009. Energy and greenhouse gas emissions associated with the construction of
alternative structural systems. Building and Environment, 34(3), pp.335-348.
De Brito, J., Pereira, A.S. and Correia, J.R., 2013. Mechanical behaviour of non-structural
concrete made with recycled ceramic aggregates. Cement and Concrete Composites, 27(4),
pp.429-433.
Dimoudi, A. and Tompa, C., 2008. Energy and environmental indicators related to construction
of office buildings. Resources, Conservation and Recycling, 53(1-2), pp.86-95.
Eguchi, K., Teranishi, K., Nakagome, A., Kishimoto, H., Shinozaki, K. and Narikawa, M., 2010.
Application of recycled coarse aggregate by mixture to concrete construction. Construction and
Building Materials, 21(7), pp.1542-1551.
Flower, D.J. and Sanjayan, J.G., 2016. Green house gas emissions due to concrete manufacture.
The international Journal of life cycle assessment, 12(5), p.282.

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González, M.J. and Navarro, J.G., 2014. Assessment of the decrease of CO2 emissions in the
construction field through the selection of materials: Practical case study of three houses of low
environmental impact. Building and environment, 41(7), pp.902-909.
Guggemos, A.A. and Horvath, A., 2010. Comparison of environmental effects of steel-and
concrete-framed buildings. Journal of infrastructure systems, 11(2), pp.93-101.
Harris, D.J., 2011. A quantitative approach to the assessment of the environmental impact of
building materials. Building and Environment, 34(6), pp.751-758.
Khudhair, A.M. and Farid, M.M., 2009. A review on energy conservation in building
applications with thermal storage by latent heat using phase change materials. Energy conversion
and management, 45(2), pp.263-275.
Morel, J.C., Mesbah, A., Oggero, M. and Walker, P., 2016. Building houses with local materials:
means to drastically reduce the environmental impact of construction. Building and
Environment, 36(10), pp.1119-1126.
Naik, T.R., 2008. Sustainability of concrete construction. Practice Periodical on Structural
Design and Construction, 13(2), pp.98-103.
Okamura, H., Ozawa, K. and Ouchi, M., 2011. Self-compacting concrete. STRUCTURAL
CONCRETE-LONDON-THOMAS TELFORD LIMITED-, (1), pp.3-18.
Pacheco-Torgal, F. and Jalali, S., 2012. Earth construction: Lessons from the past for future eco-
efficient construction. Construction and building materials, 29, pp.512-519.
Raut, S.P., Ralegaonkar, R.V. and Mandavgane, S.A., 2011. Development of sustainable
construction material using industrial and agricultural solid waste: A review of waste-create
bricks. Construction and building materials, 25(10), pp.4037-4042.

Building and Construction 20
Roodman, D.M., Lenssen, N.K. and Peterson, J.A., 2009. A building revolution: how ecology
and health concerns are transforming construction (pp. 11-11). Washington, DC: Worldwatch
Institute.
Sharma, A., Saxena, A., Sethi, M. and Shree, V., 2011. Life cycle assessment of buildings: a
review. Renewable and Sustainable Energy Reviews, 15(1), pp.871-875.
Sheety, M.S., 2013. Concrete technology. published by S. Chand & Company Ltd., New Delhi-
1999.
Tay, J.H. and Show, K.Y., 2014. Resource recovery of sludge as a building and construction
material–a future trend in sludge management. Water Science and Technology, 36(11), pp.259-
266.
Van der Lugt, P., Van den Dobbelsteen, A.A.J.F. and Janssen, J.J.A., 2010. An environmental,
economic and practical assessment of bamboo as a building material for supporting structures.
Construction and Building Materials, 20(9), pp.648-656.
Zhang, Z., Provis, J.L., Reid, A. and Wang, H., 2014. Geopolymer foam concrete: An emerging
material for sustainable construction. Construction and Building Materials, 56, pp.113-127.