This document provides information on different surface finishing techniques for concrete. It describes smoothing the surface with a hand float, and then further finishing options like magnesium, aluminum or wood floats. Troweling with magnesium or steel trowels is covered, with notes on timing to avoid damaging the concrete. Broom finishing is also explained, including using a stiff broom and dragging it over the wet surface to create a non-slip texture. The summary concludes with the importance of curing the concrete to allow proper drying over several weeks.

1. 1- PRESTRESS CONCRETE& ADVANTAGES
ANS - Prestressed concreteis a concrete construction material which is placed
under compression prior to it supporting any applied loads (i.e. it is "pre"
stressed). This compression is produced by the tensioning of high-strength
"tendons" located within or adjacent to the concrete volume, and is done to
improvethe performanceof the concrete in service.[4] Tendons may consistof
single wires, multi-wire strands or threaded bars, and aremost commonly made
fromhigh-tensile steels, carbon fibre or aramid fibre.
The prestressing of concrete has severaladvantages as compared to traditional
reinforced concrete (RC) without prestressing. A fully prestressed concrete
member is usually subjected to compression during servicelife. This rectifies
severaldeficiencies of concrete. The following text broadly mentions the
advantages of a pre-stressed concretemember with an equivalent RC member.
For each effect, the benefits are listed.
A) Section remains un-cracked under service loads Reduction of steel
corrosion Increasein durability. Full section is utilized Higher moment of
inertia (higher stiffness)
 Less deformations (improved serviceability). Increasein shear capacity
 Suitable for usein pressurevessels, liquid retaining structures. Improved
performance(resilience) under dynamic and fatigue loading.
B) High span-to-depth ratios Larger spans possiblewith prestressing (bridges,
buildings with large column-free spaces) Typicalvalues of span-to-depth ratios in
slabs are given below. For the same span, less depth compared to RC member.
Reduction in self weight Moreesthetic appeal due to slender sections More
economical sections.
C) Suitable for precastconstruction.Theadvantages of precastconstruction are as
follows.
Rapid construction / Better quality control / Reduced maintenance Suitable for
repetitive construction
Multiple use of formwork Reduction of formwork Availability of standard shapes.
2- DIFFERENCE BETWEEN PRE & POST TENSIONING
ANS -The prestress in a structureis influenced by either of the two processes: Pre-
tensioning, and Post-tensioning Pre-tensioning can be further classified into two
categories: Linear pre-tensioning Circular pre-tensioning

2. PRE-TENSIONING
Pre-tensioning is accomplished by stressing wires or strands, called tendons, to
predetermined amount by stretching them between two anchorages prior to
placing concrete as shown in fig.1. the concrete is then placed and tendons
become bounded to concrete throughouttheir length. After concrete has
hardened, the tendons are released by cutting them at the anchorages. The
tendons tend to regain their original length by shortening and in this process
transfer through bond a compressivestress to the concrete. The tendons are
usually stressed by the use of hydraulic jacks. Thestress in tendons is maintained
during the placing and curing of concrete by anchoring the ends of the tendons to
abutments that may be as much as 200mapart. The abutments and other
formwork used in this procedureare called prestressing bench or bed.
POST-TENSIONING
The alternative to pre-tensioning is post-tensioning. In a post-tensioned beam,
the tendons are stressed and each end is anchored to the concrete section after
the concrete has been cast and has attained sufficientstrength to safely
withstand the prestressing forceas shown in fig.2. in post-tensioning method,
tendons are coated with greaseor a bituminous material to prevent them from
becoming bonded to concrete. Another method used in preventing the tendons
frombonding to the concrete during placing and curing of concrete is to encase
the tendon in a flexible metal hose beforeplacing it in the forms. The metal hose
is referred to as sheath or duct and remains in the structure. After the tendon has
been stressed, the void between the tendon and the sheath is filled with grout.
Thus the tendons become bonded to concrete and corrosion of steel is prevented.
Post-tension prestressing can be doneat site. This proceduremay become
necessary or desirablein certain cases. For heavy loads and large spans in
buildings or bridges, it may be very difficult to transporta member from pre-
casting plant to a job site. On the other hand, pre-tensioning can be used in pre-
cast as well as in cast-in-place construction. In post-tensioning itis necessary to
use sometypes of device to attach or anchor the ends of the tendons to the
concrete section. These devices are usually referred to as end anchorages.
3- EXPLAIN LOW HEAT PORTLAND CEMENT & RAPID
HARDENING CEMENT
ANS - Low Heat Cement is specially blended to providea lower heat of hydration
in concrete. This unique attribute makes it ideal for mass concretepours where

3. the rate of temperature riseand the maximum temperature achieved mustbe
controlled in order to reduce the risk of thermal cracking.
Benefits of Low Heat Cement
• Assists in minimising the potential for thermal cracking in thick concrete
sections
• Significantly improved later-age concrete strengths
• Improved durability performance
• Increased workability and pumpability with large pours .Productapplications
Low Heat Cement is ideal for mass concrete applications, including:
• Constructing dams
• Largefootings, large raft slabs, wind turbine plinths
• Very high strength concrete
Low Heat Cement is ideal for use in mass concrete structures whererate of
temperature rise and maximum temperature achieved is controlled to reduce the
risk of thermal cracking.
Compatibilities Low Heat Cement is compatible with:
• Admixtures that comply with AS 1478 – Chemical Admixtures for Concrete.
• Fly ashes complying with AS 3582.1 –Supplementary Cementitious Materials for
Use with Portland cement: Fly ash.
• Ground granulated blast furnaceslags complying with AS3582.2 -
Supplementary cementitious materials for usewith Portland cement: Slag -
ground granulated Iron blast-furnace.
Low Heat Cement as the name indicates these type of cement is used inorder to
reduce the amount of heat evolved during setting. But how the heat evolved
during setting can be reduced ? Yes, the heat during setting can be reduced by
lowering the percentage of tri-calcium aluminate C3A of about 5% an higher
percentage of di-calcium silicate C2S of about 46%. Uses of Low Heat Cement: 1.
Itcan be used in mass construction works. 2. Theconcretes made by low heat
cement is highly resistanceagainst ruptures. Disadvantages of Low HeatCement:
1. Cannot be used in cold weather conditions because it will retard the setting
time than in ordinary weather. 2. The compressivestrength is lower than that of
ordinary cement.
Rapid hardening cement is similar to Ordinary Portland cement but with higher
tri-calcium silicate (C3S) content and finer grinding. It gains strength more quickly

4. than OPC, though the final strength is only slightly higher. This type of cement is
also called as High-Early Strength Portland Cement. The one-day strength of this
cement is equal to the three-day strength of OPCwith the same water-cement
ratio
Following are the advantages and uses of the rapid hardening portland cement:
(a) It is used whereformwork has to be removed as early as possiblein order to
reuseit.
(b) It is used wherehigh early strength is required. (c) Itis generally used for
constructing road pavements, whereit is important to open the road to traffic
quickly.
(d) It is used in industries which manufacture concrete products like slabs, posts,
electric poles, block fence, etc. because moulds can be released quickly.
(e) Itis used for cold weather concreting because rapid evolution of heat during
hydration protects the concrete against freezing.
Advantages of Rapid Hardening Cement: 1. The formwork of concrete can be
removed in early days, becauseit attains high strength in fewer days. 2. The
Compressivestrength in one day is 11.50 N/mm2 and in three days 21 N/mm2. 3.
the tensile strength in one day is 2 N/mm2 and in three days 3 N/mm2. 4. Require
less curing period. 5. The use of this cement allows higher permissiblestresses in
the design. Ittherefore results in economic design. 6. Itis not damaged easily.
Disadvantages of Rapid Hardening Cement: 1. Itis costly.
4- EXPLAIN READY MIX CONCRETE & LITE WEIGHT CONCRETE
ANS- Ready-mix concrete Itis concrete that is manufactured in a factory or
batching plant, according to a set recipe, and then delivered to a work site, by
truck mounted in–transit mixers. This results in a precisemixture, allowing
specialty concrete mixtures to be developed and implemented on construction
sites. Ready mix concrete is sometimes preferred over on-siteconcrete mixing
because of the precision of the mixture and reduced work site confusion.
However, using a pre-determined concrete mixture reduces flexibility, both in the
supply chain and in the actual components of the concrete. Ready Mixed
Concrete, or RMC as it is popularly called, refers to concrete that is specifically
manufactured for delivery to the customer's construction sitein a freshly mixed
and plastic or unhardened state. Concrete itself is a mixture of Portland cement,
water and aggregates comprising sand and gravel or crushed stone. In traditional
work sites, each of these materials is procured separately and mixed in specified

5. proportions atsite to make concrete. Ready Mixed Concrete is bought and sold by
volume - usually expressed in cubic meters. Ready Mixed Concrete is
manufactured under controlled operations and transported and placed at site
using sophisticated equipment and methods. RMC does not assures its customers
numerous benefits.
Advantages
• A centralized concrete batching plant can servea wide area. Site-mix trucks can
servea larger area including remote locations that standard trucks cannot.
• The plants are located in areas zoned for industrial use, and yet the delivery
trucks can service residential districts or inner cities. Site-mix trucks have the
same capabilities.
• Better quality concrete is produced. Site mix can producehigher compression
strength with less water than standard batching methods.
Disadvantages
The materials are batched at a central plant, and the mixing begins at that plant,
so the traveling time fromthe plant to the site is critical over longer distances.
Some sites arejust too far away, though this is usually a commercial rather than a
technical issue.
• Generation of additional road traffic. Furthermore, access roads and site access
have to be able to carry the greater weight of the ready-mixtruck plus load.
(Green concrete is approx. 2.5 tonne per m³.) This problem can be overcomeby
utilizing so-called 'minimix' companies which usesmaller 4m³ capacity mixers able
to reach more-restricted sites.
• Concrete's limited timespan between mixing and going-off means that ready-
mix should be placed within 90 minutes of batching at the plant. Modern
admixtures can modify that timespan precisely, however, so the amount and type
of admixture added to the mix is very important.
LIGHTWEIGHT CONCRETE
The use of LWC(Lightweight concrete) has been a feature in the construction
industry for centuries, but like other material the expectations of the
performancehaveraised and now we are expecting a consistent, reliable material
and predictable characteristics. StructuralLWChas an in-place density (unit
weight) on the order of 90 to 115 lb / ft³ (1440 to 1840 kg/m³) compared to
normal weight concrete a density in the range of 140 to 150 lb/ft³ (2240 to 2400
kg/m³). For structuralapplications the concrete strength should be greater than

6. 2500 psi(17.0 MPa). Theconcrete mixture is made with a lightweight coarse
aggregate. In somecases a partion or the entire fine aggregates may be a
lightweight product. Lightweight aggregates used in structurallightweight
concrete are typically expanded shale, clay or slate materials that havebeen fired
in a rotary kiln to develop a porous structure. Other products such as air-cooled
blast furnaceslag are also used. There are other classes of non-structuralLWC
with lower density made with other aggregate materials and higher air voids in
the cement paste matrix, such as in cellular concrete.
ADVANTAGES OF USING LWC
Reduced dead load of wet concrete allows longer span to be poured unpropped.
This saveboth labour and circle time for each floor. Reduction of dead load, faster
building rates and lower haulage and handling costs. The eight of the building in
term of the loads transmitted by the foundations is an important factor in design,
particular for the case of tall buildings. The use of LWChas sometimes made its
possibleto proceed with the design which otherwisewould have been
abandoned because of excessiveweight. In framestructures, considerablesavings
in cost can be broughtabout by using LWCfor the construction floors, partition
and external cladding. Most building materials such as clay bricks the haulage load
is limited not by volume but by weight. With suitable design containers much
larger volumes of LWC can haul economically.
DURABILITY OF LWC
Durability is defined ass the ability of a material to withstand the effect of its
environment. In a building material as chemical attack, physicalstress, and
mechanical assault:-
Chemical attack is as aggregateground-water particularly sulphate, polluted air,
and spillage of reactive liquids LWChas no special resistantto these agencies:
indeed, it is generally moveporous than the ordinary Portland cement. Itis not
recommended for use below damp-course. A chemical aspects of durability is the
stability of the material itself, particularly at the presence of moisture.
Physical stresses to which LWCis exposed are principally frostaction and
shrinkageand temperature stresses. Stressing may bedue to the drying shrinkage
of the concrete or to differential thermal movements between dissimilar
materials or to other phenomena of a similar nature. Drying shrinkagecommonly
causes cracking of LWC if suitable precautions are not taken.

7. 5- SURFACE FINISHING OF CONCRETE
ANS - Smoothand compact the surface once again witha hand float. This is the
final smoothing, bringing the more consistent"cream" of the concrete to the
surfacefor a level, durablefinish. Different materials will provide different
effects:[13]
Magnesiumfloats are very popular among professionals, sincethey are
lightweight and excellent at opening up the concrete's pores for evaporation.
Aluminum floats are very similar to magnesium, but somewhatheavier and
stronger (and so a little more difficult to handle).
Wooden floats (redwood or hardwood) arecheap but wear out quickly. They
create a rough fuzzy surfaceusefulfor very stiff concreteor if using colored
hardeners (which need to be mixed in with the rougher tool).
Laminated-canvas resin floats are used for the samepurposes as wood but are a
much moredurable (and expensive) tool.
As before, lift the leading edge slightly and make shallow flat motions across the
surface.
Consider a trowel finish. Many people skip troweling if they plan to broom, as it
only results in minor improvementin that scenario. Troweling without brooming
results in a very slick surface(unsafefor surfaces thatwill get wet) and may cause
fine cracks to develop called "crazing".[14]
Use a magnesiumtrowel in much the sameway you used previous finishing tools.
You can create a very smooth finish by passing over the slab two or three times,
waiting for the concrete to dry slightly between passes and lifting the leading
edge a little more each time.[15]
Steel trowels can also be used, but inexpert timing could cause the steel to trap
water inside the concrete and damage it.[16]
Troweling too deep or troweling "air-entrained" concrete mixes can release the
concrete's air bubbles and preventit fromsetting correctly.
Larger troweling tools (or other long-handled finishing tools) are sometimes
referred to as "fresnos".[17][18]
Thesearehandy for reaching the center of large
slabs. Alternatively, use a hand trowel but kneel on wooden boards when you
need to be on the slab to prevent leaving deep impressions.
.
Try a broom finish. Mostpeople end with a broomfinish to create a non-slip
surface. You can do this with or withouta preceding trowel finish.

8. Use a medium stiff or stiffer shop broom(the wide rectangular kind). The bristles
should be stiff enough to leave noticeable marks, and the concrete should be soft
enough to be shaped by them but hard enough to retain them (notsinking back
together).
Dip the broom into a bucket of water, then shakeoff the excess (not onto the
concrete).
Drag the broomgently over the concrete in segments. Overlap the previous
segment to ensurefull coverage.
If the surfaceis intended to drain, create the grooves in the direction liquids are
supposed to flow.[19]
Cure the concrete. The final drying process of concrete takes severalweeks, and if
"cured" at the correctrate minimizes the chance of later damage.
The simplest method is to wet the concrete's surfaceand cover it with plastic
sheeting. Weigh down the sheet's edges with heavy objects.
There are many other ways to keep the concrete wet, but these tend to require
more water or maintenance than plastic.[20]
Concrete curing chemicals are often used for professionaljobs. Thesecome in
many varieties, so consult someonefamiliar with your concrete mix for advice on
selecting one.[21]
Begin curing as soon as possible. Oncebegun, keep off foot traffic for 24 hours,
light vehicles such as bicycles for 1 week, and car traffic for 2 weeks. Complete
curing takes at least 30 days, and longer at the corners and edges.[22]
Seal the concrete. After the concrete has cured for at least a month, use a
concrete sealer to make it resistantto liquid damage and easy to clean.[23]
Clean the slab well before applying sealant.
Apply thinly to avoid puddles. If needed, wait a couple hours (or as the label
instructs you), then apply a second layer perpendicular to the first.
Allow sealant to dry completely beforewalking over or placing anything onto the
concrete. Wait three days before allowing vehicle traffic.
7- CURTAIN WALL SYSTEM & COMPONENTS
Ans- a curtain wall is any non-load bearing exterior wall with the following
characteristics:

9. 1. Suspended in front of the structuralframe.
2. Dead weight and wind loads are transferred to the structuralframethrough
point anchorages.
3. Wall element and the fastening technique permit erection of continuous wall
surfaces of any size.
Curtain wall facade is being constituted in one of the mostused at the present
time due to its facility of construction, lightness and to the great variety of
materials and finished textures that are possibleto obtain .At the present time
the materials mostly used for the structuralprofiles in curtain walls are
aluminium, steel ,glass.
Components = steel or aluminium anchors, mullions (vertical tubes), rails
(horizontalmullions), vision glass, spandrelglass, insulation and metal back pans
10- USES OF PLASTIC IN BUILDING CONSTRUCTION
ANS - Plastics are used on a daily basis throughoutthe world. The word plastic is a
common term that is used for many materials of a synthetic or semi-synthetic
nature. The term was derived fromthe Greek plastikos, which means “fit for
molding. “Oneway plastics changed the world was in cost. Itwas so much
cheaper to manufacturethan other materials and the various ways itcould be
used was staggering. Plastics are used in an enormous and expanding range of
products, frompaper clips to spaceships. They havealready displaced many
traditional materials
THE BUILDING INDUSTRY
PIPES: Electrical Conduits, Rain Water & Sewage pipes, Plumbing, Gas
Distributions.
CABLES: PVCInsulation on cables, Insulation Tapes.
FLOORINGS: Flooring tiles & Rolls.
DOMES / SKY LIGHTS: Opaqueas well as transparent.
ROOFING: Colored or double skinned for insulation.
WINDOWS & DOORS: Extruded sections for Door and windows and panels.
STORAGETANKS: Storagetanks.
HARDWARE ACCESSORIES: Washers, Nutbolts, Sleeves, Anchoring wires.
TEMPORARY STRUCTURES: Guard cabins, tents
INSULATIONMATERIALS: PVCsheets, insulating membranes.

10. PLASTIC FLOORING
Available in two types:
Hard polypropylene
Soft PVC.
Each type of plastic flooring is incredibly durable.
Generally used for Garages, and Warehouses
Both types are capable of supporting extreme weight loads and resistantto
oils/solvents.
PVC is a softer, more pliable option which typically provides a softer flooring for
standing or working.
PVC flooring is less proneto wear and tear. Italso decreases the sound pollution
level and can be cleaned easily.
PLASTIC WALLS
A structuralinsulated panel (SIP) is a sandwich of expanded polystyreneamidst
two slim layers of oriented strand board.
This type of pre-fab, compositewall board can be transferred to the work place
easily for a particular task and providegood supportto columns and other
associated essentials during renovation.
APPLICATIONS FOR PLASTIC WALLS
Commercial kitchens
Bathrooms
Washrooms
Canteen Walls and Ceilings
Food Processing Areas
Changing Areas
FastFood Outlets
Food Storage
PLASTIC ROOFING
Corrugated plastic sheeting has been used for roofing in conservatories and
buildings where transparentpanels have been required.
To protect the outer surfaceof the roof fromdamage, two layers of different
plastic materials are required. The upper part is made of colored thermoplastic
olefin or vinyl while the lower part consists of polyurethanefoam which
consumes less energy and keeps the interior of a housecooler.
CLADDING PANELS

11. UPVC products are now frequently used in place of the more traditional products
for external cladding panels, soft boards, particularly on new buildings.
Polycarbonatepanels have a high impact strength and havebeen known to
withstand hurricaneforce winds when applied to outdoor displays or building
structures such as skylights or archways.
The lightweight panels minimize the structuralsupportneeded by the building
and its transparency allows for morenatural light and when using thicker gauges
can providegreater insulation value.
SOUND & THERMAL INSULATION
Sound insulation can be provided by either a simple and heavy or a light and
complex construction, which is now replaced by the rubber and plastics materials.
Apart fromsound insulation, buildings need thermal insulation also. This can be
met by using light weight aerated concrete building blocks during the
construction of the building or by incorporating foamed plastic sheeting within
the structure.
PLASTIC DECORATIVEELEMENTS
The normal structureof a plastic decorative laminate includes a sheet of
decorative paper impregnated (saturated) with one or more resins.
Plastic decorative laminates have a wide rangeof uses, they can be used in the
furnitureindustry for kitchen cabinet counters, bookshelves and door linings,
among many other things. In the building industry they can be used for partitions
screens in order to divide spacein offices, houses, etc...
PLASTIC ADHESIVEAND SEALANTS
There are also water-based versions thatcan providebetter heat resistance.
Generally solvent-based, thesecost effective, gap-filling adhesives aresuitable for
bonding sheet flooring, adhering skirting's and architraves, signs and wall panels.
11- COMPOSITE PANELS AND THEIR APPLICATION
ANS-Compositepanels are a pre-fabricated insulated building material with
typically two metal skins bonded to an inner insulation core. Some are available
with plastic or fabric lining instead of metal for one or both skins. Such panels are
in widespread use in modern buildings, either externally as wall or roofing
material, or internally as compartmentation or linings. They are an inexpensive,
light and easy to install product with superior insulation and hygiene qualities to
many similar building materials.
Panels aremanufactured on a continuous lamination basis with metal facings -
usually steel or aluminum - encapsulating a foamed polyurethanecore. This

12. composition offers a high degree of stability, rigidity and excellent load-bearing
capacity. The thickness of the polyurethanefoam can rangefrom 30mmto
200mmdepending upon application and required insulation characteristics. These
versatile products arealso known as 'sandwich'panels due to the physical
interaction of the two materials.
SANDWICH PANEL
A sandwich panel is a structuremade of three layers: low density core inserted in
between two relatively thin skin layers.
This sandwich setup allows to achieve excellent mechanical performanceat
minimal weight.
The very high rigidity of a sandwich panel is achieved thanks to interaction of its
components under flexural load applied to the panel: core takes the shear loads
and creates a distance between the skins which take the in-plane stresses, one
skin in tension, the other in compression.
HONEYCOMB SANDWICH PANEL
Honeycomb sandwich panel has been proven as the most efficient sandwich
design with respect to mechanical performanceand weight.
Aerospaceand aircraftindustry uses the honeycomb structures as they meet the
tough requirements of related applications. The use of honeycomb sandwich
design in more common applications has been morelimited due to the batch wise
manufacturing processes and hence relatively high production costs.
ALUMINIUM COMPOSITEPANEL
Aluminum composite panel (ACP), also aluminum composite material (ACM), is a
type of flat panel that consists of two thin Aluminum sheets bonded to a non-
aluminum core.
ACPs are frequently used for external cladding or facades of buildings, insulation,
and signage. If the core material is flammable, usage may be problematic as a
building material and somejurisdictions havebanned their use.
Aluminum sheets are coated with polyvinylidenefluoride (PVDF), fluoropolymer
resins (FEVE), or polyester paint. Aluminum can be painted in any kind of color,
and ACPs are produced in a wide range of metallic and non-metallic colors as well
as patterns that imitate other materials, such as wood or marble. The coreis
commonly low-density polyethylene, or a mix of low-density polyethyleneand
mineral material to exhibit fire retardant properties.

13. 12- Write about these 3
Ans - Acoustic materials
ACOUSTICMATERIALS arethings that have ability to absorb redundantnoiseand
enhance transmission of sound. They play an important role in determining the
quality of your auditory experience in a number of settings like offices,
restaurants, concerthalls, schools, auditoriums, healthcarefacilities and
gymnasiums.
TYPES OF ACOUSTIC MATERIALS:
• SOUND ABSORBERS
• SOUND DIFFUSERS
• NOISEBARRIERS
• SOUND REFLECTORS
SOUND ABSORBERS
• These sound absorbing acousticalpanels and soundproofing materials areused
to eliminate sound reflections
to improvespeech intelligibility, reduce standing waves and preventcomb
filtering.
• Typical materials are open cell polyurethanefoam, cellular melamine,
fiberglass, fluffy fabrics and other porous
materials. A wide variety of materials can be applied to walls and ceilings
depending on your application and environment.
• These materials vary in thickness and in shape to achieve different absorption
ratings
depending on the specific sound requirements.
SOUND DIFFUSERS
• these devices reduce the intensity of sound by scattering it over an expanded
area, rather than eliminating the sound reflections as an absorber would.
Traditional spatial diffusers, such as the polycylindrical(barrel) shapes also double
as low frequency traps. Temporal diffusers, such as binary arrays and quadratics,
scatter sound in a manner similar to diffraction of light, wherethe timing of
reflections froman uneven surfaceof varying depths causes interference which
spreads the sound.
NOISEBARRIERS

14. These materials range fromdense materials to block the transmission of airborne
sound to devices and compounds used to isolate structures fromone another and
reduce impact noise.
Fireproof materials
GYPSUM :
Gypsumboard is an excellent fire-resistivebuilding material.
Its non combustible core contains nearly 21% chemically combined water, as
described earlier, which, under high heat, is slowly released as steam.
Because steam will not exceed 100 degrees Celsius under normal atmospheric
pressure, itvery effectively retards the transfer of heat and the spread of fire.
Even after complete calcination, when all the water has been released fromits
core, gypsumboard continues to serveas a heat-insulating barrier.
Moreover, tests conducted show that gypsumboard has a low flame-spread index
and a low smoke-density index.
When installed in combination with other materials in laboratory-tested walland
ceiling assemblies, gypsumboard serves to effectively protect building elements
fromfire
Concrete, oneof the most common building materials, is also an excellent fire-
resistantmaterial. Itis non-combustibleand has low thermal conductivity,
meaning that it takes a long time for fire to affect its structural, load-bearing
ability, and it protects fromthe spread of fire. It's actually significantly more fire-
resistantthan steel, and often used to reinforce and protect steel fromfire.
However, it's important to note that not all concrete is created equal. Itconsists
of cement and aggregate, and the particular kinds of aggregate materials used can
vary, as well as the amount used. Aggregate can make up 60 to 80 percent of the
concrete's volume. The exact fire-resistanceproperties change depending on the
type and amount of aggregate used. Natural aggregates tend not to performas
well. Moisture in the aggregatecan expand when heated, causing concrete to
sinter after long exposure.
STUCCO
Stucco is a plaster that has been used for centuries for both artistic and structural
purposes. Modern stucco is made of Portland cement, sand and lime, and it
serves as an excellent and durable fire-resistantfinish material for buildings.

15. Itcan cover any structuralmaterial, such as brick or wood. Itusually consists of
two or three coats over metal reinforcing mesh. A one-inch (2.54-centimeter)
layer of stucco can easily lend a 1-hour firerating to a wall.
Roof eaves (overhangs) area fire hazard, butthey can be protected with an
encasement of fire-resistantmaterial. Stucco is often recommended as one of the
best materials for boxing in hazardous eaves.
BRICKS :
As bricks are made in a fire kiln, they're already highly resistant to fire. However,
it's true that individual bricks aremuch more fire-resistantthan a brick wall.
A brick wall is held together with mortar, which is less effective. Nevertheless,
brick is commonly cited as among the bestbuilding materials for fire protection.
Depending on the construction and thickness of the wall, a brick wall can achieve
a 1-hour to 4-hour fire-resistancerating.
GYPSUM BLOCK
◦ Gypsumblock is a massivelightweight building material composed of solid
gypsum, for building and erecting lightweight fire-resistantnon-load
bearing interior walls, partition walls, cavity walls, skin walls and pillar
casing indoors.
◦ Gypsumblocks arecomposed of gypsumplaster, water and in some cases
additives like vegetable or wood fibrefor greater strength.
◦ Partition walls made fromgypsumblocks requireno sub-structurefor
erection and gypsumadhesiveis used as bonding agent, not standard
mortar.
PROPERTIES
Gypsumblocks combinethe advantages of classical masonry with modern drywall
construction. Similar to masonry, walls built with gypsumblocks aremassive,
void-freeand of high stability. Because no mortar, sand or plaster are used, the
walls are (almost) built without water, like drywalls.
Fire resistance
◦ Massivegypsumblocks havea high level of passivefire protection: 60 mm
thickness offers 30 minutes of fire resistance(F30-A in accordance with the

16. German DIN4102 standard, theEuropean EN 13501 or theBritish BS 476);
80 mm thickness offers 2 hours of fire resistance
Sound proof
◦ To improvethe sound proof qualities of gypsumblock partition walls,
insulation strips are used on all sides to connect the partition walls to
adjacent walls, ceilings and floors. The acoustic decoupling of the walls in
this way reduces the acoustic transmissions of theselightweight partition
walls significantly.