building construction Flashcards
Bogue’s compound
C3S, C2S, C3A, C4AF
cement basic compounds
lime (Cao) : 60-67% silica(SiO2): 17-25% Alumina(Al2O3): 3-8% Iron oxide)(Fe2O3):0.5 -6% Magnesia(MgO) : 0.1- 4% Sulphur Trioxide(SO3): 1-3% Soda and potash (Na2O +K2O) : 0.5 -1.3%
water permissible impurities for concreting
organic-200mg/l
inorganic - 3000
sulphates(So3) - 400
chlorides -2000 for plane
- 500 for RCC
suspended matter- 2000
PH - 4.5 to 8.5
values from IS 3025consistency of cement
measuring instrument and consistency limits
Vicats apparatus
300g plunger ,50 mm length, 10 mm dia
mould h=40, D=80
plunger should penetrate 30-35 mm deep
initial setting time for OPC and low heat
and test setup
30 min - OPC
60 min - low heat
water =0.85p
1mm square needle 33~35mm penetration
final setting time
and test setup
needle cant leave a mark on solid surface
time > 10 hrs
soundness of cement tested by
Le Chateier’s method
autoclave test
both are good for lime soundness
compressive stregth test of cement grade
33 grade cement
16 mpa -3 days
22 mpa- 7 days
33 mpa- 28 days
tensile strenght limit of OPC
2 Mpa -3 day
2.5 Mpa -7 Days
Sieve test of cement
90 micron sieve residue
OPC -10% residue
Rapid- 5%
PPC - 5%
heat of hydration for low heat portland cement
7 days -66 cal/g
28 days - 75 cal/g
what is shallow foundation
Depth less then width
what are compaction piles
piles driven in granular soil to increase bearing capacity of that soil
Timber piles
D = 300-500 mm
L < 20.D
P < 200 Kn
c-c spacing ~ 900 mm
screw piles
D = 150~300 mm
for soft clay and loose sand
disc piles
disc connected to base of hollow cast iron pipe
D.disk = 0.6 ~ 1.2 m
caissons
water tight structure for excavation and construction of foundation
Box , open, Pneumatic caisson
what are shoring structures
temporary structures required to support unsafe structure
underpinning of structure
supports provided underneath the existing structure without disturbing its stability
sill member in building
to support window or door
LINTEL
what is jamb and reveal
vertical member in side of a door
width 76~114 mm
reveal- outer part of the jamb vivible in door or window openings
or exposed vertical surface left on the sides of opening after door or window frames has fitted in position
cornice of building
horizontal moulding projection (usually made by POP)
blocking course and Frieze in building
- a course of stone provided immediately above the cornice
- a course of stone provided immediately below the cornice
stone masonry and its types
https: //civilseek.com/stone-masonry/
https: //www.aboutcivil.org/Stone-Mortars.html
http: //constructionanddesign.blogspot.com/2017/01/stone-masonry-and-types.html
bond types in brick work
http://gosmartbricks.com/10-most-popular-types-of-brick-bonds/
bats and queen closures
https://www.slideshare.net/AkkiJasani/brick-masonary-ii-73060161
racking masonry bond
bricks are inclined at any angle
eg. diagonal bond, herring-bone bond(45°), zig-zag bond(45°)
granolithic flooring
hard concrete flooring, coarse aggrigate such as granite, basalt, quartzite
terrazzo flooring
flooring made with special aggrigate of marble chips mixed with white cement
good wearing properties
mosaic flooring
small pieces of broken tiles of china glazed or of marble arranged in different patterns
linoleum flooring
are available in rolls , can be laid directly on wooden or concrete flooring,
subjected to rotting - nor recommended for bathrooms and kitchen
stairs definitions scotia soffit stringers baluster
scotia- moulding provided under nosing to beautify
soffit - under surface of stairs
stringers- sloping member which supports the steps in a stair
baluster- vertical member of wood or metal to support hand rail
steps commonly adopted for stairs and pitch angle
250 x 100 mm for residential buildings
300 x 100 mm for hospitals and public
pitch angle < 40 °
width of the stair commonly adopted
900 mm for residential building
1.5 to 1.8 m for public buildings
height clearance of overhead soffit of stairs
H > 2m
minimum depth of foundation on clay soil
0.9 ~ 1.6 m
foundation for very heavy load from column
grillage foundation
when is raft foundation required
when required area exceed 1/2 of total area
usually required in clay
pier foundation is required when
heavy structure is to be constructed in sandy soil
batter piles
driven at an inclination to resist large horizontal inclined forces
fender piles
used to protect concrete deck or any water front structure from abrasion or impact
length of precast piles
4.5m ~ 30m
franki pile
cast in situ pile having enlarged base and a corrugated stem
raymond pile
L = 6 to 12 m
top Dia = 400~600 mm
bottom dia = 200 ~ 280 mm
Mac Arthur pile
driven pile
dia restriction of drilled pile
D < 600 mm
coefficient of friction between concrete and soil
0.3 ~ 0.35
for pre cast RF piles , quality of concrete is ?
M15 ~ M20
driven piles
c-c spacing of lateral reinforcement in precast piles
S < D/2
clear cover of main reinforcement in precast piles
40 mm -normal
55 mm - sea water
size specs of DPC
1:2:4 concrete
thickness > 40 mm
minimum thickness of stone masonry wall
350 mm
haunch of arch
the lower portion of an arch between skew back and crown
mullion
a vertical bar between the panes of glass in a window.
transom
a horizontal member of a frame employed to subdivide the window opening horizontally
width and depth of jamb
width 76 ~ 114 mm
depth 57 ~ 76 mm
bay window
windows which project outwards from the wall
dormer window
A dormer is a roofed structure, often containing a window, that projects vertically beyond the plane of a pitched roof.[1]
A dormer window is a form of roof window
clerestory window
a clerestory is a high section of wall that contains windows above eye level. The purpose is to admit light, fresh air, or both.
provided near the main roof of a room and opens above adjoining verandah
compounds of bricks
Silica -50% It prevent cracking ,shrinkage and warping. makes brittle if in excess
Alumina -20~ 30 %, imparts plasticity. but can increase shrinkage and warping
Lime -5~10%, prevent shrinkage, but can cause melting
Iron oxide -5~7%,
Magnesia ~ 1%, it provide yellow tint, reduce shrinkage, but can lead to decay
Granite specs
igneous rock - quartz ,fildspar, mica
G = 2.65
strength 70 ~ 130 MPa
it is weather resistant and can be polished and used for exterior facing
Slate
Agrillaceous Rock - allumina , sand and carbonate of lime
G=2.8
strength = 60~ 70 Mpa
used in roof covering and tiles
Sandstone
Sedimentry ,stratified and silicious rock -quartz, lime, Sillica
G = 2.65~ 2.95
Str = 35~ 40 MPa
it is uesd for alshar work, moulding, carving
Limestone
sedimentry ,stratified and calcarious rock,
G =2.6
it can be used in blast furnace and stone masonry
Marble
matamorphic and calcarious rock
G~ 2.7
decoration work
what is metamorphic rock
formed due to alteration of original structure under heat and excessive pressure
kankar
30% alumina and silica
used in foundation work
chip mark
this defect is indicated by marks placed by chips on the finished surface of timber
Diagonal grain
this defect is formed due to improper sawing of timber.it is indicated by diagonal mark on straight grained surface of timber.
Torn grain
this defect is caused when a small depression is formed on the finished surface of timber by falling of a tool or so.
Wane
this defects is denoted by the presence of original rounded surface on the manufactured piece of timber.
Fungi attack timber only when
(1) The moisture content of timber is above 20%.
(2) If there is a presence of air and warmth for the growth of fungi.
Bluestain
:the sap of the wood is stained to bluish colour by the action of certain type of fungi.
Brown rot
the fungi of certain types remove cellulose compound from wood and hence the wood assumes the brown colour.this is known as the brown rot.
Dry rot
the fungi of certain types feed on wood and during feeding ,they attack on wood and convert it into powder form.This is known as dry rot.
This type of defect occur in place where there is dampness and no free circulation of air.The dry rot may be prevented by using well seasoned timber free from sap.
Heart rot
this is formed when a branch has come out of a tree.It occurs when heart woodis exposed to atmospheric agent.
Sap stain
certain types of fungi feed on cell contents of sap wood.In doing so ,the sap wood loses its colour.this is known as sap stain.It generally occurs when moisture content goes beyond 25 % or so.
Wet rot
:some varietiesof fungi cause chemical decomposition of wood of timber in doing so timber is converted into a greyish brown powder. This is known as wet rot.
White rot
this defect is opposite of brown rot.In this defect the wood assumes the appearance of a white mass consisting of cellulose compounds.
Knots
these are the bases of branches or limbs which are broken or cut off from the tree. The portion from which the branch is removed receives nourishment from the stem for a pretty long time and it ultimately results in the formation of dark hard rings which are known as the knots.
Shakes
these are cracks which partly or completely separate the fibres of wood. Following are the different types of shakes: cup shake, heart shake, ring shake, star shake, radial shake
Foxiness
this defect is indicated by red or yellow tinge in wood or reddish brown stains or spots round the pith of tree discolouring the timber. It is caused due too poor ventilation.
Preservation of timber
- Tar
- Paints
- Chemicalsalt
- Creosote
- ASCO
water absorption limit of building stone
5%
kneading in bricks
process of mixing clay , water
slag content in portland slag cement
40-70%
max size of aggrigate for RCC
25 mm
usual shrinkage in concrete
0.3~0.6 mm
moisture content limit in timber
15%
time required in kiln seasoning and air seasoning of soft wood
10- 20 days
60- 90 days
thickness of lamin board vary
12~ 25 mm
wood generally used in sleepers
kail
liquid medium and thinner used in enamel paints
varnish
thinner - turpentine
linseed oil
liquid, vehical, soluble in turpentine, alcohol, neptha
drier content limit in paints
10% (Litharge)
Distempering
Distempering : Distemper is prepared with white chalk (as base) and water (as thinner).
The main object of applying distemper to the plastered surfaces is to create a smooth
surface. The distempers are available in the market under different trade names and are
available in powder and paste forms. They are cheaper than paints and varnishes and
they present a neat appearance. They are available in a variety of colours.
Properties of Distemper :
Following are the properties of distempers:
• On drying, the film of distempers shrinks. Hence it leads to cracking and flaking,
if the surface to receive distemper is weak.
• The coatings of distemper are usually thick and they are more brittle than order
types of water paints.
• The film developed by distemper is porous in character and it allows water
vapour to pass through it. Hence, it permits new walls to dry out without
damaging the distemper film.
• They possess poor workability.
• They are less durable than oil paints.
• They are treated as water paints and they are easy to apply.
• They can be applied on brickwork, cement plastered surface, lime plastered
surface, insulating boards, etc.
what is varnish
homogeneous mixture of natural and synthetic resin
drier Litharge
1. oil varnish
2. Spirit varnish
FIELD strength test setup of cement
25 x 25 x 200 mm 2 supports 150mm distance P = 340N relative humidity 90%, T = 27+-2 sample should not fail
compressive strength test of cement
Ennorre sand , 1:3 mix
water = p/4 +3 %
mould 70.6mm X 75mm
tensile strength test(direct) of cement
12 samples of Briquettes
critical section area = 6.45 sq.cm
Le chatliers test setup
split cylinder Dia = 30 mm indicator arm = 165mm water = 0.78*p 27~32* temp , for 24 hrs then boiled for 25-30 minutes IS : 269 - 1989, 10mm max deflection
autoclave test use and setup
- used to determine unsoundness due to lime and magnesia
- mould size 25 x 25 x 250
- steam pressure increased to 21 kg/sq.cm (2.1 MPa) in 1 hr and maintained for 3 hr
-0.8% < unsoundness
IS : 269 - 1989
for OPC
ratio of allumina to iron oxide should be minimum
0.66
rapid hardning cement specifications
C3S content
specific surface area
C3S = 56% CSA = 3250 sq.cm/gm
sulphate resisting cement specification
C3A < 5%
Super sulphated cement specification
80-85% granulated blast furnance slag
10-15% hard burnt gypsem
5% cement clinkers
Low heat cement specification
C3A, C2S, C3S
C3A= 5%,
C2S= 34%,
C3S = 46%
High allumina cement allumina content ratio of allumina:lime initial setting and final setting time % of strength in 1 day
allumina > 32%
allumina:lime = 0.85~1.3
initial setting = 3.5 hrs
final setting = 5 hrs
gauged mortar
) Lime-cement mortar: It is also known as guarded mortar or gauged mortar is made by
mixing cement and lime. The advantages of lime-cement mortar are increased water retentivity,
workability, bonding properties and frost resistance.
The various defects in bricks are as follows:
(a) Over-burning of bricks: Bricks should be burned at temperatures at which incipient, complete and viscous vitrification occur. However, if the bricks are
overburnt, a soft molten mass is produced and the bricks loose their shape.
Such bricks are not used for construction purposes.
(b) Under burning of bricks: When bricks are not burnt to cause complete vitrification, the clay is not softened because of insufficient heat and the pores are not closed. This results in higher degree of water absorption and less compression strength. Such bricks are not recommended for construction works.
(c) Bloating: This defect is observed as spongy swollen mass over the surface of burned bricks and is caused due to the presence of excess carbonaceous matter
and sulphur in brick clay.
(d) Black core: When brick clay contains bituminous matter or carbon and they are not completely removed by oxidation, the brick results in black core mainly
because of improper burning.
(e) Efflorescence: This defect is caused due to presence of alkalies in bricks. When bricks come in contact with moisture, water is absorbed and the alkalies
crystallize. On drying, grey or white powdery patches appear on the brick surface. This can be minimized by selecting proper clay materials for brick manufacturing, preventing moisture to come in contact with masonry by
providing water-proof coping, using water repellent materials in mortar and by providing damp proof course.
Refractory bricks or fire clay bricks
Refractory bricks or fire clay bricks as they are sometimes called are made from fire
clay. Fire clay is a term loosely applied to include those sedimentary or residual clays which vitrify at a very high temperature and which, when so, burnt, possess great resistance to heat.
Fire clays are pure hydrated silicates of alumina and contain a large proportion of
silica (55-75%),
alumina (20-35%),
iron oxide (2-5%) with about 1 per cent of lime,
magnesia and alkalis. The greater the percentage of alumina, the more refractory the clay will be. Fire clays are capable of resisting very high temperatures upto
1700°C without melting or softening. Iron oxide or other alkalis reduce refractory qualities of fire clay. The process of manufacture of refractory bricks is same as that of ordinary bricks.
The properties of refractory bricks are as follows:
(a) These bricks are whitish yellow or light brown in colour.
(b) The weight of refractory bricks is about 30 to 35 N.
(c) The refractory bricks can resist high temperature without softening or melting.
Hence, they are used for lining blast furnace, ovens, kilns, boilers and chimneys.
(d) The water absorption of refractory bricks varies from 4 to 10%.
(e) The compressive strength of refractory bricks varies from 150 to 220 N/mm2
