*
heorye '
Filler formula
- Concrete qualities in
engineering structure § state reasons
-
_
Elaborate calculation
Weather Resistance strength characteristics by durability → check
load column take befor buckling
'
→ ,
.
maximum can
CE)
heavy traffic → steel / concrete / timber
'
wear resistance to sustain For
→
a
water shape
Cdepends
d,b÷
→ Resist sea on
→
Iyy =
"T¥{#g⇔=aas*cm•dⁿˢ
of column)
Strata PE
Resist Different
Soil
.
=
→
*µ , moment of iner tia
→ can Provide both structure & '
interior exterior
architectural finish to
depth
elements .
ratio of effective length of column to least
radius of its cross section .
go.name µm,ta*•ng [ concrete does not have ᵈ"ʳᵈᵈʳʰ+ᵈ ]
,
( slenderness ratio )
( can easily reinforcing )
'
by
-
→ Low tensile unlock , lock
Shrinks by expand when temperature changes
→ on drying
.
factors affecting concrete $ʳʰ④ʰ
"
,
→ Liable to disintegrate by alkali + sulphate attack
→ constituent materials Avatar , cement
creep resulting pre-stressed concrete aggregate admintureg]
-
→ to reduction of pre stress in ,
-
,
→ condition of : course / fine
→ Not impervious to moisture + salt solutions . agg
:
agg cement ratio / strength / /
texture
grading / quality
rock / surface
-
Chemical reactivity / thermal characteristic
-
Reduction of temp rise in concrete i shape by size
rounded not suitable cannot interlock
→
: ,
Necessary cement concrete moist known
-
to keep ,
sur face
concrete cracks
-
flaky : not suitable ,
smooth
as tiring ij prevent rise in temp +
-
irregular By angular : two stones to integrate together -
→① Cover sur face with layer of sand , spray from time to time .
Cparements
Cfor wall ]
→ method of preparation Cbatohinglmining / placing / curing ]
② spray concrete with water
→ test conditions ( moisture content , temperature
]
③ canvas sacking / absorbent material
⑨ steam curing .
to maintain
-
Quality control § accuracy to consider
ati%¥b%↑[§§%e?%j%%%eis
Lower of concrete
-
water cement lesser depth carbonation
ratio , .
consistency during concrete production .
ht / volume)
→ progressive neutralization of alkali in concrete cover by acidic gases from
specific
→ Materials should comply with
carbon dione de from
'
carbonation
'
drum miner , tilting drum
sources mainly atmosphere =
-
external
me•ÉdÉrer
→ method of storing , handling § miner , reversing , forced
action
→ more water 's the transportation properties like porosity ,
permeability ✓ diffusion & → concrete should be mined properly , transported § by tanker rapid >
,
capillarity cavities affect carbonation § durability °ʳ9ani£d
avoid
by
-
placed that will segregation loss of
by methods
carbonation to protect ingredients
with lower WC has fewer § higher resistance to
.
→ concrete
by methods for bonding successive
→ Arrangements of joints
affeetperfrermanceofstneeture.tw
steel bar .
lift of concrete can
→ carbonation depth can be reduced to maximum extent by using high strength concrete
construction joint : before concreting .
/
-
low / cement
§ proper compaction by making concrete denser water ratio .
" : natural cracking under
- contraction
tensile stress .
- Impact of water cement ratio
, curing by compacting concrete on RC members durability
'
-
expansion
4 :
change in volume from temp .
,
Pores into
→ lower water to cement ratios the fewer air
§ more compact the concrete structure ,
which translates
hydration / moisture content
higher strength '
e
to gap increase
.
→ high amount of water will reduce compressive strength due
→ typical water to cement ratio = 0-40 , 150 Kg cement ,
20 litres of water ]
→ to reduce amount of water , use an admixture
,
optimize combined aggregate gradings
add fly ash / Obtain aggregate of better par ticle shape
.
* admixtures : ca% ,
KOH , Sugars [ #celeratoru Retarder , super Plasticizers ,
Sikament NN ]
* fine particle less convenient coarse
agg
.
than
incorporating steel reinforcement on concrete
'
-
Reasons of
→ Enhance tensile strength
→ Reduce change of volume
→ Allow natural cracking of concrete , but
in controlled position .
Major categories of concrete slabs by differences .
-
i.EE?E#i*.EE.EiFE
support supzport Two
way stab
one way stab _
supported by beams
-
supported by on all four sides .
beams in only 2 L to B is
ratio of
-
sides
less than 2 -
longer
ratio of
[ :/ ]
-
L B 22
span panel CL) to
CB ) main reinforcement
shor ter panel
-
both directions
provided in ,
is
equal / greater
than 2 .
[ LIB > = 2
]
in
-
main reinforcement
only 1 direction
- Different types of slabs -
¥¥¥#
→
Flat plate .
concrete framing utilizing slab
-
system
of uniform thickness .
- includes either drop panels / column
capitals at column
-
resist heavier load Bj longer spans .
→
⇔*¥⇔¥i⇒
Hollow core stab
with either round
stressed freer products
-
pre
or shaped voids .
-
high load capacity and upto 15m spears Gong)
→
¥E¥##¥.¥
waffle stab
of molds after
- ribbed 2 grid formed by removal
concrete sets -
solid on longer span with heavier load ,
- more
heorye '
Filler formula
- Concrete qualities in
engineering structure § state reasons
-
_
Elaborate calculation
Weather Resistance strength characteristics by durability → check
load column take befor buckling
'
→ ,
.
maximum can
CE)
heavy traffic → steel / concrete / timber
'
wear resistance to sustain For
→
a
water shape
Cdepends
d,b÷
→ Resist sea on
→
Iyy =
"T¥{#g⇔=aas*cm•dⁿˢ
of column)
Strata PE
Resist Different
Soil
.
=
→
*µ , moment of iner tia
→ can Provide both structure & '
interior exterior
architectural finish to
depth
elements .
ratio of effective length of column to least
radius of its cross section .
go.name µm,ta*•ng [ concrete does not have ᵈ"ʳᵈᵈʳʰ+ᵈ ]
,
( slenderness ratio )
( can easily reinforcing )
'
by
-
→ Low tensile unlock , lock
Shrinks by expand when temperature changes
→ on drying
.
factors affecting concrete $ʳʰ④ʰ
"
,
→ Liable to disintegrate by alkali + sulphate attack
→ constituent materials Avatar , cement
creep resulting pre-stressed concrete aggregate admintureg]
-
→ to reduction of pre stress in ,
-
,
→ condition of : course / fine
→ Not impervious to moisture + salt solutions . agg
:
agg cement ratio / strength / /
texture
grading / quality
rock / surface
-
Chemical reactivity / thermal characteristic
-
Reduction of temp rise in concrete i shape by size
rounded not suitable cannot interlock
→
: ,
Necessary cement concrete moist known
-
to keep ,
sur face
concrete cracks
-
flaky : not suitable ,
smooth
as tiring ij prevent rise in temp +
-
irregular By angular : two stones to integrate together -
→① Cover sur face with layer of sand , spray from time to time .
Cparements
Cfor wall ]
→ method of preparation Cbatohinglmining / placing / curing ]
② spray concrete with water
→ test conditions ( moisture content , temperature
]
③ canvas sacking / absorbent material
⑨ steam curing .
to maintain
-
Quality control § accuracy to consider
ati%¥b%↑[§§%e?%j%%%eis
Lower of concrete
-
water cement lesser depth carbonation
ratio , .
consistency during concrete production .
ht / volume)
→ progressive neutralization of alkali in concrete cover by acidic gases from
specific
→ Materials should comply with
carbon dione de from
'
carbonation
'
drum miner , tilting drum
sources mainly atmosphere =
-
external
me•ÉdÉrer
→ method of storing , handling § miner , reversing , forced
action
→ more water 's the transportation properties like porosity ,
permeability ✓ diffusion & → concrete should be mined properly , transported § by tanker rapid >
,
capillarity cavities affect carbonation § durability °ʳ9ani£d
avoid
by
-
placed that will segregation loss of
by methods
carbonation to protect ingredients
with lower WC has fewer § higher resistance to
.
→ concrete
by methods for bonding successive
→ Arrangements of joints
affeetperfrermanceofstneeture.tw
steel bar .
lift of concrete can
→ carbonation depth can be reduced to maximum extent by using high strength concrete
construction joint : before concreting .
/
-
low / cement
§ proper compaction by making concrete denser water ratio .
" : natural cracking under
- contraction
tensile stress .
- Impact of water cement ratio
, curing by compacting concrete on RC members durability
'
-
expansion
4 :
change in volume from temp .
,
Pores into
→ lower water to cement ratios the fewer air
§ more compact the concrete structure ,
which translates
hydration / moisture content
higher strength '
e
to gap increase
.
→ high amount of water will reduce compressive strength due
→ typical water to cement ratio = 0-40 , 150 Kg cement ,
20 litres of water ]
→ to reduce amount of water , use an admixture
,
optimize combined aggregate gradings
add fly ash / Obtain aggregate of better par ticle shape
.
* admixtures : ca% ,
KOH , Sugars [ #celeratoru Retarder , super Plasticizers ,
Sikament NN ]
* fine particle less convenient coarse
agg
.
than
incorporating steel reinforcement on concrete
'
-
Reasons of
→ Enhance tensile strength
→ Reduce change of volume
→ Allow natural cracking of concrete , but
in controlled position .
Major categories of concrete slabs by differences .
-
i.EE?E#i*.EE.EiFE
support supzport Two
way stab
one way stab _
supported by beams
-
supported by on all four sides .
beams in only 2 L to B is
ratio of
-
sides
less than 2 -
longer
ratio of
[ :/ ]
-
L B 22
span panel CL) to
CB ) main reinforcement
shor ter panel
-
both directions
provided in ,
is
equal / greater
than 2 .
[ LIB > = 2
]
in
-
main reinforcement
only 1 direction
- Different types of slabs -
¥¥¥#
→
Flat plate .
concrete framing utilizing slab
-
system
of uniform thickness .
- includes either drop panels / column
capitals at column
-
resist heavier load Bj longer spans .
→
⇔*¥⇔¥i⇒
Hollow core stab
with either round
stressed freer products
-
pre
or shaped voids .
-
high load capacity and upto 15m spears Gong)
→
¥E¥##¥.¥
waffle stab
of molds after
- ribbed 2 grid formed by removal
concrete sets -
solid on longer span with heavier load ,
- more
