QUICK REFERRENCE
TO
CIVIL ENGINEERING
LAB TESTINGS
BY
VINAY KUMAR GUPTA
(DY.CHIEF ENGINEER/G
NORTHERN RAILWAY)
IMPACT TEST FOR COARSE AGGREGATE (10MM, 20MM)
(IS: 2386 Pt-IV, Para 4/ IS: 383 Para 3.4)
PASSING THROUGH 12.5MM & RETAINED AT 10MM
IN CUP IN 3 LAYERS, EACH LAYER COMPACTED 25
TIMES
WEIGHT OF SAMPLE IN CUP (A)
15 BLOWS IN IMPACT TEST APPARATUS
PASSING THROUGH 2.36 SIEVE (B)
IMPACT VALUE IN %= (B)/(Ax100)
LIMITS:IS < 45% FOR OTHER THAN WEARING COAT, 30%
FOR WEARING COATS
ABRASION TEST FOR COARSE AGGREGATE (10MM, 20MM)
(IS: 2386 Pt-IV, Para 5/ IS: 383 Para 3.5)
DEVAL TESTING MACHINE
GRADING.
SAMPLE & ABRASION CHARGE (6 SPHERES, 48mm dia.)
IN TESTING MACHINE
10,000 REVOLUTIONS @ 30-33 rpm.
RETAINED ON 1.7mm SIEVE. WASHED & DRIED.
W= (AL+(100-A)L')/100 WHERE 'W' IS PERMISSIBLE % OF
WEAR, 'A' IS % OF UNCRUSHED FRAGMENTS, 'L' IS
MAXIMUM % OF WEAR PERMITTED FOR GRAVEL OF
UNCRUSHED FRAGMENTS & 'L'' IS MAXIMUM % OF
WEAR PERMITTED FOR GRAVEL OF CRUSHED
FRAGMENTS
LOS-ANGELES TESTING MACHINE (PREFFERED TO
ABOVE)
GRADING.
SAMPLE & ABRASION CHARGE (6 SPHERES, 48mm dia.)
IN TESTING MACHINE
500-1,000 REVOLUTIONS @ 20-33 rpm.
RETAINED ON 1.7mm SIEVE. WASHED & DRIED.
W= (AL+(100-A)L')/100 WHERE 'W' IS PERMISSIBLE %
OF WEAR, 'A' IS % OF UNCRUSHED FRAGMENTS, 'L' IS
MAXIMUM % OF WEAR PERMITTED FOR GRAVEL OF
UNCRUSHED FRAGMENTS & 'L'' IS MAXIMUM % OF
WEAR PERMITTED FOR GRAVEL OF CRUSHED
FRAGMENTS
LIMITS 30% FOR OTHER THAN WEARING COAT & 30%
FOR WEARING COATS
POLISHED STONE VALUE
FOR ROADS ONLY
(IS:2386 Pt-IV, Para 6/ IS: 383)
AGGREGATE CRUSHING VALUE
SURFACE DRY
(IS:2386 Pt-IV, Para 2/ IS: 383 Para 3.3)
CYLINDER ON BASE PLATE, SAMPLE IN 3 LAYERS, EACH LAYER COMPACTED 25
TIMES. PLUNGER INSERTED AFTER LEVELLING THE SAMPLE IN CYLINDER.
APPARATUS KEPT BETWEEN PLATENS OF TESTING MACHINE. 40 TONNES LOAD
IN 10 MINUTES. TOTAL LOAD OF SAMPLE IN CYLINDER (A).
RELEASE PRESSURE. SIEVE ON 2.36mm SIEVE & WEIGH(B) FOR STANDARD
TEST
FOR OTHER THAN STANDARD TEST:
PASSING THROUGH
RETAINED ON
SIZE OF SIEVE FOR
SEPARATING FINES
25
20
4.75
20
12.5
3.35
10
6.3
1.70
6.3
4.75
1.18
4.75
3.35
850 microne
3.35
2.36
600 microne
CRUSHING VALUE = (B/A)*100…………………not >45%
TEN PERCENT FINES VALUE
SURFACE DRY
(IS:2386 Pt-IV, Para 3)
PASSING 12mm RETAINED ON 10mm. CYLINDER ON BASE
PLATE, SAMPLE IN 3 LAYERS, EACH LAYER COMPACTED 25
TIMES. PLUNGER INSERTED AFTER LEVELLING THE
SAMPLE IN CYLINDER. APPARATUS KEPT BETWEEN
PLATENS OF TESTING MACHINE. IN 10 MINUTES FOR 20mm
DISPLACEMENT OF PLUNGER. NET LOAD 'X' TONNES.
RELEASE PRESSURE. SIEVE ON 2.36mm SIEVE (PASSED
SHOULD BE BETWEEN 7.5 TO 12.5%).
REPEAT AGAIN. TAKE AVERAGE OF % PASSING 'Y' AND
AVERAGE OF LOAD 'X'.
LOAD REQUIRED FOR 10% VALUE = (14*X)/(Y+4)
SIEVE ANALYSIS FOR FINE & COARSE AGGREGATE
DRY
(IS:2386 Pt-I, Para 2/ IS: 383 Table 2,5,4 & PARA 3.2)
WEIGH 1000 gm FOR FINE AGGREGATE & 2000gm FOR COARSE AGGREGATE
IN SIEVE SHAKER FOR 2 MINUTES
WEIGH & TAKE %.
FINE AGG.
ZONE-II
COARSE
20mm
40
-
20
AGG
COARSE AGG
10mm
COMBINED COARSE
(ALL - IN - AGG.)
100
-
100
-
85-100
-
95-100
12.5
-
-
100
-
10
-
0-20
85-100
25-35
4.75
90-100
0-5
0-20
0-10
2.36
75-100
-
0-5
-
1.18
55-90
-
-
-
600 MICRONE
35-59
-
-
-
300 MICRONE
8-30
-
-
-
150 MICRONE
0-10
-
-
-
75 MICRONE
-
-
-
-
AGG.
SILT CONTENT (SAND & STONE DUST) (CPWD SPECS PAGE
42, IS:2386 Pt-II PARA 3 FOR SILT CONTENT BY
SEDIMENTATION USING SODIUM OXALATE)
TAKE ABOUT 110 ml OF SAMPLE IN A GRADUATED
CYLINDER OF 200 ml
ADD WATER UPTO 150ml MARK. ADD SALT @ 5ml/500ml OF
WATER
SHAKE WELL & LET IT SETTLE FOR ABOUT 3 HOURS
TAKE READING OF TOP(A) & BOTTOM(B) OF SILT LEVEL
SILT % = (A-B)/(Bx100) <=8% as per CPWD annex-D page 42, vol2, 15% for stone dust as per IS:383 TABLE-1
MOISTURE CONTENT (SAND & STONE DUST)
TAKE SAMPLE OF FINE AGGREGATE IN MOITURE
APPARATUS BALANCE
PUT IT IN APPARATUS CUP. TAKE CALCIUM CARBONATE
SPOONFUL. PUT IT IN 2ND CUP. PUT 2ND CUP OVER 1ST CUP
IN APPARATUS. TIGHTEN THE SCREW.
SHAKE WELL THE APPARATUS. READING IN THE METER IS
%AGE OF MOISTURE IN SAMPLE.
SIEVE ANALYSIS FOR MATERIAL FINER THAN 75mm
IS:2386 PARA 3, IS:383 TABLE 1
SURFACE MOISTURE FOR FINE AGGREGATE
(IS:2386
Pt-III, Para 5)
P1 = (Vs-Vd)*100/(Ms-Vs)
P2 = (Vs-Vd)*100/(Ms-VD)
WHERE
P1=% SURFACE MOISTURE OF SATURATED SURFACE DRY
FINE AGGREGATE
P2=% SURFACE MOISTURE IN TERMS OF WEIGHT OF WET
FINE AGGREGATE
Vs=WEIGHT IN gm OF WATER DISPLACED
Vd=WEIGHT OF SAMPLE/SP. GRAVITY
Ms=WEIGHT OF SAMPLE IN gm
WATER ABSORPTION TEST (COARSE AGGREGATE):
IS:2386 PARA 2
SAMPLE OF 2000gm. WASH THOROUGHLY. PUT IN A JAR. FILL
WITH DISTILLED WATER IMMERSED AT LEAST 5cm(IN WIRE
BASKET IMMERSED IN A TANK). 25 TIMES UP & DOWN TO
REMOVE ENTRAPPED AIR. LEAVE FOR 24 plus/minus ½
HOURS at 22-320c.
DRAIN WATER. SURFACE DRY ON CLOTHS & IN OPEN
AIR(NOT IN SUNLIGHT). MAY BE UNDER FAN AFTER 10
MINUTES OF DRYING.
WEIGH (A)
PUT IN OVEN AT 100-1100C FOR 24 plus/minus ½ HOUR. COOL
IN AIR TIGHT CONTAINER
WEIGH (B)
WATER ABSORPTION= (A-B)*100/(B)
WATER ABSORPTION TEST (AGGREGATE FINER THAN
10mm):
SAMPLE OF 500gm. PUT IN A TRAY. FILL WITH DISTILLED
WATER IMMERSED. SHAKE TO REMOVE ENTRAPPED AIR.
LEAVE FOR 24 plus/minus ½ HOURS at 22-320c.
DRAIN WATER THROGH FILTER PAPER SO THAT MATERIAL
RETAINED CAN BE PUT BACK. UNIFORM SURFACE DRYING
BY STIRRING TILL ‘FREE RUNNING’.
WEIGH (A)
PUT IN OVEN AT 100-1100C FOR 24 plus/minus ½ HOUR. STIR
INBETWEEN. COOL IN AIR TIGHT CONTAINER
WEIGH (B)
WATER ABSORPTION= (A-B)*100/(B)
SOUNDNESS OF COARSE AGGREGATE (IS 386 PARA 3.6,
IS2386 Pt 5)
TO DETERMINE RESISTANCE TO DISINTEGRATION OF
COARSE AGGREGATE BY SATURATED SOLUTION OF Na2SO4
OR MgSO4.
TESTING WITH Na2SO4
TESTING WITH MgSO4
FINE AGGREGATE
10%
15%
COARSE AGGREGATE
12%
18%
SPECIFIC GRAVITY (COARSE AGGREGATE & FINE AGGREGATE) :(IS:2386
Pt-III, Para 2)
TAKE SAMPLE OF ABOUT 500 gm PUT IN A WIRE BASKET. DIP IN WATERS
JOLTED AND WEIGHED IN WATER ALONGWITH BASKET. BASKET
EMPTIED OUT AND AGAIN WEIGHED IN WATER. DIFFERENCE OF BOTH
THE WEIGHTS IS WEIGHT OF AGGREGATE IN WATER (A).
DRY THE SAMPLE IN AIR & WEIGH. (B).
DRY THE AGGREGATE IN OVEN AT 100-110OC FOR 24 HOURS & WEIGH (
C)
SP. GRAVITY= C/B-A
APPARENT SP. GRAVITY=C/C-A
USING PYCNOMETER: SAMPLE WETTING AS ABOVE FOR 24 HOURS.
SURFACE DRY. WEIGH (A)
AGGREGATE IN PYCNOMETER & FILLED WITH DISTILLED WATER UPTO
TOP. WEIGH (B)
EMPTY PYCNOMETER. FILL UPTO TOP WITH DISTILLED WATER. WEIGH
(C )
SAMPLE IN OVEN FOR 24 HOURS. SAMPLE WEIGHED (D)
SP GR.=D/A-(B-C)
APPARENT SP GRAVITY= D/D-(B-C)
BULK DENSITY: Kg/Liter. OF NO USE PRACTICALLY. SIZES
OF CONTAINERS GIVEN
IN IS: 2386 Pt III, PARA 3
VOID RATIO: = (SP. GRAVITY-BULK DENSITY)*100/SP.
GRAVITY
(IS:2386 Pt-III, Para 3)
FLAKINESS & ELONGATION:
(IS:2386 Pt-I, Para 4
IS:383 PARA 3.1 LAST LINE)
TAKE SAMPLE IN SUFFICIENT QUANTITY SUCH THAT 200
NOS OF PIECES ARE RETAINED ON EACH SIEVE i,e
20,16,12.5,10 & 6.3 SIEVES AS APPLICABLE
WEIGH RETENTION ON 10 & 6.3mm FOR 10mm &
20,16,12.5,10 & 6.3mm FOR 20mm(A).
PASS THROUGH FLAKINESS (THICKNESS) GAUGE FOR
DIFFERENT RETENTIONS (B).
FLAKINESS=(B*100)/A (NOT MORE THAN 35% AVARAGE OF
ALL GAUGES IN DIFFERENT GAUGES.
PASS THROUGH ELONGATION GAUGES FOR DIFFERENT
RETENTIONS (B).
ELONGATION=(B*100)/A (TAKE AVARAGE OF ALL GAUGES
IN DIFFERENT GAUGES.
CUBE TESTING
IS:516 PARA 2,3,5 & IS:1199 PARA 4 (IS:9013
FOR ACT)
3 DAYS – 50%, 7 DAYS – 70%, 28 DAYS – 100% STRENGTH
CUBE STRENGTH IN N/mm2 IS LOAD IN 'N' AT WHICH THE
CUBE FAILS DIVIDED BY AREA OF CUBE IN mm2.
DEVIATION OF ANY CUBE BY >15% OF AVERAGE VALUE –
DON’T CONSIDER THE CUBE
IN CASE OF ACT R28=(Ra*1.64)+8.09 WHERE R28 IS EXPECTED
STRENGTH AFTER 28 DAYS, Ra IS STRENGTH RECEIVED
AFTER 24 HOURS WITH ACT.
LOADING RATE = 14 N\mm2 \Minute.
FOR ACT: BY BOILING WATER:: SAMPLE AT 27 +/- 2OC AT 90%
HUMIDITY FOR 23 HOURS +/- 15 MINUTES FROM TIME OF
ADDING WATER. THEN IN BOILING WATER FOR 3.5 HOURS +/5 MINUTES. REMOVE FROM MOULD. IN COOLING TANK AT 27
+/- 2OC. AGE 28 HOURS +/- 20 MINUTES.
1Mpa=10Kg/cm2
AIR CONTENT TEST IS:1199 PARA 8
FILL CONCRETE IN 3 LAYERS EACH COMPACTED 25 TIMES OR BY
VIBRATING. ALSO TAP THE SIDES WITH MALLET. REMOVE EXCESS
CONC. IF ANY
ASSEMBLE THE APPARATUS TIGHTLY & ADD WATER TILL HALF WAY IN
THE STAND PIPE. TILT WHOLE ASSEMBLY AT 300 & ROTATE TO REMOVE
ENTRAPPED AIR IF ANY.
FILL WATER TO BRING LEVEL TO ZERO AT TOP OF PIPE.
APPLY PRESSURE 'P'(.8Kg/cm2). TAP. TAKE READING OF WATER COLUMN
IN STAND PIPE i.e. h1.
RELEASE AIR PRESSURE THROUGH VENT AT TOP OF WATER COLUMN &
TAKE READING h2.
APPARENT AIR CONTENT IS h1-h2. REPEAT FOR 2nd TIME & TAKE
AVERAGE OF TWO APPARENT AIR CONTENT VALUES, A1
AIR CONTENT =A= A1-G, WHERE G IS AGGREGATE CORRECTION
FACTOR (& G IS h1-h2 WHEN THERE IS COARSE AGGREGATE INSTEAD
OF CONCRETE IN THE BOWL.)
WORKABILITY
IS:1199 PARA 5
SLUMP TEST
IN 4 EQUAL HEIGHT LAYERS IN SLUMP CONE
EACH LAYER COMPACTED WITH ROD FOR 25 TIMES.
IN 1st LAYER ROD TO GO UPTO FULL DEPTH & IN 2nd, 3rd &
4th LAYERS ROD TO GO AT LEAST UPTO NEXT LAYER.
SLUMP TAKEN AFTER REMOVING CONE.
COMPACTING FACTOR TEST: More accurate but in lab only.
VEE-BEE TEST: Preferred for stiff concrete with low & very low
workability, not so accurate.
TRIAL MIX
CLEAN THE MIXER WITH WATER & CEMENT SLURRY(BUTTERING)
PUT COARSE AGGREGATE 20MM, THEN 10MM
50% OF FINE AGGREGATE (SAND & STONE DUST ETC)
ADD 50% WATER. MIX.
ADD 100% CEMENT, BALANCE SAND & STONE DUST
ADD 40% MORE WATER. MIX. ADD SOME WATER TO ADMIXTURE &
ADD TO CONCRETE
ADD BALANCE WATER TO ADMIXTURE EMPTIED CYLINDER & ADD
TO CONCRETE
OR
PUT COARSE AGGREGATE 20mm, 10mm, SAND, STONE DUST IN THE
MIXER. ROTATE FOR SOME TIME. ADD 99% WATER. MIX.TAKE
CONTROLLED SLUMP. ADD ADMIXTURE. ADD BALANCE WATER TO
EMPTIED JAR OF ADMIXTURE & PUT IN MIXTURE.
MIX FOR 3 MINUTES
TAKE SLUMP AFTER 10 MINUTES, 30 MINUTES, 1hr., 1.5 hr., 2hrs.
SLUMP SHOULD BE AS PER REQUIREMENTS
FILL UP CUBES
PILE TESTING:
IS:2911 Pt. 4
VERT. LOAD TEST (PARA 6)
LATERAL LOAD TEST (PARA 7)
PULL OUT TEST (PARA 8)
INITIAL: ONE (TWO WHEN SOIL STRATA NOT KNOWN)
ROUTINE: ½% (MAY BE INCREASED TO 2%
MAY BE ON A SINGLE OR A GROUP OF PILES
GENERALLY TESTED AT
C.O.L.
VERT. LOAD TEST(COMPRESSION):
PILE HEAD CHIPPED TO SOUND CONC. REINF BENT OR CUT. SMOOTH FINISH BY
P.O.P. BEARING PLATE AT TOP OF PILE
LOAD APPLICATION: EACH INCREMENT ABOUT 20% OF SAFE DESIGNED LOAD
FOR RAKER PILE LOAD ALONG AXIS
LOAD APPLICATION: (LOAD SHOULD BE 25% EXCESS OF LOAD TO BE APPLIED):
(A) KENTLEDGE, (B) ANCHOR PILE © ROCK ANCHOR
SETTLEMENT:
MINIMUM TWO DIAL GAUGES, 4 FOR GROUP OF PILES
DATUM BAR SUPPORT AT 3D(SUBJECT TO A MINIMUM OF 1.5m) FROM PILE
EDGE, WHERE D IS DIA OF CIRCULAR PILE OR DIA OF CIRCUMSCRIBIBG
CIRCLE FOR A RECT OR SQUARE PILE
SAFE LOAD:
FOR INITIAL TEST PILE: LEAST OF 2/3 OF FINAL LOAD AT WHICH
DISPLACEMENT IS 12mm(UNLESS OTHERWISE MENTIONED IN DESIGN
DEPENDING ON NATURE OF SOIL & STRUCTURE) OR 50% OF FINAL LOAD AT
WHICH DISPLACEMENT IS 10% OF DIA OF PILE(7.5% OF BULB DIA FOR UNDER
REAMED PILES.
FOR ROUTINE TEST PILE: TESTED FOR 1.5 TIMES OF WORKING LOAD, THE
SETTLEMENT NOT MORE THAN 12mm
FOR GROUP OF PILES FINAL LOAD AT WHICH DISPLACEMENT IS NOT
MORE THAN 25mm(UNLESS OTHERWISE MENTIONED IN DESIGN) OR 2/3
OF FINAL LOAD AT WHICH DISPLACEMENT IS NOT MORE THAN 40mm
IN ROUTINE LOAD TEST SETTLEMENT SHOULD NOT EXCEED 25mm.
LATERAL LOAD TEST:
INCREMENT OF ABOUT 20%
DISPLACEMENT AT C.O.L.
SAFE LATERAL LOAD: 50% OF FINAL LOAD AT WHICH
DEFLECTION IS 12mm OR FINAL LOAD AT WHICH
DISPLACEMENT IS 5mm OR AS PER DESIGN.
PULL OUT TEST:
LOAD APPLIED BY REINF. OR SPECIALLY DESIGNED
BOLT(S) EMBEDDED IN PILE AT TIME OF CASTING
LOAD INCREMENT ABOUT 20%
SAFE LOAD: 2/3 OF FINAL LOAD AT WHICH DEFLECTION
IS 12mm OR FINAL LOAD AT WHICH DISPLACEMENT
CURVE SHOWS A BREAK
INITIAL LOAD AT 2.5 TIMES OF WORKING LOAD & ROUTINE
TEST AT 1.5 TIMES WORKING LOAD(OR 12mm DEFLECTION
WHICHEVER IS EARLIER)
BENTONITE SOLUTION:
- A, PARA A.3)
IS:2911(Pt. 1/Sec 2 APPENDIX
LIQUID LIMIT 300-450%
SAND CONTENT<= 7%
DENSITY: 1.12
SWELLING INDEX : TWO TIMES AFTER 12 HOURS
WETTING
pH VALUE < 11.5
CEMENT TESTS
CONSISTENCY OF CEMENT (VICAT APPARATUS)
IS:4031 Pt.4
CEMENT 500gm + 24% WATER. MIX – PASTE.
IN MOULD. SHAKE MOULD.
USE PLUNGER. FREE FALLING FROM TOP OF MOULD.
READING SHOULD BE 5-7mm i.e. 33-35mm
PENETRATION.
IF NOT TRY 25%, 26%……TILL READING IS 5-7mm i.e.
33-35mm PENETRATION.
THIS IS ‘P’ THE CONSISTENCY OF CEMENT i.e. 0.24,
0.25……….etc.
INITIAL & FINAL SETTING TIME:
IS:4031 Pt.5
CEMENT 500gm + WATER(‘P’x0.85x500). MIX – PASTE.
THIS IS STARTING TIME.
IN MOULD. SHAKE.
USE 1mm NEEDLE. FREE FALLING OF NEEDLE FROM TOP
OF MOULD.
TAKE READING. READING SHOULD BE 5-7mm i.e. 3335mm PENETRATION.
IF NOT WAIT FOR 10 MINUTES. FREE FALLING OF
NEEDLE FROM TOP OF MOULD. REPEAT TILL READING
IS 33-35mm. THIS WILL BE THE INITIAL SETTING
TIME(>30 MINUTES)
REPLACE NEEDLE WITH ATTACHMENT FOR F.S.T. WITH
A PIN AT END & A CIRCULAR CUTTING EDGE
TAKE READING AT INTERVALS TILL THE NEEDLE
LEAVES A MARK ON CEMENT TOP BUT CUTTING EDGE
DOES NOT LEAVE A MARK. THIS TIME IS FINAL SETTING
FINENESS OF CEMENT:
90 MICRONE SIEVE. 15 MINUTES SHAKING
HORRIZONTAL & VERTICAL BY HAND OR SHAKER.
RETENTION NOT MORE THAN 10%
DRYING & SHRINKAGE OF CEMENT
IS 4031 Pt10
CONCRETE PERMEABILITY TEST
IS:3085 &
MOST PARA 1716.5
ONE BAR 48 HOURS
THREE BARS 24 HOURS
SEVEN BARS 24 HOURS. (TOTAL 96 HOURS)
BREAKING CUBE DIAGONALLY. DEPTH OF MOISTURE AT
COENERS & MIDDLE.
AVERAGE OF THREE READINGS NOT MORE THAN 25mm.
COMPRESSIVE STRENGTH OF CEMENT:
IS:4031
Pt.6
SAND(IS:650-1960) – 555gm. CEMENT – 185gm
WATER – (‘P’/4)+3% OF COMBINED WEIGHT OF CEMENT
& SAND. MIX FOR 3-4 MINUTES.
CURE FOR 24 HOURS IN 90% HUMIDITY AT 27 plus/minus
20C. IMMERSE IN WATER.
3 DAYS – 160Kg/cm2 . 7 DAYS – 220Kg/ cm2
SOUNDNESS TEST:
IS:4031
Pt.??????
UNSOUND DUE TO EXCESSIVE LIME, MAGNESIA,
CALCIUM SULPHATE, GYPSUM(2-3% DEPENDING UPON
C3A).
CALCIUM SULPHATE IS USED TO PREVENT FLASH SET.
LE-CHATELIER TEST (TESTS FREE LIME ONLY):
ADD 0.78x’P’ WATER. FILL MOULD AND KEEP IT ON
GLASS. COVER WITH ANOTHER GLASS PLATE.
IMMERSE ASSEMBLY IN WATER AT 27-32 OC FOR 24
HOURS.
MEASURE DISTANCE BETWEEN INDICATOR POINTS.
SUBMERGE MOULD IN BOILING WATER. WATER FOR 3
HOURS. ALLOW TO COOL.
MEASURE AGAIN. EXPANSION SHOULD NOT BE
MORE THAN 10mm.
MAGNESIA SHOULD NOT BE MORE THAN 3%. IF MORE,
TESTED FOR SOUNDNESS BY ‘ AUTOCLAVE TEST’
HEAT OF HYDRATION:
IS:4031 Pt.9
REACTION OF CEMENT IS EXOTHERMIC WITH WATER.
120 Cal./gm
TEMP. RISE MAY BE UPTO 50% OC
COOLING CREATES SHRINKAGE & CRACKS
TEST BY VACUUM FLASK METHOD OR BY ADIABATIC
CALORIMETER (FOR ONLY LOW HEAT PORTLAND
CEMENT)
CHEMICAL COMPOSITION OF CEMENT:
OPC
&
RAPID
HARDENING
LOW HEAT
PORTLAND
PORTLAND
BLST
FURNACE
SLAG
HIGH
ALUMINA
SUPER
SULPHATED
INSOLUBLE
RESIDUE
2%
2%
2.5%
-
4%
MAGNESIA
(MgO)
6%
5%
8%
-
10%
SULPHUR AS
SO3
2.75%
2.75%
3%
-
6%
AS
SULPHIDE
(S)
-
-
2%
-
1.5%
MANGANES
E
OXIDE
MnO2
-
-
-
-
-
LOSS
ON
IGNITION
5%
4%
4%
-
5%
INHIBITOR SOLUTION:
CLEANING OF STEEL BY WIRE BRUSH FOR DUST &
RUST
APPLY ONE COAT OF CEMENT SLURRY (1 KG CEMENT:
600cc OF INHIBITOR SOLUTION (PATENT NO. 109784/67)).
ALLOW TO DRY FOR 24 HOURS IN SHADE. WATER IS NOT
TO BE USED AS INHIBITOR SOLUTION IS PREPARED IN
IONISED WATER.
STORAGE OF CEMENT:
BAGS
IS:4082 Pt.4.2
CEMENT OLDER THAN 3 MONTHS NOT TO BE USED.
CEMENT HAVING LUMPS TO BE REJECTED.
MINIMUM NO. OF WINDOWS IN THE STORE. CLOSE FITTING
DOORS. KEPT CLOSED.
BUILDING SHOULD BE DRY, LEAKPROOF, MOISTURE PROOF, DAMP
PROOF.
600mm FROM WALL.
PLANKS OVER WOODEN BATTENS. BATTENS OVER 15mm CC OR
BRICKS IN 2 LAYERS. CC/BRICKS OVER 150mm CONSOLIDATED
EARTH.
STACK WIDTH NOT MORE THAN 4 BAGS LENGTH.
STACKS HEIGHT NOT MORE THAN 10 BAGS(TO PREVENT
LUMPING).
IF HEIGHT MORE THAN 8 BAGS, BAGS SHOULD BE INTERLOCKED.
DRUMS:
DRUMS ON LEVEL GROUND. NEAR BATCHING PLANT
LID SECURILY TIED AFTER USE TO PREVENT MOISTURE
SILOS:
NEAR BATCHING PLANTS. PROPER ACCESS TO REPLACE SILOS.
CALIBRATION OF BATCHING PLANT
DONE MONTHLY
ADMIXTURE:
QUANTITIES OF 1.0 LTRS, 1.5 LTRS, 2.0 LTRS, 2.5 LTRS, 3.0 LTRS OF
ADMIXTURE ARE DRAWN ONE BY ONE FROM THE BATCHING PLANT &
MEASURED ACCURATLY BY USING GRADUATED BOROSIL GLASS
CYLINDERS.
WATER:
QUANTITY OF 125 LTRS OR 100 LTRS OF WATER IS DRAWN FROM THE
BATCHING PLANT & MEASURED ACCURATLY BY USING CORRECTLY
GRADUATED JARS AND CYLINDERS.
CEMENT:
IN SOME OF THE BATCHING PLANTS CEMET & WATER ARE FED JOINTLY.
IN SUCH CASES CALIBRATION OF WATER CAN NOT BE CHECKED
SEPARATLY & IS DONE ALONGWITH CEMENT ONLY.
WEIGHTS ARE PUT ONE BY ONE ON THE CEMENT CONTAINER & THE
CORRESPONDING READING AFTER EACH INCREMENT NOTED FROM
THE METER. 1ST OF ALL A 50 Kg WEIGHT IS PLACED & ITS
CORRESPONDING READING TAKEN. INCREMENT OF 50 Kg IS REPEATED
TILL 250 Kg. AFTER THAT 20 Kg, 20 Kg & 10 Kg. AFTER REACHING AT 300
Kg UNLOADING IS DONE IN THE SAME SEQUENCE & CORRESPONDING
READINGS AT 290, 270, 250, 200, 150…… & 0 Kg WEIGHT ARE TAKEN.
AGGREGATE:
WEIGHTS ARE PUT ONE BY ONE ON THE AGGREGATE
CONTAINER & THE CORRESPONDING READING AFTER
EACH INCREMENT NOTED FROM THE METER. 1ST OF ALL A
50 Kg WEIGHT IS PLACED & ITS CORRESPONDING READING
TAKEN. INCREMENT OF 50 Kg IS REPEATED TILL 1000 Kg.
AFTER REACHING AT 1000 Kg UNLOADING IS DONE IN THE
SAME SEQUENCE & CORRESPONDING READINGS AT 950,
900, 850,……., 250, 200, 150…… & 0 Kg WEIGHT ARE TAKEN.
IN CASE WHERE 1000 Kg WEIGHT IS NOT AVAILABLE,
ABOVE EXERCISE IS DONE FOR 500 Kg. THEREAFTER 500 Kg
AGGREGATE IS LOADED & EXERCISE FROM 500 Kg TO 1000
Kg & UNLOADING BACK TO 500 Kg IS DONE.
AVERAGE ERROR FOR EACH OF ABOVE IS CALCULATED
SHEATHING TESTS: MOST CHAPTER - 1800
AT LEAST THREE SAMPLES FOR EACH LOT NOT MORE
THAN 7000M
WORKABILITY:
1100mm LONG SAMPLE SOLDERED TO A FIXED PLATE AT
ONE END WITH A SOFT SOLDER. BENT TO A RADIUS OF
1800mm ALTERNATLY ON EITHER SIDE TO COMPLETE
THREE CYCLES AS SHOWN BELOW.
SEALING JOINTS INSPECTED TO VERIFY THAT THERE IS
NO FAILURE. 8
1800mm dia
TRANSVERSE LOAD RATING TEST:
TO ENSURE STIFFNESS OF SHEATHING IS ENOUGH TO
PREVENT PERMANENT DISTORTION.
SAMPLE PLACED ON A HORRIZONTAL SUPPORT OF
500mm LENGTH SUCH AS SAMPLE IS SUPPORTED AT ALL
POINTS OF OUTWARD CORRUGATION.
A LOAD APPLIED AS BELOW AT CENTRE OF THE
SUPPORTED PORTION THROUGH A CONTACT SURFACE
OF 12mm LENGTH(LOAD AT CENTRE OF CORRUGATION.
Dia.in mm
25-35
35-45
45-55
55-65
65-75
75-85
85-90
Load in N
250
400
500
600
700
800
1000
LOAD
500mm
12mm
TENSION LOAD TEST:
1100mm LONG SAMPLE SOLDERED TO A FIXED PLATE AT
ONE END WITH A SOFT SOLDER. FILLED WITH A
WOODEN PIECE HAVING A DIA OF 95% OF INNER DIA OF
SAMPLE. ON THE OTHER END A COUPLER IS SCREWED.
LOAD INCREMENT IN WEIGHT PAN.
NO DEFORMATION OF JOINTS. NO SLIPPING OF
COUPLER.
Dia.in mm
25-35
35-45
45-55
55-65
65-75
75-85
85-90
Load in N
300
500
800
1100
1400
1600
1800
COUPLER
WEIGHT PAN
WATER LOSS TEST:
SEALED AT ONE END. FILLED WITH WATER. OUTLET
SEALED. PRESSURE OF 0.05 MPa MAINTAINED FOR 5
MINUTES. LOSS OF HEAD NOT MORE THAN 1.5%
TO MAINTAIN A PRESSURE OF 0.05MPa
OUT LET
POST TENSIONING:
POST TENSIONING SYSTEM IS GENERALLY APPLIED IN CAST IN SITU
COMPONENTS & IN PARABOLIC PROFILING IN BOTH DIRECTIONS.
HT STRANDS ARE CUT BY CUTTING WHEELS TO THE REQUIRED
LENGTH
SHEATHING DUCTS OF APPROPRIATE SIZE ARE INSERTED IN
REINFORCEMENT CAGE AND PROFILED AFTER PROVIDING TUBE
UNITS AT ENDS
HDPE PIPE OF SMALLER SIZE IS INSERTED IN SHEATHING DUCT TO
PROTECT FROM SLURRY LEAKAGE AND MOVEMENT TO AND FRO IS
DONE AND IS TAKEN OUT AFTER INITIAL SETTING OF CONCRETE.
HT STRANDS ARE THREADED BOTH ENDS ARE CLEANED BY PETROL
BEARING PLATES AND WEDGES ARE FIXED AFTER SERIAL
NUMBERING AND WELL CLEANED. WEDGES ARE WASHED ON OUTER
SURFACE.
SINGLE PULL/ MULTIPLE JACKS ARE USED AT ACTIVE END. MARKING
ON PASSIVE END TENDONS ARE RECORDED
AFTER ATTAINING 80% STRENGTH OF CONCRETE CUBES FIRST STAGE
/FINAL STAGE STRESSING IS DONE.
STRESSING CAN BE DON AT ONE END / BOTH ENDS AS SPECIFIED.
INITIALLY SLACKNESS SHALL BE REMOVED AT ZERO LOAD.
ELONGATION OF STRANDS/ CABLES SHALL BE RECORDED AT EVERY
INCREMENT LOAD AT THE RATE OF 20% UP TO 75% OF DESIGNED UTS
LOAD.
LOCK THE WEDGES BY SELF-LOCKING DEVICE AVAILABLE IN
PRESTRESSING JACK. RELEASE THE PRESSURE GRADUALLY AND NOTE
THE SLIP AT BOTH ENDS.
FILL UP THE STRESSING RECORD AND CHECK AS PER DESIGN
ELONGATION AND UTS
THE MODIFIED ELONGATION SHALL BE CALCULATED AS PER ACTUAL
LENGTH OF TENDON, AREA OF STRAND AND VALUE OF MODULUS OF
ELASTICITY.
PROVISION FOR JACK EFFICIENCY SHALL BE ALSO BE RECORDED.
THE ACTUAL FORCE SHALL NOT BE GIVEN LESS THAN DESIGNED FORCE,
5%-INCREASED LOAD IS PERMISSIBLE LIMIT FOR ACHIEVING REQUIRED
ELONGATION.
IF THE ELONGATION HAS NOT BEEN ACHIEVED AFTER GIVING 1.05% OF
DESIGN LOAD THE MATTER SHALL BE FORWARDED TO ENGINEER IN
CHARGE.
TRANSFER SLIP SHALL BE CHECKED FOR 24 HRS AND THE STRANDS
SHALL BE CUT BEYOND 40MM OF WEDGES
EPOXY COATING SHALL BE APPLIED ON STRANDS, WEDGES AND BEARING
PLATES.
GROUTING
THE PURPOSE OF GROUTING IS TO KEEP THE TENDONS FREE FROM RUST AND
MAKING HOMOGENEOUS TO CONCRETE COMPONENTS FOR BEARING LOAD.
ALL THE CABLES ARE FIXED WITH GROUT CAP AND WATER IS FILLED MIXED
WITH 1% LIME FOR ABOUT 24HRS BEFORE GROUTING.
THE WATER IS CLEANED BY AIR JETTING AND VALVE NIPPLE RUBBER
PRESSURE PIPE. IT IS CONNECTED THROUGH GROUT HOLE IN BEARING PLATE.
RECIPROCATING POSITIVE DISPLACEMENT GROUT PUMP WITH AGITATOR IS
USED FOR MAKING GROUT BY CEMENT AND WATER CEMENT RATION .4 WITH
ADMIXTURE COMBEX-100 FOR SHRINKAGE FOR 5 MINUTES AND SCREENED BY
1.18 MM IS SIEVE AND THEN OPERATE THE PUMPING.
AS SOON AS THIS GROUT MORTAR IS SEEN ON THE OTHER END THE VALVE
SHALL BE CLOSED AND THE GROUT SHALL BE CONTINUED TILL PRESSURE IS
ACHIEVED FOR 0.7MPA AND MAINTAINED FOR ONE MINUTE. CLOSE THE
ACTIVE END VALVE. RELEASE THE PRESSURE AND PROCEED FOR NEXT CABLE.
GROUT CUBE OF L OR XL SHALL BE FILLED AT LEAST 12 NOS FOR ONE DAY
WORKING.
THE GROUT CAP, NOZZLE ETC SHALL BE TAKEN OUT AFTER INITIAL SET AND
TOP PORTION OF GROUT CAP AND GROUT HOLE SHALL BE FILLED PROPERLY
NEXT DAY.
PRE TENSIONING
PRE TENSIONING SYSTEM IS APPLIED FOR THE CABLE ELEMENTS WHERE NOS
OF COMPONENTS ARE SUFFICIENT AND SPACE IS AVAILABLE FOR MAKING
BONDS AND THERE IS LITTLE BIT DEVIATION IN CABLE PROFILING TO
HORIZONTAL PLANE.
ANCHOR HEAD AT BOTH STRESSING AND DEAD END ARE MADE FOR
RESISTING THE FORCE OF STRANDS DESIGNED FOR ELEMENTS.
SUITABLE NOS OF CASTING BED ARE MADE AND ROLLING SHUTTERS ARE
MADE FOR EASY WORKING. STEAM CURING CAN ALSO BE DONE FOR
FASTENING THE CYCLE.
TENDONS ARE THREADED THROUGH REINFORCEMENT CAGE AND REQUIRED
HOPE DEBONDING TUBES ARE PROVIDED WHEREVER NECESSARY.
QUICK RELEASE BARRELS AND WEDGES (MASTER WAGES) ARE FIXED AFTER
CLEANING STRANDS AND WEDGES.
INITIAL PULL IS GIVEN FOR REMOVING SLACKNESS OF STRAND.
STRESSING CAN BE DONE BY SIMPLE PULL JACK/HYDRAULICALLY
OPERATED MULTIPULL JACKS UP TO REQUIRED ELONGATION AND
FORCE.
THE LOAD AND ELONGATION AND MODIFIED ELONGATION SHALL
BE CALCULATED AND APPLIED AS PER POST-TENSIONED PARA 9 AND
16.
THE CONCRETING SHALL BE DONE AS EARLY AS POSSIBLE AFTER
STRESSING.
AFTER ACHIEVING 80% STRENGTH OF DESIGNED MIX, DISTRESSING
SHALL BE DONE.
DISTRESSING CAN BE DONE FOR INDIVIDUAL TENDONS FROM BOTH
ENDS AND CUTTING WIRE BETWEEN ELEMENT BEDS, PROVIDING U
CLAMPS FOR HOLDING WIRE OR BY MULTI PULL JACK
ARRANGEMENT AT A SINGLE OPERATION SLOWLY.
AFTER CHECKING TRANSFER SLIPS AND DEBONDING TUBE
SLACKNESS, CUT DOWN THE STRANDS FROM FACE OF CONCRETE
SURFACE.
SEAL THE STRANDS AND DEBONDING TUBE GAP WITH EPOXY
COATING AND MORTAR.
SP-24
Cement 4.1
Rapid Hardening cement More Finely Ground (Strength same at
28 days)
Portland Slag Cement
Resistant to Sulphates attacks &
marine environment
Portland Pozzolana cement Less heat of hydration, Greater resistance
to aggressive water. Useful for marine works & mass construction.
May be used as OPC. Some time fly ash included in manufacture.
High strength OPC
For PSC etc. (Increased Tricalcium
Silicate)
Hydrophobic Cement: OPC with certain hydrophobic contents
i.e. some acids which make the cement water repellant & cement can
be stored for more longer periods. Needs longer Mixing.
Fly Ash :
for use as Pozzolana
Water
IS 3812 Physical Chemical Properties
Oils 2% by weight of cement may reduce strength by 20% (4.3).
Sugar content upto 500 ppm is Ok.
Organic material dangerous, Sea water not good, May cause
efflorescence & rusting. But may be used under water experiment in
salt water.
Solids upto 2000 ppm of solids ok.
Setting time affected by sugar, carbonates & bicarbonates of sodium
& potassium, salts of Na, Zn, Cu & Pb. Sodium hydroxide may quick
set.
For PCC sea Water upto 35000 PPM of Salt is ok.
Admixture
Accelerating - Adding Calcium, Flrosilicates & triatholomine
Retarding
:
Useful in hot weather, Common Type are
starches & cellulose, sugar, hydroxic - Carboxylic acid & their salts.
Water Reducing or Plasticizing : Contain Lignosulphate salts or
Polyhydroxy compounds.
Air Entraining admixtures: To intentionally entrain a controlled
quantity of air into the concrete in form of discrete minutes bubbles.
Are generally organic compounds like animal & Veg Oils, resins,
alkali, Salts of sulphates.
POZZOLANAS
:
Used in four Ways.
As Ingredient of Pozzolana cement.
As a Part replacement OPC (While Manufacturing)
As a fine aggregate (While mixing for concrete)
As an admixture. (While mixing for concrete)
Generally 20% to 30% for replacement of cement. This may reduce
strength of concrete at early age.
Fly ash as Pozzolana increase workability if used as FINE
AGGREGATE As admixture. it also may decrease bleeding in mix.
Pozzolana
IS : 3812
Burnt clay Pozzolana
IS ; 1344
Reinforcement: -
IS : 432
Plain Bars
IS : 1786 High strength Deformed bars.
High strength deformed bar have strength > 40% of Plain bars.
IS: 1786
Strength of 250N/mm2 (M.S.), 415 N/mm2 &
500N/mm2 (Cold worked deformed high strength)
IS : 1139
Deformed bars, hot rolled.
Hard drawn steel wires IS: 1566.
IS: 226 Rolled steel section.
Rust in normal amount increase bond with concrete.
IS : 4082 for storage of Materials.
Durability of Concrete (7.1) (Page 3)
Absence of Durability may be due to
Internal agencies like harmful alkali aggregates, sulphates & chlorides in the
ingredients, change in Volume charge in cement & aggregates paste due to their
properties.
External agencies like weathering, industrial gases & liquids, bacterial growth etc.
Requirement for Durability: Choice of Materials Quality
Dense & impermeable concrete
Cover
Design Cracks > 0.3mm
1N
= 9.81 Kg.
M1
=
1N/mm2
=
1 x 9.81 Kg/mm2
=
1 x 9.81 x 100kg/cm2
=
981 x 15 x 15 Kg for
cube of 15x15cm
=
220725 kg
=
220.725 t
M30
=
6621 t
Cube
AGGREGATES (4.2)
Fine < 4.75 mm
Aggregate
Coarse >= 4.75mm
Zone II is Good, Zone IV only in design mixes. Zone - I not in lean
concrete.
Testing Aggregates IS : 2386
Should be free from deleterious materials such as iron, Pyrites, coal,
mica, shale, clay, alkali, soft fragments, sea shells & organic matters
(IS: 383).
Inadequate washing may leave clay film over fine & coarse
aggregates.
For high compressive strength, adopt lower maximum size.
Using Plums? (P-14)
Spacing of bars to be based upon nominal maximum size of
aggregate.
Batching of FA & CA is essential for mix.
PRESTRESSED CONCRETE
(MOST - Chapter-1800)
Cement: C3S (Tricalcium Silicate) & C2S (Bicalcium Silicate)
Minimum cement content
400 Kg/cum
Max W/C ratio
0.40
Min. strength: M35
Max nominal size of COARSE AGGREGATE 20mm (10mm less
than cover or clear distance between reinforcements)
Prestressing Steel: IS: 1785(Pt.1 &2), IS: 6003, IS: 6006, IS: 2090
Water: free from oils, acids, alkalis, salts, sugar, organic matters etc.
Prestressing materials: prestressing steel, sheathing, anchorages,
sleeves /couplings (all these to be protected from rain/ dampness)
Tendons:
Stored 300 mm above ground in covered and closed space.
Away from high temperature, dampness and humidity. No heat
treatment like welding, galvanizing etc will be done. Stored in large
diameter coils & no kinks, no notches. (5-mm dia wires 2 m dia).
Protective wrapping should be chemically neutral.
Anchorage components:
No mechanically damage, no corrosion, use correct oil/greases
(guaranteed by manufacturer). No C3S (Tricalcium Silicate )
windows, only one door in room. No humidity (instrument installed
for meaning humidity). Steel used within 3 months of manufacture.
Sheathing:
Spiral corrugated type. Cold rolled. Cold ammeaded (CRCA). MS
Steel to IS: 513. No quench hardening or tempering. Bright finish for
normal environment. Thickness not less than 0.3 mm, 0.4 mm, 0.5 mm
for ducts internal diameter 50 mm, 75 mm & 90 mm respectively. 3
samples per lot ( not exceeding 7000m)
Workability test:
1100 mm long sample soldered to a fixed plate bent to a radius of
1800 mm alternately or either side to complete 3 cycles. Sheathing
joints should be o.k.
Transverse load rating test:
To insure stiffness deformation should be less than 5 %
Tension load test:
No deformation of joint.
Water loss test:
Water at 5-mpa pressure for 5 minutes. Loss of head is not more than
1.5 % of volume. Sheathing should perfectly be manufactured at
site for big projects. Joints if unavoidable, corrugated threaded with
coupler should be used to make it slurry tight. Length of sleeve
coupler should at least be 150 mm. Joints provided with adhesive
sealing tape.
Anchorage:
(BS: 4447) To be procured for approved manufacturers only. Test
certificates of approved labs not more than 12 months. No damage.
Protect from corrosion. Threads greased. Holes if any, protected.
Free from mortar at all times. Swages bottom heads where provided
shall develop strength of 95% of safe bearing load.
Tendons:
Shall be free from Rust, Oil, Grease, Tar, Paint, Mud,
etc. Shall be straight on unwinding coils. (If kinks, bends it has to be
rejected). Patching of strands should be removed just before use. On
stands for uncoiling.
High capacity tendons to be used to reduce No of cables thereby
eliminating necessity of grouping.
Any two cables horizontal or vertical should not be less than 100 mm.
In case of pre-cast segments it shall be 150 mm.
Profile of sheathing by providing suitable ladders & spacers at about
1.0 m. Sheathing should be tied to ladders or spacers.
Profile of sheathing should not be disturbed during concreting.
Tendons if possible shall be placed just before sheathing. Till than may
be some temporary tendons inserted.
Anchorage Devices:
Cleaned.
To be set square in the line of action of the Prestressing Tendons
Cutting of wire or Strands:
Mechanical or flame cutting.
In case of flame cutting other tendons do not come in touch of flame.
Flame must be at least 75 mm from where tendon is gripped by
anchorage / jacks.
In Post-tensioning ends of tendons cut after grout has set.
Protection of steel:
Done until grouted. The corrosion protection shall not effect, concrete
or bond strength of the two.
Sheathing:
Joints should be tight especially at ends where sheathing must fit on
protruding trumpet end of anchorage & made waterproof by using heat
shrink tapes (tape is supplied in form of bandages rolls that can be
used for all diameters. With a soft flame this bandage material shrinks
on sheathing ducts & makes it waterproof.
Sheathing weighing machine can be positioned at site for large works.
Sheathing shall be water tight to prevent mortar, dust, water etc.
Grout Vents:
20 mm diameter, at both ends of Sheathing and valleys & crest along
length and not more than 20 mm apart. Plugged to withstand a
pressure of 20 mm.
Anchorage's:
Cleaned before concreting and tensioning.
Anchor cones, blocks & plates positioned & maintained such that
center line of duct passes axially through anchorage assembly.
Recessed from concrete surface at least by 100 mm.
After Prestressing wires cut, surface painted with two coats of epoxy
of 80 micron finer and entire area filled with concrete or non Shrink
mortar or epoxy concrete.
Supervision:
In the presence of representative of supplier of pretensioning system
who shall certify their correctness.
Tensioning Equipment:
Hydraulic jacks power driven, unless otherwise approved by the
Engineer.
Safe.
Where more than one wires constitute a tendon, a single multiple
stressing jack shall be used. Facility for attaching & handling the
multiple jack to the tendons shall be provided.
Can apply controlled total force gradually.
Means to directly measure force by dynamometer or gauges. Also for
linear measurement of extension of steel to nearest mm & any slip of
gripping devices at transfer.
All meters & gauges calibrated after every 3 months from approved
Laboratory.
Minimum nominal size of gauges 100 mm. Gauges such that at 75% of
breaking load, Gauge reading is between 50-80% of its full capacity.
Pressure gauges can withstand sudden release of pressure.
Master gauge can be attached to be used as a check wherever desired.
Post Tensioning:
Done only after concrete attain required strength or as per stipulated
by the prestressing system supplier, which ever is late.
Release of pressure shall be graduated to avoid shocks to steel or
anchorage.
Calculated elongation shall be adjudged w.r.t. modulus of elasticity of
steel for particular lot as given by the manufacturer
Important:
If calculated elongation is reached before final pressure, continue till
1.05 times of the calculated elongation. If still calculated pressure is not
reached inform Engineer.
If calculated pressure is reached before calculated elongation, continue
till 1.05 times of the calculated pressure If still calculated elongation
not reached then
Check correct functioning of the jack.
Determine the cable, slide it in the duct to check for any blockage in
the sheathing. Retention if cable is free.
Re-establish modulus of elasticity from lot.
If still the elongation is not obtained, inform Engineer.
Appropriate allowances for any slip at not jacking end.
No. of stages prestressing & grouting shall be reduced to a minimum,
preferably to two in case of simply supported girders
PRE-TENSIONING:
Stressing Bed:
Notice showing maximum tensioning from permitted.
In long line method, sufficient location plates should be distributed
throughout the bed to ensure proper positioning of wires. Moulds shall
be free to slide in the direction of their length to permit the transfer of
prestressing force to all the concrete elements along the whole line.
Deflections, which are in contact with tendons, shall have a diameter
not less than tendon subject to a maximum of 15 mm.
Desired force should be available in tendon after anchorage slips etc.
Trail stressing to establish the frictional resistance & slip during
anchoring.
Contractor shall submit the calculation showing that the holding
downs have been designed to withstand concentrated loads resulting
from application of prestressing force.
Tensioning Procedure:
Tensioning of wires/strands not too much in advance of concreting.
Tensioning applied gradually and uniformly.
An initial force to lift wires off the bed floor. This taken into account
while calculating elongation.
Tendons marked for elongation after initial force applied. Marked at
both the jacking end & dead end, also at couplers if used to measure
slip and draw in.
Where defected Tendons specified elongation or strain gauges at
various positions along the tendons to determine force in tendons at
those points.
Transfer of Prestress:
Hydraulic jacks can accomplish process of Prestress, some mechanical
means shall be provided to maintain the tension during the entire
period between tensioning and transfer of prestressing force to the
concrete.
Tendons should be released gradually and perfectly simultaneously.
Tendons shall in no case to be cut while in tension.
No eccentricity of prestressing force in vertical or horizontal directly
during releasing the tension.
Cubes should be cured in same environment as the concrete element.
Maximum slip of any tendon during transfer shall not exceed 3 mm.
Protection of ends:
Two coats of epoxy tar paint to give a dry film of 80-micron (second
layer before drying of first) on tendons (& concrete within 50 mm of
tendons).
Safety:
Jacks should be secured tightly.
No person behind the jack or close to line of tendons.
Safety barrier at both ends to prevent any tendon that might become
loose from recoiling.
Warning signs displayed.
No chipping, drilling or cutting of any concrete after prestressing
without approval of the Engineer.
No heating or welding near tendon is permitted, if so the affected
tendons to be rejected.
Transfer & storage of PSC units:
In upright position points of support & direction of reaction w. r. t
girder approximately same during transportation & storage.
During stacking lateral movements & instability be avoided by using
inclined side supports all around.
Tolerances:
Variation from horizontal profile, vertical profile & specified position
of member shall be limited to 5 mm.
Payments:
ONLY CONCRETE & STEEL BY WEIGHT, TENDONS BY
WEIGHT SHALL BE PAID.
DEFORMED STEEL BARS & WIRES FOR CONCRETE
REIFORCEMENT
HYSD : HIGH YIELD STRENGTH DEFORMED BARS
TMT
: THERMO MECH. TREATED BARS.
IS : 1786
Deformed Bars
Hot Rolled
Hot Rolling followed by cold
Twisting
Fe 415m Fe 500, Fe 550
Min. 0.2% Proof Stress or yield stress
in N/mm2
Chemical Composition
Fe 415
Fe 500
Fe 550
C
0.300
0.300
0.300
S
0.060
0.055
0.055
P
0.060
0.055
0.050
S&P
0.110
0.105
0.100
FOR WELDING IS : 9417
0.12 dia for dia ≤ 10mm
0.15 dia for dia 10mm < ø ≤ 16mm
0.17 ø for ø > 16mm
RIB AREA ABOVE THE CORE -:
Size (mm)
6
8
10
12
16
18
20
Area mm2
28.3
50.3
78.6
113.1
201.2
254.6
314.
3
Wt.
0.222
0.395
0.617
0.888
1.58
2.00
2.47
Size (mm)
25
28
32
36
40
45
Area mm2
491.1
616.0
804.6
1018.3
1257.
2
1591.
1
Wt.
3.85
4.83
6.31
7.99
9.85
12.50
Gross x-Sectional are in mm2
=
W/0.00785 L
Where
W=
Mass in Kg
L
=
Length in meters
TOLERANCES
Length
+ 75 - 25mm (+50 -0 if minimum length specified)
Mass
Upto 10mm ø (-) 8% +7
Over 10 upto 16
(-)6% +5
>16
(-)4%+3
Fe415
Fe500
Fe 500
Elongation % min. on gauge
length 5.65 A1/2 where
A=X-Sec Area
14.5
12.0
8.0
Tensile Strength
(Minimum)
10% more than actual 0.2%
Proof Stress & not < 485
M/mm2
8% more than actual
0.2% Proof Stress
& not < 545
N/mm2
6% more than actual
0.2% Proof Stress
& not < 585 N/mm2
2% Proof stress /Yield stress
min, N/mm2
415
500
550
BOND TEST
TEST PIECES
TENSILE TEST
BEND TEST
:
:
:
If surface area is ok it is ok.
:
IS :226
IS : 1608 - 1972, IS : 226
No transverse cracks in bent position
Fe 415
Fe 500
Fe 550
Mandrel dia.
Upto 22 dia.
3d
4 dia
5 dia
Mandrel dia.
Over 22 dia.
4 dia
5 dia.
6 dia
REBEND TEST Keep in 1000C Water for 30 Minutes & then cool.
Mandrel Dia
Fe 415 & 500
Fe 550
Upto 10 dia
5 dia.
7 dia
Over 10 dia.
7 dia.
8 dia.
CUBE MARKING & NO. OF CUBES TO BE TAKEN:
D - 1/5 RW Pile
30-12-04
T4 1/6
Sequential Transit mixer number
Name of the
structure/Identification
Date of casting
Cube No /Total cubes taken
from transit mixer
FOR R.C.C WORKS
(IS: 456-2000 Para 15.2 & 15.3)
No of Cubes: - (Generally 6 cubes from each transit mixer)
1
2
7 days
3
4
For 1m3 to 5m3
9 cubes
28 days
5
Extra
6
7
8
9
1
2
6 m3 to 15 m3 12 cubes
3
4
7 days
5
6
28days
7
8
Extra
9
10
11
12
SIMILARLY FOR: 16 m3 to 30m3
– 18 cubes including 3 extra
31 m3 to 50 m3
– 24 cubes including 3 extra
51 m3 to 100 m3
– 30 cubes including 3 extra
101 m3 to 150 m3
– 36 cubes including 3 extra
151 m3 to 200 m3 – 42 cubes including 3 extra
FOR PSC WORK: 12 cubes
1
2
3
4
5
For 35 MPa for U girder & 40 MPa
for L girder
28days
6
7
8
9
10
11
12
Extra
28 days
AGGREGATES:IS : 383 - 1970/1993
SPECIFICATIONS FOR COARSE AGGREGATE & FINE
AGGREGATE FOR CONCRETE ZONE I,II,III,IV.
COARSER
FINER
SAMPLING:
IS : 2430 - 69 IS : 2- 1960(Rounding off
values)
FINE AGGREGATE : Passing through 4.75 mm sieve.
COARSE AGGREGATE: Retaining on 4.75 mm sieve.
AGGREGATES:
Uncrushed from natural disintegration of Rock.
Crushed from Rocks/Gravels/ Stones.
Combination of above two.
COARESE AGGREGATE
Shall be hard, strong, dense, durable, clear, free from veins &
adherent coating, free from disintegrated pieces like Alkali, Organic
matter and other deleterious matter. If possible, flakiness & elongation
should be avoided.
Deleterious Materials:
Pyrites, Coal, Ignite, Mica, Shale, Clay, Alkali, Soft fragments,
Seashells & Organic impurities.
AGGREGATE CRUSHING VALUE:
Not more than 30% for wearing surfaces i.e. Roads, Runways,
Pavements etc.
Not more than 45% for others.
IMPACT VALUE:
Not more than 30% for wearing surfaces i.e. Roads, Runways,
Pavements etc.
Not more than 45% for others.
ABRASION VALUE:
Not more than 30% for wearing surfaces i.e. Roads, Runways,
Pavements etc.
Not more than 50% for others.
SOUNDNESS:
When exposed to action of FROST.
Tested with Na2SO4
Tested with MgSo4
FINE AGGREGATE
10%
15%
COARSE AGGREGATE
12%
18%
TABLE-1 :LIMITS OF DELE TERIOUS MATERIALS
DELETARIOUS
SUBSTANCE
TEST
METHOD
F.A. % BY WEIGHT MAX.
C.A. % BY WEIGHT MAX.
UNCRUSHED
CRUSHED
UNCRUSHED
CRUSHED
i)coal &
ignite
Is:2386 PtII
1
1
1
1
Clay lumps
Is:2386 Pt-I
1
1
1
1
Material
finer than 75
micron
Is:2386 PtII
3
15
3
3
Soft
fragments
Is:2386 PtII
-
-
3
-
shale
-
1
-
-
-
5
2(except for
finer
materials)
5
5
Total
TABLE-2,3,4,5(GIST) :COARSE AGGREGATES
FINE AGG.
ZONE-II
COARSE
20mm
40
-
20
AGG
COARSE AGG 10mm
COMBINED COARSE
AGG. (ALL - IN AGG.
100
-
100
-
85-100
-
95-100
12.5
-
-
100
-
10
-
0-20
85-100
25-35
4.75
90-100
0-5
0-20
0-10
2.36
75-100
-
0-5
-
1.18
55-90
-
-
-
600
MICRONE
35-59
-
-
-
300
MICRONE
8-30
-
-
-
150
MICRONE
0-10
-
-
-
75
MICRONE
-
-
-
-
COMPLETE INFORMATION ABOUT THE PHYSICAL & CHEMICAL PROPERTIES OF
AGGREGATES CAN BE HAD FROM THE SUPPLIER IN PROPER FORMATS