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Transcript of Group members: Khamis Ahmed Khamis 199900588 Khalid Hazaá Mansour 200235841 Nasser Abdullah Alnaqbi...
Silica Fume influence on RC Beams Behavior
Group members:Khamis Ahmed Khamis 199900588Khalid Hazaá Mansour 200235841Nasser Abdullah Alnaqbi 200212673
Khaled Moussalli 200337587
United Arab Emirates UniversityCollege of Engineering
Department of Civil and Environmental EngineeringGraduation Project II
Second Semester 2007/2008
Advisor: Dr. Ahmed Bushlaibi
1Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
contents
Introduction. The split cylinder test. The permeability test. The bending test. The flexural test. Conclusion.
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
2
Introduction
Using silica fume as an enhancer for the concrete beams, slabs, columns and any other concrete structure.
Concrete is very good material in compression however it is very week in tension so that is way we use reinforcement in it.
3Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Cement grains (left), silica fume particles (right) at the same magnification. The ACI 234R-96 report estimates that for a 15 percent silica fume replacement of cement, there are
approximately 2,000,000 particles of silica fume for each grain of portland cement
Why Silica Fume ?
4Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Change microstructure of the concrete
Physical aspect of silica fume :
Fills in the spaces between cement grains
Chemical contribution :
Cement releases calcium hydroxide. Silica has very high silicon dioxide.Calcium hydroxide will react with silicon dioxide to form
calcium silicate hydrate.
Why Silica Fume ?
5Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Introduction
Concrete solidifies and hardens after mixing and placement due to a chemical process known as hydration. The water reacts with cement which bonds the other components together eventually creating a stone-like material.
Reinforcement is a good indication for failure because it gives us a warning.
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Department of Civil and Environmental Engineering
Introduction
In GPI the concrete compression test was done. Was that enough ??!
Four more test were done. The split cylinder test. The permeability test. The bending test. The flexural test.
NO
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Department of Civil and Environmental Engineering
The split cylinder testThe permeability test.
The bending test.The flexural test.
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Department of Civil and Environmental Engineering
Split Cylinder Test
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Department of Civil and Environmental Engineering
Split cylinder test
This test, often referred to as the split-cylinder test, indirectly measures the tensile strength of concrete by compressing a cylinder through a line load applied along its length.
10Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
The testing machine
This test can be completed in a standard concrete compression testing machine, with only one special requirement the hinged bearing that loads the specimen.
11Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
The Experiment
12Silica Fume influence on RC Beams Behavior
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Results
7 days
Results Silica %
0% 7.50% 10% 12.50%
261 261 327 356
258 250 300 362
250 260 315 352
Avg 256.33 257 314 356.67
The results above are in MPa
13Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Results
14 days
Results Silica Fume %
0% 7.50% 10% 12.50%
270 351 342 357
270 333 347 376
285 343 342 357
Avg 281.67 342.33 343.67 363.33
The results above are in MPa
14Silica Fume influence on RC Beams Behavior
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28 days
Results Silica Fume %
0% 7.50% 10% 12.50%
370 380 450 480
370 400 435 475
340 400 445 480
Avg 360 393.33 443.33 478.33
The results above are in MPa
Results
15
15Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Results
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16Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
The split cylinder test.The permeability test.
The bending test.The flexural test.
17Silica Fume influence on RC Beams Behavior
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Permeability
Permeability describes the ease by which any species (i.e. liquid or gas) can pass through concrete.
Objective :Effect of silica fume in permeability of concrete on different percentage (0%,7.5%,10%,12.5%)
18Silica Fume influence on RC Beams Behavior
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Permeability
Most popular fluid is water Most popular gas is O2 & CO2
ConcreteSpecimen
Inflow
Flow path
OutflowWater permeatingthrough concrete
19Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Permeability test
Shape: Cylinder
v=πr2h
R=15cm=0.15mr=7.5cm=0.075mh=2cm=0.02m
V =(π )*(0.075)2*(0.02)=0.00035m3
V for 16 cylinder = (16)*(0.00035) =0.0056m3
h=2cm
R=15cm
20Silica Fume influence on RC Beams Behavior
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Calculation Water content for 16 cylinder=1.12Kg/m3
Cement content for 16 cylinder=3.3936kg
Fine Aggregate:
For 16 cylinder = 3.3432 Kg
Coarse Aggregate:
For 16 cylinder = 5.1072 Kg
Super plasticizer:
Sp=1.5 to 2 % of the total cement. SP= 1.65% * 3.3936 = 53 ml
21Silica Fume influence on RC Beams Behavior
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Experiment
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Curing
Oven3days
Water 25 days23
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
Transportation
To protect sample against air moisture24
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
Air permeability device
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Line diagram for the oxygen permeability apparatus
26Silica Fume influence on RC Beams Behavior
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The Permeability Cell
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Permeability
Pressure head gradient
l
hAkQ
Cross Section(m2/sec)
Volume Flow Rate(m3/sec)
Permeability Coefficient(m/sec)
Driving ForcePressure head (m)
Flow Pathi.e. specimen thickness (m)
28Silica Fume influence on RC Beams Behavior
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P(bar)
Volume
V(cc)t1
(sec)t2
(sec)t3
(sec)t_averag
(sec)Q
m3/secA
m2l
mhm
Km/sec
1.5 10 0.24 0.24 0.24 0.24 4.16667E-05 0.017671 0.02 1.5 3.14388E-05
2 10 0.11 0.11 0.11 0.11 9.09091E-05 0.017671 0.02 2 5.14454E-05
2.5 10 0.6 0.6 0.6 0.6 1.66667E-05 0.017671 0.02 2.5 7.54532E-06
3.01432E-05
P(bar)
VolumeV(cc)
t1(sec)
t2(sec)
t3(sec)
t_averag(sec)
Qm3/sec
Am2
lm
hm
Km/sec
1.5 10 6.8 6.82 6.77 6.796667 1.47131E-060.01767
1 0.02 1.5 1.11015E-06
2 10 2.8 2.82 2.8 2.806667 3.56295E-060.01767
1 0.02 2 2.01627E-06
2.5 10 1.6 1.65 1.63 1.626667 6.14754E-060.01767
1 0.02 2.5 2.78311E-06
1.96984E-06
0%
7.5%
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Department of Civil and Environmental Engineering
10%
P(bar)
VolumeV(cc)
t1(sec)
t2(sec)
t3(sec)
t_averag(sec)
Qm3/sec
Am2
lm
hm
Km/sec
1.5 10 11.5 11.5 11.52 11.50667 8.69061E-07 0.017671 0.02 1.5 6.55735E-07
2 10 5.21 5.23 5.25 5.23 1.91205E-06 0.017671 0.02 2 1.08202E-06
2.5 10 2.23 2.31 2.32 2.286667 4.37318E-06 0.017671 0.02 2.5 1.97982E-06
1.23919E-06
P(bar)
VolumeV(cc)
t1(sec)
t2(sec)
t3(sec)
t_averag(sec)
Qm3/sec
Am2
lm
hm
Km/sec
1.5 5 18.54 19.12 19.4 19.022.62881E-
07 0.017671 0.02 1.51.98347E-
07
2 5 8.82 8.68 8.79 8.7633335.70559E-
07 0.017671 0.02 2 3.2287E-07
2.5 5 5.41 5.4 5.41 5.4066679.24784E-
07 0.017671 0.02 2.54.18657E-
07
3.13291E-07
12.5%
30Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
The silica fume will effect on the permeability as shown in the chart, when the quantity of silica fume increase the permeability will decrease.31
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
0 2 4 6 8 10 12 140.00E+00
5.00E-06
1.00E-05
1.50E-05
2.00E-05
2.50E-05
3.00E-05
3.50E-05
% Silica Fume
K (
m/s
)
The split cylinder test.The permeability test.
The bending test.The flexural test.
32Silica Fume influence on RC Beams Behavior
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Design of RC Section Requires Determination of:
1. Concrete Dimensions
Beam width b
Depth of steel reinforcement d
Section height h = d + cover-to-center of steel
2. Area of steel reinforcement As
3. Ensure safety requirements (As) min ≤ As ≤ (As) max
Beam Design
33Silica Fume influence on RC Beams Behavior
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Step 1: Assume Concrete Dimensions (Beam width & Section height) and Section Length
Beam width b = 100 mm
Section height h = 250 mm
Section Length L = 1.8 m
Beam Design
34Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Step 2: Estimate Beam Height According to ACI Deflection Requirements
hmin = L/16 = 1800 / 16 = 113 mm
hb = 250 mm > 113 mm
Beam Design
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Step 3: Assume bar size No. 10
For bar size No. 10, db = 9.5 mm
Beam Design
36Silica Fume influence on RC Beams Behavior
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Step 4: Calculate depth of steel reinforcement (d)
Cover = concrete cover to steel center
cc = clear concrete cover (20 mm for beams)
ds = diameter of stirrups (bar size # 10)
db = diameter of steel bar (bar size # 10)
Hence, Cover = cc + ds + db/2 = 20 + 9.5 + 9.5/2 = 34 mm
d = h - cover = 250 - 34 = 216 mm
Beam Design
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Step 5: Assume grade of a steel reinforcing bar & area of steel reinforcement As
Grade 420 (i.e. fy = 420 MPa) is the most commonly used steel
Use 2 bars No. 10 (As = 142 mm2)
Step 6: Compute steel ratio (ρ)
ρ = 142 / (100 * 216) = 0.00658
Beam Design
bd
As
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Step 7: Ensure safety requirements (ρ) min ≤ ρ ≤ (ρ) max
Beam Design
fy
fc
fyofGreater
4
'
4.1
min
)600
600('85.0
)75.0( 1max fyfy
fc
MPafcforfc 30''007.006.11
39Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
40Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Step 7: Ensure safety requirements (ρ) min ≤ ρ ≤ (ρ) max
For fc' = 61.33 MPa 0.00466 ≤ ρ ≤ 0.03559
For fc' = 78.7 MPa 0.00528 ≤ ρ ≤ 0.04567
For fc' = 85.17 MPa 0.00549 ≤ ρ ≤ 0.04943
For fc' = 90 MPa 0.00565 ≤ ρ ≤ 0.05223
Beam Design
41Silica Fume influence on RC Beams Behavior
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Experiment
42Silica Fume influence on RC Beams Behavior
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Strain Gauges
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Pouring the Concrete
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The Smooth Concrete Surface
45Silica Fume influence on RC Beams Behavior
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46Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
47Silica Fume influence on RC Beams Behavior
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0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,0000
10
20
30
40
50
60
70
Comparison of 0%, 7.5%, 10%, and 12.5% Silica Fume
0% Silica Fume7.5% Silica Fume10% Silica Fume12.5% Silica Fume
Strain
Load
(kN
)
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,0000
10
20
30
40
50
60
70
Comparison of 0%, 7.5%, 10%, and 12.5% Silica Fume after 28 days
0% Silica Fume7.5% Silica Fume10% Silica Fume12.5% Silica Fume
Strain
Load
(kN
)
48
The split cylinder test.The permeability test.
The bending test.The flexural test.
49Silica Fume influence on RC Beams Behavior
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One measure of the tensile strength. Measure of an unreinforced concrete. Loading beams with tow concentrated load.
What is Flexural Strength ?
50Silica Fume influence on RC Beams Behavior
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Beam Details
51Silica Fume influence on RC Beams Behavior
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Flexural Strength Experimentally
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Flexural Strength Theoretically
fcu = 1.25 fc’
fc’ = 0.8 fcu
fr = 0.7 √ (0.8 fcu)
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Theoretical Load
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cm mm m
d1(cm) 15 150 0.15
d2(cm) 15 150 0.15
L(cm) 50 500 0.5
V(m3) 0.01125
For 7 beams 0.07875
55
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
Our Trial Mix Data
Water content for 7 beams = 200 x V
Cement content for 7 beams = 606 x V
Coarse Aggregate for 7 beams = 912 x VGrade 10_14 = 30%Grade 5_10 = 70%
Fine Aggregate for 7 beams = 597 x VDune sand = 20%Black sand = 80 %
56Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Our Trial Mix Data
57Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Experiment steps
58
WeightingPreparing
Mixing
58Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Experiment steps
59
Mixing Prism Preparing
Concrete casting
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After 2 days
60
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Concrete Compression Machine
Consist of:
Two supporting rollers
Two load-applying rollers
Steel with circular cross-section
Diameter of 20 mm to 40 mm
At least 10 mm longer
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Doing the Experiment
62Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Doing the Experiment
63Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
Doing the Experiment
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Result
65Silica Fume influence on RC Beams Behavior
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ResultTime Vs F
05
10152025
303540
4550
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Time ( Days )
F (
KN
) 0%
7.50%
10%
12.50%
66Silica Fume influence on RC Beams Behavior
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Result
67Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering
ResultTime Vs F
00.5
11.5
22.5
33.5
44.5
55.5
66.5
7
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Time ( Days )
fr (
MP
a )
0%
7.50%
10%
12.50%
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Comparison
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All the tests results were very encouraging.
Adding the silica fume to any concrete mixture will enhance the properties of the concrete far beyond its initial properties.
Increasing the amount of silica fume will result in enhancing the concrete properties.
Conclusion
70Silica Fume influence on RC Beams Behavior
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The silica fume is a very promising industry in the future.
For the next semester it is recommended for one of the GPI groups to investigate the influence of fly ash on concrete and compare it with our results.
Conclusion
71Silica Fume influence on RC Beams Behavior
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THANKS FOR
LISTENING
Silica Fume influence on RC Beams BehaviorDepartment of Civil and Environmental Engineering
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