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Silica Fume influence on RC Beams Behavior

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1 Silica Fume influence on RC Beams Behavior
United Arab Emirates University College of Engineering Department of Civil and Environmental Engineering Graduation Project II Second Semester 2007/2008 Silica Fume influence on RC Beams Behavior Advisor: Dr. Ahmed Bushlaibi Group members: Khamis Ahmed Khamis Khalid Hazaá Mansour Nasser Abdullah Alnaqbi Khaled Moussalli 1 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

2 contents Introduction. The split cylinder test. The permeability test.
The bending test. The flexural test. Conclusion. 2 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

3 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. 3 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

4 Why Silica Fume ? 4 Silica Fume influence on RC Beams Behavior
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 4 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

5 Why Silica Fume ? 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. 5 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

6 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. 6 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

7 NO 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 7 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

8 The split cylinder test The permeability test. The bending test.
The flexural test. 8 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

9 Split Cylinder Test 9 Silica Fume influence on RC Beams Behavior
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10 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. 10 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

11 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. 11 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

12 The Experiment 12 Silica Fume influence on RC Beams Behavior
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13 Results 13 7 days Results Silica % 0% 7.50% 10% 12.50% 261 327 356 258
250 300 362 260 315 352 Avg 256.33 257 314 356.67 The results above are in MPa 13 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

14 Results 14 14 days Results Silica Fume % 0% 7.50% 10% 12.50% 270 351
342 357 333 347 376 285 343 Avg 281.67 342.33 343.67 363.33 The results above are in MPa 14 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

15 Results 15 28 days Results Silica Fume % 0% 7.50% 10% 12.50% 370 380
450 480 400 435 475 340 445 Avg 360 393.33 443.33 478.33 The results above are in MPa 15 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

16 Results 16 Silica Fume influence on RC Beams Behavior
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17 The split cylinder test. The permeability test. The bending test.
The flexural test. 17 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

18 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%) 18 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

19 Permeability Most popular fluid is water Most popular gas is O2 & CO2
Concrete Specimen Inflow Flow path Outflow Water permeating through concrete 19 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

20 Permeability test Shape: Cylinder v=πr2h R=15cm=0.15m r=7.5cm=0.075m
h=2cm=0.02m V =(π )*(0.075)2*(0.02) = m3 V for 16 cylinder = (16)*( ) =0.0056m3 R=15cm h=2cm 20 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

21 Calculation 21 Water content for 16 cylinder=1.12Kg/m3
Cement content for 16 cylinder=3.3936kg Coarse Aggregate: For 16 cylinder = Kg Fine Aggregate: For 16 cylinder = Kg Super plasticizer: Sp=1.5 to 2 % of the total cement. SP= 1.65% * = 53 ml 21 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

22 Experiment 22 Silica Fume influence on RC Beams Behavior
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23 Curing Water 25 days Oven 3days 23
Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

24 Transportation To protect sample against air moisture 24
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25 Air permeability device
25 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

26 Line diagram for the oxygen permeability apparatus
26 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

27 The Permeability Cell 27 Silica Fume influence on RC Beams Behavior
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28 Pressure head gradient
Permeability Cross Section (m2/sec) Volume Flow Rate (m3/sec) Permeability Coefficient (m/sec) Driving Force Pressure head (m) Flow Path i.e. specimen thickness (m) Pressure head gradient 28 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

29 0% 7.5% 29 P (bar) Volume V(cc) t1 (sec) t2 (sec) t3 (sec)
t_averag (sec) Q m3/sec A m2 l m h m K m/sec 1.5 10 0.24 E-05 0.02 E-05 2 0.11 E-05 E-05 2.5 0.6 E-05 E-06 E-05 7.5% P (bar) Volume V(cc) t1 (sec) t2 (sec) t3 (sec) t_averag (sec) Q m3/sec A m2 l m h m K m/sec 1.5 10 6.8 6.82 6.77 E-06 0.02 E-06 2 2.8 2.82 E-06 E-06 2.5 1.6 1.65 1.63 E-06 E-06 29 E-06 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

30 10% 12.5% 30 P (bar) Volume V(cc) t1 (sec) t2 (sec) t3 (sec)
t_averag (sec) Q m3/sec A m2 l m h m K m/sec 1.5 10 11.5 11.52 E-07 0.02 E-07 2 5.21 5.23 5.25 E-06 E-06 2.5 2.23 2.31 2.32 E-06 E-06 E-06 12.5% P (bar) Volume V(cc) t1 (sec) t2 (sec) t3 (sec) t_averag (sec) Q m3/sec A m2 l m h m K m/sec 1.5 5 18.54 19.12 19.4 19.02 E-07 0.02 E-07 2 8.82 8.68 8.79 E-07 3.2287E-07 2.5 5.41 5.4 E-07 E-07 30 E-07 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

31 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 Behavior Department of Civil and Environmental Engineering

32 The split cylinder test. The permeability test. The bending test.
The flexural test. 32 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

33 Beam Design Design of RC Section Requires Determination of:
Concrete Dimensions Beam width b Depth of steel reinforcement d Section height h = d + cover-to-center of steel Area of steel reinforcement As Ensure safety requirements (As) min ≤ As ≤ (As) max 33 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

34 Beam Design 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 34 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

35 Beam Design Step 2: Estimate Beam Height According to ACI Deflection Requirements hmin = L/16 = 1800 / 16 = 113 mm hb = 250 mm > 113 mm 35 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

36 Beam Design Step 3: Assume bar size No. 10 For bar size No. 10, db = 9.5 mm 36 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

37 Beam Design 37 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 = /2 = 34 mm d = h - cover = = 216 mm 37 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

38 Beam Design 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) = 38 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

39 Beam Design Step 7: Ensure safety requirements (ρ) min ≤ ρ ≤ (ρ) max 39 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

40 40 Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering

41 Beam Design Step 7: Ensure safety requirements (ρ) min ≤ ρ ≤ (ρ) max For fc' = MPa ≤ ρ ≤ For fc' = 78.7 MPa ≤ ρ ≤ For fc' = MPa ≤ ρ ≤ For fc' = 90 MPa ≤ ρ ≤ 41 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

42 Experiment 42 Silica Fume influence on RC Beams Behavior
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43 Strain Gauges 43 Silica Fume influence on RC Beams Behavior
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44 Pouring the Concrete 44 Silica Fume influence on RC Beams Behavior
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45 The Smooth Concrete Surface
45 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

46 46 Silica Fume influence on RC Beams Behavior
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47 47 Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering

48 48 Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering

49 The split cylinder test. The permeability test. The bending test.
The flexural test. 49 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

50 What is Flexural Strength ?
One measure of the tensile strength. Measure of an unreinforced concrete. Loading beams with tow concentrated load. 50 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

51 Beam Details 51 Silica Fume influence on RC Beams Behavior
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52 Flexural Strength Experimentally
52 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

53 Flexural Strength Theoretically
fcu = 1.25 fc’ fc’ = 0.8 fcu fr = 0.7 √ (0.8 fcu) 53 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

54 Theoretical Load 54 Silica Fume influence on RC Beams Behavior
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55 55 Silica Fume influence on RC Beams Behavior
cm mm m d1(cm) 15 150 0.15 d2(cm) L(cm) 50 500 0.5 V(m3) For 7 beams 55 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

56 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 V Grade 10_14 = 30% Grade 5_10 = 70% Fine Aggregate for 7 beams = 597 x V Dune sand = 20% Black sand = 80 % 56 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

57 Our Trial Mix Data 57 Silica Fume influence on RC Beams Behavior
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58 Experiment steps Preparing Weighting Mixing 58
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59 Experiment steps Mixing Prism Preparing Concrete casting 59
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60 After 2 days 60 Silica Fume influence on RC Beams Behavior
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61 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 61 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

62 Doing the Experiment 62 Silica Fume influence on RC Beams Behavior
Department of Civil and Environmental Engineering

63 Doing the Experiment 63 Silica Fume influence on RC Beams Behavior
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64 Doing the Experiment 64 Silica Fume influence on RC Beams Behavior
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65 Result 65 Silica Fume influence on RC Beams Behavior
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66 Result 66 Silica Fume influence on RC Beams Behavior
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67 Result 67 Silica Fume influence on RC Beams Behavior
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68 Result 68 Silica Fume influence on RC Beams Behavior
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69 Comparison 69 Silica Fume influence on RC Beams Behavior
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70 Conclusion 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. 70 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

71 Conclusion 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. 71 Silica Fume influence on RC Beams Behavior Department of Civil and Environmental Engineering

72 Thanks for listening 72 Silica Fume influence on RC Beams Behavior
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