FIGURE 12: Graph showing the Modulus of rupture for concrete beams

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29 Νοε 2013 (πριν από 3 χρόνια και 9 μήνες)

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FIGURE 12: Graph showing the Modulus of rupture for concrete beams

5.4.2 Compressive Strength for concrete specimens and Flexure beams


Cylinders were molded with a diameter of 4 inches (102mm) and a length of 8
inches (203 mm) to determine the compressive strength of the concrete mixtures. The
cylinders were tested at 7 and 28 days following the ASTM C 39. Ohio Department of
Transportation (ODOT) specifies a minimum 28 day compressive strength of 4,000 psi
(28 MPa) for Class C concrete mixtures. Table XII provides the compressive strength of
concrete for 7 and 28 days. All the concrete mixtures exceeded the compressive strength
requirements. Figure 13 shows that at the end of 28 days all the specimens have a
compressive strength more than 4,000 psi (28 MPa) and thus met the ODOT 28 days
requirement. The flexural beam specimens also demonstrated a compressive strength just
above 4,000 Psi at the end of 28 days and those specimens also met the ODOT
requirements.
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Table XII: 7 & 28 days compressive strength of concrete specimens







FIGURE 13: Graph showing the 7& 28 days Compressive Strength

(Average of two samples A & B)

7 Days Compressive Strength

28 Days Compressive Strength

Percentage
replaced

Sample A

Sample B

Sample A
B
Sample B
B


(Psi) (MPa) (Psi) (MPa) (Psi) (MPa) (Psi) (MPa)
0 %

5090 35 5147 35 6212 43 5072 35.
25%

4617 32 4623 32 4186 29 5141 35
50%

4154 29 4277 29 5051 35 5140 35
75%

3379 23 3358 23 4241 29 4288 30
100 A%

3577 25 2869 20 4158 29 4474 31
100 B%

4411 30 5416 37 6165 42 6069 42

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TABLE XIII: 7 & 28 Days Compressive Strength for Flexure Beam Specimens









FIGURE 14: Graph showing the 7& 28 days Compressive Strength of concrete for
flexure beams (Average of two samples A & B)





7 Days Compressive strength for
Flex beams

28 Days Compressive strength for
Flex beams

Percentage
replaced

Sample C

Sample D

Sample C Sample D

(Psi) (MPa) (Psi) (MPa) (Psi) (MPa) (Psi) (MPa)
0 %

5468

38

5483

38

6471

45

6661

46

25%

5088

35

5177

36

4683

32

5317

37

50%

4465

31

4419

30

4432

31

4722

33

75%

3886

27

4416

30

5304

37

5265

36