FLEXURAL STRENGTH OF CONCRETE BEAM

CONCRETE: FLEXURAL STRENGTH OF CONCRETE BEAM

Reference:      A.S.T.M. C78

Procedure:     <Read this instruction carefully>

1. Follow the procedure outlined in Section 5 of attached ASTM C78specifications
2. Observe and record the maximum load.

• Prepare a report covering the ten categories in section 8 of the specification.
  In addition the report should include a detailed sketch of the cracked specimen.

Write a professional lab report using the test results for all three teams

See this youtube video clip for ASTM beam test precedure: https://www.youtube.com/watch?v=TCfQdlriFAQ

ASTM C78 is also attached. Follow the test procedure from the ASTM document.

Please show all work and details with graph

The size of the specimen: L = 18 in          b = 6 in            d = 6 in

Draw SFD and BMD using the computer. Calculate the modulus of Rupture, R.

(R = PL/bd²)

Using the f’_R = 7.5 * sqrt(f’_c)

(please see the presentation slides), calculate the compressional strength.

Don’t forget to include all the calculations and lab procedure from the ASTM C78.

Modulus of Rupture: Formula Derivation

P/2                 P/2

L/3                                    L/3                   L/3

P/2                                                                   P/2

MOMENT AT CENTER SPAN:                           MOMENT OF INERTIA I□

M = P/2 * L/2  – P/2 * L/6                                                                   I□ =   bd³

12                                                                                                                                                         n.a.

M =P/2 *  L/3

b

M = PL/6                                                         MAXIMUM STRESS IN BEAM (modulus of rupture)

R= f_c

na

fc