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Modulus of Rupture Equation:
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The Modulus of Rupture (MOR) is a measure of the tensile strength of concrete in bending. It represents the maximum stress a concrete specimen can withstand when subjected to bending before it fails. The MOR is an important property for structural design where concrete is subject to flexural stresses.
The calculator uses the standard ACI equation:
Where:
Explanation: This empirical relationship estimates the flexural strength of concrete based on its compressive strength, with the square root relationship accounting for the non-linear behavior of concrete.
Details: The modulus of rupture is critical for designing concrete elements subject to bending, such as slabs, beams, and pavements. It helps engineers determine the load-carrying capacity and predict cracking behavior in flexural members.
Tips: Enter the concrete compressive strength in psi. The value must be greater than zero. The calculator will compute the estimated modulus of rupture based on the standard ACI formula.
Q1: What is the typical range of MOR values for concrete?
A: For normal strength concrete (3000-6000 psi), MOR typically ranges from 400-600 psi. Higher strength concretes will have higher MOR values.
Q2: How does MOR relate to compressive strength?
A: MOR is approximately 10-15% of the compressive strength for normal weight concrete, though the relationship is not linear as shown by the square root function.
Q3: Are there different equations for different concrete types?
A: Yes, lightweight concrete typically uses a different coefficient (around 6.7 instead of 7.5), and other standards may have slightly different equations.
Q4: Why is MOR important in pavement design?
A: In pavement design, MOR is used to determine the required slab thickness to resist bending stresses from traffic loads without excessive cracking.
Q5: How is MOR tested experimentally?
A: MOR is typically determined through third-point loading tests on concrete beams according to ASTM C78 standards.