Flexural Strength

Flexural strength is the ability of a material to resist deformation under bending. In the case of concrete, flexural strength is an important parameter to consider in the design of plain jointed cement pavement. Here is an explanation of why flexural strength is the correct answer:

1. Importance of Plain Jointed Cement Pavement
Plain jointed cement pavement is a type of rigid pavement commonly used in highways, airports, and other heavy-duty applications. It consists of a series of concrete slabs with transverse and longitudinal joints. The pavement is subjected to various types of loads, including wheel loads from vehicles and temperature-induced stresses. Therefore, it is crucial to consider the strength properties of concrete in its design.

2. Flexural Loading in Plain Jointed Cement Pavement
One of the significant load types that plain jointed cement pavement experiences is flexural loading. Flexural loading occurs when the pavement is subjected to bending stresses due to wheel loads. The bending stresses induce tension and compression in the concrete, and the ability of the pavement to withstand these stresses is determined by its flexural strength.

3. Flexural Strength as a Design Parameter
Flexural strength is a measure of the maximum bending stress that a material can withstand without breaking or failing. In the case of concrete, the flexural strength is typically expressed in terms of the modulus of rupture, which represents the stress at which the concrete beam fails in a flexural test. This parameter is used in the design of plain jointed cement pavement to ensure that the pavement can withstand the expected bending stresses without experiencing cracking or failure.

4. Other Strength Parameters
While tensile strength, compressive strength, and shear strength are all important properties of concrete, they are not the primary design parameters for plain jointed cement pavement.

- Tensile strength: Plain jointed cement pavement is primarily subjected to bending stresses, and tensile stresses develop on the bottom face of the pavement. However, the flexural strength of concrete takes into account its tensile behavior and is a more appropriate parameter to consider.
- Compressive strength: Compressive strength is a measure of the ability of concrete to resist crushing under axial compressive loads. Although concrete in pavement experiences compressive stresses, it is the flexural strength that is critical in resisting bending stresses.
- Shear strength: Shear strength is the ability of a material to resist the sliding or shearing forces. While shear stresses may develop in the joints of plain jointed cement pavement, the primary focus of design is on the flexural strength to ensure the integrity of the concrete slabs.

Conclusion
In summary, the flexural strength of concrete is the most appropriate strength parameter to consider in the design of plain jointed cement pavement. This parameter ensures that the pavement can withstand the bending stresses induced by wheel loads without cracking or failing. While other strength parameters, such as tensile strength, compressive strength, and shear strength, are important in concrete design, they are not the primary considerations for plain jointed cement pavement.