In-depth Evaluation of the CBR Method in Flexible Pavement Design

Abstract

The California Bearing Ratio (CBR) value of the subgrade is a crucial parameter utilized in the design of flexible pavements, as recommended by the Indian Roads Congress (IRC). The choice of materials used in constructing the pavement can significantly influence its overall design and performance. Pavements play an essential role in ensuring traffic flows smoothly, safely, and efficiently. Generally, pavements are categorized into two types: flexible and rigid. Flexible pavements possess low flexural strength and exhibit a flexible structural behavior under load. In contrast, rigid pavements are characterized by their high flexural strength and rigidity. Many existing roads, which are designed based on empirical guidelines, often fail to withstand heavy wheel loads, leading to their gradual deterioration over time. To address this issue, various engineering parameters must be meticulously determined through rigorous experiments. Soil samples are collected along the proposed road alignment to assess soil properties such as consistency limits, particle size distribution (sieve analysis), and CBR values. These parameters are then used to design the appropriate pavement thickness for flexible pavements. Additionally, the road alignment is meticulously designed and established using precise surveying and leveling techniques. In this study, the total length of the road being designed and analyzed is 257 m. California Bearing Ratio tests were conducted in the laboratory to obtain accurate and reliable data for the pavement design. This comprehensive approach ensures the pavement structure can adequately support the anticipated traffic loads, thereby enhancing the road's longevity and performance.