Table of Contents
This case study examines the application of the California Bearing Ratio (CBR) method in designing a durable pavement. The CBR method is widely used to evaluate soil strength and determine appropriate pavement thicknesses for various traffic conditions.
Project Overview
The project involved constructing a roadway in an area with variable soil conditions. The primary goal was to develop a pavement structure that could withstand heavy traffic loads while minimizing maintenance costs. The CBR test was selected to assess the subgrade strength and inform the design process.
CBR Testing and Results
Samples of soil were collected from multiple locations along the proposed route. The CBR tests indicated values ranging from 5% to 15%, reflecting different soil strengths. These results were used to classify the subgrade and determine the necessary pavement thickness.
Pavement Design Process
The design incorporated the CBR values into standard pavement design charts. For areas with a CBR of 5%, a thicker base layer was required, while sections with higher CBR values needed less material. The final design included:
- Subgrade preparation
- Layered asphalt pavement
- Drainage considerations
- Material specifications
Outcome and Benefits
The implementation of the CBR-based design resulted in a pavement that performed well under heavy traffic conditions. The project demonstrated that using CBR testing can optimize material usage and improve pavement longevity, reducing long-term maintenance costs.