What Is the AASHTO Subgrade Resilient Modulus (CBR) Calculator?
Convert California Bearing Ratio (CBR) to subgrade resilient modulus MR in MPa and psi, AASHTO layer coefficient a3, and roadbed support classification.
The AASHTO Subgrade Resilient Modulus (CBR) Calculator is an analytical tool in the construction domain designed to evaluate California Bearing Ratio (CBR), Correlation Model, Moisture Condition using verified mathematical equations. It provides reproducible, deterministic calculations for academic, professional, and practical applications.
How Does the AASHTO Subgrade Resilient Modulus (CBR) Calculator Work?
This calculator computes results by taking input values for California Bearing Ratio (CBR), Correlation Model, Moisture Condition and applying the governing equation: Standard AASHTO correlation linking California Bearing Ratio penetration resistance to cyclic elastic resilient modulus.. Values are checked for dimensional consistency and processed through standard arithmetic routines.
AASHTO Subgrade Resilient Modulus (CBR) Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Standard AASHTO correlation linking California Bearing Ratio penetration resistance to cyclic elastic resilient modulus.
How to Use the AASHTO Subgrade Resilient Modulus (CBR) Calculator
- Enter your value for California Bearing Ratio (CBR) in %.
- Enter your value for Correlation Model.
- Enter your value for Moisture Condition.
- Verify your input parameters to ensure they match your design or problem specifications.
- Review the calculated results, intermediate mathematical steps, and graphical visualization below.
Step-by-Step Example Calculation
Standard Clayey Silt Subgrade (CBR = 6%)
Input Values:
Understanding Your Result
The calculated output gives the primary solution for AASHTO Subgrade Resilient Modulus (CBR) under the specified conditions. Use this value to compare against standard design tolerances, benchmarks, or reference ranges in construction.
Factors That Affect the Result
- Input precision and measurement accuracy of California Bearing Ratio (CBR), Correlation Model, Moisture Condition.
- Operating conditions, environmental parameters, and specific construction tolerances.
- Boundary constraints and deviations from nominal theoretical model assumptions.
When Should You Use This Calculator?
- When performing technical analysis or dimensioning related to AASHTO Subgrade Resilient Modulus (CBR).
- To cross-verify manual calculations or theoretical models in construction.
- For preliminary estimates before conducting detailed field measurements or laboratory testing.
Assumptions & Limitations
- The linear relation MR = 1500·CBR is specifically recommended for fine-grained soils with soaked CBR ≤ 10%.
- For coarse granular materials (CBR > 10%), power-law relations prevent overestimating subgrade stiffness.
Frequently Asked Questions
What is the difference between CBR and Resilient Modulus?+
How does seasonal soaking affect MR?+
Calculation Accuracy & Reference Note
This calculator implements verified mathematical formulas for AASHTO Subgrade Resilient Modulus (CBR) Calculator. Always verify critical results against official domain standards and manufacturer documentation.