American Concrete Pavement Association
The k-Value is a commonly applied value in concrete pavement design. It estimates the composite of support of any subgrade(s) or subbase(s) layers below the concrete pavement surface course. This web applet allows you to determine the composite k-Value with consideration for up to three subgrade/subbase layers. The conversion from resilient modulus of the subgrade to k-value was updated in the fall of 2011 to better reflect published test results; the constant conversion factor of 19.4 as suggested in the AASHTO Guide for Design of Pavement Structures 1993 is no longer used.
To determine the composite k-value for a system of subgrade(s)/subbase(s), use the calculator tool below. First either provide a resilient modulus for your subgrade soil or use the calculator to estimate it, then select the number of subgrade/subbase layers to include between the natural subgrade and concrete pavement surface course and input modulus and thickness for each layer. Finally, click the calculate button to determine the composite k value of the system.
The user accepts ALL responsibility for decisions made as a result of the use of this design tool. American Concrete Pavement Association, its Officers, Board of Directors and Staff are absolved of any responsibility for any decisions made as a result of your use. Use of this design tool implies acceptance of the terms of use.