Report

P123: Improved Subgrade Characterisation for Pavement Design Purposes: Subgrade Design CBR Less Than 3% (2020 21)

November 24, 2025

Queensland Department of Transport and Main Roads (TMR) limits the application of the rigid pavement design procedure and the mechanisticempirical method for the design of flexible pavements to subgrades with a design CBR of 3% or more. For the design of pavements with an in situ subgrade CBR less than 3%, TMR provides subgrade treatments which are assumed to increase the design CBR to an effective value of 3%.

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