Discussion on paper by P. Gibbons and S. Cowan (2018) on “Subgrade Treatment design for expansive soils in Adelaide using Australian Standard AS2870 – Is this the right approach?“

The authors have provided a useful case study with a methodology adopted for a particular project, and then raised the broader question of the application of AS 2870 as a correct approach for subgrade treatment. There are many discussions and case studies for AS 2870 with respect to buildings (e.g. Cameron, 2018 in the same AGS volume), but only limited publications with respect to roadways. While AS2870 was developed for buildings, the question on whether the principles and methodology may be applied to roadways is one which requires some discussion and research. This discussion extends nascent questions to the authors and also to other researchers in this area. Gibbons and Cowans (2018) has data based on a “live” project which understandably may not have the benefit of wider data needed for fundamental research type questions posed herein.