Laboratory Assessment of Coarse Granular Road Foundation Materials

A new performance-based specification for road foundations in the United Kingdom potentially allows any material that is fit for purpose and encourages the wider use of marginal and recycled-secondary materials. The specification provides guidance with respect to target stiffness, density achieved, and maximum allowable rutting depth under construction traffic (to avoid damage to the subgrade during construction). Full-scale field trial sections are proposed for large schemes to ensure the suitability of proposed foundation materials. However, it is prudent to develop a routine, economical, and laboratory-scale means of assessing the performance and suitability of the foundation materials before any full-scale trials are undertaken. This paper presents the findings of recent research work at Loughborough University with regard to the development of a large-scale laboratory assessment test designed specifically for granular materials. A series of tests done on four granular materials is presented in deta...