In Cheltenham, we often see that the biggest threat to a new road isn't traffic loading but what sits beneath the surface. The town spreads across Lower Lias clay formations and pockets of Cheltenham sand, and on the western edge you encounter the Cotswold limestone brash. Each of these materials behaves differently under repeated wheel loads, and a flexible pavement design that works on the gravelly outskirts will fail prematurely if copied onto the expansive clays near Pittville. We combine site-specific CBR testing with layered elastic analysis to produce a pavement structure that matches the actual subgrade, not a textbook assumption. Before finalising the formation level, many project teams also commission a CBR road investigation to validate the design modulus across the full alignment, which is particularly useful where the geology transitions within a single site.
Getting the foundation right on Cheltenham's variable clays can double the service life of a flexible pavement before the first structural intervention is needed.
