There is a significant increase in traffic loading on most roads in the developing African
countries, and South Africa is one of them. Often this increased traffic loading results in the
premature failure of pavement structures. Mechanistic-empirical (M-E) design methods based
on fundamental principles are better able to accommodate changes in the design environment.
The successful use of design methods depends on the accuracy of the input material
parameters. Therefore, as design is moving towards M-E design methods, there is a need for the
material parameters to reflect the actual pavement response to dynamic loads. The objective of
this paper is to report on the investigation of the response of cement-stabilised sub-base layers
to dynamic load by evaluating stiffness at a known strain level. This stiffness was compared
with those derived from unconfined compressive strength (UCS) tests performed at static load.
The strain and stiffness values were also evaluated against compacted density, cement content,
moisture content and material type. It was found that stiffness of some of the cement-stabilised
sub-base layers may possibly be overestimated through the use of static loads.