Road trials have been carried out to assess the potential for using bituminous materials to replace thicker layers of granular materials in road construction. The trials showed that, provided the foundation was strong enough to support the construction traffic, asphalt substitution designs with 30 mm of bituminous material replacing 100 mm of granular sub-base were structurally equivalent to standard designs. The choice of design will depend on the relative cost of the two forms of construction and on the problems that may arise from using a thinner granular foundation. Asphalt substitution has the greatest potential benefit in reconstruction where its use will lead to more economic and faster construction that will reduce the cost of traffic delays at roadworks.
Abstract