Functional requirements for asphalt mixture in the contract

The feasibility of property-related requirements to replace composition-related requirements for asphalt mixture was investigated. The investigation was undertaken to show that performance related requirements limiting the empirical character of the current requirements can be beneficial to innovation in the field of pavement design and paving materials. A laboratory investigation was conducted to determine the performance properties of base course layer material crushed stone asphalt concrete and the variation in those properties. Based on the findings from that investigation, four road trials were conducted under performance related requirements in the contract. A Producer’s Declaration specifying the asphalt mixture’s composition and performance related properties, including mixture constituents, and manufacture and processing conditions, substituted the traditional Marshall mixture design investigation. It is concluded that it is feasible to apply property-related requirements in the contract with the newly developed European Norms, however, that the standardisation of the tests needs continued attention to improve the discriminatory abilities of the tests.