Design of Pavements Incorporating Grouted Macadams

Abstract

Grouted macadam, a material that consists of a porous asphalt skeleton with 25–35% voids, filled with a cementitious grout, has traditionally been used as a specialist surfacing with excellent resistance to both deformation and fuel spillage. However, the actual engineering properties of the material have rarely been investigated in depth and design of pavements incorporating grouted macadam has relied heavily on past experience. The purpose of this study was to assess the consequences of applying analytical pavement design methods to pavements incorporating grouted macadam layers. Two different design methodologies were tested: (1) a conventional approach based on the traditional fatigue criterion used for bituminous materials; and (2) an iterative approach, which took realistic account of the actual damage accumulation within the material. For both methodologies, a comparison was made between a grouted macadam and a conventional bituminous mixture. The main conclusion drawn from this study is that extended fatigue life can be obtained from pavements incorporating grouted macadam although this advantage will be overlooked if design is carried out using the traditional fatigue failure criterion.