The first full-scale accelerated pavement testing experiment initiated in Louisiana started in February 1996. The purpose was to evaluate the historically prevalent flexible crushed stone and in-place soil cement stabilised base construction in comparison to several alternative base construction materials and construction processes for pavements designed in a semitropical climate. More than six million equivalent axle loads (ESALs) were applied to six test lanes in the first two phases of the project. The full scale loading is provided by an ALF machine, the second of its type in the United States. Surface deflection, longitudinal and transverse profiles, surface cracking, stresses and strains in the pavement structure, as well as the environmental conditions, were monitored during testing. The paper presents the initial findings in relation to rutting, roughness, cracking, layer modulus and stress/strain evolution. The experiment showed a reasonable agreement between the life of tested structures and the life predicted by the current procedure, based on the AASHTO 1993 Design Guide. The comparative tests gave a layer coefficient for a stone stabilised soil sub-base and highlighted the benefits of an inverted pavement structure in high moisture conditions. The great effect of interface bonding between layers on pavement performance was also shown. (A)
Abstract