Behavior of Some Pavement Foundation Materials Under Repeated Loading

Abstract

A wide range of alternative materials for pavement construction were studied, and assessment techniques to enable and increase their use were developed. Five secondary materials and a conventional crushed granite were considered for use in an unbound form or lightly treated with various binders (including primary and secondary binders) in a total of 11 road pavement subbase materials. The secondary materials studied were minestone, china clay sand, slate waste, fly ash, and furnace bottom ash. The laboratory program set up for this research essentially was based on repeated-load triaxial tests, and the techniques used for specimen preparation, conditioning, and testing for resilient behavior are described. In particular, the modifications of the procedures recommended by the European Committee for Standardization necessary for testing secondary materials are identified and described. The analysis of the resilient behavior of the materials studied led to the identification of two groups with identical characteristics: unbound type of behavior (which included lightly treated mixtures), and treated type of behavior. A definition of boundaries for those groups was attempted. The mechanical properties of these materials necessary for use in analytical methods of pavement design are also presented, and the implications of treatment in terms of triaxial strength and resilient modulus are discussed.