ABSTRACT
ABSTRACT: Several laboratory procedures for the determination of moisture sensitivity of pavement materials are used globally. However, current methods of saturation followed by mechanical evaluation after conditioning, yield both variable and unreliable residual strength ratios when compared with retained stiffness test results. This paper presents a new developed simple device, called moisture induction simulation test (MIST) to assess moisture-induced damage based upon cyclic pulsing of water, at pressure, into a triaxial specimen. The study investigates different saturation levels with experimental determination of stiffness ratio (Mr) and shear parameters (c and ϕ) of bitumen stabilized materials (BSMs) i.e. with foamed bitumen or emulsion binder. Mix compositions of aggregate blends with and without RAP, with different bitumen binder types and the influence of additional active filler (cement or lime) are investigated. The rating of moisture induced damage by MIST device on BSMs is discussed. Test results are validated with the known laboratory model mobile load simulator (MMLS3) device. The study found that the accelerated moisture induction process using the MIST device has potential for use as a tool to condition BSMs specimens. The use of static triaxial mechanical testing to determine moisture damage in terms of the residual cohesion at maximum saturation levels shows better ranking of mixture in term of moisture damage than, for example, a tensile strength retained (TSR) test. The validation of MIST device test results with laboratory MMLS3 device shows agreeable ranking of BSMs.
