Measurement of the viscoelastic properties of bituminous materials using an oscillating needle technique

An embedded oscillating needle is used to measure the dynamic viscoelastic properties of a stiff bituminous material. A Micro-Fourier Rheometer was us ed to cause the embedded needle to undergo pseudorandom small amplitude osc illations in the axial direction with measurement of the instantaneous resi stance force. The phase and magnitude of the force signal are used to calcu late the storage and loss moduli. A theoretical framework for this techniqu e is developed from the Mindlin solution coupled with slender body theory, and the correspondence principle of linear viscoelasticity. Experiments are performed on neat bitumen binders as well as mixtures of glass spheres in bitumen; the results show that the presence of the glass spheres dramatical ly increases the viscoelastic response functions. The results agree reasona bly well with those obtained using the parallel plate squeezing mode.