Technical Investigation of the Usability for Foamed Bitumen Stabilized Materials inAsphalt Pavements

Abstract

Asphalt recycling efforts are increasing in order to reduce the effects of high energy and rawmaterial consumption in the asphalt sector. One of the most common methods for using oldasphalt material, which still retains some value, is recycling with foam bitumen.In practice, for the preparation and evaluation of cold mixes produced using foam bitumen, ITS(Indirect Tensile Strength) and MR (Resilient Modulus) methods are generally used. Amongthese methods, ITS is mostly applied for the evaluation of the materials optimum percentagesvalues and MR test is also used for the evaluation of mixture performance.In the experimental study, firstly for the cold mixes prepared with foam bitumen, optimum foambitumen values of the production series were determined by ITS test. Then, reproductions weremade for these optimum values and resilient modulus values were determined. It was found thatthe ITS and MR values were significantly affected by the material gradation and this showedthe opposite tendency for the materials with the same gradation. The type of active filler waseffective the same as the values of the mixtures on ITS and MR. Especially, the MR resultswere affected by the bitumen grade. As a result of the study, evaluation limit values; 225 kPafor ITSDRY value, 150 kPa for ITSWET value and 70% for TSR, 400 MPa resilient modulus valueand 0.21 layer coefficient value are recommended for FBSM (Foam Bitumen StabilizedMaterial).