Rheological simulation of bituminous mixes with crumb rubber by the dry process

There is compelling evidence supporting the benefits of incorporating crumb rubber to enhance the properties of bituminous mixes. The main aim of this paper is to investigate the effect of crumb rubber on the rheological properties of bituminous mixes using the dry method. A comparison was made in terms of linear viscoelastic behaviour, between five mixtures including the control mixture and four mixtures modified with 1% or 2% crumb rubber added and the various bitumen content. This modification was conducted to replace a portion (volume) of the aggregate with an equivalent volume of crumb rubber. Complex modulus tests on cylindrical specimens were carried out for each mixture by the tension-compression method. The complex modulus tests were carried out over a wide range of frequencies (from 0.01 to 10 Hz) and temperatures (- 25 to 45 degrees C). The specimens are obtained by sawing laboratory specimens in accordance with a gyratory compactor with an air voids content of not more than 1%. The results are modelled and calibrated with the 2S2P1D rheological model. All mixtures have similar rheological behaviour and respect the specification of a BB 0/15, with a modulus values (15 degrees C, 10 Hz) is greater at 7000 MPa.