Linear and non-linear viscoelastic behavior of SBS and LDPE modified bituminous mastics

• Dynamic shear/torsional tests as a tool to evaluate mastics’ in-service performance.
• Marked differences between binders/mastics rheology due to filler contribution.
• Improved elasticity at 55 °C if 3 wt.% LDPE binder is loaded with 65 wt.% filler.
• Reduced non-linear strain susceptibility at 25 °C in 3 wt.% SBS modified mastic.

This article compares bituminous mastics modified by either the tri-block copolymer styrene-butadiene-styrene (SBS) or low density polyethylene (LDPE). Linear and non-linear oscillatory measurements were conducted at 25 and 55 °C, taken as representative of the medium and high in-service temperatures, respectively. For 3 wt.% polymer, distinct rheological responses were found. The LDPE-mastic showed enhanced linear complex shear modulus and elasticity at 55 °C. Conversely, if subjected to deformations beyond the linear viscoelasticity (LVE) limit, the SBS-mastic presented an improved capacity of complex modulus recovery, at 25 °C, when it returned to the LVE regime.

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