Novel bituminous mastics for pavements with improved fire performance

Novel bituminous mastic formulations with performing viscoelastic and mechanical properties and improved resistance to fire, are investigated. The practical performance of the mastics for pavement purposes is analysed. The study is focused on the effectiveness of different sepiolite clays and their mixtures, combined with the fire retardant action of aluminium trihydrate (ATH). Our results indicate that the performance against fire is favoured by the high porosity and density of the sepiolite, and by its lack of affinity with bitumen. Mixing two types of sepiolites we obtain a mastic which presents a synergism between the good cohesion/adhesiveness of one of the formulations and the improved fire performance of other one.

► We obtain bituminous mastics with good mechanical properties and resistance to fire.
► The mixture of Al(OH)3 with Ca(OH)2 gives better results than that with CaCO3.
► Unmodified and porous sepiolite gives good fire performance, but bad adhesiveness.
► Modified sepiolite gives a mastic with good adhesiveness, but bad fire resistance.
► Mixtures of both sepiolites and Al(OH)3 are employed to formulate a suitable mastic.