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Safer and greener road pavement with Granella®

Over fifteen thousand cubic metres of Granella® to resurface the Mestre by-pass on the A4 motorway with a draining and sound-absorbing layer.

The A4 highway trusts the Pittini Group

Granella® by the Pittini Group will be the protagonist of the ordinary maintenance program involving large sections of the road surface and joints of the road network granted to CONCESSIONI AUTOSTRADALI VENETE – CAV SPA.

This innovative material originates as a by-product of industrial waste and gains new life in a different production cycle.  In fact, the Pittini Group has succeeded in recycling steel production waste and transforming it into a new product with extremely interesting physical and mechanical characteristics, which is much valued as an artificial aggregate in the construction of bituminous surfaces.

The intensive traffic of heavy vehicles, which affects the section of the A4 Mestre by-pass, an important artery for road traffic in Northern Italy, requires special attention as far as safety and maintenance are concerned, which are the main causes of inconvenience to users and disruption.

In the quest to draw together the need to guarantee the performance of the road surface for its duration and expected load conditions and to ensure environmental sustainability, Works Management has chosen Pittini – Ferriere Nord as its supplier.

Granella® is better than natural aggregates

The adhesion coefficient depends on the characteristics of the road surface, especially the roughness of the wear layer. Continuous stresses produced by traffic cause a progressive deterioration of road surface performance, which depends on polishing of aggregates: in fact, reducing surface porosity decreases adhesion.

The use of Granella® increases the micro-roughness of the road surface and ensures durability, since deterioration of the mechanical characteristics, resistance to fragmentation and of the functional features is very slow, even where there are significant volumes of traffic.

The high PSV, Polished Stone Value, of Granella® ensures at least an additional 10 CAT, Transversal Adhesion Coefficient, points compared to surfaces made with conglomerates containing natural aggregates – basalts, porphyries, diabase – hence increasing the adhesion and control of vehicles in all situations.

In addition, the advantage of Granella® is its higher sustainability: by significantly reducing the use of depletable natural raw materials, it is able to meet the needs of attention and respect for the environment.

During the maintenance program, which started in 2018 and is forecast to end in 2022, a total of 430 thousand square metres of road will be resurfaced, thanks to the use of over 15 thousand cubic metres of Granella® in two different grain sizes: 4-8 mm and 8-14 mm.

After milling the existing layer, a bituminous emulsion is applied, followed by a single layer of modified high viscosity bitumen and synthetic aggregates, Granella®. The works will be completed when all horizontal road signs have been put in place and normal vehicle circulation is restored.