REFLECTIVE CRACKING RESISTANT SAND-ASPHALT

VIASAFProtection for durability

KEY BENEFITS

Longer pavement service life

Greater user safety

Simple application

KEYFIGURES

Surface cracks on roads, both visible and invisible, not only reduce driving comfort for motorists

but also and above all entail a risk of rapid pavement deterioration as water seeps into the

pavement structure.

For this reason Eurovia has developed a number of techniques to prevent reflective cracking.

These techniques can be used in both corrective and preventive maintenance.

The versatile and effective Viasaf solution is suitable for use in both maintenance and new

construction.

VIASAF REFLECTIVE CRACKING RESISTANT SAND-ASPHALT

Shrinkage-bending test devised by the Laboratoire régional des ponts et chaussées in Autun

Viasaf has been tested in a variety of configurations:

> 15mm Viasaf + 50mm SCAC> 15mm Viasaf + 35mm Rugovia® M> 20mm Viasaf + 40mm Rugovia® M

All these complexes were classified "very effective" (r > 0.9).

Viasaf is a reflective cracking resistant sand-asphalt. It is applied in an intermediate layer over a cracked (or potentially cracked) substrate. It prevents the propagation to the pavement surface of thermal shrinkage cracks in materials treated with hydraulic binders and in concrete slab joints.

Viasaf dissipates the stresses caused by variations in crack opening and offers excellent elongation and self-repair characteristics.

Viasaf also offers good rutting resistance and sufficient cohesion to ensure that the surface course is not subject to fatigue loading.

These technical requirements are achieved thanks to a binder selected from among the Eurovia-devised range of Polybitume® polymer-modified bitumens or from the Styrelf® range of binders.

Viasaf acts as a membrane that can be sufficiently deformed to absorb the stresses induced by cracks and joints.

Applied in a thickness tailored to the level of traffic, the surface course that must be laid in conjunction with Viasaf ensures the excellent skid resistance required for user safety.

Results:

> pavements better protected from cracking

> enhanced driving comfort and safety

> a durable and therefore cost-effective investment.

ELIMINATING CRACKS

Viasaf formulas have a high richness modulus (about 5.5) and a high fines content (12 to 15%). These mix designs contain 8 to 10% binder and are very rich in mastic to ensure achievement of the desired properties. They are applied with conventional roadworks equipment.

Viasaf has a special composition based on a dense 0/4 or 0/6mm grading and is very rich in highly polymer modified bitumens. It is applied in an average thickness of 20mm.

The Laboratoire Régional des Ponts et Chaussées laboratory in Autun has devised a shrinkage-bending test that simulates the opening of a shrinkage crack under traffic. The material to be tested is bonded to a pre-cracked asphalt mix and subjected simultaneously to slow elongation and cyclical vertical bending. A ratio (r) is established between the time it takes for the test material to crack and that taken by a control complex made up of 20mm sand mixed with pure bitumen and overlaid with 60mm of semi-coarse asphaltic concrete (SCAC), also made with pure bitumen.

All the complexes tested with Viasaf were classified as "very effective".

The rutting resistance of Viasaf is very satisfactory, as illustrated in the results obtained for a complex made up of 20mm Viasaf and 40mm Rugovia® M.

Rutting depths are substantially less than those required for thin layers of asphaltic concrete (EN 13108-1 standard).

TECHNICAL DEPARTMENT

18, place de l’Europe - 92565 Rueil-Malmaison cedex

Tel.: +33 1 47 16 38 00 - Fax: +33 1 47 16 38 01

www.eurovia.com

technique@eurovia.com

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FLEXIBILITY AND STRENGTH COMBINED WITH DURABLE PERFORMANCE

Rutting depth measured at 60°C according to the EN 12697-22 standard

at 1,000 cycles 6.5%at 3,000 cycles 7.5%at 10,000 cycles 8.9%