Asphalt concrete HA

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As the safety of the road has become a major
concern in our society, the needs in skid resistance
have increased, especially on the exposed itineraries
(high speed, blends, braking…).
The skid resistance of a surface layer corresponds
to its capacity to mobilize friction forces between
the pneumatic and the road to allow acceleration,
vehicle’s guidance and braking.

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Asphalt concrete HA

  1. 1. Asphalt concrete HA Let’s keep your grip! The last one varies according to the geologic nature of the operated deposits, to the mineralogical composition and to the size of the minerals forming the rock. As the safety of the road has become a major The durability of the microtexture depends especially concern in our society, the needs in skid resistance on the resistance to polishing of the aggregates, have increased, especially on the exposed itineraries measured in the laboratory by the accelerated (high speed, blends, braking…). polishing coefficient called PSV (Polished Stone The skid resistance of a surface layer corresponds Value) according to the standard NF EN 1097-8. In to its capacity to mobilize friction forces between the pneumatic and the road to allow acceleration, vehicle’s guidance and braking. It depends on two characteristics: > the macrotexture of the surface layer (irregularities of the surface between 0.5 and 50mm), > the microtexture of the chippings (irregularities of the surface smaller than 0.5mm). the first approach, one supposes that the higher the PSV value is, the more material is "skid resistant". This durability can also be evaluated by the Wehner and Schulze test that allows to express the evolution of the skid resistance coefficient of materials or of an asphalt concrete in terms of traffic.
  2. 2. k ey figures Results of Wehner and Schulze test between an aggregate and two mixtures of aggregates PSV value higher than 56 More than 1.5 million tons of aggregates with high PSV produced by Eurovia every year v aried aggregates Eurovia, European leader in the production of aggregates, has a network of more than 400 quarries worldwide elaborating every year about 100 million tons of aggregates. In order to satisfy the requirements of the projects and the standards regarding PSV (NF EN 13043), Eurovia produces materials for surface layers with PSV values between 50 and 64. 0.5 0.4 0.3 0.2 Rugovia® TM 50% PSV = 52 + 50% PSV = 60 Rugovia® TM 80% PSV = 52 + 20% PSV = 60 Rugovia® TM 100% PSV = 52 0 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 The asphalt concretes for surface layers that have an exceptional skid resistance are now characterized by Eurovia with the letters HA. This concerns surface courses produced with aggregates or with a mix of aggregates with a PSV higher than 56. For example the very thin Microvia® TM, gap graded bituminous micro concrete 0/6, designed with aggregates the average PSV of which is higher than 56, becomes a Microvia® TM HA. c onclusive tests However, sometimes quarries located near the jobsites do not show the PSV conditions required in some bids. In the contrary, some high quality deposits are too far away to be economically competitive. By mixing high PSV aggregates with good quality materials but with lower PSV, it is quite possible to meet the needs of the client. When laying different VTLAC on highways with high traffic the surface characteristics at early stage have been compared. There are several advantages: Proposing a performing technical solution at competitive price, Offering a new perspective to quarries far from activity centers, Average SFC PSV (NF EN 1097-8) (NF P 98-220-3 and 4) VTLAC 51 0.64 VTLAC HA no. 1 58 0.68 VTLAC HA no. 2 51 (80%) 58 (20%) 0.67 Rugovia® et Microvia® are registered trademarks. Saving high potential resources. 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 - October 2013 - 500 copies – Photos: Eurovia photo library t he winning mixture

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