The technique of ultra-thin white topping, which has been used in the USA since the beginning of the 1990s, is characterised by a thickness of between 5 and 10 cm. They are characterised by a mesh of closely spaced joints in which the distance between the joints depends on the thickness. This is a technique that is used mainly for urban applications (crossroads, bus stops, parking areas, etc.) and on roads where the traffic levels are low to moderate. To define the aspects of design and implementation more clearly, a programme of on-site trials has been defined. An initial phase, carried out at the end of 1999, was made up of four test areas of 240 sq.m. each, installed on the N50 - Tournai entity, close to a heavily frequented commercial zone. With thicknesses of 5, 6, 8 and 10 cm, each test area was divided into 2 sections, one of which included steel fibres. The second phase is scheduled for 2002 and, while adopting the same construction design for the concrete wearing course (four « inlay » test areas produced after milling the existing asphalt surface), special attention will be paid to the bonding with the support by installing a new bituminous layer first, as well as varying the interface conditions
