Lincolnshire County Council approves RoadMesh® to reinforce asphalt used in A151 road strengthening scheme
31/07/2000
Maccaferri Ltd, specialists in retaining structures, slope reinforcement and erosion protection, is re-launching its RoadMesh® hexagonal steel mesh following a period of research and product development. Primarily used to prevent surface cracking in flexible asphalt pavements, RoadMesh® has been approved for use by the Highways & Planning Directorate at Lincolnshire County Council for the A151 Bourne – Twenty road strengthening scheme.
A single carriageway road, the A151 is seven metres in width. In a contract with a total value of £240,000, Maccaferri supplied main contractor, RMC Surfacing (Eastern) Ltd, with 9,400 sq. m of Type L RoadMesh® in 25m rolls at a cost of £24,500.
Lincolnshire County Council specified mesh reinforcement to prevent surface damage caused by the cyclic shrinkage and swell typical on the County’s fen roads. Incorporating a mesh grid strengthens the asphalt and assists in preventing ruts and other surface damage. When considering which type of mesh material (steel, glass fibre, polymer or geocomposite) offers the optimum asphalt reinforcement, two key factors must be considered, material stiffness and interaction stiffness.
Of the three, steel mesh offers inherent material stiffness. Recent research work has also demonstrated that Maccaferri’s steel RoadMesh® achieves significantly greater interaction stiffness with the surrounding bituminous materials than other readily available grids.
Thin section grids with a low profile, for example glass fibre grids, do not generate good interlock with the existing or newly placed bituminous layers. Geocomposite materials with a smooth geotextile base also inhibit good interlock reducing interface stiffness. Lincolnshire CC has used various grids on its fen roads in the past, but based on experience and a site trial, a steel mesh was specified for the Bourne to Twenty project.
Commenting on the resurfacing, Tim Mawson from Lincolnshire County Council said: “It was a very straightforward job. While it is too early to put a figure on it, I am sure RoadMesh® will extend the life of the road surface.”
Available in two specifications, Type S is used in the construction of new roads and is laid near the foundation strata where it will improve the load bearing capacity. Type L, the type used by Lincolnshire County Council, can be laid immediately under the top surface to control reflective cracking and lower down for structural reinforcement.
Featuring a double twist wire mesh manufactured from galvanised mild steel, the new RoadMesh® has strong straight transverse bars at regular spacing to provide additional reinforcement.
Highway engineering materials are a recent addition to Maccaferri’s range of structural engineering solutions. The company has participated in recently completed research work at Nottingham University studying the effect of reinforced bituminous layers.
Maccaferri is also represented at the Nottingham Asphalt Research Consortium (NARC), chaired by Professor Brown, Head of Faculty at the University. Providing the commercial perspective, Maccaferri’s Technical Director, Philip Staten is one of the industry representatives on the Consortium.
Maccaferri believes that the recent research work at Nottingham coupled with verifiable trials will provide a cost benefit analysis demonstrating the extent to which mesh grids extend the life of road pavements. In addition, Philip Staten also represents Maccaferri on the HAPAS Special Group 11, set up to arrive at guidelines to assess and measure new materials and methods of construction.
The UK subsidiary of an Italian-based engineering company, Maccaferri Ltd specialises in gabions, geotextiles, geogrids and geomats. In addition to a full range of products for retaining structures, slope reinforcement and erosion protection, the company offers an in-house design and consulting service.
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