Pavement improvements with Tensar Glasstex

Tensar's Glasstex paving composite, has extended pavement life for Hertfordshire Highways by reinforcing the asphalt layer on a badly cracked road.

Tests by Hertfordshire Highways (Hertfordshire County Council's highways department) have confirmed that using Glasstex on the busy roundabout in Hitchin, has extended pavement life by at least 4 years bringing about 40per cent savings in road maintenance.

Sample cores taken from the reinforced pavement at the Meadowbank Roundabout, on the A505 Cambridge Road, were compared with samples from the adjoining unreinforced road.

Paul Patmore, Senior Engineer at Hertfordshire Highways who worked on the project, said: "Using the Glasstex for asphalt reinforcement has produced unexpectedly good results, which will not only save costs, but also bring benefits for road safety and reduced traffic disruption.

"Glasstex has clearly succeeded in mitigating the development of reflective cracking, and prolonging pavement life and maintenance intervals on the site.

We would now certainly consider using it in similar circumstances elsewhere on our roads".

Some 2000m2 of Tensar Glasstex composite were installed at the site 10 years ago, during major re-surfacing and strengthening of the approach roads and roundabout.

The roundabout and its immediate approaches in particular had suffered severe loading from quarry lorries and buses including high multi- directional shear stresses from the associated cornering, braking and acceleration forces.

Heavy fractures in the concrete base had produced extensive reflective cracking in the asphalt surface layer.

To provide a solution, 90 mm of asphalt was milled off at the roundabout and adjoining stretches of the A505.

At the roundabout and immediate approaches, hot 200 pen straight run bitumen was spray applied, over which specialist installer Foster Contracting machine laid the Tensar Glasstex.

To complete the road surface, a conventional HRA binder course and then a 30mm asphalt surfacing layer were laid over the Glasstex.

Within six years, the unreinforced roadway had deteriorated sufficiently to require resurfacing, while the Glasstex reinforced roundabout did not warrant any remedial work.

After ten years in service, the roadway was again showing signs of wear, and Hertfordshire Highways and Foster Contracting decided to investigate the state of the materials and degree of cracking.

The Tensar Glasstex had been laid over different bases varying from crumbling concrete and asphalt to sound asphalt.

Coring revealed that the Glasstex appeared to be undamaged, well coated with bitumen and fully bonded to the upper and lower layers of pavement.

Over particularly badly crumbled base areas, some cracking could be seen to appear in the overlay, but, in comparison to the unreinforced A505 road, these were negligible.

"With an ageing road network and ever rising costs," commented Craig Andrews, Tensar Area Civil Engineer, "highways engineers should consider using proven asphalt reinforcement solutions like Glasstex.

It extends road life, reduces maintenance and provides a very cost effective alternative to more radical requirements such as completely replacing the pavement base".

Back to top