THE PROBLEM
Total reconstruction of a 400m length of the road pavement was required due to deterioration of the existing pavement structure. However only 600mm total thickness was available due to underlying services. This was considered insufficient using traditional construction.
THE SOLUTION
The use of Tensar TriAxTM geogrid to reduce the sub-base thickness and asphalt reinforcement to increase the strength of the bituminous layers.
PROJECT DESCRIPTION
The pavement of Lavender Road, Enfield consisted of bituminous material overlying concrete on a soft becoming firm sandy clay formation. The pavement had deteriorated to the point where full reconstruction was necessary but only 600mm thickness was available due to the presence of underlying services. Half of this is bituminous material therefore only a 300mm thickness was available for the granular sub-base. This would be insufficient based on a formation CBR of 1%.
London Borough of Enfield’s Design Engineer, Darren Bryant reported, “Following previous experience of the use of Tensar geogrids to reduce granular layer thicknesses, we contacted Tensar to discuss the possibility of reducing the thickness to 300mm. This was achieved by using Tensar TriAx geogrids and limiting construction traffic travelling on the unsurfaced sub-base.’’
“Due to the reduced thickness we decided to strengthen the pavement layer further by the use of the asphalt reinforcement product Tensar Glasstex® placed between the road-base and the binder layer.’’
