Asphalt Reinforcement

Controlling reflective cracking with Tensar

Reflective cracking in asphalt pavements typically occurs over the joints of underlying concrete slabs or cracks in cement bound base layers. Additionally, it can also be caused by the expansion, contraction and bending from thermally induced movement of the substrate, or by traffic induced shearing and in widening schemes by differential settlement where the old and new slight meet.

How Tensar asphalt grids and composites can help

Tensar’s asphalt reinforcement grids interact with the bitumen bound layer to add tensile stiffness, limiting asphalt strains and reducing the development of cracking. Furthermore, if and when cracks do eventually develop, they are generally much smaller. Structural asphalt grids can also reduce surface rutting associated with low stiffness mixes, subject to slow heavy wheel loading at high temperatures. Asphalt composites are grids bonded to a textile fabric that absorbs bitumen from the bond coat and can act as a stress relief membrane (also known as a Stress Absorbing Membrane Interlayer or SAMI). The fabric can also act as a barrier to assist in te prevention of water entering the pavement underlayers.

The benefits

Resist reflective cracking: asphalt reinforcement can reduce the development of cracks in the surface layer caused by the movement, bending and shearing of the concrete slab or cement bound substrate. The SAMI effect can also reduce strain in the overlay

Reduce fatigue cracking: reinforcement can reduce the traffic induced tensile strain in the bottom of the asphalt layer that leads to cracking, reducing the chance of cracking occuring

Control cracking due to differential settlement: with road widening, using Tensar TriAx™ geogrid to stabilise the new unbound aggregate layer plus a high modulus asphalt reinforcement layer can reduce longitudinal cracking caused by differential settlement

Reduce Surface Rutting: inclusion of a structural asphalt grid which interlocks with the asphalt mix may restrict lateral movement associated with surface ruts in low stiffness mixes

A proven solution

Over the last 25 years, Tensar’s asphalt reinforcement systems have been subject to extensive independent research and testing at many leading international institutions, including the UK’s University of Nottingham, with performance experience gained from several monitored installations in many countries.