Asphalt overlays need protection from the shortcomings of the surface upon which they are laid. All too often, the life of the new asphalt is greatly reduced by the cracks propagated from the joints or faults in the underlying surface. This then allows water and salts to penetrate and the rapid deterioration of the surface asphalt begins.
It is becoming increasingly common for an anti-crack membrane to be installed before laying new asphalt to reduce this problem.
Cracks in the highway emanate from either;
Stress Absorbing Membranes are used when reflective cracks are showing through from layers below the surface, known as reflective cracking.
Whether the wearing course layer is removed and replaced or simply overlaid, movement in the sub-layers which created the cracked surface in the first instance will, without some form of treatment, create new cracks in the new surface. This cracking will propagate at a rate of approximately 1 year for every 25mm of wearing course applied.
Treating the cracks with a Stress Absorbing Membrane prior to overlay, provides the following benefits:
Jointmaster is a polymer modified, rubberised bitumen compound containing glass fibre reinforcement. The compound is applied as a molten screed directly over the cracks and joints in the surface prior to being overlaid. It fills and seals the cracks in one pass, leaving a membrane focused solely at the point where the movement is concentrated.
This systems offers savings over full surface membranes as the material is laid only at the points where the movement is causing an issue.