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 of new asphalt to reduce this problem.
Rhino can offer two solutions to combat reflective cracking when overlaying cracked concrete and asphalt surfaces.
Causes of cracking
Cracks in the highway emanate from either;
- The surface; where the surface course is fatigued by the traffic
- The sub-base; from movement of the underlying layers
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.
Treatment options
Treating the cracks with a Stress Absorbing Membrane prior to overlay, provides the following benefits:
- Seals the cracks against further water ingress
- Bridges the crack, shifting the concentration of movement across a larger area, minimising its impact
- Increases the time until reflective cracks will show through the new surface
- Keeps water out of the sub-structure for longer
We have two options available to you
- Option 1: We supply and install a molten screed system which treats just the cracks and joints
- Option 2: We supply a complete self adhesive membrane for you to install yourself
Stress Absorbing Membrane Interlayer. Full contracted supply and apply.
Jointmaster SAMI (Stress Absorbing Membrane Interlayer)
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.
- Full supply and apply contracting service
- Selectively treats just the cracks and joints, not the whole surface
- Proven to significantly reduce the occurrence of reflective cracking
- Able to be trafficked by site traffic
- Provides a watertight seal
- Fast installation, up to 500 lin.m achievable in a shift
- Can be applied throughout the year
- Applied in recommended widths of 200mm for longitudinal cracking and 300mm for transverse
- Treatment applied at 5mm thickness when overlaying with 75mm of new asphalt
- Treatment rebated into the surface by 10mm or 20mm for thinner overlays
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Anti crack membrane for self installation.
For self installation, the Rhino stress absorbing membrane is available to be applied by your own surfacing crews.
Rhino SAMi sandwiched between layers of asphalt
Rhino stress absorbing membrane is a pre-formed membrane which is cold applied directly onto the road surface prior to overlay. It can be laid onto a planed or unplaned surface. Suitable for concrete or asphalt. This membrane comes as a 1 metre wide roll in 20 lin.m lengths and can be cut to suit. A triple layer construction consists of a self adhesive bituminous compound, a reinforced crossover glass fibre mesh and a polyethylene film. The film melts upon application of the hot asphalt, binding the reinforcing layer into the structural matrix of the new road.
- Waterproof membrane sealing the underlying layers, eliminating damage caused by water pumping.
- No specialist skills or equipment required to install.
- Self adhesive bituminous compound which is cold applied and very easy to stick down.
- Can be applied directly onto milled or un-milled surfaces, asphalt or concrete, all without need for tack coat.
- Traffickable by site traffic without rucking up or detaching.
- Supplied in rolls 20 metres long by 1 metre wide for installation by your own crews.
| Technical Information | Value | Test |
| Thickness | 1.5mm ± | EN 1849-1 |
| Mesh Melting Point | >400⁰c | ASTM D 276 |
| Tensile Strength Long | >40,000 N/m | ISO 4606 |
| Tensile Strength Trans | >24,000 N/m | ISO 4606 |
| Elongation at Break Long | 2% | ISO 4606 |
| Elongation at Break Trans | 1.6% | ISO 4606 |
| Adhesion Strength | >250 N | ASTM D 1000 |
| Vapour Permeability | 77.85 kg/m²*s*Pa | UNI EN 1931 |
Installation in Sheffield
Sheffield City Council chose Rhino preformed self adhesive membrane prior to renewing the asphalt wearing course on Tonwnhead Street at the approach to a busy junction. 3 rolls were purchased (total 60sq.m) to help alleviate cracking in the surface on this bus route
Townhead Street, Sheffield prior to the renewals
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The first roll of membrane goes down on the planed |
2nd roll warmed a lttle with a gas torch. It was a cold |
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| Working along the site. Each roll 20 metres long by 1 metre wide |
Site plant driving on the membrane |
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| Sheffield City crew preparing the first rip of asphalt | Hot asphalt applied directly onto the membrane |
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| The initial layer of surfacing | Rolling the apshalt |
Registered Office: One Bell Lane, Lewes, East Sussex BN7 1JU Company Registration No 04006938