Prismo Group — Quality Reflects

Solution

ThormaJoint – The original asphaltic plug bridge expansion joint system. Over a million linear metres of ThormaJoint have been installed worldwide in conditions from the arctic to tropical climates. ThormaJoint is engineered for use across the full bridgedeck including footways and kerb areas. With our worldwide group of licensees and trained crews covering our global customer network you can be sure the quality of the installation lives up to the reputation of the product.

Bridge expansion joints are subject to water and salt penetration or mechanical failure which, if left untreated, puts structures and bearings at risk. Serious damage can follow quickly. Many jointing systems currently available have proven ineffective or prohibitively expensive. ThormaJoint asphaltic plug joint system is an effective solution to this problem. Asphaltic plug joints consist of a flexible mixture of bitumen based binder and stone which is recessed into the road surfacing above the expansion gap in the bridge structure. This flexible ‘plug’ of material provides movement capability to allow the bridge to move under the actions of traffic and changes in temperature of the bridge. ThormaJoint is flexible to accommodate movements at the bridge gap but at the same time it is stiff enough in a vertical direction to support loading from traffic. The material is waterproof and prevents ingress of water to the expansion gap. It is suitable for use on a wide range of bridge designs with horizontal movement capacity up to ±25mm.

Prismo has developed a full range of products for all climates from severe cold conditions in arctic regions to the heat of tropical areas in Middle East, Africa and Asia. Based on over 20 years of experience there is no other bridge expansion joint system that can beat ThormaJoint for effectiveness, value and reliability.

Applications

Installation guidelines.

• Locate the expansion gap and mark out the joint recess area.
• Remove the asphalt surfacing to the desired width by saw cutting and pneumatic chisel cutter. The asphalt should be completely removed full depth to expose the deck.
• A clean join to the asphalt is essential.
• Waterproofing membrane should be removed as appropriate.
• Clean out the recess and the expansion gap and prepare with a Prismo hot compressed air lance to clean dry and warm the surfaces of the recess.
• Caulk the expansion gap using Thormafoam.
• Tank (precoat) the recess with hot BJ200 binder to seal the joint and improve adhesion of the joint to the asphalt.
• Install the bridge plate over the gap.
• Preheat BJ stone to 150°C to 190°C and place into the joint to a maximum depth of 40 mm, but not less than 20mm.
• The layer should then be flooded with binder heated to the correct temperature.
• This process should be repeated until the joint is within 25mm ±5mm of the surrounding road surface.
• Apply the ThormaJoint pre-mix layer.
• Compact using a vibrating palte compactor or vibrating roller.
• Seal the surface using BJ200 binder.

Advantages

• Completely watertight – helps to prevent structural deterioration caused by ingress of water-borne salts into the expansion joint area
• Flexible in all directions – eliminating the need for a complex mechanical system. It will accommodate a total horizontal movement
  of ±25mm
• Provides a smooth riding surface – little or no increase in surface noise when driven over
• Quick to install – reducing expensive down time, road closures and minimises disruption to the road user
• Easy to repair – can be easily repaired in case of accidental damage
• Can be planed off – no need to remove joint prior to resurfacing operations. Joint can be planed off with the surrounding road surface
  and subsequently topped up
• Can be surface dressed – joint can be treated with a skid resistant surlace dressing material to increase safety performance
• Maintenance free – no mechanical parts to wear which require replacement
• Drainage – system can be employed within the Thormajoint to remove unwanted sub-surface water from the immediate vicinity
• Custom design – being constructed on site, each individual Thormajoint is custom designed and constructed for exact matching to
  each individual installation location
• Partial width installation – can be installed over the entire width of a carriageway or at any chosen partial width

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