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HOTFALT ® is a patented bridge joint system. It is an asphaltic plug joint and provides an ideal solution for the Bridge Engineer, for those structures with low to medium capacity movement. It complies with the requirements of the Department of Transport's, Highways and Departmental Standard BA26/94 and BD33/94 . It is registered with the Highways Agency and is included in their list of approved registered products SA1 Manual The HOTFALT joint system's main components are the polymer modified bitumen compound and the selected aggregates. It performs by elastic and plastic deformation of the joint matrix, through a combination of traffic action and bridge deck movement. The joint is constructed in situ in a prepared joint trench, centrally above the bridge joint air gap. It extends the full depth of the road surfacing, protection and waterproof layer down to the bridge deck concrete. |
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The bitumen compound consists of a blend of polymer modified bitumen, mineral fillers and chemical additives. The standard grade is generally suitable for most UK installations. Other grades are available where climatic or special conditions demand. The blend of aggregates used is specially selected to determine size and shape. It is double washed and bagged for delivery to site. A bridging plate, normally of aluminium is used to seal and support the joint above the joint gap. Sub surface water drainage, together with a hydraulic pressure relief system can be provided within the joint. The surface of the finished joint is generally surface dressed with a high PSV aggregate. |
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HOTFALT FEATURES Expansion joints are necessary to accommodate cyclical and non-cyclical movements, they must adapt to movement and traffic loads. The Visco-elastic bitumen accommodates longitudinal, rotational and transverse movements. A special formulated primer provides excellent bonding to the vertical faces of the asphalt surfacing and the concrete deck, providing a watertight seal. The joint drainage provides an outlet for sub surface water and the hydraulic pressure relief system assists the removal of water which can build up at the back of the joint due to the pumping action of traffic. This does not negate the requirement for adequate sub surface drainage. British motorways take some of the heaviest volumes of traffic. The in service use on the UK's busiest motorways has demonstrated Hotfalt's ability to withstand the deteriorating effects of traffic loads, structural movement and climatic conditions. There are no pre-manufactured units. Installation drawings are not required. It is easily repaired in cases of accidental damage. Our experienced self-contained crews of HOTFALT installers provide a rapid placement service. Additional teams can work together to meet the demands of lane rental contracts. The HOTFALT installation is adaptable. Its insitu formation eliminates the need for site surveys to determine surfacing depths before installation; joint depth and width are adjusted on site at the time of installation. It is capable of taking up surface irregularities in the bridge deck. |
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In the early 1970's there was a need to find an alternative joint system to replace those currently in use. Buried joints and epoxy nosings were proving to be an unsatisfactory solution for the low to medium capacity movement joints on highway bridges. In1978 the technical staff of ASL Contracts developed a system using a visco-elastic asphalt that became the Hotfalt® joint. After extensive development work and trials with the TRRL, the new joint system was found to be a durable and resilient solution. The joint was granted a patent in 1982 and since that time, in excess of 100,000 lineal metres of the Hotfalt® system have been installed on highway bridges and other structures. Hotfalt® in service provides joints with a total movement factor of 50mm; it is highly resistant to flow at elevated road temperatures and gives a watertight joint without debonding. |
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FLEXIBLE