The UniPak ironwork installation system is designed to prevent bedding failure – one of the main factors contributing to the current poor performance of chamber tops (reference: Highways England’s CD 534).
WRc and Nottingham University research observes that up to 89% of ironwork failures have suffered foundation issues and that in 44% of cases foundation issues are the sole cause of failure.
The UniPak system specifically addresses issues of:
- Poor performance of cement based mortars under traffic and weather conditions
- Premature road opening before bedding has reached full strength
- Incorrect mixing of mortar components
- High notch sensitivity of conventional bedding materials
- Use of inappropriate or poor-performance packing materials
- Easy to store
- Simple to use
- Standard installation methods Ideal for all BS EN 124 highway applications (groups 1 to 4)
- Exceeds CD 534 (formerly HA 104/09) and WRc requirements
- Repeatable and consistent performance
- Early road opening
Three, outwardly simple components, are our innovative solution to an age old problem.
It started with an exploration of why 89% of highway ironwork failures suffer foundation issues and 44% are solely due to foundation failure.
Conventional packing and cement bedding just weren’t good enough for the job. Unchanged methods over a hundred years had to change. To the fore now is an emphasis of service life, long term economies and rapid road opening after works completion. UniPak is the solution.
Even better, the three components – mortar, packing plates and wedges – can each be used with conventional materials, should working practices or existing stocks levels dictate. Performance won’t be the maximum achievable (using the complete UniPak system), but the principles of mortar & packing remain unchanged, so UniPak is easily integrated with the ‘old’ installation methods.
UniPak mortar avoids all the problems of cement based mortar by using a two part polyester resin material - the same material UniPak packing plates and wedges are made from - and a proven material in highway construction. The resin product allows rapid road opening due to its fast cure time. Operatives simply mix both parts, thus giving a consistent and repeatable result with no performance loss due to judgement or personal mix preference.
UniPak mortar tubsThe mortar has a very low slump factor, compared with other products, which gives excellent support of ironwork in an uncured condition. Its inherent low notch sensitivity means resistance to cracking caused by sharp and angular ironwork frames, a common point of failure.
It comes in three tub sizes, suitable for surface boxes to the largest of covers, to reduce waste to a minimum. The UniPak mortar is suitable for all BS EN 124 highway applications, groups 1 to 4.
Adjustment units are available in two widths (100 & 150mm) and three thicknesses (15, 25 & 45mm) and are easily cut and fixed using conventional techniques. They interlock with bedding mortar and resist lateral forces with no reliance on friction or mortar adhesion. As they are manufactured from the same resinous compound as UniPak mortar and block wedges, it forms an integral part of the system.
Other makes of packing boards are manufactured from wood pulp and swell and weaken over time. Their smooth surfaces mean lateral forces break the mortar bond and angular edges result in the cracking of surrounding brittle foundation materials. Wrekin UniPak addresses all these issues and is a superior product in every regard.
They can be used with conventional cement mortars, but optimum longevity is achieved using the three UniPak components as a system. These packing plates are suitable for BS EN 124 highway applications, groups 1 to 4.
The blocks support the ironwork, giving optimum strength of bedding mortar/packing plate layers, both while curing and under load, following road opening. It is left in place after installation and as it is manufactured from the same resinous compound as UniPak mortar and packing plates, it forms an integral part of the system.
As the ironwork is rigidly supported, the contractor is no longer constrained by the curing rate of the mortar - even if conventional cement types are used.
The step wedge design allows 5mm adjustment steps, up to 75mm per block and, as they are stackable, allows them to fill large voids. They are suitable for BS EN124 UK highway applications, groups 1 to 4.