Collaboration at work in Harlesden

Sealed and delivered in under 2 hours.

Demand within the UK is growing for a quick and reliable method to apply waterproofing sealant solution. This need is being driven by the UK’s variable weather conditions, high volumes of traffic and time restraints.

TfL with CONWAY AECOM have just carried out a trial of a new waterproofing material on the A3220 West Cross Route. The new product significantly reduces application, curing time and lane rental costs which enhances journey time reliability since works can be carried out overnight.

An 84 square meter trial took place on a problematic stretch of the A3220, near the busy Westfield shopping centre. The waterproofing was almost 20 years old and had started to deteriorate around the expansion joint, water tended to accumulate and pond with the gradient of the carriageway. Due to the large volumes of traffic and time restraints it was difficult to rectify, and a product which could cure within the allocated time had to be sourced.

The trial took place on Sunday 5th May between 00:00 and 09:00 hours during a full closure of the northbound A3220 West Cross Route, between the Holland Park roundabout and the A40 Northern roundabout.

The failed section of road surface was milled to a depth of 100mm and on removal of the existing membrane, moisture was found on the concrete’s surface which indicates that the waterproofing had failed. In most areas there was no adhesion between the waterproofing and concrete deck. The deck surface was cleaned and dried using a heated lance before the trial product was applied manually by a specialist subcontractor in three layers using rollers.

The primer was applied by roller followed by natural quartz which was scattered onto the primer before it cured. The second layer membrane was applied within 20 minutes of the primer. The laying and waiting for this one coat to cure took 40 minutes. The final layer, the tack coat was then applied and again natural quartz was broadcast onto the wet tack coat. This layer was cured within 45 minutes hence the total waterproofing application took 2 hours, before surfacing works commenced.

Matt Smith, Tunnels and Structures Manager said:

“We are delighted with this product, the speed of application and curing time is a huge advantage over other products. It took us 2 hours to waterproof 84 square metres instead of over 20 hours and we are keen to use this product on other problem areas throughout the North West contract.”

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