Bran Sands ETW, Middlesborough

Specialist UK Restorations were appointed by BAM Nuttall to address a number of issues affecting the existing reinforced concrete Final Settlement Tanks (FST’s) at Bran Sands Effluent Treatment Works, for Northumbrian Water Limited.

Vertical cracks were present through the full section of the FST launder channel walls at regular intervals, and these cracks in conjunction with the abrasion of the scraper mechanism wheel, had resulted in spalling and wearing away of the top surface of the launder channel concrete walls. Specialist UK Restorations, in conjunction with Sika Ltd, produced a full material specification to alleviate the full list of defects as highlighted by the structural report prepared by AMEC.

In order to allow the concrete repair works to be undertaken we first used abrasive blast cleaning to remove the existing epoxy tar coating. All damaged concrete was then cut back and removed down to a sound base. As per the specification we carried out in the initial repairs by applying Sika MonoTop-610, which acts as a bonding bridge for the MonoTop concrete repair mortars. Sika MonoTop-615 high build repair and re-profiling mortar was then trowel applied, prior to applying Sika MonoTop-620 cementitious smoothing coat/leveling mortar and pore sealer. Each area being reinstated back to its original line and level incorporating any surface features that were previously present e.g. rebates, chamfers and the like. Due to the chemical structure of the effluent housed in the fully restored tanks, SUKR also applied Sika Poxitar F, a heavy duty protective coating for steel and concrete structures.

Upon completion of the remedial works, SUKR had as much as is reasonably possible, returned the tanks to their original design condition. Providing a smooth finish to allow the scraper wheel to travel along, but also be resistant to abrasion from the action of the scraper wheel.