Specialist Painting Group are working with ENC Industrial Services Ltd on the refurbishment of the River Don Rail Bridge.
The River Don Rail Bridge is a 50 meter rail bridge that spans the River Don. The existing protective coating system comprises of several layers including red lead, bitumen and micaceuos iron oxide. The MIO has been applied over the bitumen, due to to the different surface tensions extreme mud cracking is visible in the MIO over the entire structure.
The project includes the removal of the existing protective coating system using HICO2 and the installation of a new two component epoxy and polyurethane coating system.
The micaceuos iron oxide has been applied over a bitumastic material. The MIO is a more rigid product than the bitumen. The bitumastic material is also a thermoplastic which can become more homogenous in elevated temperatures. Due to the different surface tensions and rigidity the MIO has severely cracked across the entire structure. The rail bridge has numerous areas of exposed steel work that is heavily corroded.
Due to the sensitive location over the River Don. This rail bridge posed several problems when deciding the safest and most effective method of removing the hazardous, existing coating system. On this occasion the decision was made to utilise High Intensity Co2 to remove the existing coating system prior to mechanically preparing the substrate.
The High Intensity Co2 process uses industrial grade dry ice to remove an existing coating system. The method of removal is a very effective means of blast cleaning that results in no spent blast media being created. The HICO2 process gives us the opportunity to blast clean in situations where more traditional methods are not suitable.
The HICO2 process uses micro thermal shock, kinetic energy and sublimation to remove coating system and surface contamination from the substrate. The HICO2 process is particularly effective when removing thermoplastic products such as bitumen.