CSC was engaged by ASDA / Key Electrical to refurbish a 185m² section of the existing service yard at their Moorthorpe store in South Elmsall, West Yorkshire.
The works required the excavation of the existing concrete / bituminous surface and sub-soils to a depth of 350mm by 15t machine with hydraulic breaker as required, with the disposal of all material offsite to a licenced facility for disposal/re-cycling.
Precast concrete kerbs were installed to the two open edges of the perimeter and a layer of DOT type 1 sub-base 150mm thick was laid with falls to the existing drainage channel system and compacted over the surface of the foundation.
The area 16.3 x 11.4m was split into two bays of 5.7m in width with the introduction of a stop end of road forms and prepared to receive a reinforced concrete slab 200mm thick. The sub base was covered with a separation layer of visqueen and a layer of A393 mesh reinforcement was installed in the upper surface of the slab on a support system of steel chairs.
Steel dowels were installed in the road form stop end in preparation to form an expansion joint. Following the preparation works a grade C40 AEA (air entrained) mix of concrete was placed by labour with the aid of a concrete pump and screeded to level and compacted by a vibrating beam tamp.
Compaction of the concrete was supplemented with the introduction of a vibrating poker. The surface was completed by floating prior to the application of a final brush finish with trowelled margins. The process was repeated for the adjacent bay 48hrs later.
The day after placement of concrete, lateral joints were cut into the surface of the concrete at appropriate intervals and all joints were sealed with a polysulphide sealant following a curing period.