QCF 45

Concreting Project at Overstone Grange Farm.
Whilst working on the Grain Pit, I was asked to replace the entire frontage of the existing grain store. This was a fairly good sized project. It involved digging out the old ground and separating the contents to recycle as much as I could. This was a request from the Farmer to try to reduce costs. The top coat was crushed road tarmac, the next layer was Type 1 MOT and the base layer was clay. I had an area of approx 30m x 10m to prepare ready for new concrete slabs. I had to divide this area into 5 sections as requested by the client because different areas of the slab had different uses. 3 sections had to have a brushed finish with a troweled edge for the wheeled machines to grip to. The other 2 sections had to have a smooth finish. The reason for this was a machine with a grain bucket. The bucket needed to be able to scoop the grain without hindrance and tip the contents over the grain walling. We started to clear out the existing ground with a 3

Tonne machine, dug trenches for the new drainage, installed a new manhole chamber below the new slab, then ordered crushed hardcore for the sub base. I used a compaction roller to lay the sub base in phases. The reason for the phases was to make sure I had a good base prior to the concrete slab being poured. Once we had a solid sub base, we started to mark out each slab and put Road form shuttering in place. This was used to shore up the concrete when pouring. I then proceeded to place reinforced mesh sheets with spacers underneath. Once this was all done, I was ready to call for the concrete. I took measurements of the length, width and average depth of the area and calculated them to give me my volume of concrete needed. At the time, I had adverse weather conditions so I had to call off the delivery twice otherwise the heavy rain would have destroyed the finish. It was too big an area to protect and work with at the same time in bad conditions. I didn't want to risk 18 m3 of concrete being destroyed. When the pour commenced, I made sure that I was adequately protected whilst working with wet concrete. All PPE was worn to minimise risk. When the

pour was complete, we would tamp the concrete all over several times. The slab would then be left for a few hours to start to set. I would then use a pole float to start to dress the surface prior to using a stiff floor brush to drag across the slab for effect and the dressing the edges with an edging trowel. The client was told not to drive on it for 5 days so that the slab has plenty of time to go off. This process was repeated 4 more times. The final stage was a bit more complex, this involved the slab around the grain pit. The slab around the grain pit had a lot of steelwork within it, this was to carry the steel grid above the pit and access to a inspection chamber. I had to work out the surface

area as before but I had to subtract the surface area of the pit to calculate my concrete volume. This stage of the project was critical because this is where the whole project had to be 100% precise. It involved welders, steel fabricators, the grain auger being fitted and my brickwork, concreting skills and calculations. Thankfully it all came together considering the Client only letting me having nearly zero tolerances to work with.