When laying concrete, always try and finish the job in one continuous operation. If, however, a job cannot be completed in one day. Leave the last section to be laid with its edge as rough as possible. This acts as a key to ensure a good join between new and old work when the job is continued. Before restarting the work brush the rough edge with a ‘slurry of cement and water mixed to the consistency of cream.
Where the job involves concreting to a thickness of 50mm 2in or more, insert 150mm 6 in non-ferrous nails into the rough edge of the concrete. Simply press the nails at intervals of 100 mm 4 in into the concrete while it is still soft, leaving half of each nail exposed. This, again, will help bind the edges together.