What mix ratios of cement do you recommend for general purpose concrete?
For 2.5m3 of general mix concrete the following quantities are:
35 bags of General Purpose Cement (nominal 25 kg)
1.25m3 damp sand
1.8m3 coarse aggregate or 2.5m3 all-in aggregate – ballast.
These quantities do not include any allowance for wastage. When purchasing materials, however, it is recommended that the quantities of aggregates are rounded up to the nearest half or full cubic metre and an extra 10% of cement is added to allow for wastage.