The water/cement ratio is the ratio of the weight of water to the weight of cement in the fresh concrete mix. The water/cement ratio controls the strength of the concrete and its permeability. The lower the water/cement ratio the higher the compressive strength and the lower the permeability of the hardened concrete. The lower the permeability the greater the potential durability of the concrete.

Example: 180 litres of water and 300kgs of cement per m3 = 0.6