CEMENT 42.5R-42.5N

Traditionally, sand-cement mixes have always been specified in terms of mix proportions by volume and not by performance. This is still almost universal practice in South Africa. SABS 0109 specifies mix proportions for sand-cement screed flooring as being one 50kg bag of cement to 130 litres of sand measured damp and loose. The reason for this is that sands bulk appreciably when damp and serious inconsistencies will occur if the sand is ‘batched’ by volume without due regard to its moisture content. For example the mass of 130 litres of dry sand is about 210 kg, while the mass of the sand component of 130 litres of damp sand is about 150 kg. This Code of Practice (SABS 0109) gives detailed recommendations for finishes for concrete floors and is well WORTH consulting.