ABSTRACT
The list of problems that follows the general preamble on cements refers to problems either encountered by the author or possible future ones. Some crushed rock sources are often denigrated for being too flakey when a closer examination of the processing might well reveal that only two stages of gyratory crushing is used where three or four stages would be better for the production of most concreting aggregates. The cheapest ingredient is often taken for granted and its properties ignored, concentration only being placed upon the quantity used and its macro effects. True waterproofers are products that stop the passage of water through the matrix, maintaining their performance under high hydrostatic prsssure. As with aggregates, cements, additives and admixtures approved samples should be kept in airtight documented labelled containers. An approved source of material does not necessarily guarantee that there will be consistency in deliveries.
