Concrete Mix Proportions
Concrete mix proportions should be chosen in such a way that concrete of adequate workability is obtained. Workability of concrete mix should be such that it can be compacted well using the available means of compaction. The recommended values of workability of concrete can be taken from IS : 456-1978. Concrete should surround all the tendons and other reinforcement well and should fill the formwork space completely so that the maximum density is achieved. When concrete hardens, it should have the needed strength, durability and surface finish.