Module 1: Underwater and Roller-Compacted Concrete

The main points from this module are as follows:

- For ordinary underwater concrete, highly cohesive mix proportions are required to minimise material segregation.
- Anti-washout admixtures with designated capacity should be used on anti-washout underwater concrete.
- For concrete meant for marine structures, Cement should be replaced with an appropriate amount of ground granulated blast furnace slag or fly ash, which is highly resistant to seawater's action.
- Fresh concrete that is to be compacted by a roller should be dry to the extent of resisting the roller's sinking.
- Roller compacted concrete is mainly used where large volumes of concrete are required with a further condition that it is largely unreinforced such as in gravity dams and pavements