General notes on concrete
Concrete is characterised by two main states, fresh and hardened, which in simple terms describe the mobility (or lack of mobility) of the material. There is also a transition state where the ‘fluid’ material stiffens and starts to gain strength.
These two states are influenced by the constituents and how they are put together ie the mix design process, which in turn are dictated by the construction requirements both in terms of placement and required service properties.
Normal weight, reinforced, structural, prestressed, and high strength are all types of concrete commonly in use.