A hydraulic cement sets and hardens by chemical interaction with water, and hardens even under water, making it a water proof cement. Structural strength occurs when the concrete has gained sufficient strength to carry loads, as when pavement is strong enough for auto traffic. Slump is a measure of the consistency of the concrete. Porosity is a measure of the voids in concrete. The durability of concrete is directly related to porosity.
Fewer voids result in better durability.
A super plasticizer is an additive used in concrete to increase its flowability or slump. Bleed water is excess water leaving the surface of fresh concrete. This causes small fissures to open up. Plastic shrinkage cracking is cracking caused by rapid evaporation of water from the concrete surface soon after it is placed. Warm dry winds cause plastic shrinkage cracking.