The first relates to its ease of use and the second relates to its finished strength. Workability relates to the ease of placing and compacting the concrete. Workability is assessed on site by the slump test. A slump between 25 -100 mm is generally acceptable. Excessive water content and mixes deficient in the finer grades of aggregate and sand are most prone to segregation.
Segregation seriously reduces the strength of the concrete.
Curing is the process by which the concrete gains strength. It is important that the concrete is kept moist so that water is available for the hydration reactions to take place. This may be difficult under the conditions that commonly occur on building sites. Additives are added to concrete to improve its workability but these usually reduce the desireable properties of the finished concrete. They include air entraining agents, water reducing agents, accelerators and retarders and waterproofing agents.