Cement Paver Blocks

The setting of concrete is a chemical reaction ( hydration ) between the cement and the water, its is not a Concrete drying process.
This reaction is called hydration of Cement, it evolves that heat as does any chemical reaction, ones its start and the process is irreversible.
There is an initial set when the concrete will cease to be liquid but have little strength (e.g. 8 to 24hrs. old), thereafter the concrete Now will gradually gain regular strength over time until it achieves the full strength required.
Differing Concrete mix proportions and Ordinary Portland Cement or Pozzolanic Portland Cement types will achieve required strengths in differing time of spans.