This can be as simple as pushing a wide blade over the fresh concrete surface to make it flat (screeding).Floating and troweling is a process of compacting and smoothing the surface which is performed as the concrete is starting to harden.When this is impractical due to the distance required or the size of the job, the fresh concrete can be pumped through a system of pipes or hoses to the site by special concrete pumps.Concrete that is to be pumped has more stringent requirements for workability.Consolidation Once the concrete is in place, it should be consolidated to remove large air voids developed during placement and to make sure that the concrete has flowed into all of the corners and nooks of the formwork.
Roller compaction is a simpler and more cost-effective technique that is suitable for roads and very large mass concrete structures such as dams.
To cure properly, the cement paste must be fully saturated with water.
If the relative humidity level inside the concrete drops to near 90% the hydration reactions will slow, and by 80% they will stop altogether.
Right: A concrete truck being filled with fresh premixed concrete.
(Images courtesy of the Portland Cement Association).