During Casting:

You should follow the general principles for concrete care and make intact and suitable level for the concrete. Use the vibrator during the casting.

After Casting:

Concrete spraying with water should be done as follows:

• Water spray to all parts of molded concrete should be done after 10 hours from casting time.
• Water spray should be done regularly for several times during the day for one week.
• The external surface of the molded parts should be maintained in wet case during spraying days (it is advised to use burlap to maintain the moisture of concrete).  

The use of additional water at site is prohibited due to its adverse impact on concrete quality and compressive strength.

• Increase workability without adding water.
• Reduce mixing water and water-cement ratio.
• Retarder setting time due to high temperature or long distance.
• Reduce bleeding (Control cement hydrations).
• Improve pump ability and finish leveling of concrete.
• Reduce segregation.
• Increase compressive strength especially early age strength.
• Decrease concrete permeability and increase durability.
• Reduce the corrosion of reinforcing steel.

Slump test to a measure of consistency or relative ability of the concrete to flow.

• Samples are made at the site according to Saudi specifications and compact and proper settlement.
• Avoid any vibrations of the samples or transfer them after pouring directly.
• Avoid taking samples in the sun and provide a suitable place to making samples in terms of temperature according to specifications.
• Samples are transferred after it reaches hardening final setting time while avoiding any vibration or crushing of samples during transport.
• Samples shall be removed from the mold and kept in curing water tanks at a temperature of  (23 ± 2 ° C ) until the time of testing.

Concrete, like all other materials, will slightly change in volume when it’s dried out throughout it’s life time. The volumetric changes of concrete structures due to loss of moisture by evaporation.

Plastic shrinkage:

Plastic shrinkage occurs very soon after pouring the concrete due to increased evaporation rate of water from the surface of fresh concrete, especially high ambient temperature, low relative humidity, high wind speed, and high concrete temperature.

Drying shrinkage:

The shrinkage that appears after setting time and hardening of concrete after the first 24 hours, both plastic and drying shrinkage are triggered by moisture loss to the environment.

• Reduce water-cement ratio.
• Pre-wet formwork and subgrades.
• Use plastic cover to maintain moisture above the surface directly after pouring.
• Avoid casting at high temperatures and high wind speed.

SCM such as pozzolan, fly ash, silica fume & ground granulated blast-furnace slag (GGBFS) also react chemically in concrete to produce a hydrated compound.

• Pozzolan and slag reduce the pore structure of the paste in concrete and reduce the permeability of concrete and increase durability.
• Increase compressive strength at a later age.
• Increase corrosion protection and reduce chloride permeability.
• Improve sulfate resistance.
• Increase resistance to freezing and thawing.
• To produce green concrete by reducing the emission of carbon dioxide CO2.
• Reduce the heat of hydration in mass concrete when part of cement is replaced by using ( fly ash or slag ).