Plain concrete has

significantly lower tensile strength than its compressive strength. Therefore,

reinforcements are required to compensate for the low tensile strength of

concrete.

A concrete cylinder cured in

100% relative humidity at 20 °C for 14 days is expected to have a higher compressive

strength than a concrete cylinder (the same mixture design) cured in 50%

relative humidity at 15 °C for 14 days.

Immersing a hardened concrete

in water should be avoided because it changes the water-to-cement ratio.