According to the National Ready Mix Concrete Association (NRMCA), strength for concrete air cured for one day followed by 27 days moist cured will be approximately 8 percent lower than for concrete moist cured for the entire period.
The strength reduction is 11 percent and 18 percent for concrete specimens initially cured in air for three days and seven days, respectively.
Care should be taken to maintain curing water temperature at not more than 20 degrees Fahrenheit cooler than the concrete to prevent cracking due to thermal stresses.
Immersion is mainly used in the laboratory for curing concrete test specimens.
American Society for Testing and Materials (ASTM) has developed two standards for making and curing concrete specimens. Both documents provide standardized requirements for making, curing, protecting, and transporting concrete test specimens under field or laboratory conditions, respectively.
ASTM C192 provides procedures for evaluation of different mixtures in laboratory conditions.
Fogging can minimize plastic shrinkage cracking until the concrete attains final set.
Effect of curing temperature on compressive strength development is presented in Figure 2.
There are three main functions of curing: 1) Maintaining mixing water in concrete during the early hardening process Ponding and immersion Ponding is typically used to cure flat surfaces on smaller jobs.
Sec 501.2 of the Standard Specifications include specific requirements of material to be used.
Plant inspectors are responsible to the resident engineer for verifying acceptability of all materials before they are incorporated into the work.