Title: Considerations in the Prevention of Damage to Concrete Frozen at Early Ages
Author(s): George C. Hoff and Alan D. Buck
Publication: Journal Proceedings
Appears on pages(s): 371-376
Keywords: age-strength relation; cold weather construction; concretes; damage; freeze-thaw durablity; freezing; fresh concretes; measuring instruments; volume change; water.
Various protection concepts and considerations associated with placing fresh concrete in an enviroment where it will undergo early age freezing are reviewed. These include volume change concepts, critical strength and critical age concepts, and freezable water considerations. An experimental program is also presented to relate the dilation of concrete from one cycle of freezing to the critical (minimum) strength that the concrete would need to resist damage from that freezing. This was done in an attempt to validate the minmum (critical) compressive strength of 500 psi (3.5 Mpa) reccommended in ACI 306-78, Cold Weather Concreteing. Critical dialation criteria are presented. An evaluation of concrete mixtures of varying proportions indicated that, based on dilation criteria for determining the single freezing frost resistance of coincrete, the critical (minimum) strenth [500 psi (3.5 Mpa)] and critical age requirements of ACI 306R-78 are conservative and acceptable. This does not preclude the possiblity that some perminant loss of strength my occur, however, when frozen at an early age.