Air Content in Dry Cast/PreCast Box Culverts
Air Content in Dry Cast/PreCast Box Culverts
(OP)
I have recently speced out pre cast box culverts. The box culverts that are being used are cast by the "dry cast" method. The concrete mix designs were submitted with "zero" slump concrete and air content of 2%. My question is, "Is there any literature to support 2% air is adequate for freeze thaw conditions?" The precaster said that the air cannot be increased in this method of casting. Any help would be greatly appriciated.






RE: Air Content in Dry Cast/PreCast Box Culverts
"Air-entrainment shall conform to ASTM C-231 (AASHTO T-152)"
RE: Air Content in Dry Cast/PreCast Box Culverts
Functionally, you should be able to specify more air (and get it) but they have to choose between "no slump" and reasonable air content. As the air content increases, so does the "flowability" of the concrete, so technically the more air they add, the less likely they will get true "no slump" concrete. They should, however, be able to control their mix to achieve both appropriate air content values and achieve the consolidation and placement control they desire.
RE: Air Content in Dry Cast/PreCast Box Culverts