C35/45 Concrete Mix Design
C35/45 is specified where exposure is more severe than typical carbonation conditions — commonly chloride exposure from de-icing salts or coastal airborne salt, or significant freeze-thaw risk.
Typical exposure classes
Often paired with XD1–XD2 (chloride exposure other than seawater) or XF2–XF3 (freeze-thaw, often with de-icing salt), reflecting more aggressive environments than typical building carbonation exposure. See exposure classes and durability.
Designated Concrete equivalent
Closely associated with RC35/45. See the designated concrete catalogue.
Typical uses
Car parks, bridge elements, roads-adjacent structures exposed to de-icing salts, and other elements in more demanding chloride or freeze-thaw environments.
Frequently asked questions
Does C35/45 need air entrainment?
Where the exposure class includes a freeze-thaw class (XF), yes — a minimum air content is required in addition to the strength class; see air entrainment.
What is the BS 8500 designation closest to C35/45?
RC35/45 is the closest Designated Concrete equivalent.