CRMCA Technical Advisory:
Deicer Scaling Resistance – Updated Residential Concrete Requirements
ACI Committee 332 Residential Concrete Work has changed the minimum quality requirements for concrete exposed to freezing/thawing in the presence of deicer chemicals, exposure Class RF3. The most recent Code, Residential Code Requirements for Structural Concrete ACI 332-20, now requires that the concrete have both a design compressive strength f’c of 4500 psi and a maximum w/cm of 0.45. Prior to 2020, the 332-14 Code only required a design strength of 4000 psi.
These requirements would apply to essentially all exterior flatwork where the use of deicing chemicals would be anticipated. Examples cited in the 332-20 Commentary include elements such as “driveways, curbs, steps, stairs, and porches”.
The application of these more robust concrete quality requirements accompanied by proper placing, finishing, and curing practices should totally eliminate the problem of surface scaling of concrete driveways and sidewalks.
This is a significant positive change, and the residential concrete construction industry should make every effort to embrace and advance these new quality criteria.
Technical Services Engineer