Water - Cementitious Material Ratio For Coastal Construction 1

[bkever]

Are structures located on the coast considered to be subject to "sea spray" and therefore subject to section 4.2.2 of ACI 318?

 

[henri2]

That's what my copy of PCA's Notes on ACI 318 Section 4.2, paragraph 6 says....w/c ratio 0.40 max...f'c 5000 psi min. FEMA recommends these same requirements (ACI 318 table 4.2.2)for concrete used in homes built in coastal areas

http://www.fema.gov/fima/mat/pdfs/fema499/hgcc_fact08.pdf

PCA carried out a long term study on the effects of seawater on reinforced concrete

http://www.cement.org/pdf_files/CT012sea.pdf

About the concrete mixtures for this environment. I wonder if fly ash or any other cementitious material is used, and if so, how much cement replacement is permitted? And the admixtures..what's commonly used?

 

[Lutfi]

Yes they are. I follow these guidelines strictly. I live in Florida near the beach and this is a serious problem. Most of the condominiums suffer as result.

I go a step further by adding corrosion prohibitors to the concrete mix. It is cheaper to have proper mix than coming back and repairing spalling concrete.



Regards,
Lutfi

 

[henri2]

Thanks for the info Lufti.

Do the concrete mixtures require air-entrainment?

 

[bkever]

Thanks for your help. One more question, what type of covering would eliminate this requirement? Stucco? Traffic coating? Epoxy coating the deck? The PCA Commentary mentions these as "added" protection but does not go into what the definition of exposed to seawater spray is intended to mean. This has become a big ticket item on a project and we are looking for any alternatives to reduce cost.