Replies

1. GBA Editor
   Martin Holladay | Feb 24, 2012 02:59pm | #1

   Madhura,
   When salt is applied to concrete bridges or sidewalks in cold climates to reduce icing, the salt is injurious to the concrete and the steel reinforcement. It's common to see concrete deterioration under these circumstances. So I assume that using seawater to mix concrete is not a good idea.

   Most sources recommend that water used to make concrete should be potable quality water.

   I haven't been able to track down many research papers on the issue, though. Here's one:

   http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA078857

   " Literature on the quality of water for mixing and curing concrete indicates that relatively few investigations on this subject have been conducted. It seems to have been generally agreed that water fit to drink was fit to use in concrete mixing, and even fewer limitations were applicable to curing-water quality. Tests were conducted by the Missouri River, South Atlantic, and Ohio River Division Laboratories, and the Waterways Experiment Station to determine the effects of pH values of water on the strength of concrete and the staining properties of elements found in water. It was found that various contaminants can render distilled water unfit for mixing or curing concrete."

2. 
   cornercanyon | Feb 24, 2012 07:25pm | #2

   Some homes in the San Diego neighborhood, Loma Portal, built before WWII had concrete foundations made using beach sand. Many of these have required foundation work in the last twenty years. Most information is anecdotal, I have personal knowledge of one home in particular.

   The fix was to lift the home, tear out the foundation, repour and reset. The theory was the salt included in the original concrete caused the failure. I don't recall any suggestion other than replacement to stop the salt from breaking down the concrete.

3. 
   davidmeiland | Feb 24, 2012 10:04pm | #3

   Plenty of houses in San Francisco have foundations made using sand from Ocean Beach. The few projects I've worked on we replaced crumbling concrete.

4. 
   bdrfab | Feb 24, 2012 11:13pm | #4

   In short, yes and no. With respect to the reinforcement rods, it depends on if the rods were epoxy coated or not. However I would think it would be more susceptible to Alkali-silica reaction failure, depending on the aggregate. Bet it has efflorescence like crazy that you can't get rid of...