Submerged in salt water
Posted by Vincent on February 12, 2007
I don’t know much about concrete. I plan on building a small structures with a stainless steel rebar in it. It will be submerged in salt water and getting the pounding of waves majority of the time. I don’t know the proper mix-ratio of cement, rocks, and sands or if there other admixture that need to be added to it in order for it not to crumble to pieces or fall apart. Can a regular pre-mixed bag of conrete/cement from local hardware or home improvement center be strong enough to do the job?
The best option for you would be to get a pre bagged concrete mix from a hardware or home improvement center and try to add the least amount of water possible and still be able to place the concrete to make the concrete durable. The strength and durability of the concrete depends mainly on the water to cement ratio, so the least amount of water the better it is for you. So, just add water sufficient for you to mix and place the concrete well. Try to get a concrete mix, which claims to give the highest strength.
If you want to make your own concrete then follow the recommendations of ACI 211 (American Concrete Institute manual of concrete practice) to arrive at the mix proportions of cement, sand, stone, water for the concrete.
The addition of Type I Portland cement or the addition of supplementary cementitious materials like Fly ash, Silica fume and slag in appropriate amounts will also help to improve the durability of the structure. I would recommend you to use a high range water reducing admixture (Type A or Type F as per ASTM C 494, Type F would be better) in the concrete mix, which will enable you to produce a workable concrete mix with less water.
