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Name:   
Heading: 1.1.1High Chlorides Aggregates
Message:
I must use marine aggregates (with high chloride content) for concrete production.
There is no possibility for washing the aggregates.
According to your experience is there any admixture (or teqnique)to "neutralize" the chloride effect in concrete?
Has anybody experience from the Middle East countries ?

Best Regards
Spiros Licoudis



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spiros licoudis


Your main problem may not come from simply using marine aggregates but from the other contaminants assosiated with the unwashed aggregates and not nessarily the chloride in the marine aggregates. Why can you not wash the aggregates with sea water to remove all the organic material and clays first. If the chloride content in your concrete is no more than 1% after your potable batchwater ( I do not believe you intend to use sea water!!!!) is used then your concrete should be OK. I have data on such a pour and the structure after 38 years is doing fine.
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John Macdonald


John is right that the organics may cause problems with setting and admixture reactions. As to the chlorides, there is a risk of corrosion, depending on the exposure of your in-service concrete. Once you find or calculate your expected chloride levels, you can compare them to guide values (from IBC or ACI 318&222R)and evaluate your risk.

If you find the chlorides to be too high, one option to address the chlorides could be an admixed corrosion inhibitor. There are multiple ones available and you will have to work with your supplier to see what is available in your area.

Matt Sherman, PE
Simpson Gumpertz & Heger
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Matthew Sherman
 
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