Concrete Mix "Chloride Ion Requirements"

[EngStuff]

3 part question.

1. I have a 42" concrete footing that would require it to be open to the atmosphere. This footing will have pavement all around it except on top. Every day or other day we would collect all the snow with salt at this spot. looking through ACI 318-14 Table 19.3.1.1 It seems like I meet Class F3, w0,c2. Now onto table 19.3.2.1. I need to meet w/cm = .40 for a 5000psi concrete per F3 and C2 with a maximum water-soluble chloride ion (CL-) content in concrete, percent by weight of cement = .15(nonprestressed concrete) For my condition, is this about right?

2. How do we call out the chloride ion content? Next to my water content ratio? Should I just put "chloride ion content <0.15"?

3. If I drop the footing down 6" and have them cover the footing with the pavement. Would I have to worry about all this?

Thanks!

 

[STrctPono]

You can put a note in the Structural General Notes and a note in the specs that states:

"The total water soluble chloride ion content that is contributed from the ingredients including water, aggregates, cementitious materials, and admixtures shall not exceed 0.15% by weight of cement when tested in accordance with ASTM C1218 at age between 28 and 42 days.

If your ready mix suppliers are used to providing this test then they may comply... but if they are not used to providing this type of information it may fall on deaf ears and you may not have a lot of clout to force them to show their hand. In my experience it is never an issue. The reason why.... Our cement comes from Taiwan and there is a Laboratory Test Certificate that accompanies every submittal that gives the chemical breakdown of the material and no calcium chloride is present.

The aggregates that we use are usually a mix of local coarse and fine aggregates with a mix of British Columbia dune sand. I don't see where a large source of calcium chloride would occur in the aggregates unless it picked up some during shipping.

Most chemical admixture companies are aware that their products are not going to be marketable if it contains large quantities of calcium chloride. For instance, BASF sends us a letter for their Master Pozzolith 322 stating that "based on chlorides originating from all the ingredients used in its manufacture, contributes less than 2.4 ppm chloride ions by weight of the cement."

MasterSet Delvo states that it is less than 1.4 ppm.

MasterGlenium is less than 2.3 ppm

MasterMatrix VMA 362 is less than 1.6 ppm.

MasterSure Z60 is less than 0.7 ppm.

MasterLIFE SRA 035 is less than 1.4 ppm.

Master X-Seed 55 is less than 0.7 ppm.

This would be for a standard 9,000 psi mix we use for bridge girders. Total ppm of calcium chloride is 8.1 ppm which is equivalent to 0.00081%.... a non issue.

Control the w/c ratio, consider pozzolans, ADD A CORROSION INHIBITOR (Calcium Nitrite or Amine Carboxylates), and if it really is exposed to deicing salts I would serious consider using corrosion resistance steel or perhaps even GFRP if you can make it work out. The pavement will do nothing to slow the corrosion so don't rely on that.

 

[EngStuff]

STrctPono,

Thanks for the quick response, this was very helpful!