type V cement vs Type II combinations for sulphates and chlorides 2

[GBMRAO]

Dear Fellow Engineers,

I have few questions. i am working on a project in Florida where there is moderate aggressive for sulfates to extremely aggressive for steel.
In my specification, i have suggested to Type V cement and because of the nonavailability, the client is requesting if we have any alternative.

i could not find any specific documentation but online blogs say to use TYPE II cement with % of flyash and slag which will help.

Does any know how to approach and find an alternate mix design?

 

[STrctPono]

I have seen ACI articles that have studied this and recommend that the best sulfate resistance (in lieu of Type V cement) come from 22-32% cement replacement with Class F Fly Ash. In addition, you should also limit the W/C ratio to 0.40.

 

[JedClampett]

In the Southwest (thinking Las Vegas and Phoenix), I can get a multi grade I/II/V cement, pretty much whether I want it or not. Maybe a cement technologist on this site can answer me, why this isn't available everywhere? Seems like it would be doggone useful to not worry about cement grade as much.
I've run into the same problem as the OP and it's really inconvenient to have to require a fly ash mix.

 

[STrctPono]

A Type 2 cement with 32% fly ash replacement will be roughly equivalent to a Type 5 cement mix if strictly comparing the total amount of tricalcium-aluminate that is being used in the two mixes.

 

[DayRooster]

Did something similar to STrctPono on a project in Kentucky. But we added slag and fly ash to achieve the proper mix for sulfate resistance in lieu of Type V. Worked directly with the concrete supplier. If I’m not mistaken, we even ran a lab test to qualify the mix per the provision allowing this substitute in ACI 318.

 

[GBMRAO]

Great thank you all for your responses. I think it's the shortage and availability at this point of construction. It has to be shipped for little further and time delays and construction schedule. It was also the client's request to check for alternates.

found these options: but nothing like this defined in ACI or such articles.

403S.8 - Mix Design Options
For the structural concretes identified in Table 5 (Classes C, H and S) and any other class of concrete designed using more than 520 lbs. of cementitious material per cubic yard (310 kgs per cubic meter), one of the mix design options presented below shall be used.

For the non-structural concretes identified in Table 5 (Classes A, B, D and I) and any other class of concrete designed using less than 520 lbs. of cementitious material per cubic yard (310 kgs per cubic meter), one of the mix design options presented below will be used, except that Class C fly ash may be used instead of Class F fly ash for Options 1, 3 and 4 unless a sulfate-resistant concrete is required.

A.Option 1: Twenty (20) to thirty-five (35) percent of the cement may be replaced with Class F fly ash.B.Option 2: Thirty-five (35) to fifty (50) percent of the cement may be replaced with ground granulated blast-furnace slag.C.Option 3: Thirty-five (35) to fifty (50) percent of the cement may be replaced with a combination of Class F fly ash, ground granulated blast-furnace slag or silica fume. The combination may not include more than thirty-five (35) percent fly ash and no more than ten (10) percent silica fume.D.Option 4: Type IP or Type IS will be used and up to ten (10) percent of the cement may be replaced with Class F fly ash, ground granulated blast-furnace slag or silica fume.E.Option 5: Thirty-five (35) to fifty (50) percent of the cement may be replaced with a combination of Class C fly ash and at least six (6) percent of silica fume, ultra fine fly ash or metakaolin. The combination may not include more than thirty-five (35) percent fly ash and no more than ten (10) percent silica fume.F.Option 6: A lithium nitrate admixture will be added at a minimum dosage of 0.55 gal. of thirty (30) percent lithium nitrate solution per pound of alkalis present in the hydraulic cement.G.Option 7: When hydraulic cement only is used in the design, the total alkali contribution from the cement in the concrete does not exceed 4.0 lbs. per cubic yard, when calculated as follows:
alkali (lbs. per CY) = .01 (lbs cement/CY) (% Na2O equivalent in cement)

where (% Na2O equivalent in cement) is assumed to be the maximum cement alkali content reported on the cement mill certificate.