Bad Concrete Mix

[Boatman37210]

In a previous post asked for coating solutions for a newly poured cement carport.   Have not coated  with any sealer or tile.  Have a problem.

 

Surface is more like chalk that is easily removed using a nail. Either the mix was wrong or the finishers started working the top before the water had time to bleed down. I lean toward the mix being wrong. When it was delivered I thought it looked like it had too much water. I looked at my contractor to see his reaction and there was none. I assumed he felt it was okay. So much for trusting my contractor.

 

Do not want to have to tear up and replace, so need a solution that will give me more serviceable life than doing nothing. At some point I may have to replace, but for now had rather try to salvage the situation best I can short of replacing.

 

Paint will not stay. I am not against tiling, but fear they will not stay since the base is weak. Leaning toward maybe acrylic or polyurethane. Since I do not know what will work for sure, looking at a low cost solution. Do not want to throw good money after bad.  If a more expensive solution would actually fix the problem, then I would consider.  Looking for a good cost vs benefit solution.

 

I could remove the surface, but that would only work if the mix was okay and the surface was the problem. If the mix was bad, not sure if removing the surface would help.

 

Any ideas on how to fix would be appreciated.

 

 

[Kwasaki]

Hopes this helps. 

 

http://www.nrmca.org/aboutconcrete/cips/01p.pdf

[manfredtillmann]

a very common problem these days as more and more cement is being replaced by other components in the process of making concrete.

cement has a huge greenhouse gas footprint as it requires large amounts of heat to be produced.

in australia it is not uncommon for up to 60 different materials to be used in a single batch of concrete. one large component is fly ash.

the result is concrete with little surface strength, increased cracking and shrinkage to name just a few problems. a nightmare for concretors with guys having been in the business for 45 years despairing when confronted with the results of their efforts.

 

there are few good working solutions but check out: https://assets.master-builders-solutions.basf.com/Shared Documents/EB Construction Chemcials - US/Construction Systems/Brochures/MBS_Cures_and_Surface_Treatments_Brochure.pdf

or

http://www.cementaid.com/pdf/DIAMITE.pdf

 

i have used 'Diamite' often in the last few years, it is easy to apply, water based and gives a good result for 12 months or so depending on traffic.

 

 

[CGW]

Consider applying "stone wash" on top?

 

 

 

[sometimewoodworker]

You can stabilise the floor quite easily and very cheaply.

 

Buy a 10kg box of TOA adhesive latex No.LA-44 (about ฿350) mix with water at 1:5 latex:water. Using a paint roller and paint tray roll it on the floor. The box has covered about 260sqm and we have some left over. It will make about 75 litres.

 

We have just done that to stop dusting and it works, you seem to have a more extreme problem so you may need to do a second coat. You can tile over it later if you want