Concrete spalling on garage apron - Need advice

[juice8200]

The concrete apron in front of my garage door started to spall last winter when the temperature dropped below Zero here in southern Indiana. This Winter the spalling has worsened. The house was built in late 2017 and I have never used any salt on the driveway, however I think the salt bought in by the vehicles melted in the garage and the salt water ran out to the apron. I also wonder if too much water might have been added during placement, especially at the top.

Much of the top concrete near the spalled areas can be pealed off with my fingernail, so I am thinking about grinding down the apron area to get rid of any loose areas. However, I am not sure what to do at the edge, maybe just grind it down as well, not sure...

As you will notice in the pictues that one side of the apron is way worse than the other half. This is beacse one vehicles goes out in the winter much more than the other.

I have been thinking about the best ways to repair this and need some help decieding on the best way.

I came across this video on Youtube and was thinking" that it might work". They seem to be using Smith’s Poly PCF-45 and some dry quartz to fill in the areas that are too deep to grind. I like the idea of being able to use the area in a short amoumt of time after the repair, but I am concerned about the product as it asys it is not UV stable. "– Finish will yellow and may chalk over time with Ultra Violet Light exposure". Maybe some sort of UV protectant can be added afterward...

Video:

Product Used: https://www.smithpaints.com/?ae_global_templates=poly-pcf-45

I also was also looking at the Sakrete Top ‘N Bond Concrete Patcher or the RapidSet NewCrete, but I really don't know which one would be better for this or if there is a better product.

Can you help me find the best way to repair this? Thanks - Justin

 

[ConCretin]

If I had to guess, I'd say they didn't use air entrained concrete because most of the slab was inside and not subject to moisture in freeze/thaw conditions but the exposed apron is. I'd remove as much of the damaged concrete you can and overlay it with something like Ardex CD. The better you do with the prep, the better chance you have of the repair lasting so follow the instructions carefully. I'd then apply a good quality sealer to try and keep the moisture out of the concrete.

 

[larry4406]

If I had to guess, I'd say they didn't use air entrained concrete because most of the slab was inside and not subject to moisture in freeze/thaw conditions but the exposed apron is. I'd remove as much of the damaged concrete you can and overlay it with something like Ardex CD. The better you do with the prep, the better chance you have of the repair lasting so follow the instructions carefully. I'd then apply a good quality sealer to try and keep the moisture out of the concrete.

Interesting...

I will have to ask this question of my concrete guy on what they do on our garages. They pour the house slab and garage slab same day, but they are always different pours with different trucks for strength reasons (higher psi in garage vs house) but I have never thought about the air entrained for the garage slab.

Learned something new!

 

[NDJ]

Isnt there some 'rule' that air-entrained concrete is not suitable if it will be surface finished ? (troweled etc)

 

[ConCretin]

Isnt there some 'rule' that air-entrained concrete is not suitable if it will be surface finished ? (troweled etc)

It's not really a hard and fast rule but there are some things to keep in mind with air entrained concrete especially in hot or windy conditions. The chemical used to entrain air slows down bleed water and if you seal the surface too soon with a steel trowel, water and air will pool under the hardened surface and create voids, which leads to de-lamination. A broomed finish doesn't seal the surface the way a trowel does thereby eliminating the issue.

Air entrained concrete is designed to resist damage caused by freeze/thaw conditions caused by moisture. A good finisher can manage this problem under most conditions but since there's usually no need for air entrainment in interior concrete, it's often not worth the risk.