https://allgaragefloors.com/can-i-fill-my-contraction-joints/

https://www.naturalhandyman.com/iip/infdriveway/infdrivewaygarageseam.html

I would not use what Chessie suggests as that is an asphalt type product, black in color. I would use Big Stretch or similar is a concrete gray color were it me. The process would be the same.

I did not make a suggestion. I posted some links on what others have done. Seems to me that googling is the right way to make a decision. But I agree about the color. I used a couple of different products to fill the cracks in my driveway, but cracks are different than expansion joints so I would not have any experience in that area.

Actually, no. That is not correct. It is actually best to keep expansion joints waterproofed, although this should not be done for at least a year after the concrete has been in place, to allow for full shrinkage. I've not done mine, but I have looked into it.

https://www.homerepairtutor.com/concrete-expansion-joints/

https://trim-a-slab.com/how-it-works/

https://www.pavepatch.com/slabgasket-c-40.html?gclid=Cj0KCQjw6uT4BRD5ARIsADwJQ1_NkdmyI8ObuMDHDfC-l7pHcx5edF1pQU-FUrKoD82WZ1iTbNuSPO0aAk6UEALw_wcB

https://www.concretenetwork.com/concrete-joints/sealing-filling.html

Anyone familiar with below products ?

https://www.homedepot.com/p/SAKRETE-PermaSand-40-lb-Paver-Joint-Sand-65470004/202070568#product-overview

https://www.homedepot.com/p/SAKRETE-Paver-Set-40-lbs-Tan-Paver-Joint-Sand-65470077/313803284

It looks like they can be put into the gap. Thoughts ?

Sure they could be put into the expansion joint...but why? They serve no purpose. If you are interested in the advice you got last year on this question, use a waterproofing product. Those products in the links you just posted won't do that.

Use flexible self-leveling jointsealer

Thanks @kudzu9. I heard that those products have waterproofing capability and flexible characteristics. If so they seem much easier to install, just pour into the gap and add water. That's why I was asking.

Why would you even want to fill it? lol

@Stax Because the gap traps all kinds of things over time

So? My two car garage has the same "gap" Nothing apparent and its been there since 1973.

Nothing in mine either, and its been there since 1966.

water goes down in that joint and has eroded a huge amount of dirt from under the garage and driveway. I can put a two foot stick down in the hole now. It does need something to keep water from creating a potential pothole. @Stax @Chessie