What is This Construction Material / Concrete Sealer?

[Ben]

See the pics below. This appears to be some kind of a seam sealer/buffer between various concrete pads that run up to the house and the foundation concrete. First pic is a closeup, second pic is just a location reference.

The material itself feels like a fiberboard of some kind. Definitely not caulk or other rubberish sealant. It looks like maybe it was placed there prior to pouring the various concrete pads around the house when it was built. Is this maybe for (still new to me) places that get real Winter to maybe buffer expansion and contraction from temp, freezing water, etc.? I have several places where it appears to be breaking apart from age and I figure I should replace it to at least fill in the gaps and keep water intrusion out.

On the other hand, I just had a new patio poured and while they connected it to the foundation with rebar, they just poured right up to the foundation without using this fiberboard or whatever layer. It was a reputable concrete company that gets good reviews, so I have to assume they knew what they were doing.

Anyway, anyone know what this is called and should I try to stuff some more of it in the gaps or maybe use something else?

Note: I just realized dummy me took the reference pic where the new patio was poured, but ignore that. It is only for a visual reference that the area I'm talking about is where the horizontal and vertical concrete surfaces meet.

[bedlamite]

https://www.menards.com/main/paint/concrete-blacktop-sealers/concrete-repair/1-2-asphalt-expansion-joint/1831223/p-1444445320379-c-5650.htm

[Hawkmoon]

Yeah -- what you are seeing is not in any way a sealer. It's really a filler/bond breaker. Ideally, it should stop about 1/4" to 1/2" below the top surface of the concrete, and the gap should be filled with an elastomeric sealant. One of the best for this purpose is SikaFlex 1-A.

[Ben]

Okay, that Menard's link looks exactly like it.

I would have to doublecheck, but  I don't think ANY of it is below the top surface of the concrete. Most of it seems to actually be sticking 1/2" above it. Maybe pushed up from expansion over the years? Should I just leave that alone?

On using something like the Sikaflex - can I just apply that stuff directly into the gaps (assuming there is still expansion joint material below the surface)? Or do I need to try and cut and place some of the expansion joint material into the places where there are gaps first?

[charby]

Welcome to the land of ground frost. Frost moves everything.

[Hawkmoon]

On using something like the Sikaflex - can I just apply that stuff directly into the gaps (assuming there is still expansion joint material below the surface)? Or do I need to try and cut and place some of the expansion joint material into the places where there are gaps first?

No on just pumping the stuff into the gaps. Elastomeric sealant is not "caulk," The goal is to keep water out, so the stuff has to be able to bond to the concrete on both sides, and stretch as the two chunks of concrete move. Go to this link:

http://can.sika.com/dms/getdocument.get/e6406c2e-5dff-34c2-b52d-a71127437c5f/Sikaflex_1a_factsheet_EN.pdf

Scroll to page two and read the installation instructions. Ideally, the depth of the sealant at the middle of the joint will be half the width. That means of the gap is 1/2" wide, you want to set the back rod and then tool the joint to end up with a sealant depth of 1/4" at the middle of the joint. This allows the sealant to flex and stretch when the concrete moves, expends, and contracts.

This is one of those situations where more is definitely not better.

[K Frame]

Yep, fiber spacer to create the expansion joint/seam between the slabs.