Not really home improvement per se but I thought this board may have the best expertise. I am building a wash rack for show cattle and I have a concrete slab that's been poured for well over a decade. How can I mount two posts or pipes into the concrete slab? Is it even possible?

Wedge Anchors or Titen HD anchor bolts through the flange on the bottom of your pipe. Super easy.

I would just buy a bollard if you don't feel that you can weld one yourself.

This might not work for you but I had a problem of sheered off wooden 4x4's in concrete. The lawnmower guy thought he could nudge the gate open - the gate was locked and he ended up knocking it over and cracking the 4x4's.

I listened to a couple of friends and they said to burn out the stumps - that didn't work - then the suggested to drill them out - that didn't work.

Then i went magnetfishing and at this one bridge I saw a piece of rebar sticking out of the concrete about 4 ft high.

I thought to my self hat it I drill into the stumps and put a piece of rebar into it. Then I drill a hole in the 4x4 and put it over it? So I tried it. Drilled the hole but the rebar in and drilled a hole in the 4x4 and put it over it. Yes it spun like a top until I tied it into the rest of the fence and the I hung my gate again. I filled in rest with concrete.

It is solid as a rock.I would think this approach might work it with you. Drill your holes fill in with concrete remainder of hole put your pole, 4x4 or what ever over it and then tie the tow poles tighter with wood or something else.

Not an expert but it worked for me. You could also go with the shallowminded14's method.

Are you trying to set pipes off the tie rail to keep calves from swinging? If you want them to be removable and the floor flush when removed then you'll have to saw cut and jackhammer out a 12"-18" square. Set your sleeves and fill the void with sackrete. If permanent is ok, just weld the pipe to a 6" x 6" base plate and bolt it to the concrete with wedge anchors or red heads.

Wood or steel posts?

If wood, Simpson strong tie makes a lot of brackets that can be used to anchor to concrete.

If steel, you'll either need to weld a flange with bolt holes onto the bottom of your pipe and use wedge anchors or similar to anchor to the slab or get someone to core you two holes and grout fill after placing the posts.

If drilling holes, use a rotary hammer instead of just a hammer drill. You can rent one or Harbor freight actually has decent one if you think you ever want a small demo hammer for something (ripping out tile, other projects).

A hammer drill will take forever with good size holes where the rotary hammer will just zip them right in.