Why does my floor turn lighter if I burn it?!

[Number21]

So I stumbled upon a little accident today - if I burn my dark, dirty old concrete floor with a torch, the color lightens up considerably. It was almost like using a tiny sandblaster, with no mess, just burning this hole with my torch:

It may not look like much, but if I did the whole floor, it would probably be considerably brighter! It would look even better after being pressure washed.

But I'm curious as to why the hell this is happening? I expected it to turn darker where I burned it. Is there maybe some kind of old sealer on this floor that I'm burning off? Maybe it would be easier to just use some kind of stripper?

 

[TireTracks]

You probably were burning off all the oil and grease that have accumulated over the years. My .02

 

[jmh21586]

That and you evaporated all the moisture out of that spot. Or you burned off the sealer.

 

[tatra]

careful as when concrete is heated too much it can explode violently..........

 

[Jaguar Fan]

careful as when concrete is heated too much it can explode violently..........

+1 ^^^ Or heated too quickly.

Ask me how I know.

 

[Number21]

That and you evaporated all the moisture out of that spot. Or you burned off the sealer.

Not moisture - still looks the same today. If it's just a sealer, is there a stripper I can use to take it all off? Otherwise I'm gonna buy one of those big ice melting torches and do the whole thing...

Oddly, I've done the same thing in my home garage with a concrete floor and no sealer, it made scorch marks.

 

[tcianci]

you need to find a different hobby

 

[porschedude996TT]

careful as when concrete is heated too much it can explode violently..........

It is called "Spalling", My $.02. Hey what happend to my "Cents" Symbol on my keyboard?

 

[JTG]

Hey what happend to my "Cents" Symbol on my keyboard?

Here it is ¢ !!!

Hold down the Alt key and type 0162.

 

[Falcon67]

Here it is ¢ !!!

Hold down the Alt key and type 0162.

Now you are totally geeking out.

Spalling - how it's done:

Now look what ya done to Kenny Barnes' new multi-million dollar drag strip

That strip in the middle is busted concrete.