How to remove chalky 'cut-lines' from newly poured concrete driveway?

Question

concrete guys used what seems to be an orange chalky substance to mark lines for cutting. Very little has naturally worn off with rain etc... I'd like to clean it off myself before it sets in anymore. Would a mild soap do? Or do I need a special cleaner?

Thanks for your help.

Answer 1

Pressure washer usually works best, but make sure you have at least 7 days cure on it before you try.

Answer 2

if it's bright orange in color, it'll come off with a broom or even a garden hose with a spray nozzle.  If it's red, unfortunately that's 'permanent' chalk- it's got a pigment that's a real pain to get to go away.  After the concrete is over a week old try using a pressure washer.  If that doesn't work, then you'll be stuck with the lines for quite some time.  Concrete is porous and what happens with the red stuff is that it's kind've like a stain or dye.  It seeps into the pores and basically stains the surface. I'm a cementhead myself, and I've been doing this for 16 years now....and what I usually do when I cut a driveway is use white or blue chalk, because it's not permanent.  If you do use a sealer, you have to wait 28 days from the time it was poured to apply it...so you've got time.  And it also has to be absolutely dry.  If you get impatient, and you want to seal it sooner, you can use a 'cure and seal', which is a water based product-that can be applied immediately after it's hard.  Also, keeping the driveway damp for a week will result in a stronger driveway- it'll cure stronger.  I know the last little bit was way off base, it's just a few tips- a driveway is no small investment, and some contractors don't take the time to say the little things.

Answer 3

If they appied a cure and seal coating over the concrete, it might be there awhile.

Either way, I would just let it wear off, If you scrub concrete you may get a different look where you do and don't scrub.

You may very well dislike the marks left by cleaner more than the chalk residue.

Some chalk is made to wear off , some is permanent - many don't know the difference.

Answer 4

You might want to try some detergent and and a scrub brush and hit it gently so as to not wear off the fresh finish. If that does not work, you can use a pressure washer set very low to try to pull it out, but this can damage the finish on fresh concrete very easily. Another idea which I think would be superior to pressure washing, is get some muratic acid, place (1) part into a bucket and add (5) parts water. Use a medium bristle scrub brush and scrub the affected areas with the solution, once you hit an area, rinse it off quickly. If the muratic acid sits for too long it will etch the concrete, but if watered down well enough it's a good method for getting chalk stains out of the surface.