intentionally removing top layer of concrete from driveway

[rhwalston]

customer has driveway with moderate downward slope which at bottom has slight upward slope to parking pad outside garage. driveway is essentially white concrete, parking pad sort of a grasyish beige. the two colors meet BETWEEN expansion joints with the pad concrete maybe a millimeter or 2 higher and sloping down to the driveway cement. they meet in a slight arc, not a straight line. i assume that if they had been poured at different times there would be an expansion joint seperating them. it looks as though the driveway may have been buffed off or the like resulting in the different color, but i'm not at all sure that's the case. the customer wants me to try to pressure wash the top layer of concrete off the pad to try to make it match the driveway. pad is probably 30' by 30'. i told him "no," that if i hit the driveway hard enough to take off enough to reach a different color concrete i'd be certain to blow holes in it and/or open up cracks before i reached the point where the color would change(assuming it would). he accepted my answer but was not convinced. anyone have any thoughts on this? is there a reason the pad might be composed of a different mix of concrete, or the surface finished differently, than the pad? is there a practical way to make the colors more uniform? i took pics but the light was wrong so they don't accurately depict the way the two colors meet. thanks for any thoughts.

 

[sweeper]

With out seeing pics, this is just a guess, It may have been poured out by 2 cement trucks, Meaning, 1 truck didnt have enough in it to pour all of the driveway and needed a 2nd truck to finish up pour, This happens alot in track homes where they are pouring muilty drives and walks in same day. If the plant didnt make the same mix, it will turn out different, They could have put more, sand, concrete, rock, may have added a bit of calicum to get it to set faster, many things could have happened. Only way that I can think of to get them to match up would be using a concrete stain on all of it, If you do, make sure that you use the same patch numbers on stain, or you coould end up with the same problem between stain batches. Best way to not have that happen is to mix all cans of stain into one large container, then it will all be one color to cover and no different cans used. Hope that helps