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.