I poured a 24x40 concrete approach about 2 months ago. I cut lines in it the next day and sealed it within the week. I know concrete cracks, but when the slab gets wet, there is a darkened web all through out. I have noticed some of the cracks are starting in the darkened areas. It kind of worries me that it will keep going. I posted a picture since it's hard to explain, if I did it right anyway. The only thing I can think of doing this, is the sealant. I have done concrete work off and on before, but never use sealant. This is the first time I have seen something like this. Any information would be appreciated. Thanks.