I am talking 1/4 to 1/2 inch thick, some smaller areas thicker than that...Here is my idea, tell me if this might work. (This is an asphalt driveway, BTW). Dig out the cracks with a can opener or something pointed to make some depth, blow out the dirt with a leaf blower, fill the crack liberally with quick dry cement, sweep off the excess, mist with the garden hose to set the cement, then cover the driveway with black sealant.
Is this too Mickey Mouse to work or what?
Thanks,
Bluesman