You can use the trowel upside down to hold the mortar so it can be pushed into the joint by the pointing tool. Being an amateur, you will be working very slowly. Mortar begins to set in 15 minutes, and after that it cannot be used effectively. Now hairline and wider cracks have occurred between the driveway and sidewalk. If the sidewalk was poured separately from the driveway, a crack is guaranteed to occur.
Cracks also can occur in a steel-reinforced slab of concrete.
You cannot afford to ignore these cracks, as minor as they may be. Q. I screened in a porch and deck. Staple screening to the bottom of the deck, and regularly vacuum out the debris that will collect in the gaps. Put indoor-outdoor carpeting on the floor boards. A reader said she did this and the gaps between the boards did not show through the carpet.