I've been wanting to clean up the area around my mailbox for some time now but I've had one issue bothering me that I wasn't sure how to resolve. The curbs on our street are made from large slabs of granite set on their edge into the ground and, where the curb meets my driveway, the slab comes up short. This causes drainage water to turn the corner into the driveway and scour soil from the space between the curb stone and the driveway, depositing piles of sand and dirt in the driveway. I wanted to find a stone that would fit into the space, closing in the corner and continue the granite style but my options were limited. I would have to find a piece of granite close to what I needed then sculpt it to fit the gap. Besides being more work than I wanted to get into I didn't think it would be strong enough to handle being driven over repeatedly.
I decided to use concrete to fill in the space and to shape the concrete to continue the curb's look as best I could. Regular concrete would do the job but it has a tendency to slump and lose its shape while setting. To use regular concrete I would have to build forms to fit in the awkward shape of the gap. I chose instead to use ShapeCrete for this project because it is easily shaped into custom shapes and it is more resistant to slumping than regular concrete. ShapeCrete is a special blend of concrete and fillers that, when properly mixed, takes on a clay-like consistency that can be easily molded and shaped. This allowed me to mold and shape a filler that blends in well with the existing granite and fills the gap between the curb and the driveway concrete.
Step 1: Prep the Area
To get started, clear the area that to be filled of all soil to give yourself plenty of room to work. Once cleared, clean off the surfaces of the stone and concrete that will be bonding with the ShapeCrete because a clean surface is required to assure a strong bond.
Step 2: Mix and Place the ShapeCrete
Once you have prepped the area, mix up and place your ShapeCrete.
The ratio of water to ShapeCrete is very important here because the ratio determines how firm the mix will be and, therefore, how workable and how resistant to slumping it will be. You want to have a very clay-like consistency that doesn't slump over when you shape it. The instructions call for a 4:1 ratio of mix to water to get the clay-like consistency. I used Playtex gloves from the grocery store when mixing to allow me to get a good blend and to work the ShapeCrete until the consistency was what I needed.
The stone and concrete should be wetted when you go to place the filler to help with bonding. Once the concrete is in place you can begin shaping it to the desired shape. Although these photos don't show it very well, using a small piece of wood I shaped the surface of the concrete to have markings and surface variations to match the granite stone. The coloring doesn't match well but that will change with time.
Step 3: Fill in Soil and Gaps in the Concrete, Plant Some Nice Plants
Once the ShapeCrete has cured you can fill in around it with soil as needed. In my case I also had to repair a crack in the driveway so I used regular concrete patch for that. I also used the concrete patch to fill in between the ShapeCrete filler and the street tarmac. No need to waste good ShapeCrete there.