First, the organic ground must be removed and replaced with a crushed stone. The area then is formed up creating a pitch of 1/8" to 1/4", allowing water to flow in that direction. Once the forms are up, the subgrade is ready to be graded. Depending on the project, the slab thickness should be 4" to 5" thick. Grading the subgrade uniformly is crucial. Not only does it make it easier to estimate the amount of concrete needed for the job, it cuts down the chances of unwanted cracking, since concrete will crack at the thinnest depth of the slab. Concrete will always crack. That is the reason for control joints, to control the crack. Once the subgrade is graded it must be compacted. #3 rebar is now put into place 18" on center, wherever stamped concrete is being placed. Depending on the temperature, the subgrade is sometimes dampened.
Next, the project is ready to cast the concrete in place. Here at Turner Concrete we standardly use a 4000 PSI chirt-free mix (6 bag chirt-free mix). Fiber mesh is also used as a secondary reinforcement to the #3 rebar when stamping concrete.
Once the concrete is down, struck off, and floated, the color is ready to be added. There are basically two ways to color concrete. The first method, integral, is where the coloring is mixed right in the concrete truck, giving the concrete color throughout the slab. It sounds good, but there are many inferior qualities compared to the second method. The second, is called the dry shake-on method. After the concrete is floated, the dry powder (which is called color hardener) is broadcast across the slab. The color hardener is then floated in. This process is repeated a second time to ensure an even coloring. This method of coloring colors approximately the top 1/8" of the slab, but increases the surface strength significantly to about 7000 to 8000 PSI. Once the concrete is set to the right stiffness, a second, different color is broadcast across the slab. This is called a release agent. What a release agent does is keep the concrete from sticking to the impression mats. The release agent also gives the pattern a realistic two-tone effect. The slab is now ready to be stamped.
Depending on the weather, the release agent is usually power-washed off the next day. After washing off your new decorative project, the slab is left to cure for about a week. We then come in and acid wash the entire stamped area. This takes away any unwanted release agent left on the slab and prepares the slab for sealing. Here at Turner Concrete, we like to detail and hand pencil in every joint. This gives our work of art a most realistic effect. Finally we spray on a crystal-clear, non-yellowing, ultraviolet-resistant sealer designed specifically for outdoor stamped concrete that has high traffic areas. A non-slip shark grip powder is mixed in with the sealer, making your decorative concrete not slippery when wet.
Following the correct procedures will give your decorative art piece years upon years of endurance and years upon years of beauty.