GBR Concrete - Dayton, Ohio

The basic process is a brief overview of a basic concrete pour. Although most of the steps are the same for other processes like color and stamped, there may be additional steps that are not shown here.

Pre-job Checklist Upon arrival, the Crew Leader will go over a number of checklist items to insure that you and your property are respected and that you are informed before the crew begins.
Site Plan & Layout If you have a design our crews will spray that design on the ground and gain your approval. If not, our crews will work with you to spray a suggested design on the ground with curved lines, flares, etc., to add character and design to your home. As well, if possible in his schedule, and if requested ahead of time, our on-staff Designer can drop by at the start of the job to assist in the layout. Our Crew Leader will work with you on the design to insure that he is forming the project to your desires and to make sure when he’s actually placing the forms, that you’ve given your approval ahead of time. Once the forms are placed, we ask you to look over the design to make sure that, before we order concrete, you’re satisfied with the design. Note: Please understand that our Crew Leaders are not officially designers and are limited.
Excavation After the project area is marked, we begin excavating and or removing the old surface, in order to build the sub-base. Our crews will take all necessary precautions to protect surrounding obstacles and underground utilities. Our Dispatcher will automatically call for the Ohio Utilities Protection Service (OUPS). OUPS will identify the following: Utility Color Codes When utility company representatives mark a location, they use colored flags and/or paint to identify the type of underground service: Red - Electric power lines, cables, conduit and lighting cables colored markings Yellow - Gas, oil, steam, petroleum or gaseous materials colored markings Orange - Communication, alarm or signal lines, cables or conduit colored markings Blue - Potable water colored markings Purple - Reclaimed water, irrigation and slurry lines colored markings Green - Sewers and drain lines colored markings Pink - Temporary survey markings colored markings White - Proposed excavating
Building the Sub-Base The concrete industry has learned that a firm foundation is critical in preventing concrete from sinking and causing uncontrolled cracking. Eighty percent of the integrity of concrete is dependant on the foundation. The Federal D.O.T. has proven the best foundation is formulated using crushed limestone, which is the foundation in highway construction. Our standard pricing includes up to 4 inches of crushed limestone, compacted to provide a consistently compacted foundation.
Controlling Cracking All solid surfaces, such as concrete and asphalt, spread over a certain size area of the ground will crack--subject to minor earthquakes, movements of the ground, freeze/thaw conditions, etc. So, to control the inevitability of cracking the placement of control joints are critical. Nature has made it clear that concrete cracks about every 8-10 ft apart. So, to control this cracking, control joints are used to intentionally weaken the concrete in a straight line so when it cracks it cracks straight and the crack is one inch below the surface so the crack is not easily seen. Our standard spacing of these control joints is around 6-8 ft apart--to give the greatest crack control.
Reinforcements There are a number of different types of reinforcement materials used in concrete construction. Steel wire mesh was a preferred material used in residential concrete construction 40-60 years ago to provide tinsel strength to concrete. The industry, at that time, did not focus much attention on a solid foundation, but placed more emphasis on pouring it thick and using the wire mesh to hold it together after it cracked. Steel wire mesh was never used to prevent concrete from cracking, simply hold it together after it cracked, which is why you see older driveways with very few control joints in them and uncontrolled cracks all over the driveway, especially down the middle. The preferred reinforcement for the last 40 years has been the introduction of a poly-propylene fiber mesh. Fiber mesh is mixed into the concrete at the ready-mix plant and when placed provides many different advantages over the steel wire mesh. Please feel free to read these qualities at: www.fibermesh.com The benefits of the fibermesh are tremendous, and worth the extra money, to provide the best product the industry offers to our customers. On certain projects, that require an inordinate amount of tinsel strength, such as dumpster truck pads, commercial ramps, etc., we also may recommend the use of a wire mesh along with a commercial-grade fibermesh. Regardless, if our customers prefer the steel wire mesh over the fibermesh, it can be substituted for the fibermesh.
The Pour Depending on the size of your concrete project, the placing of the concrete may be broken up into sections to allow proper finishing and access. If the project is a driveway, it is common that a crew will schedule each concrete truck to be ready to deliver as soon as another truck empties their load. This will provide a strong monolithic pour that has a clean uniform look. At this stage our crews will screed, or level, the top of the new slab making sure the surface is level while at the same time, insuring that the slab is graded away from structures for proper water run-off.
Finishing Once the concrete has been placed, the crew will screed the surface with a wood or magnesium board to gain a general leveling of the surface. Next, they will float the surface to gain further leveling of the surface with a magnesium bar attached to a long pole that’s moved back and forth over the surface. This process pushes the larger stones further down into the concrete, bringing the softer "cream" to the top—providing a beautiful flat finish. When the concrete becomes a little harder the crew will start to trowel the surface. This is normally a manual operation for smaller slabs, but we often use mechanical machines to help with larger pours. On certain projects, an additional hand-troweling process is accomplished to further smooth the surface. At this point in the process, based on your preference, control joints are troweled into the wet concrete. These are deliberately placed grooves to control cracking. Like we stated earlier, all concrete and asphalt surfaces will crack. This is a normal and expected event as it expands with temperatures and the ground moves. These grooves provide a medium for a controlled crack for both durability and esthetics. Not only can control joints be troweled in by hand, but also some customers prefer a saw-cut control joint. This process is completed after the concrete has hardened, normally by the next day after placement. We use a concrete saw and cut lines about 1/8 inch wide and one fourth the thickness of the slab. So if the slab is 4 inches thick, the joint is cut 1 inch deep. The depth of the cut is to intentionally weaken the concrete so that it will crack in that weakened area. The saw-cut control joint provides a very nice finish option and, at a later date, can be filled with a styrafoam backer rod and self-leveling joint filler—to prevent water intrusion, thus lengthening the life of the slab. Outdoor slabs are finished with a light-broom finish to allow for traction and maintain the slabs air entrainment characteristics to withstand freeze/thaw cycles. Air entrainment is simply a process of introducing a detergent-like product into the concrete mixture forming bubbles or vacancies that allow expansion during freeze/thaw cycles. Without air entrainment the concrete surface would eventually begin flaking off. Also, poorly finished concrete, by an uncertified finisher, can cause this similar flaking process, which is why GBR Finishers are industry-certified by the Ohio Ready-mix Concrete Association. Most companies don’t take the time or spend the money to certify their finishers which is why we replace slabs that are no more than 3 or 4 years old. Common mistakes are over-troweling concrete, simply troweling it too much, which trowels out the air entrainment. Also, if the placement of concrete isn’t controlled properly, under the right conditions with the right amount of help, too much concrete is placed that sets up too fast and the only way to get a finished look is to throw water on it, which dilutes the strength of the concrete surface and in a few years the top will begin to flake off—a problem known as spalling. Porches, garage floors, or indoor slabs will receive a slick finish, unless a light broom finish is preferred.
Curing the Concrete The last step for our crew is to apply a dissipating curing compound to the surface of the new concrete. Concrete needs water to properly cure and it’s even more important during the first 5-7 days. The old process of curing was to place burlap on the surface and keep it wet for 5-7 days. This moisture allows the chemical process to continue and the concrete to increase in density by the day. If it dries out prematurely, the concrete will stop the all-important curing and become weakened as a result. The most efficient way to allow the concrete to retain it moisture at the time of placement is to apply a dissipating curing compound to the surface within two hours of finish. The dissipating curing compound provides a membrane on the surface to protect it from the sun, or it would otherwise evaporate the water out of the slab prematurely. Basically, it allows the concrete to keep its moisture at the time of placement, longer. The use of a dissipating curing compound also allows the concrete to be properly sealed at later date without having to strip surface. Some companies use a cure and seal product at the time of finish for curing and later has to be stripped off to apply a penetrating sealer. Note: Please refer to the “Paving Maintenance” section for information on properly sealing concrete.
Optional Landscaping GBR Crews can also help property owners finish their projects with topsoil placement and reseeding. GBR only uses the best materials.