FAQ

CONCRETE REPAIR QUESTIONS

AThis is one of those loaded questions with many experts agreeing and disagreeing. Concrete is a durable material that has roots reaching back to the roman coliseum era. However, because of the Canadian climate, our concrete has to endure many freeze-thaw cycles and environmental impacts. In our opinion, adequately poured and sealer protected concrete can last for a lifetime as long as it is cared for correctly. Although, various factors play a role in its ability to last a lifetime. Some factors to consider are, pouring and finishing skill level, temperature, salt or chemicals, admixtures, air entrainment. The best way to keep your concrete looking great is proper maintenance.

AThe best sealer to use depends on your application and what you are trying to achieve. The sealers break down into two categories—water based and solvent-based sealers. Consequently, both of the sealers offer protection against wear and tear and stain resistance. However, this doesn’t mean you can allow your leaky car to drip oil without consequence. Solvent and water based concrete sealers are both easy to apply and offer UV resistance. As mentioned above the seal you choose will depend on your application and substrate if you are looking for the “wet, shiny” look on decorative concrete. You will then want to choose a solvent-based sealer or feel free to contact us for help. If you want to achieve a matte finish, so it looks like it did previous to sealing, but has protection from the elements, you will want to choose a water based concrete sealer.

ACement is an essential component in both concrete and mortar. Cement comes in a variety of mixtures to be added with aggregates, sand, water and admixtures to form concrete. It is generally made of limestone, clay, and silica sand. These materials are crushed and combined with other additives then heated to above 1480 C. The result is a clinker material, which is ground into a fine powder and packaged to use for mixing various kinds of concrete. So concrete is a mixture of all the ingredients like a cake resulting from mixing all of its ingredients. Flour would be the cement in this analogy.

ACuring is how long it takes for the concrete mixture to reach a strength so that you can use it. This means parking your vehicle on it, walking on it, or playing a game of road hockey. Depending on the mixture and the air temperature outside, curing can take a couple of days to a month. The concrete has to maintain moisture and how adequate temperatures for the cement hydration to occur. The chemical reaction gives off heat, which will start gathering psi or mpa depending on the term you would like to use. It is important to note that most experts agree that 28 days should elapse before you use your new concrete.

Typically walking can be done within 24 hours if the temperature allows. Once concrete reaches 5 degrees or less, the curing process basically stops.During the early curing, the concrete’s internal structure is forming to provide strength and low permeability depending on the admixtures used. Water is needed during the curing process, and as such misting water on the concrete to replace any lost moisture will help the process and dissipate the heat.

AConcrete cracks are likely on most projects, so it’s practical to set reasonable expectations for your job. One of the main reasons rebar or steel reinforcing is used is for this reason—concrete cracks. Rebar and control joints are used along with the best concrete pouring practices to minimize cracking. Sometimes noticeable cracks will develop under support loads which should be monitored. Shrinkage cracks and general hairlines may appear overtime when it comes to slabs, driveways, patios, basements, steps. The facts are that it is unrealistic to expect concrete not to crack regardless of the best design and construction practices. It is very normal to expect some amount of cracking on every project. The Concrete Doctors want to ensure awareness by all parties that cracking will occur when concrete is used. Please contact us if you have any questions or concerns.