Concrete 101
Composition of Concrete
Concrete is made up of four major components which are water, cement fine aggregate (sand) along with coarse aggregate (rock). Sometimes, recycled cementitious materials such as fly ash and slag are used in place of cement, creating a range of different impacts on concrete’s hardened and plastic properties. Admixtures can be added to the mix to speed up curing times and increase the workability, strength, or alter the properties of the concrete. Different proportions of these primary ingredients make up the various forms of concrete. For one of the best compositions of concrete, you can contact John at Quality Concrete NC or call them at (541) 283-0954
Air Entrainment
Air enhances the strength of concrete in conditions that are susceptible to freezing, freezing, salts, groundwater and alkali reaction. It also improves the working capabilities of concrete. The tiny air pockets ease internal pressure on concrete by creating chambers that water can expand when it is frozen. The proportion of air generally ranges from four to eight per cent of concrete’s overall volume, but it could depend on the specific request of the client and the specific conditions.
Reinforcement
Concrete is a great material for construction and has remarkable compressive strength, it is as a weak material in tension. When concrete is paired with other materials with strong tension, like reinforced bar made of steel (rebar) and wire meshes, they is able to be able to resist tension and boost the strength of flexural elasticity.
Slump
Slump is a measure of the consistency and fluidity of concrete. It demonstrates the workability and flow that concrete is freshly mixed. In simple terms, the greater it is, the drier the mix. A four-inch (4″) slumps are common in normal concrete weight and is ideal choice for pumping. Slumps above the average can result in lower strength as well as durability and permeability of concrete. Admixtures are a better choice instead of water in order to attain greater slumps to ensure the strength and durability in your concrete.
Water-Cement Ratio
The ratio between cement and water is the proportion between the amount of weight water for the amount of cement employed in a concrete mix. This is vital to the general high-quality of concrete. A lower ratio of water cement will result in a higher flexibility and compression strength, less shrinkage cracking, less permeability, and an improved resistance to weather and wear. However, this can reduce the workability of concrete, making it harder to put in. The water-cement ratios usually range between 0.4 to 0.6. Lower ratios of water cement are utilized to make concrete with greater strength.
Interior vs. Exterior
The weather plays an important role in the finalization, installation and longevity of concrete. Concrete used in the interior is generally not subject to the natural variations of the weather and usually does not require air entrainment since it is less likely to break than exterior concrete. The primary difference lies in the finishing on the concrete. If you finish the concrete too soon (before the water that has accumulated time to rise to the surface) could trap the bleed waterand set the stage for future surface issues. Exterior concrete typically has the “rough broom” finish to give traction to vehicles and pedestrians, thus reducing the chance of slipping or falling. Contact Brian from Concrete In Tampa or call them at 813-680-5542 for any concrete services you need in Tampa, Florida.
Hot and Cold. Cold Weather
Concrete is dependent on temperature, which means it sets faster in hot weather, and slowed down in cold conditions. Mixtures are typically added to delay the setting time in the heat of summer (retarder) and accelerate the setting time during cold temperatures (accelerator).
Concrete that has been freshly poured can be difficult to pour. the heat can create problems like:
- A rapid slump loss
- Set time increased
- The demand for water has increased
- Problems in controlling the air that is entrained
Be cautious when you add water to the concrete on the job site since it could negatively impact the concrete, leading to a decrease in durability, strength and an increase in the likelihood to crack.