Despite receiving a D+ on the most recent infrastructure report card, our nation's bridges scored a C+ owing to a large percentage of structurally deficient bridges. Concrete quality, as well as the material performance and structural integrity, depend on the proportioning, mixing, putting, and curing of the concrete being done correctly. The concrete mixing and pouring methods that are often utilized to create high-quality raw materials and finished products are described here.
Concrete Mixing Procedures
Standard concrete typically contains 60-75% aggregates (coarse and fine), 7-15% cementitious materials, and 14-21% water with an entrapped air or intentionally entrained air by absolute volume. To thoroughly mix and homogenize all the components, it takes time and effort. There are three typical ways to mix concrete:
Hand blending:
As the name suggests, hand mixing entails manually mixing concrete on flat iron sheet plates or brick platforms. Small undertakings involving home repair are handled using this method. With this approach, it is challenging to attain quality and consistency.
Automated mixing:
Using a motorized or permanent mixer is an effective approach to achieve a homogenous concrete mix for bigger projects. A small portable drum mixer may be used for machine mixing, and bigger stationary mixers, such as worksite mixers in portable plants and central mixers in ready-mix plants, can be used.
Rough Mix:
In a concrete factory, ready mix concrete is created, combined, and batched before being supplied to the project in a freshly mixed form. For projects that need just a small amount of onsite area, this approach is a practical option. The raw ingredients are weighed and loaded into the ready-mix truck for thorough mixing in a dry batch concrete factory. The raw components are thoroughly combined in a stationary central mixer for a wet batch concrete factory before being delivered by a ready-mix truck.
Mixing apparatus
Portable mixers are a perfect choice for smaller tasks because of their size, speed controls, and fuel usage (both gasoline and electricity). Ready mix trucks, on the other hand, are more often employed for bigger applications. There are time restrictions to be aware of while using ready-mix concrete.
According to Pavement Interactive, "In general, quick turnarounds between mixing and application may better prevent the issues of early hardening and slump loss that arise from probable transit delays. Concrete is a brittle building material no matter how it is mixed. First off, it is of little value if it starts to set before being applied and consolidated. Second, if it is too mixed and agitated, the benefits of certain admixtures may be lessened or it may lose its air entrainment.
For major building projects, on-site central and jobsite tailored mix facilities are experts at producing enormous quantities of concrete. To properly balance and mix concrete, they use a variety of tools, including horizontal shaft mixers, conveyors, and silos. Having a central mix facility on-site and an effective method of transporting concrete together gives projects easy access to concrete of better average quality while still being cost-effective.
Large operations and projects in distant places might also benefit from custom onsite mixing plants. This approach often matches the placement pace required for certain occupations better.
Small concrete trucks are often used for deliveries to residential neighborhoods, commercial buildings and construction sites. They are also sometimes called mini-trucks because they are much smaller than typical delivery trucks.