What Does a Concrete Contractor Do?
Concrete Contractors Dallas TX are required to meet strict structural standards on commercial projects. This ensures that their work is of high quality and safe for the public to use.
Concrete contractors also need business skills to run their own company. This involves managing paperwork, finances, and estimating. This can be learned through business school or by balancing jobsite experience with office work.
Formwork is the temporary structure that holds the concrete until it hardens. The contractor and architect-engineer work together to determine the best formwork system for a project. It can be made of timber, plywood, steel, glass fiber-reinforced plastic, or other materials. It can arrive on site in component pieces, ready to assemble, or it can be prefabricated at the factory. Depending on the material, it can be used for a single application or reused a number of times.
The formwork supports its own weight and the concrete that is poured into it, as well as construction loads like equipment, materials, workers, and so on. It also provides a means to control the shape and position of the concrete while it is being poured. Formwork is usually built from a combination of timber and plywood. It can be designed to be dismantled easily and quickly without damaging the concrete.
It is important to select high-quality formwork for a project. It should be practical and waterproof, able to withstand shrinkage and swelling, and resistant to the effects of vibration, compaction, pouring, curing, and temperature changes. It should also be strong enough to resist abrasion and impact damage. It is also a good idea to design the formwork carefully to limit the use of slender sections, which saves time and wood.
Formwork must be properly supported to prevent it from collapsing or becoming displaced as the concrete is poured. This can be done by adding braces or tie rods to the supports or by using timber pegs, walers, or lumber kickers to hold them in place. It is also a good idea to use form oil on the interior of the forms to prevent concrete from sticking.
Once the concrete is poured and has set, the formwork is removed, which is called “stripping” in construction parlance. It can then be repositioned elsewhere on the construction site, stockpiled for future use, or destroyed. Proper formwork construction is critical to ensuring the safety of workers and the structural integrity of the concrete. It is also a key factor in speeding up floor-to-floor construction and increasing resource efficiency.
Pouring
Concrete contractors need to be able to take the weather conditions into account when working with concrete. If it’s too hot, cold, or wet, the concrete will set improperly and not be as strong or durable. The right concrete contractor will know how to deal with these conditions without compromising the integrity of the finished product.
Pouring concrete can be a labor-intensive job, especially on large projects. The concrete has to be poured in a very precise way so that it doesn’t run off the form or into the wrong area. Pouring on sloping surfaces can be particularly challenging, as the concrete has to be carefully guided down to avoid flooding or spillage. Concrete contractors may also use a boom pump to lift concrete into hard-to-reach areas. This is a great way to get concrete into corners and crannies that would be difficult to reach with tailgates or wheelbarrows.
Before the concrete can be poured, it must be properly prepared to reduce the risk of heaving and frost. For example, the area should be clear of grass, rocks, trees, and debris and graded to expose bare earth. A tarp can help protect the surface from rain and wind while it sets. For large projects, earth-moving equipment speeds up the process and reduces labor requirements.
After the concrete has been poured, it needs to be kept moist until it sets. Concrete that is exposed to the elements will dry and lose strength faster than concrete that is covered. Concrete contractors can keep the concrete moist by spraying it with a hose or placing a sprinkler beside the slab. They can also cover it with a special concrete-setting blanket.
In extreme hot or cold weather, a professional concrete contractor will keep the concrete in a cooler area and mix it with cold water to prevent it from freezing and setting too quickly. They may also use ice to slow down the drying and curing processes. They will also make sure the forms and reinforcing steel are above freezing, free of ice or snow, and have adequate insulation to protect them from the cold concrete. In addition, they can construct heated shelters to protect the concrete from cold winds and rapid evaporation of water.
Screeding
Screeding is the first step in finishing concrete, and it is done to create a flat, even surface for other materials to be laid on top of it. It is essential that this stage of a concrete construction project be carried out correctly, as it can prevent ridges and bumps in the final surface once it has cured. In addition, it will help to reduce cracking and settling, which may occur if there are too many high or low spots in the finished concrete.
During the screeding process, contractors use straight edges to remove excess concrete and bring the top surface of the concrete to its proper grade. This is known as “strikeoff.” There are a variety of tools used for screeding, including hand tools (wood and magnesium) and mechanical equipment such as a power concrete screed or roller. The machine has a gasoline motor attached to it, which helps smooth and vibrate the concrete as it is flattened.
Concrete contractors use various types of screeds, depending on the type of floor they are constructing. For example, a cement sand screed can be used for floors that require an insulated layer or are being constructed in damp conditions. This type of screed can be laid bonded or unbonded, and it may have polypropylene fibers added to it to provide additional strength or crack control.
Both a power concrete screed and a roller screed can be used to speed up the time it takes to finish a floor. They also both have the advantage of reducing vibration, which can cause damage to the concrete or flooring surface. They are also more efficient than hand tools, which can be tiring to operate over a long period of time.
Before screeding, the area should be clean and free of debris. Workers should lay polythene sheets or another form of membrane to keep the concrete and the screed separate from each other. These should be overlapped and taped together, and they should go up the walls by about 10 cm. This will protect the wall from damage as the screed dries and shrinks, and it will also provide insulation against cold or noise.
Inspection
Concrete inspectors conduct a variety of inspections to ensure that construction processes and the final product comply with specifications and codes. This can include testing of soil and aggregates as well as monitoring concrete placement. Depending on the nature of a project, inspections may be conducted at different stages of construction, such as pre-concrete placement, during concreting, and post-concrete placement. Inspectors may also be involved in inspecting work units, documents, and procedures related to quality control.
During the field testing process, concrete samples are taken from the site and tested in the laboratory to determine various properties of the in-place concrete, including compressive strength, cement content, chloride and sulfate content, permeability, aggregate type and gradation, alkali-aggregate reactivity, density, and air voids. In addition, nondestructive tests may be performed, such as delamination, void mapping, carbonation, concrete cover, spacing of rebars, and more.
When performing special inspections, it is critical to know how to correctly interpret the results of field tests. Incorrect interpretation of test results can result in the wrong decisions being made about what needs to be repaired, which could damage the integrity of the concrete structure. A basic knowledge of the chemical makeup and performance characteristics of concrete can help inspectors interpret results correctly.
The most common issue affecting concrete is corrosion due to sulfates. This can be caused by an excessive amount of gypsum used in the concrete mix or by contaminants introduced during the manufacturing process. The sulfates corrode the steel reinforcement, causing spalling of the concrete and ultimately structural failure.
Other potential problems for concrete structures can be caused by construction practices, environmental factors, and structural movement. It is important to identify the causes of the issues in order to perform proper repairs and prevent future problems. Inspectors should always be sure to record the location and severity of any observed defects.
Inspectors should also ensure that they have all the required documentation for the project at hand. This can be done by ensuring that the correct plans and specifications are being followed, as well as verifying that all special inspections have been conducted. In addition, the inspector should be certain that the correct formwork is being used to avoid potential issues such as leaking and improper loading.
