In Situ Concrete Stairs? The 92 Correct Answer

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Precast concrete or in-situ concrete? This is a crucial question for anyone moving forward with a commercial construction project. Depending on your particular needs, you may choose to go with one over the other.

Because on-site concreting is custom, it’s incredibly versatile. However, it is also much more expensive, labor intensive and time consuming. While precast concrete elements must be transported to the job site, their unparalleled quality, affordability, and durability set them apart from their on-site competitors. In fact, precast concrete has established itself as the preferred approach in concrete construction.

Consider these stats from Concrete Manufacturers, a trade magazine focused on the concrete industry. Demand for precast concrete here in the United States is growing at a projected 6.4% growth to $12.2 billion in 2018.

Whether you’re tackling a new build or just want to keep up with the latest building and manufacturing trends, this guide will put the differences between the two approaches into perspective.

WHAT IS PRECAST CONCRETE?

Precast concrete is poured and formed over rebar or wire and then cured externally. Concrete is poured into prefabricated molds and then cured under ideal conditions in the production plant itself.

Once cured and ready for use, these preformed concrete products are transported to the construction site where they are assembled into the desired structure.

WHAT IS SITE CONCRETE?

Unlike precast concrete, cast-in-place concrete, sometimes called cast-in-place concrete, is poured, formed, and cured on site.

Like precast concrete, site concrete is formed in a mold and then lifted into place. However, one of the advantages over prefabricated panels is that they don’t have to be moved far to be lifted into place. For a building that requires large, cumbersome, custom concrete forms, on-site machining is usually the way to go. Some forms are just too big to fit in the back of a pickup truck. Conversely, the savings from precast concrete are scaled up, meaning that for a small structure, cast-in-place concrete can be cheaper.

Finally, precast concrete requires more joints and is therefore less suitable for regions prone to earthquakes. For those building in locations where buildings must be “seismic” cast-in-place is usually the preferred option.

However, these are very specific cases where Site Cast is the best approach. There are significant disadvantages that will be explored in more detail later.

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ADVANTAGE OF FINISHED PARTS

Factory controlled equals factory quality: Concrete strength and quality depend on the hardening process. A large part of this is, among other things, the air conditioning.

Curing concrete in a factory allows you to tightly control the climate to ensure the curing process takes place under ideal conditions. This means you can have more confidence in the precision of the mold and manufacture, as well as the strength and consistency of the casting.

Factory Efficiency: In addition to the quality control benefits, factory poured concrete is produced more efficiently, which reduces costs. Since precast concrete parts can be manufactured using assembly line techniques, each pour requires far less labor and therefore costs less labor.

Versatility: A common argument against precast concrete is the perceived lack of versatility. While there are limitations to customization, there are other ways in which a perceived lack of versatility strays far from base. Because factory-made precast concrete is supplied to such a wide range of customers for an equally wide range of applications, precast is in many ways more versatile than site-mixed concrete. A wide variety of motifs, colors and finishes are available, as well as smaller prefabricated architectural elements.

Economies of scale: In addition, since precast concrete elements use standard shapes, slabs can be mass-produced, which improves economies of scale. Additionally, because precast concrete is factory-made and standardized, there are fixed prices that allow you to accurately budget for construction costs and avoid overspending.

No formwork on site: The formwork for the concreting process on site is time-consuming and space-consuming. In addition, in-situ curing requires leaving molds in place for extended periods of time. Not only does this take up space on site, but it also requires you to look into the weather forecast as these forms need to harden under certain conditions.

Additionally, there are thorny cost concerns associated with planning. An unexpected delay of even one day can dangerously overwhelm a project. By eliminating logistical concerns, planning becomes easier, which in turn helps avoid unexpected costs.

In other words, the formwork work on site is a logistical headache. By using factory casting, you can save yourself all the stress associated with coordinating labor and logistics on site.

Efficient and sustainable use of materials: Finally, by using precast concrete elements, you maximize material efficiency. Due to the precision of precast concrete, material waste is minimized. This is much more difficult on site, as the labor inefficiency of concrete preparation motivates contractors to mix more concrete than necessary, just in case.

Additionally, concrete is a recyclable material, which means you can build green efficiencies into your precast concrete products.

COMPARISON OF PREFABRICATED VS. CONSTRUCTION SITE CAST CONCRETE

Perhaps the best way to see how great precast concrete is is to point out the differences between precast concrete and site concrete head-on. Here are some key aspects between the two methods being placed side by side

Quality Control: Because precast concrete is mixed, poured and cured in a factory, ideal conditions and exact dimensions can be maintained throughout the process. Unfortunately, the logistics of site casting make this far more of a challenge. They are exposed to the humidity and temperature of the day you water. You have to do the job with far less precise tools. The result is an inferior quality product even under the most ideal conditions!

Labor Efficiency: Prefab parts are much more labor efficient. Because the work is done in a factory, effort is maximized by using tools and machinery that simply aren’t available on the job site. Therefore, with on-site casting, jobs that could be done with machines must be done by hand instead. This is much more labor intensive, increasing labor costs and making the process more expensive.

Since no machinery is involved, the labor required for on-site casting must be skilled rather than unskilled. Thus, not only are more man-hours required, but those man-hours are also more expensive!

Curing Conditions: Because curing conditions can be controlled in a factory, they can be accelerated without sacrificing strength or quality. That’s just not the case locally. While there are certain things you can do to speed up on-site curing, they’re difficult and generally not worth the logistical hassle and expense. In addition, they run the risk of receiving lower-quality concrete due to the difficulty of accounting for sensitive variables. When you need accelerated curing, precast is the only way to safely move forward.

Full Strength: Because concrete gains strength over time, it is not fully solid immediately after drying. In the case of precast concrete elements, however, this curing process takes place before it arrives at the construction site. This is not the case with in-situ concrete. Before you can place the concrete, you must wait until the concrete poured on site has fully cured. This can delay construction and increase costs. It is far more time and cost efficient to have fully cured concrete slabs ready as soon as they arrive.

Also, because precast concrete is strength tested during factory quality controls, you don’t need to perform on-site strength tests. Strength testing is extremely important to ensure your building is safe. So if you’re casting in situ, this is a step that cannot be skipped. Because this process is outsourced to the factory using precast concrete elements, your job site becomes much more time and cost efficient.

Pour Ahead: Precast concrete allows you to pour your materials ahead of time and store them until needed. Unfortunately, with site concrete, it’s all but impossible to overlap tasks and improve efficiency. Because of the space and labor required for on-site pouring, you generally have to pause construction while you wait for your materials to be ready. This is an expensive way to stand around and wait.

Weather: An unexpected rainstorm can halt construction if it occurs while you’re watering on site. Fortunately, this is not a problem with prefabricated solutions. If it’s raining when your precast panels arrive at the site, you can lift them in place like you would on a sunny day.

Insulation: Because precast concrete is factory-made, certain elements can be built into the concrete that cannot be added to the cast-in-place. Additional insulation is one of the most common elements. Adding additional insulating materials within the concrete slab can save you both labor and architectural design space when constructing a building. Instead of hanging and lining the interior of your building with insulation, the panels you lift in place have the insulating power of traditional concrete with additional suspended insulation.

As more builders seek green ratings for their building, both for good PR and energy savings over the life of the building, precast concrete offers a distinct advantage.

Special Reinforcement: Just as special insulation can be added to the precast concrete element, special structural reinforcement can also be added. For certain projects this is critical as it allows the slab to support loads of a thickness that is simply not possible with traditional poured concrete. By reducing the amount of materials needed to make a building structurally sound, you save money while putting less strain on available resources.

In addition, specialized high-strength concrete requires precise conditions for both mixing and curing. These conditions cannot be checked on site. However, because factory construction allows for increased environmental control, you can use high-strength specialty concrete for your construction. Again, this allows you to create architectural designs that cannot be achieved in any other way.

EXAMPLES OF PREFAB BUILDINGS

Charter Arts School – PA:

When constructing this precast concrete building, there were two main concerns: design and safety. As an art school, design was important. The building should conform to modern aesthetics and create a learning environment conducive to exploring the possibilities of visual arts. But as a school, student safety was paramount. That is why the builders opted for prefabricated hollow chamber floorboards. This type of system has a superior fire rating. In addition, the construction reflected the organization’s commitment to sustainability.

Hershey Medical Center-PA:

Because this building was added to an already existing campus, its design needed to blend with other buildings on campus. Although precast elements were used throughout, a custom concrete mix was required. Additionally, because Hershey Medical Center is a fast-growing medical resource of invaluable value to the area, construction plans were swift and construction was completed in 4 months.

Destination Retail Center – PA:

New retail construction is often completed as part of a large scale development where land is plentiful. However, urban retail constructions, like this new Target Retail Center, require work in limited areas with limited land. However, as a representative of a national brand, the building should also reflect the architectural branding of the parent company.

Therefore, parking lots were placed under the warehouse, which required prefabricated parts with superior strength. At the same time, construction had to be done quickly as the construction work was disrupting the surrounding neighborhood. Again, the efficiency of prefabs was critical to getting this job done on time.

FIND A QUALITY FINISHED PARTS MANUFACTURER

As you can see, the benefits of precast concrete make it the preferred choice for commercial construction around the world.

However, if you are building in the middle of the Atlantic, look no further than Nitterhouse Concrete Products. We have been supplying the region with high-quality concrete products since 1923, working with architects and contractors large and small to bring their visions to life.

Even if you occasionally have to resort to site concrete, down the road precast concrete offers superior versatility, functionality, affordability, and labor efficiency. If you’re not already using prefabs for your projects, it’s time to make the switch. And even if you’re already familiar with the value, consider getting the attention you need from your manufacturing partner.

When you’re ready to take the next step and get your next construction project underway, contact one of our experts for additional planning support.

Contact Nitterhouse Concrete today

Related content from Nitterhouse Concrete:

April 10, 2018 WHAT IS PRECAST AND IN-SITU CONCRETE AND WHICH ONE SHOULD YOU CHOOSE?

Cast-in-place concrete or cast-in-place concrete is the concrete use that forms on site and is poured directly into these molds. The concrete can either be transported already mixed in large mixer trucks or mixed on site and poured into specified forms.

Precast concrete, on the other hand, refers to any piece of concrete that is poured at a location other than the final construction site and the hardened (hardened) piece is transported to the construction site when the site is ready for delivery, whether prestressed or reinforced with conventional rebar.

To determine which technique to use for your project, you first need to know what the difference is between the two and the pros and cons of each.

Here we have some key differences between the two techniques. As effective as each of them is, both techniques have their own pros and cons, and for each project you need to establish those points and determine what works best for that particular project. For example, in-situ concrete is highly dependent on the weather. If conditions are not ideal, the project can take double the time and even compromise the quality and durability of the structure.

Because of precast panel size limitation, precast concrete cannot be used for two-way structural systems, and due to economies of scale, you can only make regular shaped buildings.

Nonetheless, both techniques are very effective and widely used by large project owners. The key to success, whether you’re pouring in-situ or precast, is streamlining the entire workflow from quoting to delivery. By using the right technology and planning ahead, you can save a lot of time and money. For example, using a 3D modeling or BIM software on your project can immensely minimize costly surprises and waste, improve the overall efficiency and quality of the final product, and most importantly, ensure that error-free elements are delivered to the right place, at the right time!

ESTIMATING, PLANNING AND CASTING BETTER WITH DESIGNABLE 3D CONCRETE MODELS!

Interested in learning more about how precast steel compares to in situ?

If you’ve had bad experiences building underground with cast-in-place concrete, you’re not alone. Perhaps due to unforeseen problems, you have overstepped the program. Or perhaps the final product after the completion of your construction project was not to the standard or within required tolerances.

It may even have started leaking, leading to even more headaches and stress – especially if your project was in an area with high water tables.

What if I told you there’s a better way?

Below I use my experience as a subcontractor specializing in prefabricated steel substructures to make an on site comparison to prefabricated steel – including all the pros and cons you need to weigh your decision.

in-situ concrete

Also known as the most traditional underground construction method, prime contractors and construction crews have been using on site for 80 to 100 years. Very little is fabricated or constructed externally, although sometimes the reinforcement or formwork may be modular and supplied part assembled.

This is usually a full site approach, digging a large hole, with timber formwork and steel reinforcement brought on site and assembled by steel fixers and carpenters. The concrete is then poured between the formwork.

Once the structure is erected, the waterproofing is applied.

This method of building underground may be traditional, but it can be very challenging. Often the environment can be difficult, plus you need workers to enter the excavation and complete the work. And that’s not even mentioning the weather conditions in typical good old UK!

Not to mention the logistics involved in moving the materials and general site restrictions. All of this can affect build quality, which can mean increased risk, stress, and problems for you and your team.

TIP: In situ is probably still the best solution if your substructure needs to cover a large area – for example (super basement).

The advantages of in-situ concrete:

It’s usually the cheapest method

It can be very effective if constructed properly

It is a proven method that has been used for over 100 years

It works well on large-scale substructures

The disadvantages of in-situ concrete:

There is a chance it will leak after construction – often caused by reduced skills and on-site quality control during construction

On-site work is very labor intensive – and can take a long time. You also have to wait for the concrete to set before you can load it

This method can be slightly out of tolerance (around +-20mm).

In order for your team to work safely, you need a large dig site

Quality control on the finish is not guaranteed

It only lasts about 30 years in the ground

There tends to be a lot of waste

Problems can arise if batches of concrete are mixed up. I.e. when concreting by the factory, the wrong concrete mix is ​​delivered. This issue is not discovered until 28 days after cube testing is complete and may result in sections of concrete having to be broken out.

Ideally Used For: Large-scale scenarios make on-site an effective choice – in fact, this is often the only way to complete large-scale projects.

Typical cost: £500 – £2,000 per square metre

Prefab Steel

Perhaps you’re beginning to get a good idea of ​​why a more innovative method might be a better alternative. This comes in the form of prefabricated steel. It is manufactured entirely from steel, externally in a factory environment, with strict quality control and constant monitoring and control.

Unlike in situ, this newer, almost revolutionary method will not leak or crack as it is uniquely constructed from steel plates which are then welded together. Think of it like the hull of a boat.

It’s a particularly good solution when your project is in an area with high water tables, or when time constraints are absolutely critical to your construction program – reducing time on site by 70-80%. It can also be built to very, very high tolerances (+-2mm/3mm) and reduces long-term maintenance costs.

TIP: Would you like to learn more about steel prefabrication? Read my recent blog: “What is underground steel prefabrication and how does it work?”.

To sum it all up:

Advantages of prefabricated steel:

Jobs can be completed 70-80% faster (typically within days versus weeks/months)

This method will not leak

It is built to very, very high tolerances (+-2mm/3mm)

The long-term costs are much cheaper because less long-term maintenance is required

Prefabricated steel substructures can last over 100 years in the ground

It comes with a full design package from your subcontractor

Disadvantages of prefabricated steel:

It can seem expensive

It is an innovative method that very few people know about. People unfamiliar with a concept are generally skeptical about it

Ideally Used For: When your substructure is on the critical path of the program, needs to be built to tight tolerances/precision engineering, or when a project is in an area with high water tables and long-term water intrusion is a concern.

Average cost: £1,000 – £3,000 per square metre

Advice from a specialized subcontractor

Still weighing your options? It may be a good idea to seek out a subcontractor who specializes in prefabricated steel so they can discuss your options and give you a better idea of ​​what is possible. It is not always the case that prefabricated steel is the best option – for example when your project is of a large scale.

But it’s still worth talking to. Most people are skeptical about prefabricated steel as a method of underground construction until they’ve seen the product being made – or installed and used it themselves.

So you could ask to see samples of their work and even reach out to some past clients to ask about their experiences.

Conclusion

I hope this blog has given you a better idea of ​​how precast steel compares to cast-in-place concrete – or in other words, the new versus the old. Conventional cast-in-place concrete has been used for 80 to 100 years and is still a good option for large projects. However, there are several advantages over prefabricated steel (as mentioned above).

Do you have questions about on-site vs. prefabricated steel substructures? Feel free to leave a comment. I promise to answer!

What does on site mean?

In situ (also referred to as insitu or in-situ) is a Latin expression commonly used in the construction industry, meaning “on site”, “in place” or “in position”. It refers to work carried out on site itself, often in a finished position as opposed to an off-site location as in prefabrication or pre-assembly techniques.

The most common use of the term “in situ” refers to concrete, with components such as slabs, beams and piles being referred to as “cast in situ” to distinguish them from precast concrete components that are fabricated off-site.

In general, on-site construction techniques tend to be more labor and time intensive, but they are more responsive to changes that may occur on site. Prefabricated components, on the other hand, must be designed in detail beforehand and can only be modified to a limited extent after production.

In situ can also be used to refer to in situ tests, such as tests conducted in situ to determine the density or shear strength of soils. For more information see: In-situ investigation of soils.

In the context of soil, in situ can also refer to soil that is still in its original state and has not been ‘cut’ from one area of ​​a site and ‘filled in’ elsewhere.

See also: on site.

Concrete is a very important building material. Cast-in-place and precast are two main methods of concreting process. In this article we will see which concrete method is better to pour cast-in-place or ready-mixed concrete. Now let’s start with their introduction.

Cast in-situ concrete

Cast on site

Concrete poured on site is called in-situ concrete. In-situ concrete, also called in-situ concrete. It is the traditional pouring method used for most projects around the world. In this method, the formwork is made on site and liquid concrete is poured into the formwork and then cured.

precast concrete

precast concrete

In the precast concrete process, concrete is made using a reusable form that is cured in a controlled environment, transported to the job site and fixed there. A controlled environment here is nothing more than a precast plant.

Precast concrete elements are poured and cured in a precast plant and then transported to the construction site, and only the jointing is done on the construction site.

I hope you have the idea what cast-in-place concrete and precast concrete are?

Now let’s start our topic of difference between cast-in-place concrete and precast concrete according to some factors.

Factors influencing the choice of cast-in-place or ready-mixed concrete

These are some factors that are very important when choosing a pouring method on the project.

Time Quality Labor Costs Construction Speed ​​Curing Conditions Weather Conditions Similar Components Formwork (Formwork and D-Formwork) Concrete Handling Number of Joints Seismic and Wind Resistance Contractor Selection Material Waste Material Storage Material Quantity On Site Inspection Plastering Relocation Cost Cranes Lack of Knowledge

time

For precast concrete elements such as floor beams, supports can be poured in advance, saving time. whereas,

With the cast-in-place method, the elements cannot be cast in advance, which is why this process takes more time to complete the project.

quality

Quality can be easily controlled and maintained as precast concrete is manufactured in a factory. Thus, ideal conditions and accurate measurements can be maintained throughout the process. Offers better quality than in-situ concrete in terms of durability, stability and reliability. The water-cement ratio can be properly adjusted in precast and poured in-situ concrete, which can lead to better quality control.

while in-situ concrete is calculated on site. Therefore, the quality refers to the processing.

Cement slurry often flows through poorly fitted formwork, which can result in poor quality concrete.

labour costs

In the precast concrete method, fewer workers are required because only the joining of components needs to be done on site, and less skilled workers are also required for this work. Thus, labor costs can be saved.

The cast-in-place method requires a larger number of workers because all the works like pouring, mixing, shelling and curing have to be done on the site and it also requires more skilled manpower for this world. And all of these factors can increase the labor cost of the project.

build speed

The precast concrete method requires less time for on-site construction compared to the cast-in-place method. Because the prefabricated parts are transported to the construction site and can be directly lifted and placed in the desired position without waiting for the strengthening. It requires minimal support hugging, speeding up construction time and saving on costs.

Whereas pouring in place takes more time. Since concrete takes at least 20 days to reach 99% strength of its total strength, once an element is created, it takes seven days to create a new element that depends on the previous one, since concrete is 65% of its total strength in seven days.

curing conditions

In the construction industry, curing takes a lot of time during project execution. For precast concrete, the curing conditions of the concrete process can be controlled in a factory, and high early strength can be achieved using accelerated curing, the most commonly used curing techniques, or atmospheric pressure steam curing, warm water curing, boiling water curing, and autoclaving.

Therefore there is no need to harden the elements on site as the elements are already hardened in the factory as the prefabricated elements can be installed immediately without having to wait for them to gain strength and modularity as cast in place will.

Therefore, it saves time and also reduces construction costs.

While in the case of cast-in-place concrete, limited curing is a difficult task and therefore not worth it, you will have to wait for the curing time to finish. This increases the construction time in the construction industry in direct proportion to the costs.

weather condition

In the case of precast concrete elements, the weather conditions have no influence on the calculation work. If the precast concrete manufacturing facility can operate regardless of the weather, precast concrete will not shrink, deform, move or deteriorate when exposed to climatic changes. Assuming it rains and your prefabricated panels arrive at the site, you can just leave them in place.

While in the case of cast-in-place concrete, unexpected weather conditions can delay the pour book and if concreting takes place in cold weather you can add the cost of curing time.

Similar components

Similar components are produced quickly in precast concrete construction. This leads to increased productivity and economic costs, reducing construction time, which can contribute to an early return on investment. In prefabricated construction. You can save the cost of concrete formwork, and the formwork requires less manpower.

Therefore, you can save the cost of manpower to do inspection in prefab construction. Therefore, it requires less reinforcement compared to inexpensive cast-in-place concrete. According to a research article published in the Journal of Construction Engineering (reasearchgate.net), precast concrete slabs are on average 23.22% cheaper and precast columns 21.4% cheaper than cast-in-place concrete structures, especially for mass production. while cast-in-place concrete is a cheaper form of construction for small structures.

formwork (formwork and D-formwork)

Shuttering and stripping takes more time and space, increasing the cost of design, standardization, and repetition. With the precast method for repeated parts similar to walls only taller than buildings, there is greater potential for standardization and repetition. The mold for the finished parts can be used for a large number of repetitions, reducing the unit mold cost.

On the other hand, when it comes to cost-intensive in-situ concrete, the reputation of the formwork is very low compared to prefabricated parts. Therefore, when limited standardization and repetition occurs, the custom situ method is more beneficial.

Also read: formwork (formwork)! Components and types of formwork

Handling of precast concrete parts

Precast concrete requires heavy machinery and cranes to handle, lift and install heavy elements.

With an in-situ concrete method, construction can take place without cranes.

number of joints

There is a large selection of training systems for precast concrete parts. In precast concrete construction, the joint becomes very critical and requires careful attention.

Whereas in the case of cast-in-place concrete there will be fewer joints in the structural system and no serious attention to joints is required.

Resistance to earthquakes and wind pressure

Precast concrete elements are less resistant to earthquakes and wind forces. Therefore, they are not recommended against seismic or wind loads.

whereas cast in-situ concrete components are more resistant to earthquakes and wind forces

contractor selection

Precast concrete needs a qualified and technical contractor.

Costumes for a concrete structure, on the other hand, can be built by local contractors.

waste of material

The material waste in precast concrete construction is negligible compared to cast-in-place concrete. Whereas in the case of a cast-in-place method, the waste is more real. Prefabricated components can be reused, expanded and upgraded internally as structures do not need to be demolished and can be easily renovated internally, conserving resources, reducing waste and landfill.

On the other hand, cast-in-place structures cannot be reused.

material storage

With prefabricated construction, no space is required for storing materials and formally you can order these prefabricated parts ex works as required, i.e. space-saving.

With the cost-in-situ method, on the other hand, you have to record the price result for the material storage.

amount of materials

Compared to the cost in situ method, the precast method requires less cement, less water, less steel, and less labor because it is factory-made to produce precast concrete, uses advanced mix designs, and uses better vibration.

On the other hand, the cast-in-place method requires a larger amount of material.

on-site examination

With the precast concrete method, the strength test is carried out in the factory. An on-site strength test is therefore not required.

On the other hand, on-site concrete strength testing is extremely important to ensure the safety of your building. So if you’re casting on location, this is that tape that can’t escape.

cleaning needs

With prefabricated walls, a smaller amount of plaster is required due to the smooth surface compared to cast-in-place concrete.

On the other hand, in the case of custom concrete structures, it is a little difficult to achieve a smooth finish on walls. Therefore, a larger amount of plaster is required.

Up to here we are discussing both precast and in-situ concrete. There are many benefits of precast concrete. Here, you can think, why not use mainly precast concrete instead of cast-in-place method? Now let’s find the reason why.

move costs

In order to carry out the precast concrete construction, transportation and relocation costs are higher because very few precast plants are available due to the long distances from the factory.

cranes

We cannot fix the precast concrete parts without a crane. Cranes are very expensive to rent or buy. This is the 2nd reason to stop using precast concrete elements.

lack of knowledge

Before deciding on the precast concrete method, you need to check the following points of building type and size. Generally, precast concrete method is used for larger projects, check members reputation, if same type of floors, then you can choose precast technology, otherwise it is not feasible.

construction technology

Animation depicting the construction of a multi-story building using aluminum handset formwork.

Steel and plywood formwork for cast-in-place foundation

Cast-in-place concrete or cast-in-place concrete is a building construction technology in which the walls and ceilings of the buildings are poured into formwork on site.[1] This differs from precast concrete technology, where slabs are poured elsewhere and then brought to site and assembled.[2] It uses concrete slabs for walls instead of brick or wooden panels, and formwork is used for both walls and roofs.

Advantages of this technology are strength of the building, insulation and versatility for different types of buildings. A disadvantage is the high amount of work involved in installing and removing the formwork.[3]

See also[edit]

References[edit]

Need help deciding?

If you are looking for assistance in deciding what is best for your space, please feel free to contact us. Our in-house designers, who are knowledgeable about these tiles, will be happy to help you.

Use the same contact if you are looking for samples or a quote.

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Prestressed concrete is the most durable, reliable and strong concrete that is widely used in the construction of mega buildings and bridges. It is a type of concrete in which high-strength tendons placed in tensile areas of the cross-section are loaded during construction of the element to counteract tensile stresses created by applied loads.

Prestressed concrete is very advantageous for constructing crack-free components and counteracting the effects of shrinkage and temperature. This prevents the ingress of harmful substances, which helps prevent reinforcement corrosion.

The prestressed concrete allows the construction of girders and girders with longer spans in addition to increasing the load-bearing capacity with the same component cross-section.

However, the construction process in prestressed concrete requires extensive supervision and complicated jigs and equipment

in all phases.

Advantages of prestressed concrete

In contrast to conventional concrete components, prestressed concrete withstands the entire concrete cross-section of the applied load. This is because the concrete does not crack in the tension zone and therefore would participate in bearing loads. The spans of prestressed beams and girders are longer compared to those of reinforced concrete. A longer span increases uninterrupted floor space and parking opportunities. Longer spans result in fewer joints, which means less maintenance is required. The possibility of steel corrosion and subsequent concrete deterioration is reduced because concrete is crack free. It has a long shelf life. Due to the absence of cracks, prestressed concrete components are able to withstand stress reversal, impact, vibration and shock. In a prestressed concrete beam, dead loads are practically neutral. Consequently, the dead weight of the structure is reduced, resulting in reduced material consumption. Thinner slabs, which are important for high-rise construction because more slabs can be built at the same cost than traditional thicker slabs. The use of curved tendons and the pre-compaction of the concrete help to resist shear forces. The amount of steel required in prestressed concrete is 1/3 of that required for reinforced concrete, but the steel for the former should have high tensile strength. The development of prestressed concrete leads to the construction of a substantial fluid-retaining structure that would otherwise not be possible. Large liquid containment structures constructed of prestressed concrete are inexpensive and preferably resistant to cracking and consequent leakage. Prestressed concrete can be used to advantage in all those structures where stress is created, such as: B. Anchors and hangers of a bowstring girder, railway sleepers, electricity pylons, upstream side of gravity dams, etc. Prestressed concrete girders usually have little deflection.

Fig. 1: Thin concrete floor made of prestressed concrete

Fig. 2: Prestressed concrete bridge

Disadvantages of prestressed concrete

Cast-in-place concrete gives large, solid shapes. Credit: Hemera Technologies/AbleStock.com/Getty Images See more photos

Cast-in-place concrete is a common type of building material for commercial and residential buildings alike. It involves pouring liquid concrete into removable formwork, and then dismantling the formwork once the concrete has hardened to leave a solid wall. In-situ concrete goes back to early experiments by Thomas Edison. Modern builders continue to reap its benefits and work to overcome its drawbacks.

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Strength

The main advantage of in-situ concrete is its high strength. In-situ concrete is suitable for basement walls and house foundations. It is also relatively resilient to structural damage in the event of an earthquake, flood, or other natural disaster. Builders can make cast-in-place even stronger by using steel rebar or rebar that is placed in the form before the concrete is poured.

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work requirements

One of the only real downsides to cast-in-place concrete is the labor involved. Builders must first construct formwork for the walls they want to pour, and then install the formwork and mix the concrete. Pouring the concrete and waiting for the formwork to be removed takes time, which increases the duration of a construction job and results in a higher hourly wage for the work crews. Building basements with precast concrete requires no molds and offers a less labor-intensive alternative.

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insulation

Another advantage of in-situ concrete is the high level of insulation. This includes thermal insulation, which prevents basements from absorbing the cold temperatures and moisture from the earth that surrounds them. In-situ concrete also insulates against noise and makes houses quieter. Its insulating properties extend to insects, mold and mildew, none of which can easily penetrate cast-in-place concrete as there are no natural cracks or gaps between sections of building material.

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versatility

Cast-in-place concrete is very versatile, meaning builders can use it for a variety of types of homes and buildings. Computer modeling programs allow builders to design highly precise, customizable shapes. In other cases, builders can reuse standard molds for cast-in-place basement walls. This versatility makes in-situ concrete suitable for both modest homes and large, architecturally challenging projects.

Although concrete is one of the most commonly used building materials, there are many disadvantages associated with it. Some of these disadvantages of concrete are modified by adding admixtures or modifying the concrete structure and constituents. Still, there are many limitations associated with concrete. The main limitations of concrete are listed below.

1. Concrete is a quasi-brittle material

Three main types of failure of materials are brittle, quasi-brittle failure and ductile failure. Typical failures of brittle and ductile failures are glass and mild steel, respectively. Brittle materials fail at the onset of tension or when the tensile strength is reached. In contrast to these materials, concrete exhibits strain softening behavior, these materials are referred to as quasi-brittle materials.

Brittle and quasi-brittle materials such as concrete experience very little deformation before failure. The lower the deformation, the lower the warnings. Apart from that, concrete has low fracture toughness. This is a major disadvantage of regular concrete. For these reasons, concrete is used in conjunction with steel to carry tensile loads, and concrete effectively carries compressive loads. Thus, reinforced concrete is second-generation concrete. Concrete gives stability to the structure.

2. Low tensile strength

The compressive and tensile strengths of concrete are not the same. In fact, the tensile strength of concrete is 1/10 of its compressive strength. Fibers and other polymers are incorporated into concrete to increase its tensile strength.

3. Concrete has low toughness

A material’s ability to dissipate impact energy is called toughness. It is the area under the load displacement curve. Another limitation of concrete is that the concrete has significantly lower toughness compared to steel. The toughness of concrete is only 1-2% of steel. Fiber reinforced concrete gives concrete better toughness.

4. Concrete has low specific strength

The ratio of strength to density is called specific strength. The specific strength of ordinary concrete is half that of steel, ie 20. Specific strength is controlled by decreasing density and increasing strength. Lightweight concrete and high strength concrete mitigate these limitations of concrete.

5. Formwork is required

Fresh concrete is liquid. Formwork is required to shape it and support its own weight. Formwork can be made of plastic, steel or wood. The formwork is expensive to install and procure. The installation requires intensive work and time. Precast and prefabrication techniques are used to overcome these concrete limitations.

6. Long curing time

Concrete reaches the specified compressive strength within 28 days after pouring and curing. Full power development requires an appropriate ambient temperature, which is controlled over a month. This is another disadvantage of concrete. The curing time is shortened by steam curing or microwave curing or by using additives.

7. Working with cracks

Concrete traction surface has a cover to protect the rebars. If the tensile stress on extreme fibers exceeds the tensile strength of the concrete, the concrete cracks and leads to corrosion of the reinforcement. For the design it is assumed that normal reinforced concrete cracks under service loads. To overcome this limitation of concrete, third generation concrete, prestressed concrete, is introduced.

8. Demands strict quality control

Concrete requires strict quality control and skilled labor when mixing, placing and curing concrete. This is important for excellent concrete quality. If this is not the case, concrete can have problems with poor strength, durability and performance.

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Concrete is the most commonly used building material worldwide and has been for centuries. As society has progressed so have the building materials we use and this has resulted in quite a variety of types of concrete that we now have available. The two most common are normal concrete and reinforced concrete, and which one you use always depends on the specific project. Below we outline the pros and cons of both types of concrete so you can make the right choice for your needs.

The pros and cons of regular concrete

Plain concrete, also known as pure cement concrete or PCC, is most commonly used for paving and flooring. Manufactured from a mixture of cement, aggregate and water, the different types of aggregate and the ratio of materials used result in different types of cement with slightly different properties. This is one of the key selling points of ready-mixed concrete, as the exact values ​​and types of aggregates can be accurately measured and monitored to provide the required grades without deviation. The automated manufacturing process limits the potential for human error, saving time and resources.

While there are differences in the composition of concrete, the simplest concrete has the same strengths and weaknesses. It’s incredibly strong under pressure while weak under tension, meaning it can withstand large amounts of weight on a solid, immobile surface. However, when placed under tension, it is much weaker and can often break and warp. This makes it the perfect material for ground floor layers and provides a stable and level base for reinforced concrete to build on while limiting its use in larger construction projects.

The advantages and disadvantages of reinforced concrete

Reinforced concrete or reinforced cement concrete (RCC) is actually very similar to PCC in terms of the materials used. The only major difference in its composition is the addition of steel reinforcement. By pouring the wet cement around rebar, the resulting composite material has much higher strength under tension, but still retains the properties that make PCC so effective.

Because concrete retains its strength under compression and steel resists any bending or stretching thanks to its tensile strength, RCC is a much more versatile building material.

Thanks to the increased bending capacity of the concrete-steel mix, it withstands the downward weight as well as wind pressure or displacements that cause slight twisting and stretching. It is the ideal material for taller and heavier buildings and for roads and bridges.

Steel is the most common material used to make rebar because it responds to very similar temperature changes as concrete, meaning it expands and contracts with the concrete rather than breaking it from the inside.

As you can see there is no real answer as to which type of concrete is better as they both serve different roles. Any concrete structure example will require both plain and reinforced concrete, and hopefully this article will help you tell the difference and make the right choice for your project. At Al Manaratain we pride ourselves on the quality of the concrete blocks, concrete pavers, precast concrete products and precast concrete products that we offer. Whether you need plain concrete or reinforced concrete you can rest assured that we have exactly what you need and can provide further help and advice if required.

What does on site mean?

In situ (also referred to as insitu or in-situ) is a Latin expression commonly used in the construction industry, meaning “on site”, “in place” or “in position”. It refers to work carried out on site itself, often in a finished position as opposed to an off-site location as in prefabrication or pre-assembly techniques.

The most common use of the term “in situ” refers to concrete, with components such as slabs, beams and piles being referred to as “cast in situ” to distinguish them from precast concrete components that are fabricated off-site.

In general, on-site construction techniques tend to be more labor and time intensive, but they are more responsive to changes that may occur on site. Prefabricated components, on the other hand, must be designed in detail beforehand and can only be modified to a limited extent after production.

In situ can also be used to refer to in situ tests, such as tests conducted in situ to determine the density or shear strength of soils. For more information see: In-situ investigation of soils.

In the context of soil, in situ can also refer to soil that is still in its original state and has not been ‘cut’ from one area of ​​a site and ‘filled in’ elsewhere.

See also: on site.

Need help deciding?

If you are looking for assistance in deciding what is best for your space, please feel free to contact us. Our in-house designers, who are knowledgeable about these tiles, will be happy to help you.

Use the same contact if you are looking for samples or a quote.

Today there is a vast array of on-site manufactured flooring including traditional home-made concrete, granolite and sand cement screeds, as well as a bewildering array of specialist proprietary flooring. These include epoxy and polyester resin mortar as well as cement-bound floor coverings made from bitumen and polymer emulsions. This article looks at the most common types of flooring, describes their uses, and addresses some of the most common mistakes that come from poor materials and workmanship, as well as heavy use.

expression

Conditions in which genetic resources are present in ecosystems and natural habitats, and in the case of domesticated or cultivated species, the environment in which they have evolved their distinctive traits. [CBD] – the preservation of ecosystems and natural habitats and the maintenance and restoration of viable populations of species in their natural environment and, in the case of domesticated or cultivated species, in the environment in which they developed their distinctive characteristics. [CBD] – the conservation of biological diversity within the evolutionarily dynamic ecosystems of the original habitat or natural environment. [GBA]