Precast Concrete vs Site Cast concrete

What is Precast Concrete?

Precast Concrete is poured and moulded (form) over rebar or wire and then cured offsite. This involves pouring concrete into pre-made moulds and cured under optimal conditions within the manufacturing plant.

The products are then shipped to the job site where they are assembled.

What is site-cast concrete?

Site-cast concreted is poured, moulded and cured on site. Just as precast concrete, on-site concrete is formed in a mould and then erected in place. One of its benefits over precast slabs is that it doesn’t need to be moved far to be lifted into place. Lastly, precast concrete requires more joints and, therefore, makes it less acceptable for earthquake-prone areas. 

Comparing Precast vs. Site Cast Concrete

The most reliable means to see just how great precast concrete is to highlight the differences between precast and site-cast concrete directly. Here are some critical aspects between the two methods placed side-by-side.

Precast Concrete – Prep Work 

  • Excavate the land as required.

On-site poured concrete

  • Required excavation and on-site forms to be designed and installed.

Precast Concrete – Weather 

  • Utilizes a controlled environment; the climate does not present a factor in forming.

On-site poured concrete

  • Unexpected weather circumstances will hinder progress. Cold weather can append cure time.

Precast Concrete –  Strength 

  • Stringent strength requirements are met before leaving the plant. Consistency across all precast materials.

On-site poured Concrete

  • Variables factor into your final product: temperature, wind, humidity etc. can affect final strength.

Precast Concrete – Quality control 

  • The controlled environment prevents any external variables. All concrete must pass rigorous testing. Ideal conditions are maintained.

On-site poured concrete

  • Concrete is subjected to external variables and varying conditions. All testing requirements must be performed on-site.

Other benefits of Precast Concrete

Economies of scale: Moreover, slabs can be mass-produced, improving the economies of scale and avoid running over budget.

Quality control: Since precast concrete is mixed, poured and cured at the plant, ideal conditions and measurements can be maintained throughout the process. Sadly, the logistics of site casting make this considerably extra challenging. 

Manufacturing efficiency: In addition to quality control, cast concrete is efficiently made, pushing down costs.

No on-site formwork: The formwork required for on-site concrete pouring is both time and space-intensive, requiring you to be at the mercy of the weather. An unanticipated delay of even a day can drive a project seriously over-budget.

Labour efficiency:  Because work is done in a factory, the effort is maximized through the use of tools and machinery that isn’t available on the job site. This is much more labour-intensive, thus increasing labour costs and making the process more expensive. 

Versatility: Precast is more versatile than site-poured concrete. An ample variety of motifs, colours, and finishes are available.

Efficient and sustainable material use: Minimal waste of materials as concrete is a recyclable material.

Even further benefits!

Curing conditions: Since curing conditions can be controlled in a plant, the process can be accelerated without sacrificing strength or quality. 

Full strength: Concrete gains strength over time. Yet, with precast concrete, the hardening process takes place before arriving on the job site. That’s not the case with on-site poured concrete. Furthermore, you do not need to conduct strength tests on site.

Cast ahead of time: You can prepare the casting of your materials ahead of time, keeping them until needed. 

Weather: You are at the mercy of the environment. This isn’t an obstacle when it comes to precast concrete. Rain or shine, you can lift them into place just as you would during a sunny day.

Specialized reinforcement: For certain projects, this is essential, as it enables the panel or slab to support loads at a thickness that clearly isn’t feasible with conventional poured concrete. Moreover, specialized high strength concrete, such as pre-stressed concrete, requires precise conditions for both mixing and curing. These requirements cannot be met on-site, thus allowing them to create architectural designs that cannot be obtained from any other means.

As you can see, the benefits of precast concrete make it the preferred choice of commercial construction. If you require any further information or get started on your next project, please contact one of our experts for additional information.

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