In situ concrete refers to concrete that is poured and sets directly at its final location on a construction site.
Based on the provided reference, in situ concrete is defined by a specific action: Concrete poured into shutters which retain the concrete during setting into its final form and position is termed in-situ concrete. This means the process fundamentally involves:
- Pouring: Fresh concrete is mixed and transported to the construction site.
- Shutters (Formwork): Temporary molds, known as shutters or formwork, are erected at the precise location where the concrete element is needed.
- Placement: The concrete is carefully poured or placed into these shutters.
- Retention and Setting: The shutters hold the wet concrete in place, giving it its desired shape and preventing it from spreading while it undergoes the chemical process of hydration and hardens (sets).
- Final Form and Position: The concrete hardens within the shutters, taking on its final shape and becoming a permanent structural element in its designated position.
This distinguishes it from other methods, as the reference notes: "If the concrete is cast in locations which are different from the final positions it is referred to as precast concrete."
Key Aspects of the In Situ Process
- Site-Specific Casting: The defining characteristic is that the concrete element is created directly at the site where it will function structurally.
- Use of Formwork: Shutters or formwork are essential to contain and shape the concrete until it gains sufficient strength.
- Setting in Place: The hardening process occurs in situ, meaning "in place".
This method is widely used for various structural elements, including:
- Foundations
- Walls
- Slabs
- Beams
- Columns
The quality of the final in situ concrete element is heavily reliant on the correct design and assembly of the formwork, as well as the proper mixing, placement, and curing of the concrete itself.
