Precast Concrete (Wet Precast)
Precast concrete is used to build structures which are delivered after hardening. Concrete used for the production of precast structures requires an industrialized production process, and a good concrete mix design with continuous optimization is essential.
The following production steps are connected to different technical challenges within the precast production and final erection of finished elements:
- Build up and preparation of reinforcement
- Preparation of formwork - tight formwork and correct application of suitable mold release agent
- Concrete production - cost efficient mix design that complies to standards and fulfils technical requirements
- Transport and installation of fresh concrete - sufficient slump life and high flowability for fast installation
- Finishing of the concrete surface - no time delay within production and improved finishing characteristics
- Curing of concrete - application of curing agent as soon as possible and reduced heat/steam curing of concrete
- Formwork removal - fast early strength development for short formwork cycles
- Repair of any surface defects and damages - fast and easy application of suitable repair mortar or system
- Application of concrete protection - utilisation of impregnation that offers intended protection purposes
- Transport of precast concrete element to construction site
- Repair of damages, which occurred during transportation - fast and easy application of suitable repair mortar or system
- Erection of elements and sealing of joints - highly durable sealing of joints according to technical requirements
- Final grouting of gaps and bonding/anchoring of built in parts
Precast Concrete (Semi-dry Concrete)
Semi-dry concrete is used for the manufacture of small precast concrete products, such as concrete paving stones, building blocks, kerbstones, paving slabs and tiles, garden products (edgings, palisades, landscaping elements), pipes and manholes, and roof tiles.
The special characteristics of semi-dry concrete are:
- Granular aspect after mixing
- Instantly de-moldable
- Stability of un-hydrated concrete
- Dimensional accuracy immediately after compaction (green strength)
- Heavy machines are required to manufacture concrete products out of semi-dry concrete.
The advantages of this process are:
- Only one form per product shape (low capital investment)
- A compacting installation for all the products
- Production flexibility due to rapid changing of the formwork for a new product type
- Swift, efficient and industrialized production with high output