Precast concrete is produced by casting concrete in a reusable ‘mould’ or ‘form’ which is then cured in a controlled environment, transported to the construction site and lifted into place. This is in contrast to conventional concrete which is delivered to site in its plastic state and poured into forms in-situ.
There are many benefits associated with the use of precast concrete components.
Each product requires proper design, use of the correct materials and manufacturing processes with skilled and knowledgeable personnel. Specific benefits include:
- Dimensional accuracy and tight tolerances
- Speed of construction
- Reduction of onsite man hours
- Reduction of onsite activity, noise, and disturbance
- Reduction of onsite waste
- Minimal maintenance
- Large spans available from prestressing
A variety of finishes are available to suit the end use. Exposed aggregate finishes give non slip surfaces. Textured and patterned surfaces can provide pleasing appearances to enhance the environment.
Formliners, honing or polishing, chemically treating or acid etching, painting or other special coatings are all available as surface treatments whether for appearance, environmental or durability considerations.
Corrosion of steel reinforcement in concrete is the most frequent problem affecting the durability of reinforced concrete structures. Corrosion caused through chloride attack is one of the main mechanisms of deterioration affecting the long-term performance and serviceability of such structures. The reasons are normally a combination of insufficient concrete cover, and inadequate quality of concrete protecting the reinforcing.
Factory produced precast is manufactured to tighter tolerances by experienced workers following established quality procedures using specifically designed concrete mixes. Precast factories are experienced at handling a range of concretes and can ensure necessary compaction, finishing and curing is achieved.
Precast concrete is manufactured under controlled conditions in a special purpose facility dedicated to efficient and economical production of quality components for delivery to the customer. The large reuse and turnaround of product justifies the investment of high quality moulds.
The type of precast concrete products that can be made is endless and products can be categorised into a number of product groups:
Precast concrete products can withstand the most extreme weather conditions and will hold up for many decades of constant usage. That makes precast perfect for many agricultural applications. Precast products are in use throughout most agricultural applications and include water troughs, feed troughs, culverts, effluent bunkers, feed pads and walls, stock stops, under passes and Y panels.
Precast concrete building components are used in structural applications such as foundations, beams, floors, walls and architectural applications such as cladding. It is common to employ precast concrete building components in both architectural and structural capacities at the same time (total precast structures).
Prestressing is a technique of introducing stresses of a predetermined magnitude into a structural member to improve its behavior. Prestressing is used to introduce compression into regions where tension stresses will be created by applied loads. This technique is usually found in concrete beams, columns, single and double tees, wall panels, and hollow core slabs.
Water and Wastewater Products
Water management products are structures designed for underground installation that have been specifically engineered for their application.
These precast concrete products include septic tanks, cesspits, pipes, manholes and rainwater tanks. Many products are modular in design and are available in a number of configurations. The structures and all connections are constructed with watertight integrity so that the contents discharge only through the proper outlet and at a prescribed flow.
Precast concrete transportation products are used in the construction, safety and site protection of our road and railway transportation systems. Products include railway sleepers, bridge Super Tees, segmental bridge units, tunnel segments, sound walls and barriers.
Consistently manufactured EverSure will meet the cement requirements for the production of Precast concrete. The use of EverFast should be considered if a high early strength is required for demoulding or release prestressing strands or the concrete is placed in colder ambient conditions.
The inclusion of Microsilica 600 enhances durability properties. Microsilica 600 will improve the concrete strength and durability through a pozzolanic reaction producing additional calcium silicate hydrates, fine powder packing mechanism and the improvement of bond at the aggregate paste interface. There will also be an improvement in bond at the concrete/reinforcement interface.
Alternatively the use of an optimised ternary blend of Microsilica 600 and EverPlus Class C Fly Ash from our product solution range can be supplied for your specific durability requirements.
The inclusion of EverPlus Class C Fly Ash improves long term concrete strength and durability through a pozzolanic reaction producing additional calcium silicate hydrates but will impact on early concrete strengths. The primary benefits in precast concrete are realised through the spherical particle shape of the EverPlus Class C Fly Ash and will assist with concretes that are extruded or manufactured dry to aid compaction.