Precast elements and concrete products

Traditionally, a planetary countercurrent mixer is used to make precast concrete. This is the best option because of mixing efficiency. It is easy to put several discharge hatches in the planetary mixer, for example, due to the shuttle system for the drain washing water. Maintenance is also easy thanks to the large deck hatches.

Tecwill precast concrete plants are equipped with a durable and high-quality planetary countercurrent mixer. The mixer features:

• A homogenous mix with a shorter mixing time
• Easy maintenance with large service doors
• Wide range of options, including moisture and temperature probes, a high-pressure cleaning system, sampling and mixer camera
• Multiple discharge gate options

The most suitable method is determined by the size of the precast factory. At a small factory, concrete can be moved in a casting hopper by a bridge crane.

In a larger factory, a casting hopper is too slow. A shuttle and track system are needed to move the concrete from the mixer to the casting points.

There may be several casting points at a large factory – some fixed and others mobile casting machines – to produce hollow-core slabs, for example.

When manufacturing, each batch is poured into the precast element or concrete products. If the amount of water in the concrete batch is incorrect, elements will have a tone or quality variation manifested as a difference in color or strength, for example.

Accurate aggregate moisture measurement and the right water amount in the batch will reduce quality issues with the concrete.

Self-consolidated concrete or self-compacting concrete (SCC) is a highly “liquid” mix that flows easily and compacts under its own weight. A high-range superplasticizer (water-reducing admixture) is used in the mix.

The traditional mixing method is to first mix the dry ingredients – cement and aggregate – and adjust the batch moisture. Then, water and a superplasticizer are added. The mixing time of this method is very long, reducing plant capacity and increasing wear on the mixer.

Tecwill’s wet method improves moisture control. The artificial intelligence-controlled dosing and weighing ensure accurate amounts of materials for each concrete batch. The mixing uses the so-called “wet mixing” method, which shortens mixing time and improves capacity.