Preparation of the concrete mix

Preparation of the concrete mix, as a rule, the concrete plants equipped with mechanized and automated units. These plants can be composed of small, medium and large factories reinforced concrete, as well as independent or made ​​in collapsible form and operate directly on the site. These factories, workshops, assemblies, depending on the issue needs a concrete or mortar mix.

Technological scheme of production of concrete and mortar are single-stage (tall) or two-stage (pic. 7.7 and 7.8).

Pic. 7.7. Single-stage scheme of mixed concrete and mortar:

1 – storage of cement, 2 – conveyor system for feeding inert materials, 3 – feed bin, 4 – dispensers, 5 – hoppers, 6 – mixer, 7 – storage hopper

In addition to such fixed or collapsible concrete solution nodes can be used mobile (cell) concrete solution mounted assembly of heavy vehicle trailers. They usually composed of a two-stage scheme.

The mechanism that determines the quality of concrete, concrete unit performance, the frequency of works is a concrete mixer.

Mixers are (pic. 7.9) gravitational stirring (gravity component) and forced (Pic. 7.10) Gravity - with tilting drum and a discharge chute.

Concrete forced mixing can be divided into cyclic and continuous action.
The most common compulsory mixer – is with rotating bowl used for preparation of hard concrete mixtures.

The duration of cycle in batch mixers:

Т_ц = t_а + t_п + t_в , (7.1)

where t_а, t_п, t_в – respectively, the duration of loading, unloading and mixing the mixture.

Pic. 7.8. The two-stage scheme of production of concrete and mortar:

1 – feed bin, 2 – dispensers, 3 – hopper, 4 – skip hoist, 5 – mixer, 6 – storage hopper