A concrete hardening retarder which comprises a polymer (A) having the ability to retard concrete hardening.

By using the polypropylene fibres, the setting process of the concrete improves, so that the liquid-tightness of the eventual concrete construction is improved.

Once said elements have been coupled, centring is positioned and the concrete is then poured; setting then follows.

In one embodiment, a circular blade is coated with a chemical which retards the setting of the concrete.

This process, however, multiplies the work at the site and takes long time to cure the concrete.

After an iron rein forcement has been imbedded in the fresh concrete and the fresh concrete has set, it protects the iron reinforcement against corrosion.

This parameter is closely correlated with the setting time of fresh concrete and the durability characteristics of hardened concrete.

The apparatus provides an alternative means to retaining a concrete foundation in place during concrete pouring and setting at a competitive or cheaper cost than traditional methods.

A method of accelerating the hardening of concrete by carbonation with a gas consisting wholly or partly of carbon dioxide.

  Accordingly, a sufficient supporting force can be exerted upon the long span temporary wall of great overall length, and the precast method results in a decrease in the time spent on concrete setting which in turn shortens the construction period.

The method includes substituting a lightweight fine aggregate for at least a portion of the natural fine aggregate in a concrete mixture, mixing the components, pouring the mixture, and curing the poured concrete.

The strands may be pre-tensioned (tension before casting) or post-tensioned (after casting).

The forces from the lacking support points (2) are transferred to the other support points (3,4) by means of pre-tensioning cables (5) which are cast into concrete and are tensioned after the curing of the concrete.

Coussot P, Grossiord JL: Understand the rheology of the circulation of blood to the taking of concrete.

Concrete is poured to occupy space between at least the form, the surface and a portion of the floor assembly so that, after the concrete is set, the supports are removed and the floor assembly is supported by the concrete.