Dynamit Nobel Aktiengesellschaft

Gunter Vogel

Hansjurgen Hass

Klaus Deneke

Kurt Allemann

Horst Hanisch

Rudolf Burkhardt

Disclosed is a spray concrete which, even at a water-cement ratio of 0.45 to 0.55, is still easy to work, can be sprayed well, and sets and hardens rapidly. It contains, in addition to the conventional additives, additions of naphthalinesulfonicacid-formaldehyde condensation products and highly concentrated alkaline aqueous solutions of potassium aluminate, potassium carbonate and caustic potash. The concrete according to the invention displays an especially rapid solidification when it contains up to 3% by weight alkali silicates or an adequate amount in highly dispersed silicic acid (SiO.sub.2). The additives are incorporated into the concrete preferably directly at the worksite prior to spraying.

Easy-working spray concrete

The present invention relates to liquid mixtures of alkali metal silicates, water, and trialkoxysilanes of the general formula R--Si(OR').sub.3, which harden to form silica-containing gels within a predetermined length of time. The mixtures can contain additional means for influencing the gelling and the gel strength. The most important field of application of the gels in accordance with the invention is the stabilization of soils in architecture and civil engineering.

Gel-forming mixture based on an alkali silicate and a trialkoxysilane

The present invention relates to liquid accelerators for the setting of concrete mixtures. These accelerators have a long shelf life even in higher concentrations than the liquid accelerators known heretofore and, within the defined concentrations, produce no precipitation. The new accelerators are characterized by containing only potassium aluminate, potassium carbonate and potassium hydroxide in a defined range. They can be used in any known hydraulic binding agents, they shorten the set time of these binding agents, and they improve the compressive strength of the products made with them.

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Hennef, Germany

Gunter Vogel