Trass

Trass (old spelling: trass ) is the name for a natural pozzolan, which is mixed with, among others, as an additive certain cements. It consists mainly of silicon and aluminum compounds.

Origin

When a meteorite impact in today Ries was formed by metamorphism Bavarian tuff, Ries Trass or suevite.

Rhenish trass is a volcanic tuff which was created by the eruption of Laacher See volcano in the eastern Eifel and finds himself in Brohltal and in Nettetal.

As Austrian Trass or Gossendorfit a converted vulcanite is called, which consists mainly of opal and alunite. He was quarried Gossendorf in Gossendorf in box Bach, who was recently shut down. On the basis of this deposit was of the Styrian Mining Company (now w & p / Baumit ) developed the Trassit as a binder ( a pozzolanic lime - finished plaster ).

Use

Trass is latent hydraulic and is used with the addition of water and binders, cement and / or building limes and aggregates for mortar. Trass without the addition of binders to be unsubstantiated.

Trass is an outmoded term that is still used in part for the new European cement classes such as Portland composite cement, pozzolanic cement and composite cement today. Trass as aggregate upgraded mortar largely waterproof. It is used for example for the lining of pools, for laying and grouting of natural stones and slabs as well as mortar and grout in stone restoration work. A special pozzolanic mortar is used in the renovation of ettringite -contaminated masonry.

Another important advantage of the Trassmörtel is that much less efflorescence occur in their use of natural stones than in unsuitable for natural stone pure Portland cement. Trass connects largely with the split in the cement stone formation of hydrated lime, calcium hydroxide. If hydrated lime to the surface, it connects to the CO2 contained in the atmosphere to lime and manifests in the form of efflorescence. The formation of efflorescence due to other causes such as nitric will not be prevented by a Trasszusatz. In addition, the alkalinity of the mortar is not significantly reduced.

In the exhaust emission Trass from the Ries for the removal of odors by adsorption will be used.

Standardization

Cements with Trass are in accordance with CEM II ( Portland composite cement ), CEM IV ( pozzolana ), CEM V ( composite resin ) standardized. The properties for use in cements were previously standardized in DIN 1164 requirements and tests specified in DIN 51043. The detected by the standard DIN 51043 Trass is a pozzolanic tuff. It consists mainly of silicon dioxide (silica ) and aluminum oxide (alumina). Further constituents are oxides of alkali and alkaline earth metals.