• Trass — pozzolan for lime mortars by Rose of Jericho
1 1

Trass

Trass

£26.40 inc. VAT
£22.00 ex. VAT
£26.40 inc. VAT
£22.00 ex. VAT
Sale Sold out

Trass is a reactive natural pozzolanic additive. Pozzolans improve the strength and durability of lime mortars. Pozzolans are defined as materials which, though not cementitious in themselves, contain constituents which will combine with lime at ordinary temperatures in the presence of water to form stable insoluble compounds possessing hydraulic properties.

Trass is ground ‘tuffstein’ from the Rhine valley in Germany. Tuffstein is a rock-like compacted tuff of volcanic dust and ash. Rhenish trass has been known for some 2000 years, and mortars containing trass have been found in old Roman buildings along the Rhine. It has been increasingly used in lime mortars since the early 18th century, and was experimented with by John Smeaton in 1756 for the Eddystone lighthouse, although an Italian pozzolana from ‘Civita Vecchia’ was ultimately used.

This is sold in 40kg bags and cannot be sent via courier due to weight limitations. Due to this, please select one of the pallet options available.

 

This product is 40kg
Trass — pozzolan for lime mortars by Rose of Jericho

Trass

£26.40
£26.40
View full details

Learn more

Usage/Purpose

Trass is a reactive natural pozzolanic additive for addition to lime mortars to improve strength and durability.

Shelf Life

Hydraulic limes and natural cement deteriorate with age. Use fresh material.

Colour

Mortar colour is determined by the sand or aggregate mixed with the hydraulic lime or natural cement. It is normally necessary to include brick dust and sometimes also earth pigments to match the colour and texture of historic samples.

Observations

Experienced operatives with experience of the successful use of hydraulic lime or Natural Cement should be employed. Accurate volumetric site mixing is essential. Hydraulic lime mortars do not behave as modern cementitious materials, and set by a combination of the hydration of the hydraulic compounds and ‘carbonation’. Carbonation in the presence of moisture is a slow process and the control of the drying and curing by ‘tending’ and protecting is crucial to success and long term performance. Protections are essential.

Availability

Hydraulic Lime and Natural Cement normally ex stock. It is important to select the correct grade of hydraulic lime.