New approaches to increase water resistance of gypsum based building materials

T. Aberle, P. Emmenegger, F. Vallée, L. Herschke | Nouryon Chemicals AG | Sempach Station, Switzerland
Gypsum is a major binder in a variety of dry mortar formulations such as gypsum lime plasters, finish plasters, gypsum board jointing compounds or anhydride screeds.
Gypsum offers a number of advantages for the use as a building material.
It is largely available in most countries. Application and workability properties are excellent. Gypsum based materials have nearly no shrinkage problems and provide high fire resistance. In addition, carbon food print of gypsum is significant lower compared to cement.
The main disadvantage of gypsum, especially versus cement, is the poor water resistance. There are only limited possibilities to increase water resistance of gypsum building products, because the common hydrophobizing agents which are used for cementitious systems are not working in gypsum based materials.
The present paper discusses existing and new approaches to increase water resistance of gypsum based dry mortars.