Papers

Why nonionic starch ethers act as anionic flocculants in cementitious systems (2017)

Conference Paper, 26. Konferenz „Rheologische Messungen an mineralischen Baustoffen“, 2017, Regensburg

 

Starch ethers are added to mortars in order to modify the rheology of the fresh mortar by bridging flocculation. The proper function as flocculant for cement requires that the starch ether molecules possess anionic charged functional groups. With this in mind, the different types of commercially available starch ethers are evaluated. Two types of starch ethers can be dis-tinguished, which differ in the dependence of the effect on dosage. All starch ethers are anionic charged at pH values above 11. At neutral pH, CM-HP-starches are more efficient flocculants than HP-starch.

Performance of Starch Ethers in Drymix Mortars (2016)

Conference paper, XVIII International Scientific Conference “Modern technologies of dry mixtures in construction”, MixBuild 2016, Moscow

 

Starch ethers are added to mortars in order to modify the rheology of the fresh mortar by bridging flocculation. The proper function as flocculant for cement requires that the starch ether molecules possess anionic charged functional groups. With this in mind, the different types of commercially available starch ethers are evaluated. Two types of starch ethers can be distinguished, which differ in the dependence of the effect on dosage. The interactions of starch ethers with calcium ions are discussed and recommendations are given for the targeted selection of the appropriate product.

Rheological Lab Testing of Building Formulations (1994)

Conference Paper, ConChem Conference 1994

 

Rheology is the science of flow and deformation of matter. It concerns the relationships between shear stress Τ, shear strain λ and time t. Ideal systems are described by simple, linear equations as, e.g., Hooke’s Law for ideal solids or Newton’s Law for ideal liquids. Reality is more complicated than ideal and therefore ideal systems are rather the exception than the rule. This is true for food, cosmetics, coatings, plastics and building formulations just to mention a few. Under building formulations we mean a blend of binders which could be cement or plaster with aggregates like silica sand or limestone and last, but not least, additives to improve performance. After addition of water, mortars result which, depending on the composition, are used as machine plasters, tile cements, masonry mortars, joint fillers, grouts, self-levelling compounds etc.