BAUHAUS UNIVERSITÄT WEIMAR

Silicate coatings for concrete components with waterglass systems by means of ­neutral salt initiation

1 Viscosity increase in potassium waterglass solutions (WG A, WG B and WG C) by acid initiation by means of triacetin addition (triacetin volume per 100 g WG) All Schuch
2 Viscosity development in mixtures of potassium waterglass solutions WG A and/or WG B and fused silica (45 g WG, 55 g QM) by neutral salt addition MX
3 Stiffness development in WG B - QM mixtures (45 g WG, 55 g QM) after addition of various alkaline earth salts (3 g), characterized by measurement of the velocity of sound in the material
4 Coatings (thickness about 0.4 cm) on fiber cement plates after 1 and 110 days in a laboratory atmosphere
5 Chronological development of the shore D hardness in laboratory atmosphere and the gravimetric material loss of the base mixture with inclusion of water (250 ml H2O, 1 h; 100 °C drying, 4h and correction of the additional drying loss in parallel measurements), gel initiator CaSO4 (AII)
6 DSC characteristic of the coat material (20 d)
7 IR spectrum of the coat material (20 d) in comparison with that of the fused silica QM
8 XRD recording of coat material (20 d) with ZnO addition as crystalline standard
9 DSC measurement curves of mixtures after heat treatment at 100 °C (12 h), “time lapse” preparation
10 XRD recording of the “time lapse sample” (WG B 95 %, GI CaSO4 (AII) 5 %) with ZnO addition as crystalline standard
11 Components and their interaction in the coat formation
Table 1 Key figures of the used potassium waterglass solutions (WG)

The objective of the investigations was the proof of the use of the neutral salt initiation as a construction material in the protecting silicate coating of concrete components, e.g. industry floors, factory finished parts or reinforced concrete construction parts, by means of waterglass fused silica suspensions.

1 Colloid formation and sol-gel transition in

waterglass solutions

As early as around 1950, publications appeared describing and/or correlating the turbidity appearances and increasing viscosities of “aging” alkali waterglass solutions with the aid of the advanced light scattering measurement technology and establishing a relation to the formation of colloidal particles In “filtrated” sodium waterglass solutions with increasing waterglass module, particles with molecular weights of up to 10 000 (molar module 3.75) were found [1]. What is particularly remarkable is that a work by Brady and...

TEXT Prof. Dr. Christian Kaps (i. R.), Dr.-Ing. Kai Schuch, Dipl.-Ing.(FH) Stefan Stäblein, Bauhaus-Universität Weimar/Germany

This article appeared in

ZKG 3/2016

This article appeared in

ZKG 3/2016

Ressort:  Materials
subscription Content

Related articles:

Issue 12/2014

Innovative binder based on activated fly ash for products with chemical and corrosive load

Cement based products are in general not resistant against acids. Ca-ions built during the hydration dissolve in small quantities in water and cause...

more
Issue 6/2017 Wuhan University of Technology | Wuhan Textile University

Chloride penetration resistance of ­micron-nano materials modified mortar used as a concrete coating

This study is intended to assess the ability to counter chloride diffusion of concrete applied with inorganic coating modified with different...

more
Issue 02/2013

Formation of intermediate phases during hydration of C3S

The described model concepts can be employed as the basis for the development of binding agents possessing a significantly lower energy content and...

more
Issue 10/2018 UNIVERSITY OF APPLIED SCIENCES NUREMBERG GEORG SIMON OHM

Effects of fumed silica on material engineering parameters of external rendering, with special emphasis on thermal conductivity and compressive strength

A 5 vol.% addition of fumed silica is seen to reduce the thermal conductivity of a CS IV plinth render by nearly 29 %, from λ10, dry = 0.45 to 0.32 W/(m·K). At the same time, the compressive strength...

more