State of the art

Liquid colors and batching systems for liquid color

Fig. 1 Floor-mounted container with delivery container mounted on top. The connection of the lance to the air for loosening up the liquid color is circled in red. The position of the air lances in the containers is schematically indicated by blue lines. Abb. 1 Standbehälter mit aufsitzendem Lieferbehälter. Der Luftanschluss der Lanze zum Auflockern der Flüssigfarbe ist rot eingekreist vergrößert dargestellt. Der Verlauf der Lanzen in den Behältern ist durch die blauen Linien schematisch angedeutet.

Fig. 2 One-chamber scale as batching vessel for liquid color, fitted with a three-way valve. This type of valve enables the liquid color to circulate in the conducting system without creating dead zones.

Abb. 2 Einkammerwaage als Dosiergefäß für Flüssigfarbe, ausgestattet mit einem Dreiwege-Ventil. Diese Ventilart ermöglicht ein totraumfreies Zirkulieren der Flüssigfarbe im Leitungssystem.

Fig. 3 Mobile batching plant fitted with a 2-chamber scale.
Abb. 3 Mobile Dosieranlage ausgerüstet mit einer 2-Kammer-Waage.

Fig. 4 Mobile batching plant fitted with an inductive flowmeter.

Abb. 4 Mobile Dosieranlage ausgestattet mit einer induktiven Durchflussmessung.

Fig. 5 Mobile batching plant fitted with a platform scale; on the left, the control unit for the system.
Abb. 5 Mobile Dosieranlage ausgestattet mit einer Bodenwaage, links die zum System gehörende Steuerung.

 Liquid color pigment preparations have been successfully used for coloring concrete for decades. A look at the individual areas of applications in the concrete industry makes it apparent that liquid colors are in broad use: not only concrete paving blocks and concrete roofing tiles and many other products made of no-slump concrete are colored with pigment suspensions: precast concrete components and ready-mixed concrete have also been colored for a number of years with liquid color.

This was made possible by the normative specifications in DIN EN 12878: “Pigments for the coloring of building materials based on cement and/or lime - Specifications and methods of test.” These guidelines make the preparation of liquid color mix formulations possible for use in reinforced concrete [1].

The use of liquid colors, compared to solid pigment forms, powder, granules, and compact pigments [2] has advantages and disadvantages. The crucial advantages that speak for the use of liquid color are the following:

» The pigment particles are completely dispersed in the liquid color. No great...