Cement additives based on PCE

1 The three columns of modern cement grinding

2 The mechanism of grinding aids: a) saturation of surface charges, b) prevention of coating, c) dispersion in the separator

3 Specific surface acc. Blaine in relation to additive dosage at constant grinding time

4 Effect of formulations of PCE-1 with TEA on water demand and flow table spread, active ingredient of additives was 40 %, dosage 0.10 % of cement

5 Specific surface (Blaine) of samples ground with formulations of PCE-1 and TEA in different mixing ratios at constant grinding time; active ingredient of additives was 40 %, dosage 0.05 %; Reference: without additive

6 Specific surface of ground clinker after constant grinding time; additives 40 % solution of PCE-1, TEA and a mixture of PCE-1 and TEA (1:2), dosage 0.05 % of cement

7 Flow table spread of a CEM II/B-M (V-LL) 42.5 N after grinding with and without PCE-2 additive

Summary: The rising demands on modern cements require continuous development of cement additives. Polycarboxylate ether (PCE), although used around the globe as concrete admixtures, remain largely unknown for the use in cement. This article examines the effects of PCE cement additives on the basis of a series of tests performed both in laboratory and on industrial scale. The use of these additives allows a more efficient grinding, systematic control of cement quality and the addition of higher percentages of clinker substitutes.

1 Introduction

Additives have been used in cement grinding since the 1930s. Initially, the main purpose of their use was to increase the production rate, whereas substances which additionally raise the strength of the cement have increasingly come into use from the 1970s onwards [1].

A trend towards reducing the clinker factor of cements, and thus enlarging the amounts of clinker substitutes used – such as GBFS, fly ash and limestone – is observable around the world [2]. The quality of such “composite” cements depends to a very great extent on the type and quantity of the clinker substitutes...