International Concrete Abstracts Portal

Title: Evidences about the Interactions between Grinding Aids and Cement Particles Surface

Author(s): Valerio Antonio Paternò, Sara Ottoboni, Marco Goisis, and Paolo Gronchi

Publication: Special Publication

Volume: 302

Issue:

Appears on pages(s): 211-226

Keywords: additive; cement; clinker; contact angle; grinding aid; surface tension; wetting

Date: 6/1/2015

Abstract:
The measure of wettability of cement particles and the evaluation of the type and the strength of active surface sites of clinker particles were carried out to score the efficacy of organic grinding aids. The first analysis, based on the Washburn method, allows measuring the contact angle of cement with different solvents and is directly related to the surface tension. The second analysis, based on the Hammett method, helps to classify the sites that may be responsible of the surface tension. Milled clinker (portland clinker CEM I 52, 5R; 0,025% w/w DEG and TEA) was investigated. Firstly the wetting rates of powder with 4 different solvents (ethanol, n-hexane, toluene, and formamide) were detected using a tensiometer. Then the powder dispersions in a solvent were titrated by acid solutions to get information on the acid/basic character of the surface sites. Techniques and results are shown.