Title: Influence of Non-adsorbed Polymers on Fluidity of Cement Paste

Author(s): Kazuki Matsuzawa, Daiki Shimazaki, Hirokatsu Kawakami, and Etsuo Sakai

Publication: Symposium Paper

Volume: 329

Issue:

Appears on pages(s): 267-278

Keywords: chemical admixture; cement paste; fluidity; non-adsorbed superplasticizer; low water-cement ratio; density of functional groups

DOI: 10.14359/51711220

Date: 9/26/2018

Abstract:
In cement paste with low water-powder ratio, non-adsorbed superplasticizer molecules increase the fluidity of paste, but their function is not investigated in detail. This study investigates the influence of non-adsorbed superplasticizer on the fluidity of cement paste using several superplasticizers having different molecular structures. The paste consisted of belite-rich low-heat Portland cement, ultra-fine silica particle, and polycarboxylate-based superplasticizer solution. First, a superplasticizer having moderate amount of functional groups was added to the paste, and adsorption was saturated. Subsequently, another superplasticizer was added. The influence of subsequent addition was related to the molecular structure of another superplasticizer. Another superplasticizer having few functional groups decreased adsorption of the first superplasticizer but the fluidity did not change. Another superplasticizer having moderate functional groups did not change adsorption but increased the fluidity. Another superplasticizer having many functional groups increased adsorption but decreased the fluidity.