Title:
The Role of Surface Area and Compacity of Nanoparticles on the Rheology of Cement Paste 25.3
Author(s):
Oscar A. Mendoza Reales, Emílio C. C. M. Silva, Maria D. M. Paiva, Pedro Duda, and Romildo Dias Toledo Filho
Publication:
Symposium Paper
Volume:
320
Issue:
Appears on pages(s):
25.1-25.14
Keywords:
nanoparticles; rheology; surface area; viscosity; yield stress
DOI:
10.14359/51701063
Date:
8/1/2017
Abstract:
Nanoparticles have a great influence on the rheology of cement matrices due to their inherent physical and chemical properties. This work quantifies the relation between matrix rheology and surface area of nanoparticles (carbon nanotubes, nanosilica and nanoclay), by comparing them with the effects of some equivalent microparticles (microsilica and metakaolin). Class G cement pastes blended with micro- or nanoparticles were prepared using a water-to-cementitious material ratio of 0.45 and a viscosity modifying agent to
prevent segregation and settlement. Static yield stress, dynamic yield stress, and plastic viscosity were determined to characterize the rheology. The first was measured directly, while the other two were obtained by fitting a Bingham model to the descending portion of a flow curve. It was found that micro- and nano- particle substitutions of similar composition and surface area have similar effects on the rheological parameters, indicating that the influence of nanoparticles is mainly governed by their specific surface area.