Reference: X. Feng, E.J. Garboczi, D.P. Bentz, P.E. Stutzman, T.O. Mason, Cement and Concrete Research 34 (10), pp. 1787-1793 (2004).

(PDF Version of Original Paper)

Go back to PartI Chapter 4 Section (2f) Go back to Table of Contents


Estimation of the degree of hydration of blended cement pastes by a scanning electron microscope point-counting procedure

X. Feng, E.J. Garboczi, D.P. Bentz, and P.E. Stutzman
Materials and Construction Research Division
National Institute of Standards and Technology
Gaithersburg, Maryland 20899

T. O. Mason
Department of Materials Science and Engineering
Northwestern University
Evanston, IL 60208


Abstract

A scanning electron microscope (SEM) point-counting technique was employed to study the hydration of plain portland cement pastes and blended cement pastes containing fly ash or slag. For plain portland cement pastes, the results for the degree of cement hydration obtained by the SEM point-counting technique were consistent with the results from traditional loss-on-ignition non-evaporable water content measurements; agreement was within ± 10 %. The standard deviation in the determination of the degree of cement hydration via point counting ranged from ± 1.5 % to ± 1.8 % (one operator, one sample). For the blended cement pastes, it is the first time that the degree of hydration of cement in blended systems has been studied directly. The standard deviation for the degree of hydration of cement in the blended cement pastes ranged from ± 1.4 % to ± 2.2 %. Additionally, the degrees of reaction of the mineral admixtures were also measured. The standard deviation for the degree of fly ash reaction was ± 4.6 % to ± 5.0 %, and ± 3.6 % to ± 4.3 % for slag. All of the analyses suggest that the SEM point-counting technique can be a reliable and effective analysis tool for use in studies of the hydration of blended cement pastes.

Keywords: A. Hydration; D. Blended cement; Fly ash; Granulated blast-furnace slag; Point counting.


Go back to PartI Chapter 4 Section (2f) Chapter Section Go back to Table of Contents