Spectroscopic Investigation of Cement Hydrate Phases and Their Chloride Binding Properties

The chloride binding capacity depends on the structure and surface properties of the individual hydrates. Portlandite and AFm surfaces have high affinity for chloride due to their positive zeta-potentials. For C-S-H samples, the chloride binding capacity increases with increasing C/S ratio due to increased numbers of surface Ca-OH sites and decreased polymerization of silicate chains. Aluminum substitution in C-S-H is unfavorable for chloride binding due to reduced layer charge and increased chain polymerization. For all hydrate phases the mechanism of chloride binding is not simply electrostatic attraction. Formation of metal-chloride clusters in the solution and sorption in the Stem layer may contribute substantially. The bound chlorides near the cement hydrate surfaces are in water solvated environments similar to those in the bulk solution and are in rapid exchange (>2kHz) with free chloride in the bulk solution. The chloride concentration near the surfaces is much higher than in the equilibrium bulk solution, and the reorientational frequency of the water molecules solvating the bound chloride is slower than those in the bulk solution. Chloride has a well-defined structural site in Friedel's salt. In solid solutions between Friedel's salt and hydroxyl-AFm, chloride occurs predominantly in Cl-rich domains except at high OH-contents.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Materials Science and Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Yu, Ping

Contributors dc:contributor

• Kirkpatrick, R. James

• Engineering, Materials Science

Language dc:language

eng

Identifier

(MiAaPQ)AAI9990201

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/82936