Microstructure and thermal properties of inorganic geopolymeric materials synthesized from metakaolin at 65°C have been investigated for their further application as a thermal barrier for concrete structures. Thermogravimetric analysis of two geopolymer compositions revealed good thermal stability of this material at temperatures of up to 1000°C. Substantial expansion of the samples with addition of silica were observed during heat treatment at 450°C and 800°C, accounting for the differences in microstructure between the two compositions as was seen with scanning electron microscope. Infrared analysis revealed the presence of additional structural groups for silica-containing specimens.

The ability of mortar samples to withstand elevated temperatures was based on the degree of compressive strength loss as well as the microstructure changes that were observed before and after the exposure of specimens to 450°C and 800°C for one hour. As compared to unprotected concrete, the reduction in strength at 450°C was 12% and 14% less for mortar cubes coated with metakaolin-based geopolymer and that with addition of amorphous silica, respectively. At 800°C, the observed difference was more than 20%. Infrared analysis and electron spectroscopy studies of heat treated mortar showed little signs of deterioration when samples were coated with geopolymer. Consequently, it was determined that geopolymer can be used as a suitable coating for thermal protection of concrete.

Library of Congress Subject Headings

Polymers--Thermal properties; Polymers--Microstructure; Concrete coatings

Publication Date


Document Type


Student Type


Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)


Benjamin Varela

Advisor/Committee Member

A. Teixeira-Pinto

Advisor/Committee Member

Andy Langner


Physical copy available from RIT's Wallace Library at QD381.9.T54 P74 2005


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