Document Type
Thesis
Date of Award
5-31-1990
Degree Name
Master of Science in Civil Engineering - (M.S.)
Department
Civil and Environmental Engineering
First Advisor
Methi Wecharatana
Second Advisor
C.T. Thomas Hsu
Abstract
Fly ash generated from coal-burning power plants has been an increasing problem to the utility company in terms of storage and disposal in compliance with the environmental regulations. Presently, fly ash has been widely used in the concrete mix. Research shows that fly ash can improve many properties of fresh and harden concrete. Landfill is another significant usage of fly ash. Usually, fly ash is stored in dry and weathered conditions. The properties of fly ashes from different sources and in different storage conditions are different.
In this research, the compressive strength of mortar containing cement replacement of Deep Hollow, Hudson, PSE&G dry, and PSE&G weathered fly ash was studied. The effect of fly ash-kiln dust combination on the compressive strength of cement mortar was also investigated. Kiln dust is added to provide CaO content to fly ash in developing cementitious property of the composite for the disposal of fly ash. The behavior of fly ash and kiln dust mixture was also evaluated in this research.
The experimental results showed that any percentage replacement of portland cement by fly ash or fly ash-kiln dust on an one-for-one basis resulted in a lower compressive strength cementitious matrix of up to 90 days of curing. In fly ash mortar, the higher the percentage of fly ash used, the lower the compressive strength of mortar. With proper proportioning kiln dust can enhance the pozzolanic quality of Class F fly ash in mortar. It was found that a combination of kiln dust and fly ash can process calcium silicate hydration similar to portland cement, but the reaction is not as fast and efficient as that of portland cement. In the mixture of fly ash and kiln dust, additional sand generally provides a lower compressive strength. It was noted that dry fly ash provided higher compressive strength than weathered fly ash. These experimental results might be of significance to the use of fly ash in construction and waste disposal projects.
Recommended Citation
Yu, Yitao, "Effects of fly ash and kiln dust on the compressive strength of cement mortar" (1990). Theses. 3023.
https://digitalcommons.njit.edu/theses/3023
