Date on Master's Thesis

8-2025

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Civil and Environmental Engineering

Committee Chair

Sun, Zhihui

Committee Member

Kim, Young Hoon

Committee Member

Robinson, Brian

Author's Keywords

cement; supplementary cementitious material; muscovite; clay; pozzolanic reactivity; calcination temperature

Abstract

An effective strategy for reducing CO2 emissions in the global cement industry is replacing a percentage of cement with supplementary cementitious materials (SCMs). As the availability of conventional SCMs such as fly ash and slag is decreasing, alternative SCMs such as calcined clays have been studied for their use as effective pozzolans. The present work investigates the feasibility of using a waste product from the quarrying industry known as blue clay as a viable SCM. It is composed of multiple clay minerals, predominantly muscovite. Raw and calcined at four temperatures (500, 650, 800, and 950°C), blue clay was analyzed in characterization, hydration, and reactivity studies to determine the effect of calcination on its chemical, mineralogical, and physical properties and reactivity. Results indicate that as blue clay is calcined, chlorite clays decompose and there is an increase in specific surface area until 650°C. As temperatures are raised to 800 and 950°C, clay content decreases and specific surface area decreases. As blue clay is heated it also becomes more flowable in mortar. There is also an increase in amorphous content upon calcination. Though early reactivity is poor, late stage TGA and compressive strength test results show higher reactivity for calcined samples. Results confirm that calcination of blue clay improves its reactivity demonstrating compressive strength gain in mortar samples comparable to that of fly ash when calcined at 950°C. It is shown that blue clay is an effective and viable SCM when heated to 950°C in late-stage tests.

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