Date of Award

January 2014

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Surojit Gupta

Abstract

We propose a Green Cement Paradigm (GCPa) for fabricating environmentally friendly cementitious materials. By using GCPa, we report for the first time, the usage of Class C Fly Ash as a sole source of cementitous phase without any activation by alkali. During this study, Class C Fly Ash, and its composites with sand were fabricated at different compaction stresses by maintaining a low w/c (w-water, c-cement) ratio of 0.17-0.24 in the compacts. The porosity and the number of days for curing played a significant role in the evolution of compressive strength. The experimental results indicate that the curing for 28 days is the optimum time required for strength development. For example, the Class C Fly Ash samples cold pressed at ~86 MPa and cured for 28 days showed a compressive strength of ~29.5 MPa. The effect of additional Ca(OH)2, high temperature curing and carbonation on the compressive strength development of the class C FA samples is reported. SEM, EDS, TGA/DSC and XRD investigations were employed to explain the obtained results. The possibility of fabricating lignin based polymer composites was investigated. The mechanical properties of the composites were reported in terms of yield strength and flexural strength.

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