VALUE-ADDED USE OF NON-WOOD BIOMASS COMBUSTION ASH TOWARDS PRODUCTION OF SUSTAINABLE, ECONOMICAL AND HIGH-PERFORMANCE GEOPOLYMER CONCRETE

Event Date/Time: 
April 24, 2018 - 2:00pm
Event Location: 
3546D Engineering
Speaker: 
Sharif Alazhary
Master's Thesis Defense

Abstract

Non-wood biomass ash-based hydraulic cement formulations were developed to meet the ASTM C1157 requirements for the 'General Use' class of hydraulic cements. Values of wheat straw, corn stalk, and rice husk combustion ashes as raw materials for production of hydraulic cements suiting concrete production were evaluated. The biomass ash was supplemented with other abundant waste and natural materials in order to produce a balanced chemistry for production of hydraulic cement. The alkali aluminosilicate (geopolymer) cement chemistry used in this investigation is robust, and allows for the value-added use of large byproduct volumes. Transformation of raw materials into hydraulic cement was accomplished using mechanochemical effects without resorting to elevated temperatures. Mechanochemical processing of the hydraulic cement was accomplished using a conventional ball mill. This approach to processing and the selections of raw materials yield highly sustainable hydraulic cements. Besides the ASTM C1157 requirements, moisture stability was found to be an important consideration in development of non-wood biomass ash-based hydraulic cements. Achievement of moisture stability required simple refinements of the cement chemistry. Steps were taken to optimize the formulation and processing conditions of the biomass ash-based hydraulic cement. The end product is an economically viable cement with relatively low energy content and carbon footprint that meets standard requirements for general use in production of concrete materials that match or surpass the fresh mix workability and the hardened materials performance attributes of conventional Portland cement concrete.