Toward Low Carbon Footprint and Lightweight Masonry Alkali-activated Material

Authors

Zina Ebrahim, University of Nebraska-LincolnFollow
Mohammad Mastali, Infrastructure Services Group. Scotia, New York
Marc Maguire, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

6-12-2023

Citation

This article was submitted to the 14^th North American Masonry Conference (2023), Omaha, Nebraska, United States

Comments

Copyright 2023, the authors. Used by permission

Abstract

The portland cement concrete industry and the masonry industry are undergoing changes in response to skilled labor shortages and concerns over climate and pollution. There may be interest from parts of the industry in lower carbon footprint and lightweight masonry products. Toward this aim, the use of hemp shiv--the woody core of the hemp plant--in alkali-activated concrete was investigated herein and shown to have a wide range of impacts on the hardened state characteristics of a material suitable for structural concrete masonry units (CMUs) in accordance with ASTM C90 requirements. Hemp shiv is well known for its use in hempcrete, which is a mixture of shiv and lime. However, alkali-activated concrete is a sustainable alternative to portland cement concrete that can be used as a binder for hemp-based concrete. This study investigates the potential of developing hemp-based alkali-activated material to be used in the production of sustainable masonry units. The effects of adding hemp shiv to alkali-activated materials on mechanical characteristics and CO₂ emissions are investigated in this study and shown to be a suitable material for CMUs. A parametric study was carried out to define the effects of using different alkali-activator content on the compressive strength and density of the developed sustainable masonry units. In addition, a sustainability study was carried out on the developed CMU-suitable materials to investigate their global warming potential and degree of carbon dioxide sequestration. According to the findings, the final material can have densities and strengths of up to 75 lb/ft³ and 2500 psi, respectively. Furthermore, a carbon dioxide uptake capability up to 126 lbCO_2eq/ft³ was measured for the developed masonry units.