Sustainable 3D Concrete Printing for Eco-conscious Construction: Recycled Aggregates and Low-carbon Binders
type: CreativeWork
description: The construction industry faces increasing pressure from rapid urbanisation, rising infrastructure demand, and global climate imperatives, yet it remains a major contributor to environmental degradation. Concrete, and in particular Portland cement, contributes significantly to this challenge, accounting for nearly 10% of global CO₂ emissions, while inefficient waste management practices direct millions of tonnes of construction and demolition waste (CDW) to landfills annually. Additive manufacturing in the form of 3D concrete printing (3DCP) has emerged as a promising technology that can potentially address inefficiencies currently associated with the construction industry such as improving productivity and reducing labour, material use, construction time, and waste generation. However, the environmental advantages of 3DCP are constrained by the high binder content of printable mixtures, which continue to rely heavily on ordinary Portland cement and virgin aggregates. This dissertation investigates strategies to reduce cement dependency, incorporate recycled aggregates, and improve the sustainability of 3DCP without compromising printability or constructability. A total of thirteen novel, potentially sustainable, mixtures were designed of which eleven were fully characterised through rheological testing, 3D printing and mechanical testing. The research demonstrates that significant reductions in Portland cement can be achieved through the use of supplementary cementitious materials (SCMs) such as fly ash, silica fume, slag, and metakaolin, while simultaneously increasing the aggregate-to-binder ratio to 1.75. Printable mixtures were developed with 60% of the total binder volume consisting of SCMs. The first three mixtures developed using this technique achieved adequate compressive strengths, improved stiffness ranging from 29 – 37 GPa, and excellent surface quality in printed elements. A critical review of low-carbon printable mixtures confirms the practical potent…
abstract: The construction industry faces increasing pressure from rapid urbanisation, rising infrastructure demand, and global climate imperatives, yet it remains a major contributor to environmental degradation. Concrete, and in particular Portland cement, contributes significantly to this challenge, accounting for nearly 10% of global CO₂ emissions, while inefficient waste management practices direct millions of tonnes of construction and demolition waste (CDW) to landfills annually. Additive manufacturing in the form of 3D concrete printing (3DCP) has emerged as a promising technology that can potentially address inefficiencies currently associated with the construction industry such as improving productivity and reducing labour, material use, construction time, and waste generation. However, the environmental advantages of 3DCP are constrained by the high binder content of printable mixtures, which continue to rely heavily on ordinary Portland cement and virgin aggregates. This dissertation investigates strategies to reduce cement dependency, incorporate recycled aggregates, and improve the sustainability of 3DCP without compromising printability or constructability. A total of thirteen novel, potentially sustainable, mixtures were designed of which eleven were fully characterised through rheological testing, 3D printing and mechanical testing. The research demonstrates that significant reductions in Portland cement can be achieved through the use of supplementary cementitious materials (SCMs) such as fly ash, silica fume, slag, and metakaolin, while simultaneously increasing the aggregate-to-binder ratio to 1.75. Printable mixtures were developed with 60% of the total binder volume consisting of SCMs. The first three mixtures developed using this technique achieved adequate compressive strengths, improved stiffness ranging from 29 – 37 GPa, and excellent surface quality in printed elements. A critical review of low-carbon printable mixtures confirms the practical potent…
author: Colyn, Markus Leon
language: en
date published: 2026-03
date modified: 2026-07-24T04:40:12Z
provider: Stellenbosch University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Stellenbosch : Stellenbosch University