Periodic Reporting for period 1 - DigiMat (Digital fabrication and integration of Material reuse for environmentally friendly cementitious composite building blocks)
Okres sprawozdawczy: 2022-01-01 do 2023-12-31
The construction industry has yet to embrace the technological advancements seen in other sectors. Instead, it continues to rely on outdated methods to manage complex modern projects, resulting in high costs and inefficiencies. For instance, in traditional concrete, over 60% of the total cost is spent on formwork and labour. A promising technology that could transform the industry is the 3D printing of concrete. This innovative process builds solid parts layer by layer and has been recognised by the European Parliament as one of the most significant technologies. In addition, the cement industry is responsible for approximately 25% of all CO2 emissions from industry and generates the highest amount of CO2 per dollar of revenue. The production process of Portland cement involves decomposing carbonates, such as limestone and coal, at a high temperature of 1500 °C. It has been reported that every ton of OPC production releases 0.73-0.85 tons of CO2. As a result, CO2 emissions from raw materials and fuel combustion account for 5-7% of global total CO2 emissions. Furthermore, the extraction of construction virgin aggregates, such as sand and gravel, accounts for the majority of global non-metallic mineral consumption (41% gravel and 31% sand), which reached approximately 5 billion tons in 2010. Construction materials' use and impact on CO2 emissions, global warming, and natural resource conservation necessitate critical tools to minimize environmental effects. Therefore, research priorities should focus on employing innovative technological solutions to address specific needs, such as utilising 3D printing of prefabricated building blocks and using recycled construction materials obtained from demolition of buildings. DigiMat has been a collaborative training project for the past 2 years that brought together academia and industry to merge the expertise of diverse disciplines and cutting-edge 3D printing technology. The goal was to create a sustainable cementitious feedstock derived from construction and demolition waste as well as industrial by-products, which could be utilised to produce eco-friendly cast and 3D printed load-bearing building blocks. The main objective of the proposed plan was to develop a diverse collection of alkali-activated cementitious composites that could be used for both traditional and 3D printing construction processes. These materials would be designed explicitly for load-bearing applications that possess exceptional mechanical properties or non-load-bearing applications with superior physical characteristics, such as thermal and sound insulation. The goal of this project was to gain a scientific understanding of the relationship between design, material, process, environmental impact, and the overall quality of the end product. An interdisciplinary approach was taken, employing experimental techniques and trial and error on both micro and macro scales. We have successfully created various alkali-activated cementitious composites which can be 3D printed or conventionally cast. These innovative composites utilise waste materials from industrial by-products, construction and demolition waste, end-of-life plastics, and mining waste, serving as eco-friendly replacements for both ordinary Portland cement and natural sand aggregates in low-carbon concrete. We have identified a diverse array of potential waste resources and crafted tailored mix designs for each material. This marks the inception of a new era for feedstocks in 3D printable objects, characterized by optimised environmental, economic, mechanical, durability, and insulating properties.
DigiMat has made excellent progress and has followed the original plan with some modifications (detailed in the Final Report). In the project's initial phase, research was carried out to develop recycled printable feedstock formulations for non-load-bearing and load-bearing elements. A wide range of materials, including binder materials, construction demolition waste aggregates, and additives were thoroughly analysed through multiple analytical techniques. This led to the creation of a series of mixtures that are ideal for use in non-load-bearing and load-bearing elements. Alkali-activated materials with excellent mechanical, physical, and durability characteristics were successfully developed. In the second phase, the focus was on assessing the properties of freshly prepared materials and their rheology. To accomplish this, a range of techniques was utilised to evaluate the fresh and rheological characteristics of the developed mixtures. Then, the results of previous phases were used to select and modify the best 3D printable mixes. Through collaboration with an academic partner, a medium-scale extrusion-based 3D printing system that is perfectly compatible with DigiMat's 3D printable materials has been developed. This effective system is now ready for large-scale applications. The investigation proceeded by meticulously testing the developed materials and technology through the evaluation of load-bearing capacity parameters, durability, physical properties, and porosity of samples. WP4 has undergone restructuring based on a literature review conducted by the Fellow and the supervisor. The decision to restructure was made based on evidence that suggests numerical simulation of the extrusion-based 3D printing process is not sufficient for detecting and predicting various failures in cementitious composites. Relying solely on numerical simulations may result in incomplete assessments. Consequently, WP4 has been modified to develop AAM and LC3 mixtures with enhanced physical properties due to the emergence of new trends in developing low-carbon cementitious composites. For dissemination and exploitation of results (WP5), all activities were carried out precisely in line with the original plan. Within the framework of WP5, meetings were conducted with upcoming MSCA-IF candidates at Brunel University London and other partner universities. The knowledge gained from this project was freely and openly shared through various channels such as publications, conferences, workshops, and social media platforms. Furthermore, targeted data was employed to bolster cooperation among the Fellow, Host, and Project Partners. Throughout training and personal development (WP6), the Fellow was engaged in a range of training activities and research proposal applications, all of which contributed to solidifying his independent scientific position.
The DigiMat project contributes to the progress of printable building materials technology. Its findings have notably advanced the field while aligning with the EU's Strategic Plan, reducing the consumption of raw materials and energy in producing cementitious building blocks. The focus was on a new generation of waste-driven low-carbon cementitious composites, addressing composition, density, and the use of various waste streams as binder materials and natural aggregate replacements, aimed to optimise the mechanical and insulating performance of both 3D printed and conventionally cast building blocks. The project advances low-carbon cementitious composites derived from waste materials, underscoring their formulation and properties. The research has immense potential in creating high-performance building blocks, contributing significantly to Net-Zero Buildings.