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Sustainable Building Lime Applications via Circular Economy and Biomimetic Approaches

Periodic Reporting for period 1 - SUBLime (Sustainable Building Lime Applications via Circular Economy and Biomimetic Approaches)

Reporting period: 2021-01-01 to 2022-12-31

Lime is an enabling material obtained from the calcination of the limestone in an industrial process, and it is one of the earliest industrial commodities known to humankind; its production and uses have grown with time, and it continues to be one of the essential building blocks of modern society. It is stressed that the EC's objective with its Economic Growth Programme is to promote, within the context of the EU’s wider industrial policy, the competitiveness of industries related to raw materials, including minerals such as lime.
Lime is fundamental in many industrial value chains as the iron and steel production industries, in environmental applications (flue gas cleaning, water and sludge treatment), soil improvement and protection, civil engineering, construction materials, agriculture, and in food and feed additives. Approximately 18% of the market is dedicated to construction materials and civil engineering.
Lime mortars have kept extensive applicability in the European and worldwide scenario of masonry construction, both as joint material in between masonry units and as a plastering material. When compared with cement, the benefits of using lime-based mortars include: a) Low water penetration; b) Increased breathability and moisture control; c) Increased bond strength and reduced cracking; d) Lower efflorescence; e) Easier and cheaper building maintenance; f) Workability and water retention resulting in optimum material use and productivity; g) Lower carbon footprint. In addition, lime-based mortars are fully compatible with ancient masonry, a key issue in conservation of heritage buildings.
SUBLime intends to train researchers in multiple scientific and engineering fields aiming a better understanding and development of sustainable innovation solutions for lime mortars/plasters in new construction and conservation of the built heritage. The project covers the main features of lime-based applications in the masonry construction, including material characterization, numerical modelling of multi-physics behaviour, functionality, and sustainability in lime use, all within a framework of performance-based design. Innovations are focused on added functionalities and sustainability aspects in lime mortars and plasters, strongly based on novel biomimetic and closed-loop recycling approaches. SUBLime introduces and develops new sustainable solutions with added functionalities such as self-cleaning, self-healing or enhanced CO2 capture capabilities, and considers closed-loop recycling.
The main scientific achievements of SUBLime in this reporting period are:
ESR1 – Yu Zeng was able to extend a microstructural simulation framework towards lime-based material.
ESR2 – Guilherme Munhoz performed different experimental campaigns on assessing the volume stability of lime mortars, focusing on creep and shrinkage.
ESR3 – Francesco Santoro has enabled creating micropillars on the crystals' surface through etching of calcite crystals, increasing its resistance to water-related damage and self-cleaning.
ESR4 – Teodora Ilić has tackled the mechanism and kinetics of carbonation through experimental campaigns with the objective of accelerating CO2 capture.
ESR5 – Franco Grosso used different microorganisms towards the development of a novel biomineralization method with the goal of enhancing hardening and self-healing of lime-based mortars.
ESR6 – Vadim Grigorjev optimized mixture proportioning including recycled aggregates with particular emphasis on the lower particle sizes.
ESR7 – Monika Pultorak is working on developing new experimental techniques for fresh property characterization, and new approaches into mortar mixtures are being tested.
ESR8 – Thomas Russo developed cost-effective systems towards the measurement of elastic modulus and is currently developing a portable adiabatic calorimeter.
ESR9 – Agustin Laveglia and ESR15 – Luciano Sambataro developed a flexible life cycle analysis calculation tool.
ESR10 – Dulce Valdez has been experimenting on different mortar mixes towards characterizing salt crystallization (efflorescence).
ESR11 – Seyedsalar Ahmadi and ESR12 – Kristian Falkjar are studying homogenization techniques through comparison with detailed simulation of brick and mortar systems.
ESR13 – Ahmad Fathi developed a cost-effective measurement method required for developing an extensive experimental campaign on delayed deformations.
ESR14 – Armando Zagaroli prepared a large-scale experimental campaign on masonry elements, focusing on soil settlements and earthquake behaviour.
Dissemination of the results obtained so far has already taken place via participation in conferences in Portugal, USA, Japan, Slovenia, Germany, Belgium and Spain.
Within SUBLime 3 training weeks (Spain, Greece, Germany) were organized, and 3 others are planned (Netherlands, Portugal, Poland).
SUBLime is providing original contributions in areas that are mostly unexplored in the context of lime-based materials: microstructural and chemical characterization; test methods for delayed effects and durability; simulation of microstructural development and upscaling towards the meso- and macro-scales; deep understanding of the basic mechanisms of phenomena like creep and shrinkage; new functional materials that provide self-cleaning, self-healing or other capabilities like accelerated hardening to traditional materials. Innovations towards carbon neutrality (or even negativity), and increased sustainability are highlighted in view of current EU objectives on environmental performance.
Some of the major breakthroughs anticipated from SUBLime are:
• Development of cost-effective cyberphysical systems that allow testing of relevant properties generalizing access of the industry to advanced property testing and quality control.
• Take important steps towards the full integration of simulation levels from the micro-scale to the masonry level, including the use of lime-based mortars.
• Novel bacterial methods to enhance setting/hardening and prevent crack formation in lime-based mortars and plasters.
• Novel nanoparticle-based surface coatings, compatible and synergetic with lime-based mortars and plasters.
• Novel enzyme-based biomimetic strategy for the enhanced and accelerated capture of atmospheric CO2 during the carbonation process.
• Recycled concrete aggregates, up to the fine grading, will be used in lime-based building materials, optimizing the processing of such recycled materials and their performance, while maintaining a low product-performance variability.
• Revision of standard provisions regarding mortars and plastering mortars (declaration of additional physical and mechanical features and the method of their determination).
The Report ‘Competitiveness of the European Cement and Lime Sectors’ (2018) states that the lime and plaster industries represented more than 20 Mt/y and estimated €4.2 billion turnovers with €1.4 billion value added, with approximately 15 000 direct employees, which further add to 30 000 indirect employees. The expected economic impact of SUBLime, as for example the development of new products with added functionality, are considerable. The societal impact in terms of environmental and sustainability issues, especially considering topics such as CO2 footprint reductions, incorporation of recycled material or improving serviceability of construction are clearly targeting several of the United Nations Sustainable Development Goals.
Environmental scanning electron microscope analysis on lime-based mortar under drying/rehydration
Development of cost-effective experimental systems and comparison with commercial solutions
Example of microstructure simulation
Pore network of lime-cement mortar sample using Micro-CT scan
Environmental scanning electron microscope analysis on etched calcite
Overview of the SUBLime scientific WPs