An Investigation of Suitable Healing Agents for Vascular-Based
Self-Healing in Cementitious Materials
Yasmina Shields, Tim Van Mullem, Nele De Belie & Kim Van Tittelboom
Abstract: Self-healing cementitious materials can extend the service life of structures, improve safety during repair activities and reduce costs with minimal human intervention. Recent advances in self-healing research have shown promise for capsule-based and intrinsic healing systems. However, limited information is available regarding vascular-based self-healing mechanisms. The aim of this work is to compare different commercially available healing agents regarding their suitability in a selfhealing vascular network system by examining a regain in durability and mechanical properties. The healing agents investigated include sodium silicate, two polyurethanes, two water repellent agents and an epoxy resin. Sealing efficiencies above 100% were achieved for most of the healing agents, and both polyurethanes and the epoxy resin showed high regain in strength. The results obtained from this study provide a framework for selecting a healing agent given a specific application, as a healing agent’s rheology and curing properties can affect the optimal geometry and design of a vascular network.
Reference of this article: Shields, Y.; Van Mullem, T.; De Belie, N.; Van Tittelboom, K. An Investigation of Suitable Healing Agents for Vascular-Based Self-Healing in Cementitious Materials. Sustainability 2021, 13, 12948.
DOI: 10.3390/su132312948
Keywords: vascular networks; healing agents; self-healing concrete; durability; mechanical recovery
Affiliations:
Yasmina Shields, Tim Van Mullem, Nele De Belie & Kim Van Tittelboom: Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of
Engineering and Architecture, Ghent University, Technologiepark Zwijnaarde 60, B-9052 Ghent, Belgium
The full article can be found here: https://doi.org/10.3390/su132312948 or can be downloaded as pdf here
Understanding the Impacts of Healing Agents on the Properties
of Fresh and Hardened Self-Healing Concrete: A Review
Harry Hermawan, Peter Minne, Pedro Serna & Elke Gruyaert
Abstract: Self-healing concrete has emerged as one of the prospective materials to be used in future constructions, substituting conventional concrete with the view of extending the service life of the structures. As a proof of concept, over the last several years, many studies have been executed on the effectiveness of the addition of self-healing agents on crack sealing and healing in mortar, while studies on the concrete level are still rather limited. In most cases, mix designs were not optimized regarding the properties of the fresh concrete mixture, properties of the hardened concrete and self-healing efficiency, meaning that the healing agent was just added on top of the normal mix (no adaptations of the concrete mix design for the introduction of healing agents). A comprehensive review has been conducted on the concrete mix design and the impact of healing agents (e.g., crystalline admixtures, bacteria, polymers and minerals, of which some are encapsulated in microcapsules or macrocapsules) on the properties of fresh and hardened concrete. Eventually, the remaining research gaps in knowledge are identified.
Reference of this article: Hermawan, H.; Minne, P.; Serna, P.; Gruyaert, E. Understanding the Impacts of Healing Agents on the Properties of Fresh and Hardened Self-Healing Concrete: A Review. Processes 2021, 9, 2206.
DOI: 10.3390/pr9122206
Keywords: self-healing concrete; crystalline admixture; bacteria; microcapsules; macrocapsules; fresh properties; hardened properties
Affiliations:
Harry Hermawan, Peter Minne & Elke Gruyaert: Department of Civil Engineering, Materials and Constructions, Ghent Technology Campus, KU Leuven, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium
Pedro Serna: Instituto de Ciencia y Tecnología Del Hormigón (ICITECH), Universitat Politècnica de València, Camino de Vera S/n, 46022 Valencia, Spain
The full article can be found here: https://doi.org/10.3390/pr9122206 or you can download the document here
A review of vascular networks for self-healing applications
Yasmina Shields, Nele De Belie, Anthony Jefferson & Kim Van Tittelboom
Abstract: Abstract Increasing awareness for sustainability has led to the development of smart self-healing materials, which can extend the service life and improve safety without human intervention. Vascular networks are observed in biological systems, such as leaf venation and blood vascular systems, and provide inspiration for self-healing mechanisms in engineered systems. Embedding a vascular network in a host material has the advantage of addressing varying magnitudes of damage and allowing for an indefinite replenishment of the healing agent, which are current limitations of intrinsic and capsule-based self-healing systems. These networks are demonstrated in polymer and composite materials, with fabrication methods including removal of sacrificial elements, electrospinning, and an array of additive manufacturing (AM) techniques. Advances in AM allow more complex network configurations to be realized that optimize fluid distribution and healing potential. This review intends to provide a comprehensive overview of the current progress and limitations of the design approaches, fabrication methods, healing mechanisms, and relevant applications of embedded vascular networks. Additionally, significant research gaps and future research directions for vascular self-healing materials are described.
Reference of this article: Shields, Y., De Belie, N., Jefferson, A., & Van Tittelboom, K. (2021). A review of vascular networks for self-healing applications. SMART MATERIALS AND STRUCTURES, 30(6)
DOI: 10.1088/1361-665X/abf41d
Keywords: Self-healing, vascular networks, biomimetic
Affiliations:
Yasmina Shields, Nele De Belie & Kim Van Tittelboom: Magnel-Vandepitte Laboratory for Structural Engineering and Building Materials, Ghent University, Belgium
Anthony Jefferston: Cardiff School of Engineering, Cardiff University, United Kingdom
The full article can be found here: https://doi.org/10.1088/1361-665x/abf41d
Addressing the need for standardization of test methods for self-healing concrete: an inter-laboratory study on concrete with macrocapsules
Tim Van Mullem, Giovanni Anglani, Marta Dudek, Hanne Vanoutrive, Girts Bumanis, Chrysoula Litina, Arkadiusz Kwiecień, Abir Al-Tabbaa, Diana Bajare, Teresa Stryszewska, Robby Caspeele, Kim Van Tittelboom, TullianiJean-Marc, Elke Gruyaert, Paola Antonaci & Nele De Belie
Abstract: Development and commercialization of self-healing concrete is hampered due to a lack of standardized test methods. Six inter-laboratory testing programs are being executed by the EU COST action SARCOS, each focusing on test methods for a specific self-healing technique. This paper reports on the comparison of tests for mortar and concrete speci-mens with polyurethane encapsulated in glass macrocapsules. First, the pre-cracking method was analysed: mortar specimens were cracked in a three-point bending test followed by an active crack width control technique to restrain the crack width up to a predefined value, while the concrete specimens were cracked in a three-point bending setup with a displacement-controlled loading system. Microscopic measurements showed that with the application of the active control technique almost all crack widths were within a narrow predefined range. Conversely, for the concrete specimens the variation on the crack width was higher. After pre-cracking, the self-healing effect was characterized via durability tests: the mortar specimens were tested in a water permeability test and the spread of the healing agent on the crack surfaces was determined, while the concrete specimens were subjected to two capillary water absorption tests, executed with a different type of waterproofing applied on the zone around the crack. The quality of the waterproofing was found to be important, as different results were obtained in each absorption test. For the permeability test, 4 out of 6 labs obtained a comparable flow rate for the reference specimens, yet all 6 labs obtained comparable sealing efficiencies, highlighting the potential for further standardization.
Reference of this article: Tim Van Mullem, Giovanni Anglani, Marta Dudek, Hanne Vanoutrive, Girts Bumanis, Chrysoula Litina, Arkadiusz Kwiecień, Abir Al-Tabbaa, Diana Bajare, Teresa Stryszewska, Robby Caspeele, Kim Van Tittelboom, Tulliani Jean-Marc, Elke Gruyaert, PaolaAntonaci & Nele De Belie (2020) Addressing the need for standardization of test methods forself-healing concrete: an inter-laboratory study on concrete with macrocapsules, Science andTechnology of Advanced Materials, 21:1, 661-682,
DOI: 10.1080/14686996.2020.1814117
Keywords: Round robin test, self-healing concrete, standardization, macrocapsules, polyurethane, capillary water absorption, water permeability, active crack width control technique, machine learning
Affiliations:
Tim Van Mullem, Robby Caspeele, Kim Van Tittelboom & Nele De Belie: Magnel-Vandepitte Laboratory for Structural Engineering and Building Materials, Ghent University, Belgium
Giovanni Anglan, Paola Antonacii: Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Turin, Italy and Responsible Risk Resilience Centre, Politecnico di Torino, Turin, Italy
Marta Dudek, Arkadiusz Kwiecień, Teresa Stryszewska: Faculty of Civil Engineering, Cracow University of Technology, Cracow, Poland
Hanne Vanoutrive, Elke Gruyaert: Department of Civil Engineering, KU Leuven, Belgium
Girts Bumanis, Diana Bajare: Department of Building Materials and Products, Institute of Materials and Structures, Faculty of Civil Engineering, Riga Technical University, LV-Riga, Latvia
Chrysoula Litina, Abir Al-Tabbaa: Department of Engineering, University of Cambridge, Cambridge, UK
Tulliani Jean-Marc: INSTM Research Unit PoliTO-LINCE Laboratory, Department of Applied Science and Technology, Politecnico di Torino, Turin, Italy
The full article can be found here: https://doi.org/10.1080/14686996.2020.1814117
Self-healing concrete research in the European projects SARCOS and SMARTINCS
Nele De Belie, Kim Van Tittelboom, Mercedes Sánchez Moreno, Liberato Ferrara and Elke Gruyaert
Abstract: Self-healing concrete and preventive repair of structures will slow down the development of cracks and/or arrest the ingress of aggressive agents. When the cracks are closed or a decrease in crack width is achieved, this will be associated with improved durability of the structure. This paper describes the literature review and inter-laboratory comparison carried out within the COST Action CA15202 (SARCOS), as well as the research planned within the recently started International Training Network SMARTINCS.
Reference of this article: De Belie, N., Van Tittelboom, K., Sánchez Moreno, M., Ferrara, L., Gruyaert, E. (2021). Self-healing concrete research in the European projects SARCOS and SMARTINCS. Plenary keynote lecture. In: Sena-Cruz J., Correia L., Azenha M. (eds). Proceedings of the 3rd RILEM Spring Convention and Conference (RSCC2020). Volume 3: Service life extension of existing structures. University of Minho, Guimarães, Portugal, 9-10 March 2020. RILEM book series Vol. 34, p. 303-307. ISBN 978-3-030-76464-7, ISBN 978-3-030-76465-4 (eBook).
DOI: 10.1007/978-3-030-76465-4
Keywords: Self-healing Concrete, Repair, Durability, Healing Efficiency
Affiliations:
Nele De Belie, Kim Van Tittelboom: Magnel-Vandepitte Laboratory for Structural Engineering and Building Materials, Ghent University, Belgium
Mercedes Sánchez Moreno: Inorganic Chemistry Department, University of Córdoba, Spain
Liberato Ferrara: Department of Civil and Environmental Engineering, Politecnico di Milano, Italy
Elke Gruyaert: Department of Civil Engineering, KU Leuven, Belgium