Non-destructive evaluation of ductile-porous versus brittle 3D printed vascular networks in self-healing concrete
Yasmina Shields, Eleni Tsangouri, Claire Riordan, Cristina De Nardi, Jose Ricardo Assunção Godinho, Ticho Ooms, Paola Antonaci, Dave Palmer, Abir Al-Tabbaa, Tony Jefferson, Nele De Belie & Kim Van Tittelboom
Abstract: Vascular self-healing concrete is an innovative technology that can potentially improve the durability and longevity of concrete structures. However, limited research is available concerning this type of self-healing compared to intrinsic or capsule-based healing. As the rheology and curing properties of a healing agent can dictate the optimal design configuration of a vascular network, a series of testing procedures for evaluating healing agents is further explored. In this study, the suitability of various commercially available healing agents is considered using a vascular network system in mechanical loading and water absorption test set-ups. In this particular configuration, high sealing efficiencies were obtained for most of the healing agents used, and the polyurethanes and epoxy resin that were studied showed high load regain values. This work provides a testing methodology to select a healing agent in terms of its mechanical load regain, sealing efficiency, rheology, and curing properties, and can be used to determine a suitable healing agent for vascular healing applications.
Reference of this article:Yasmina Shields, Eleni Tsangouri, Claire Riordan, Cristina De Nardi, Jose Ricardo Assunção Godinho, Ticho Ooms, Paola Antonaci, Dave Palmer, Abir Al-Tabbaa, Tony Jefferson, Nele De Belie, Kim Van Tittelboom, Non-destructive evaluation of ductile-porous versus brittle 3D printed vascular networks in self-healing concrete, Cement and Concrete Composites, Volume 145, 2024, 105333, ISSN 0958-9465
Affiliations:
Yasmina Shields, Ticho Ooms, Nele De Belie and Kim Van Tittelboom: Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of Engineering and Architecture, Ghent University, Ghent, Belgium
Eleni Tsangouri: Dept. Mechanics of Materials and Constructions (MeMC), Vrije Universiteit Brussel (VUB), Brussels, Belgium
Claire Riordan and Dave Palmer: Micropore Technologies Ltd, Redcar, UK
Claire Riordan and Abir Al-Tabbaa: Department of Engineering, University of Cambridge, Cambridge, UK
Cristina De Nardi and Tony Jefferson: School of Engineering, Cardiff University, Wales, UK
Jose Ricardo Assunção Godinho: Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz Institute Freiberg for Resource Technology, Chemnitzer Straße 40, 09599, Freiberg, Germany
Paola Antonaci: Department of Structural, Geotechnical and Building Engineering, Politecnico di Torino, Turin, Italy
The full article can be found here: https://doi.org/10.1016/j.cemconcomp.2023.105333
Effect of microstructure heterogeneity shapes on constitutive behaviour of encapsulated self-healing cementitious materials
Sina Sayadi, Evan Ricketts, Erik Schlangen, Peter Cleall, Iulia Mihai and Anthony Jefferson
Abstract: Self-healing cementitious materials with microcapsules are complex multiscale and multiphase materials. The random microstructure of these materials governs their mechanical and transport behaviour. The actual microstructure can be represented accurately with a discrete lattice model, but computational restrictions mean that the size of domain that can be considered with this approach is limited. By contrast, a smeared approach, based on a micromechanical formulation, provides an approximate representation of the material microstructure with low computational costs. The aim of this paper is to compare simulations of a microcapsule-based self-healing cementitious system with discrete-lattice and smeared-micromechanical models, and to assess the relative strengths and weaknesses of these models for simulating distributed fracture and healing in this type of self-healing material. A novel random field generation technique is used to represent the microstructure of a cementitious mortar specimen. The meshes and elements are created by the triangulation method and used to determine the input required for the lattice model. The paper also describes the enhancement of the TUDelft lattice model to include self-healing behaviour. The extended micromechanical model considers both microcracking and healing. The findings from the study provide insight into the relative merits of these two modelling approaches.
Reference of this article: Effect of microstructure heterogeneity shapes on constitutive behaviour of encapsulated self-healing cementitious materials Sina Sayadi, Evan Ricketts, Erik Schlangen, Peter Cleall, Iulia Mihai, Anthony Jefferson MATEC Web Conf. 378 09004 (2023)
Affiliations:
Sina Sayadi, Evan Ricketts, Iulia Mihai and Anthony Jefferson: School of Engineering, Cardiff University, Cardiff CF24 3AA, UK
Erik Schlangen: Faculty of Civil Engineering and Geosciences, TUDelft, Delft 2628 CN, the Netherlands
The full article can be found here: http://dx.doi.org/10.1051/matecconf/202337809004
Sustainability and Economic Viability of Self-healing Concrete Containing Super Absorbent Polymers
Davide di Summa, Didier Snoeck, José Roberto Tenório Filho, Philip Van den Heede, Sandra Van Vlierberghe, Nele De Belie & Liberato Ferrara
Abstract: Recent studies highlighted the need to investigate the sustainability of innovative cement-based composites. In this regard, some works focused their attention on the use of Super Absorbent Polymers (SAPs) blended into the concrete matrix also employed to promote the autogenous healing, which can result into extended durability. In this study the Life Cycle Assessment (LCA) methodology takes into account the impacts associated to the whole service life of a structure. Thus, the eco-profile of a wall made up of concrete containing SAPs, was compared to the one of a reference wall without those additions. Four scenarios were considered to estimate the frequency of the repairing activities needed because of the chloride induced corrosion. Two corrosion models were adopted: a uniform one for scenarios 1 and 2, with a service life of 50 and 100 years respectively and the hemispherical pit model, for scenarios 3 and 4 with 50 and 100 years of service life as well. Additionally, a Life Cycle Cost (LCC) analysis was developed to investigate the overall costs. The results highlight the better performances for SAP-containing concrete with a reduction up to 11% for the overall costs and up to 55% for the environmental burdens.
Reference of this article:di Summa, D. et al. (2023). Sustainability and Economic Viability of Self-healing Concrete Containing Super Absorbent Polymers. In: Escalante-Garcia, J.I., Castro Borges, P., Duran-Herrera, A. (eds) Proceedings of the 75th RILEM Annual Week 2021. RW 2021. RILEM Bookseries, vol 40. Springer, Cham
Affiliations:
Davide di Summa, Didier Snoeck, José Roberto Tenório Filho, Philip Van den Heede, and Nele De Belie: Department of Structural Engineering and Building Materials, Ghent University, Magnel-Vandepitte Laboratory, Tech Lane Ghent Science Park, Campus A, Technologiepark Zwijnaarde 60, 9052, Ghent, Belgium
Sandra Van Vlierberghe: Department of Organic and Macromolecular Chemistry, Centre of Macromolecular Chemistry, Polymer Chemistry & Biomaterials Group, Ghent University, Krijgslaan 281, S4, 9000, Ghent, Belgium
Davide Di Summa, and Liberato Ferrara: Department of Civil and Environmental Engineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
José Roberto Tenório Filho: SIM vzw, Technologiepark Zwijnaarde 48, B-9052, Ghent, Belgium
The full article can be found here: https://doi.org/10.1007/978-3-031-21735-7_37
Effect of matrix self-healing on the bond-slip behavior of micro steel fibers in ultra-high-performance concrete
Salam Al-Obaidi, Shan He, Erik Schlangen, and Liberato Ferrara
Abstract: This study investigates the bond-slip behavior of micro steel fibers embedded into an Ultra-High-Performance Concrete (UHPC) matrix as affected by the self-healing of the same matrix in different exposure conditions. The UHPC matrix contains a crystalline admixture as a promoter of the autogenous self-healing specially added to enhance the durability in the cracked state. For the aforesaid purpose, some samples were partially pre-damaged with controlled preload (fiber pre-slip at different levels) and subjected to one-month exposure in 3.5% NaCl aqueous solution and in tap water to study the fiber corrosion, if any, and the effects of self-healing; after that, they were subjected to a pull-out test, to be compared with the behavior of analogous non-pre-slipped samples undergoing the same curing history. Moreover, some samples were cured in the chloride solution, intended to simulate a marine environment, to study the effect of marine curing on the pull-out behavior of steel fiber. The steel fiber corrosion and self-healing products attached to the surface of the steel fiber were analyzed via Scanning Electron Microscopy (SEM), and Energy -Dispersive Spectroscopy (EDS). The results indicate that the newly healed particles formed on the highly damaged fiber-matrix interface significantly enhance the friction phase of the bond-slip behavior and result in a significant residual capacity compared to non-pre-slipped specimens. On the other hand, the self-healing effect in specimens subjected to low damage pre-slip contributed more to the chemical adhesion region of the bond-slip behavior. Owning to the dense microstructure of the matrix, curing in 3.5% NaCl aqueous solution was not found to significantly affect the pull-out resistance as compared to the samples cured in tap water.
Reference of this article: Al-Obaidi, S., He, S., Schlangen, E. et al. Effect of matrix self-healing on the bond-slip behavior of micro steel fibers in ultra-high-performance concrete. Mater Struct 56, 161 (2023).
Affiliations:
Salam Al-Obaidi and Liberato Ferrara: Department of Civil and Environmental Engineering, Politecnico Di Milano, Piazza Leonardo DaVinci 32, 20133 Milan, Italy
Salam Al-Obaidi: Roads and Transportations Engineering Department, University of Al-Qadisiyah, Diwaniyah 58001, Iraq
Salam Al-Obaidi, Shan He and Erik Schlangen: Department of Civil Engineering and Geoscience, Delft University of Technology, 2628, CN, Delft, The Netherlands
The full article can be found here: https://doi.org/10.1617/s11527-023-02250-5
Microstructural characterization of crack-healing enabled by bacteria-embedded polylactic acid (PLA) capsules
Shan He, Zhi Wan, Yu Chen, Henk M. Jonkers and Erik Schlangen
Abstract: The current study investigates short-term and long-term crack-healing behaviour of mortars embedded with bacteria-based poly-lactic acid (PLA) capsules under both ideal and realistic environmental conditions. Two sets of specimens were prepared and subjected to different healing regimes, with the first set kept in a mist room for varying short durations (i.e., 1 week, 2 weeks, 3 weeks and 8 weeks) and the second set placed in an unsheltered outdoor environment for a long-term healing process (i.e., 1 year). Alteration of microstructure because of self-healing was characterized by backscattered electron (BSE) imaging and energy dispersive X-ray spectroscopy (EDS) via crack cross-sections. Results show that visible crack healing enabled by bacteria began after 2 weeks in a humid environment. The healing products initially precipitated at crack mouths and gradually moved deeper into cracks, with the precipitated calcium carbonate crystals growing larger over time. After 8 weeks, healing products can be found even a few millimetres deep inside cracks. Observations of crack healing in a realistic environment revealed significant differences compared to healing under controlled conditions. While no healing products can be found at crack mouths, a substantial healing process was observed throughout the entire crack depth. It is likely that the environmental actions such as rainfall and/or freeze and thaw cycles may have worn away the healing products at crack mouths and thus led to a deeper ingress of oxygen into cracks, which promoted the activation of healing agents and associated calcium carbonate precipitation deep inside a crack.
Reference of this article: Shan He, Zhi Wan, Yu Chen, Henk M. Jonkers, Erik Schlangen, Microstructural characterization of crack-healing enabled by bacteria-embedded polylactic acid (PLA) capsules, Cement and Concrete Composites, Volume 143, 2023, 105271, ISSN 0958-9465
Affiliations:
Shan He, Zhi Wan, Yu Chen, Henk M. Jonkers and Erik Schlangen: Microlab, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, the Netherlands
The full article can be found here: https://doi.org/10.1016/j.cemconcomp.2023.105271