Evaluation of the self-healing capacity of concrete with low-cost macro-capsules
Niranjan Prabhu Kannikachalam, Emmanuel Cailleux, Nele De Belie Liberato Ferrara & Liberato Ferrara
Abstract: This study focuses on the evaluation of the efficiency of a low-cost macrocapsule, using commercially available pharmaceutical capsules with specific modifications, for self-healing concrete. The macrocapsules were developed by the Belgian Building Research Institute in a previous study. The healing agent is a resin based on alkyd-urethane, a low-cost commercial product, which was selected for its compatibility with concrete and shell, and also for the following reasons: resin release, adhesion to concrete, and reduction in capillary water absorption. After their manufacturing, the macrocapsules were carefully integrated within the concrete mix at 5 volume-%, and cubes and slabs for compressive and impact tests were cast. Small beams 160 x 40 x 40 mm3 containing each three capsules (placed 15 mm above the bottom surface) were tested for flexural strength and capillary water absorption. The effect of self-healing was evaluated by sorptivity test for two different crack mouth opening displacements of 0.5 mm and 0.9 mm. In both cases, the cracks were partially or completely healed, and the mechanical properties of the macrocapsule specimens were quite the same as the reference specimens. This demonstrates that the modified low-cost macrocapsules are sufficient to heal large cracks without losing the concrete mechanical properties.
Reference of this article:Evaluation of the self-healing capacity of concrete with low-cost macro-capsules Niranjan Prabhu Kannikachalam, Emmanuel Cailleux, Nele De Belie and Liberato Ferrara MATEC Web Conf., 378 (2023) 02015
Affiliations:
Niranjan Prabhu Kannikachalam,and Liberato Ferrara: Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy
Niranjan Prabhu Kannikachalam and Nele De Belie: Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of Engineering and Architecture,
Ghent University, Ghent, Belgium
Emmanuel Cailleux: Buildwise (previously BBRI: Belgian Building Research Institute), Research Facility, Limelette, Belgium
The full article can be found here: https://doi.org/10.1051/matecconf/202337802015
A comparison of potential healing agents for vascular-based self-healing concrete
Yasmina Shields, Vanessa Cappellesso, Tim Van Mullem, Kim Van Tittelboom & Nele De Belie
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:A comparison of potential healing agents for vascular-based self-healing concrete Yasmina Shields, Vanessa Cappellesso, Tim Van Mullem, Nele De Belie and Kim Van Tittelboom MATEC Web Conf., 378 (2023) 02026
Affiliations:
Yasmina Shields, Vanessa Cappellesso, Tim Van Mullem, Kim Van Tittelboom and Nele De Belie: Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of Engineering and Architecture,
Ghent University, Ghent, Belgium
Vanessa Cappellesso: Department of Civil Engineering, Materials and Constructions, KU Leuven, Ghent, Belgium
The full article can be found here: https://doi.org/10.1051/matecconf/202337802026
Repair of Concrete in Environments with Chlorides or Subjected to Freeze-Thaw Scaling
Vanessa Cappellesso, Tim Van Mullem, Elke Gruyaert, Kim Van Tittelboom & Nele De Belie
Abstract: Crack formation further decreases the durability of structures when chloride ions associated with freezing temperatures are present. Therefore, preventing the entry of aggressiveness is imperative to guarantee the service life. Repair actions might recover the liquid-tightness when cracks occur. A water repellent agent (WRA) and a sodium silicate (SS) solution were applied to self-repair cracks in the current research. The repair occurred by manual injection of cracks to obtain a proof-of-concept for the possible self-healing efficiency. Two extreme conditions have been assessed after the healing period, the first referring to continuous immersion in a chloride solution, and the second applying freeze-thaw conditions with de-icing salts. Chloride ingress was evaluated through the colour change boundary test. In addition, optical microscopy analysis was used to measure the crack width and to observe differences before and after exposure. SS prevented the chloride ingress through the crack in both conditions. However, the method used to verify chloride ingress did not give consistent results for the WRA due to its hydrophobicity. Microscopic analysis showed that both agents could avoid chloride ingress in the cracks. For the samples exposed to freeze-thaw cycles, only chloride ingress measurement could indicate the healing performance as the scaling destroyed the surface.
Reference of this article: Cappellesso, V.G., Van Mullem, T., Gruyaert, E., Van Tittelboom, K., De Belie, N. (2023). Repair of Concrete in Environments with Chlorides or Subjected to Freeze-Thaw Scaling. 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:
Vanessa Cappellesso, Tim Van Mullem, Kim Van Tittelboom and Nele De Belie: Magnel-Vandepitte Laboratory, Department of Structural Engineering and Building Materials, Faculty of Engineering and Architecture,
Ghent University, Ghent, Belgium
Vanessa Cappellesso and Elke Gruyaert: Department of Civil Engineering, Materials and Constructions, KU Leuven, Ghent, Belgium
The full article can be found here: https://doi.org/10.1007/978-3-031-21735-7_25
Bond behaviour evaluation between steel reinforcement and self-healing concrete containing non-axenic biomasses
Harry Hermawan, Mustafa Mert Tezer, Willy Verstraete, Nele De Belie, Pedro Serna and Elke Gruyaert
Abstract: Although steel reinforcements are used to withstand tensile forces in concrete, cracks are an unavoidable phenomenon. The presence of cracks, in fact, increases the risk for lowering the service life and durability of concrete structures. A critical issue occurs when due to splitting forces, cracks appear in concrete along the tensioned rebars which damage the bonding between the steel and concrete matrix. As a mitigation plan, the cracks should be healed at short notice and the bonding has to be recovered by the potential use of healing agents. This paper aims to investigate the bond behaviour of steel reinforcement in self-healing concrete. Two biomasses were employed as healing agents namely HTN (bacteria-based) and YEAST (fungi-based). The fresh and hardened properties of the normal and self-healing concretes were initially evaluated. The bond properties were investigated by performing pull-out tests on three different states of concrete: uncracked, cracked, and healed. Results revealed that the additions of biomasses did not induce negative effects on the compressive strength of hardened concrete. Moreover, the average bond strength of uncracked concretes containing HTN and YEAST improved by 20% and 8%, respectively, as compared with normal concrete. The introduction of a crack caused a significant reduction in bond strength regardless of the addition of healing agents. Nevertheless, it was found that the bond strength was slightly recovered after healing under water immersion.
Reference of this article: Bond behaviour evaluation between steel reinforcement and self-healing concrete containing non-axenic biomasses Harry Hermawan, Mustafa Mert Tezer, Willy Verstraete, Nele de Belie, Pedro Serna, Elke Gruyaert MATEC Web Conf. 378 02009 (2023)
Affiliations:
Harry Hermawan and Elke Gruyaert: KU Leuven, Ghent Technology Campus, Department of Civil Engineering, Materials and Constructions, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium
Harry Hermawan and Pedro Serna: Instituto de Ciencia y Tecnología Del Hormigón (ICITECH), Universitat Politècnica de València, Camino de Vera S/n, 46022, Valencia, Spain
Mustafa Mert Tezer and Nele De Belie Ghent University, Department of Structural Engineering and Building Materials, Magnel-Vandepitte Laboratory, Tech Lane Ghent Science Park, Campus A, Technologiepark Zwijnaarde 60, B-9052, Ghent, Belgium
Mustafa Maer Tezer and Willy Verstraete: AVECOM nv, Industrieweg 122P, 9032 Wondelgem, Belgium
The full article can be found here: https://doi.org/10.1051/matecconf/202337802009
Applicability of cementitious capsules in concrete production: initial assessment on capsule robustness, mechanical and self-sealing properties of concrete
Harry Hermawan, Alicia Simons, Silke Teirlynck, Pedro Serna, Peter Minne, Giovanni Anglani, Jean-Marc Tulliani, Paola Antonaci and Elke Gruyaert
Abstract: The use of macrocapsules in self-healing applications offers a potential benefit by carrying a larger amount of healing agent in comparison with microcapsules. However, the application of macrocapsules is still limited to paste and mortar levels on lab-scale. This is due to a concern that most capsules might be broken when mixed with concrete components. In this study, cementitious tubular capsules were used and they were considered as a partial replacement of coarse aggregates (2 vol% gravel). The capsules have a dimension of 54 mm and 9 mm in length and outer diameter, respectively. A water-repellent agent (WRA) was entrapped in the capsules as a proposed agent to seal the crack. Initial results revealed high survivability of capsules during concrete mixing: 100% survival ratio when tested in a drum mixer and 70–95% when tested in a planetary mixer. The mechanical and self-sealing properties of concrete containing embedded capsules were evaluated. With the addition of capsules, around 8% reduction of compressive strength was noticed, but no further effect on splitting tensile strength was detected as compared with concrete without capsules. Ultrasonic pulse velocity (UPV) tests confirmed that the presence of capsules also did not significantly affect the compactness of the hardened concrete. Furthermore, the embedded capsules were able to break when a crack was introduced and it was found that 90% sealing efficiency was achieved by capsule-based concrete as a result of the successful release of sealing agent into the crack.
Reference of this article: Applicability of cementitious capsules in concrete production: initial assessment on capsule robustness, mechanical and self-sealing properties of concrete Harry Hermawan, Alicia Simons, Silke Teirlynck, Pedro Serna, Peter Minne, Giovanni Anglani, Jean-Marc Tulliani, Paola Antonaci and Elke Gruyaert MATEC Web Conf., 378 (2023) 02013
Affiliations:
Harry Hermawan, Alicia Simons, Silke Teirlynck, Peter Minne and Elke Gruyaert: KU Leuven, Ghent Technology Campus, Department of Civil Engineering, Materials and Constructions, 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
Giovanni Anglani and Paola Antonaci: Department of Structural, Geotechnical and Building Engineering (DISEG), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
Jean-Marc Tulliani: INSTM Research Unit PoliTO-LINCE Laboratory, Department of Applied Science and Technology (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
The full article can be found here: https://doi.org/10.1051/matecconf/202337802013