Towards a more sustainable construction industry: Bridging the gap between technical progress and commercialization of self-healing concrete
Laís Bandeira Barros, Mirjam Knockaert, & José Roberto Tenório Filho
Abstract: The construction sector has a large impact on the environment due to greenhouse gas emissions and the large use of natural resources. For this reason, several initiatives and action plans are developed and implemented in Europe, under the impulse of the European Commission, to foster the market of sustainable construction. The goal is to use smarter and more durable materials in order to decrease CO2 emissions in the production stage and prolong the service life of infrastructure. In this regard, significant research has been performed into the development of self-healing technologies for concrete. By improving concrete durability and, therefore, increasing the service life of construction structures, self-healing concrete can have a positive impact on the environment and the economy. Despite a growth of research interest, the focus has so far mostly been on the technical aspects of self-healing concrete. More holistic approaches, which consider the process from technical progress to commercialization have been relatively neglected. To fulfil this need, this study examines the commercialization of self-healing concrete, identifying the hurdles and facilitators along its value chain through semi-structured interviews with stakeholders. The value chain has four stages: (1) R&D, (2) technology manufacturing, (3) distribution and (4) use in construction. We identify the lack of real scale demonstration projects as one of the most important hurdles. This hurdle is relevant in the R&D stage, as such also affecting the other stages. At the same time, there is a consensus that the greatest facilitator to draw the market’s attention to the commercialization of self-healing concrete is the increasing demand towards more sustainable materials. Our study includes an overview of the actions that can be undertaken to reduce the impact of the hurdles and enhance the deployment of self-healing concrete in the construction industry.
Reference of this article: Laís Bandeira Barros, Mirjam Knockaert, José Roberto Tenório Filho, Towards a more sustainable construction industry: Bridging the gap between technical progress and commercialization of self-healing concrete, Construction and Building Materials, Volume 403, 2023, 133094, ISSN 0950-0618
Affiliations:
Laís Bandeira Barros and Mirjam Knockaert: Ghent University, Department of Marketing, Innovation and Organisation, Faculty of Economics and Business Administration, Tweekerkenstraat 2, Ghent 9000, Belgium
Mirjam Knockaert: Technical University Munich, Entrepreneurship Research Institute, Arcisstraße 21, 80333 Munich, Germany
José Roberto Tenório Filho: Ghent University, Department of Structural Engineering and Building Materials, Technologiepark-Zwijnaarde 60, Ghent B-9052, Belgium
The full article can be found here: https://doi.org/10.1016/j.conbuildmat.2023.133094
Novel production of macrocapsules for self-sealing mortar specimens using stereolithographic 3D printers
Claire Riordan, Giovanni Anglani, Barbara Inserra, Dave Palmer, Abir Al-Tabbaa, Jean-Marc Tulliani and Paola Antonaci
Abstract: The use of capsule-based technology for self-sealing and self-healing cementitious systems has been extensively investigated for both macro- and microencapsulated additions. In this study, macrocapsules, produced using a novel technique were characterised and compared, evaluating mechanical triggering, bonding with the cementitious matrix, and self-sealing efficiency upon integration into cementitious mortar specimens. Macrocapsules containing a commercially available water repellent agent were produced in two ways. Stereolithographic additive manufacturing (3D printing) was used to produce novel rigid acrylate macrocapsules as well as alumina ones. Cementitious macrocapsules produced with a rolling technique were also used as a comparison. The capsules were characterised in terms of watertightness, water uptake, and shell morphology. Following this, the capsules were integrated into cement mortar prisms and subjected to controlled cracking by three-point bending to evaluate the triggering and subsequent self-sealing effect. The results highlighted influential process parameters that can be optimised and explored for further capsule-based self-sealing in structural applications.
Reference of this article: Claire Riordan, Giovanni Anglani, Barbara Inserra, Dave Palmer, Abir Al-Tabbaa, Jean-Marc Tulliani, Paola Antonaci, Novel production of macrocapsules for self-sealing mortar specimens using stereolithographic 3D printers, Cement and Concrete Composites, Volume 142, 2023, 105216, ISSN 0958-9465
Affiliations:
Claire Riordan and Abir Al-Tabbaa: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
Dave Palmer: Micropore Technologies Ltd, Wilton Centre, Redcar, TS10 4RF, UK
Giovanni Anglani and Paola Antonaci: Department of Structural, Geotechnical and Building Engineering (DISEG), Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129, Turin, Italy
Barbara Inserra and Jean-Marc Tulliani : Department of Applied Science and Technology, Politecnico di Torino, INSTM R.U. Lince Laboratory, Corso Duca Degli Abruzzi 24, 10129, Turin, Italy
Corresponding author:
The full article can be found here: https://doi.org/10.1016/j.cemconcomp.2023.105216
PVDF-based coatings with CNT additions for strain monitoring of mortar substrates subjected to bending
Gabriele Milone, Jean-Marc Tulliani and Abir Al-Tabba
Abstract: Sensing coatings are rapidly entering the field of non-destructive tests. While cement-based composites are proving an excellent interaction with new/recent structures, polymer-based coatings, already employed for structural retrofitting purposes, can provide a valuable alternative. This study investigated the production, application, and use of poly(vinylidene fluoride) (PVDF) coatings. A 10w/v% PVDF-to-solvent ratio became the best trade-off between electrical conductivity and bond strength with the substrate. Different concentrations of Carbon Nanotubes (CNT) were investigated: 0.05, 0.10, 0.25, 0.50, and 0.75% by weight of PVDF. The conductive PVDF-CNT composites were brushed on the casted mortar beams with screws embedded as electrodes. The mortar beams and attached polymer coatings were then subjected to bending stress. The Gauge Factor was obtained by comparing the substrate’s strain with the coating’s electric response. The sensing intervals in the Fractional Change of Resistance-strain curves varied in relation to the CNT concentration. For instance, adding 0.50w/v% of CNT gave the highest sensitivity up to 0.2‰ strain, followed by a lower – still sufficient – gauge factor. PVDF-based coatings with CNT additions of 0.25 and 0.75w/v% witnessed a comparable sensing performance in the same strain limits, abruptly increasing and finally stabilizing to a low gauge factor. In contrast, both 0.05 and 0.10w/v% resulted in a low monitoring potential overall. The varying sensing zones experienced by the coating were attributed to the microscopical behavior of CNT within the PVDF matrix. In conclusion, the results highlighted the potentiality of polymeric coatings for sensing, monitoring, and inspection of concrete structures.
Reference of this article: PVDF-based coatings with CNT additions for strain monitoring of mortar substrates subjected to bending Gabriele Milone, Jean-Marc Tulliani and Abir Al-Tabbaa MATEC Web Conf., 378 (2023) 05001
Affiliations:
Gabriele Milone and Abir Al-Tabbaa: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK
Jean-Marc Tulliani: Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin 10129, Italy
The full article can be found here: https://doi.org/10.1051/matecconf/202337805001
Structural performance of reinforced concrete beams with self-healing cover zone
Shan He, Mladena Luković, Henk Jonkers and Erik Schlangen
Abstract: In the current study, experiments were carried out to investigate the structural performance of reinforced concrete (RC) beams with a self-healing cover zone. The cover zone consists of a 1.5-cm-thick layer of bacteria-embedded strain hardening cementitious composite (SHCC) for a combination of crack width control and crack healing. The aim is to bring together two emerging technologies (i.e., self-healing and strain-hardening) that show great potential for realizing highly efficient concrete structures. RC beam without the self-healing cover was also prepared as the control specimen for comparison purposes. The experimental program includes loading the beams to failure in four-point bending configuration and sawing the beams to segments for crack pattern analysis and crack healing. Results show that the beams with selfhealing cover exhibited a 45-60% improvement in structural capacity. The crack patterns of the hybrid beams were also largely modified. While the reference beam formed only a few major cracks, the hybrid beams formed around 40 fine cracks in the constant bending moment region with an average crack width smaller than 0.2 mm even at maximum load. By having an improved cracking behavior and an enhanced self-healing capacity, it is expected that the beams with a self-healing cover will possess an extended service life at the expense of minimal additional cost.
Reference of this article: Structural performance of reinforced concrete beams with self-healing cover zone Shan He, Mladena Luković, Henk Jonkers and Erik Schlangen MATEC Web Conf., 378 (2023) 08004
Affiliations:
Shan He, Henk Jonkers and Erik Schlangen: Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft 2628 CN, the Netherlands
Mladena Luković: Concrete Structures, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2628 CN, Delft, The Netherlands
The full article can be found here: https://doi.org/10.1051/matecconf/202337808004
Strain Hardening Cementitious Composite in Reinforced Concrete Cover Zone for Crack Width Control
Shan He, Mladena Luković and Erik Schlangen
Abstract: In the current study, experiments were carried out to investigate the cracking behaviour of reinforced concrete beams consisting of 1-cm-thick layer of Strain Hardening Cementitious Composite (SHCC) in the concrete cover zone. The hybrid SHCC/concrete beams with different types of interfaces were tested and compared with control reinforced concrete beams without a SHCC layer. A new SHCC/concrete interface that features a weakened chemical adhesion but an enhanced mechanical bonding was also developed to facilitate the activation of SHCC. The beams were tested in four-point bending configuration, while Digital Image Correlation (DIC) was used to evaluate crack pattern development and crack widths. Results show that hybrid beams possessed similar load bearing capacity but exhibited an improved cracking behaviour as compared to the control beam. The maximum crack width of the best performing hybrid beams exceeded 0.3 mm at approximately 53.3 kN load, whereas in the control beam it exceeded 0.3 mm at only 32.5 kN load. It is thus expected that the hybrid beams developed in the current study will possess an improved durability and enhanced self-healing potential as a result of having smaller cracks, leading to an extended service life at the expense of minimal additional cost.
Reference of this article: He, S., Luković, M., Schlangen, E. (2023). Strain Hardening Cementitious Composite in Reinforced Concrete Cover Zone for Crack Width Control. In: Ilki, A., Çavunt, D., Çavunt, Y.S. (eds) Building for the Future: Durable, Sustainable, Resilient. fib Symposium 2023. Lecture Notes in Civil Engineering, vol 349. Springer, Cham.
Affiliations:
Shan He and Erik Schlangen: Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft 2628 CN, the Netherlands
Mladena Luković: Concrete Structures, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2628 CN, Delft, The Netherlands
The full article can be found here: https://doi.org/10.1007/978-3-031-32519-9_115