Assessment of Sustainability and Self-Healing Performances of Recycled Ultra-High-Performance Concrete
Abstract: This research focuses on the evaluation of the sustainability of recycled ultra-high-performance concrete (R-UHPC) in a life cycle analysis (LCA) perspective, and with reference to a case study example dealing with structures exposed to extremely aggressive environments. This involves the assessment of the self-healing capacity of R-UHPC, as guaranteed by the R-UHPC aggregates themselves. Recycled aggregates (RA) were created by crushing 4-month-old UHPC specimens with an average compressive strength of 150 MPa. Different fractions of recycled aggregates (0 to 2 mm) and two different percentages (50 and 100%) were used as a substitute for natural aggregates in the production of R-UHPC. Notched beam specimens were pre-cracked to 150 μm using a three-point flexural test. The autogenous self-healing potential of R-UHPC, stimulated by the addition of a crystalline admixture, was explored using water absorption tests and microscopic crack healing at a pre-determined time (0 days, 1 month, 3 months, and 6 months) following pre-cracking. Continuous wet/ dry healing conditions were maintained throughout the experimental campaign. The specimens using R-UHPC aggregates demonstrated improved self-healing properties to those containing natural aggregates, especially from the second to the sixth month. To address the potential environmental benefits of this novel material in comparison to the conventional ones, an LCA analysis was conducted adopting the 10 CML-IA baseline impact categories, together with a life cycle cost (LCC) analysis to determine the related economic viability. Both LCA and LCC methodologies are integrated into a holistic design approach to address not only the sustainability concerns but also to promote the spread of innovative solutions for the concrete construction industry. As a case study unit, a basin for collection and cooling of geothermal waters was selected. This is representative of both the possibility offered, in terms of structural design optimization and reduction of resource consumption, and of reduced maintenance guaranteed by the retained mechanical performance and durability realized by the self-healing capacity of R-UHPC.
Reference of this article: Niranjan Prabhu Kannikachalam, Davide di Summa, Ruben P Borg, Estefaia Cueca Asensio, Matteo Parpanesi, Nele De Belie and Liberato Ferrara, Assessment of Sustainability and Self-Healing Performances of Recycled Ultra-High-Performance Concrete, ACI Materials Journal, V. 120, No. 1, January 2023, DOI:10.14359/51737336.
Niranjan Prabhu Kannikachalam, Ruben P Borg, Estefaia Cueca Asensio, Matteo Parpanesi, and Liberato Ferrara: Politecnico di Milano, Department of Civil and Environmental Engineering, piazza Leonardo da Vinci 32, 20133 Milan, Italy
Davide Di Summa, 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
Fatigue behavior and effect of stimulated autogenous self-healing in Ultra High-Performance Concrete
Abstract: This paper investigates the mechanical response under fatigue cycles in Ultra-High-Performance Con- crete (UHPC) under four-point flexural loading, focusing on the effect of damage recovery triggered by stimulated autogenous self-healing. Thin beam specimens were pre-cracked up to 0.25 mm residual crack opening displacement under monotonic loading and then subjected to cyclic loading with a fre- quency of 5.5 Hz and a load amplitude equal to 10-80% of the load corresponding to the load at residual pre-crack width. Cyclic loading was applied for 700,000 cycles or up to the attainment of 1 mm total crack opening displacement at maximum load, whichever was reached first. Specimens were then healed underwater, and the fatigue tests were repeated to failure after the scheduled healing period of 1, 3, or 6 months. Self-healing performance was assessed via ultrasonic pulse velocity test and micro- scopic image analysis. Furthermore, the effects of self-healing in fatigue-crack growth rate, stiffness degradation, and critical crack opening were identified together with the benefits brought in as residual fatigue life recovery. The three-month healed specimens showed up to twenty times reduction in the rate of crack opening displacement as compared to the same specimen before the healing period.
Reference of this article: Niranjan Prabhu Kannikachalam, David Alejandro Clerque Vela, Yanira Ginori Ocampo Pacheco, Francesco Lo Monte, Nele De Belie Liberato Ferrara & Liberato Ferrara Proc. of the 14th fib International PhD Symposium in Civil Engineering Sep. 5 to 7, 2022, Rome, Italy, pages 297-304 ISBN: 978-2-940643-17-2
Niranjan Prabhu Kannikachalam, David Alejandro Clerque Vela, Yanira Ginori Ocampo Pacheco, Francesco Lo Monte 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
Chapter 8: Contextualizing technology transfer: a review of university-industry transfer in the construction industry
Abstract: In this chapter, we take a business-related contextual perspective into the technology transfer literature, and focus specifically on understanding what we know and what is still to be explored in terms of technology transfer in the construction industry. We take the construction industry as a representing an interesting setting for a review with a contextual dimension for several reasons, like, at least in Europe, the construction industry has often been considered a mature, traditional industry, often conservative and attached to familiar technology, but heavily challenged by an increased global competition, urging the firms in this industry to engage in innovation. Furthermore, next to synthesizing current knowledge, and contrasting it to the tech transfer literature in general, this chapter also presents a research agenda for future research into this intriguing field.
Reference of this article:Bandeira Barros, L., Knockaert, M., & Lecluyse, L. (2022). "Chapter 8: Contextualizing technology transfer: a review of university-industry transfer in the construction industry". In Handbook of Technology Transfer. Cheltenham, UK: Edward Elgar Publishing. Retrieved May 8, 2023
Effect of healing agents on the rheological properties of cement paste and compatibility with superplasticizer
Abstract: Self-healing concrete is considered as a new generation of concrete with the ability to heal cracks without human intervention. The healing agents are incorporated into the concrete to activate the healing mechanism and to improve the healing efficiency. While both lab- and large-scale projects have shown that the addition of healing agents can have a possible positive effect on the hardened concrete properties (e.g. compressive strength), unfortunately, the evaluation of fresh properties of self-healing concrete mixes is often neglected. In the current study, the effect of healing agents is clearly identified starting from the paste level. Different techniques were used to study the effect of healing agents on the consistency, viscosity and adsorption behaviour of PCE-based superplasticizer in cement paste. A crystalline admixture and bacteria were used as healing agents, and CEM III/A was used as the binder component of the paste. The results showed that the inclusion of bacteria did not influence the rheological properties of the cement paste and no incompatibility issues were found with the superplasticizer. On the other hand, the presence of the crystalline admixture in the paste interfered with the rheological properties of the cement paste as a reduction of workability, an increase of paste viscosity, and an increased adsorption of superplasticizer.
Reference of this article: Effect of healing agents on the rheological properties of cement paste and compatibility with superplasticizer Harry Hermawan, Guadalupe Sierra Beltran, Virginie Wiktor, Pedro Serna, Elke Gruyaert MATEC Web Conf. 361 05008 (2022)
Harry Hermawan and Elke Gruyaert: KU Leuven, Ghent Technology Campus, Department of Civil Engineering, Materials and Constructions, Gebroeders De Smetstraat 1, 9000 Ghent, Belgium
Guadalupe Sierra Beltran and Virginie Wiktor: Cugla B.V., R&D center, Rudonk 6b, 4824 AJ Breda, the Netherlands
Pedro Serna: Instituto de Ciencia y Tecnología Del Hormigón (ICITECH), Universitat Politècnica de València, Camino de Vera S/n, 46022, Valencia, Spain
A review of the efficiency of self-healing concrete technologies for durable and sustainable concrete under realistic conditions
Abstract: Self-healing is recognized as a promising technique for increasing the durability of concrete structures by healing cracks, thereby reducing the need for maintenance activities over the service life and decreasing the environmental impact. Various self-healing technologies have been applied to a wide range of cementitious materials, and the performance has generally been assessed under ‘ideal’ laboratory conditions. Performance tests under ideal conditions, tailored to the self-healing mechanism, can demonstrate the self-healing potential. However, there is an urgent need to prove the robustness and reliability of self-healing under realistic simulated conditions and in real applications before entering the market. This review focuses on the influence of cracks on degradation phenomena in reinforced concrete structures, the efficiency of different healing agents in various realistic (aggressive) scenarios, test methods for evaluating self-healing efficiency, and provides a pathway for integrating self-healing performance into a life-cycle encompassing durability-based design.
Reference of this article: Vanessa Cappellesso, Davide di Summa, Pardis Pourhaji, Niranjan Prabhu Kannikachalam, Kiran Dabral, Liberato Ferrara, Maria Cruz Alonso, Esteban Camacho, Elke Gruyaert & Nele De Belie (2023): A review of the efficiency of self-healing concrete technologies for durable and sustainable concrete under realistic conditions, International Materials Reviews, DOI: 10.1080/09506608.2022.2145747
Vanessa Cappellesso, Davide di Summa, 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
Vanessa Cappellesso and Elke Gruyaert: Department of Civil Engineering, Materials and Constructions, KU Leuven, Ghent, Belgium
Davide di Summa, Niranjan Prabhu Kannikachalam and Liberato Ferrara: Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy
Pardis Pourhaji and Maria Cruz Alonso: Consejo Superior de Investigaciones Científicas, Instituto Eduardo Torroja de Ciencias de la Construcción (CSIC-IETcc), Madrid, Spain
Kiran Dabral and Esteban Camacho: Research and Development Concretes, València, Spain