Special Issue "Advanced High-Performance and Ultrahigh Performance Concrete Materials and Structures"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Construction and Building Materials".

Deadline for manuscript submissions: 31 March 2022.

Special Issue Editor

Prof. Dr. Moncef L. Nehdi
E-Mail Website
Guest Editor
Department of Civil and Environmental Engineering, Western University, London, ON N6B 5L9, Canada
Interests: construction materials; sustainability; machine learning; deep learning
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The annual cost of corrosion related damage in reinforced concrete structures worldwide exceeds five trillion dollars. Meanwhile, the cement and concrete industry has become a major consumer of natural resources and generator of greenhouse gas emissions. Hence, the sustainability and durability of concrete have gained strategic importance. Ultrahigh-performance concrete (UHPC) has recently emerged as a very promising solution for these challenges, considering its exceptional compressive strength, tensile ductility, and durability properties. Indeed, it is now possible to design and build UHPC structures that will never corrode, can sustain exposure in the harshest environments, and resist some of the most severe loading scenarios during their service life, while having a positive environmental footprint.

However, UHPC has not gained broad acceptance and integration into today’s construction market. To help overcome the hurdles facing the implementation of the UHPC technology, this Special Issue will highlight recent value-added contributions to the state-of-the-art and state of practice on UHPC. We seek high-quality research manuscripts addressing key UHPC aspects, including the following topics:

  • measurement and control of the rheology and early-age behavior of UHPC;
  • specialty materials and novel mixture proportioning;
  • nanostructure and advanced characterization of UHPC;
  • sustainability and novel binders with low-CO2 footprint;
  • mechanical performance under extreme loading, impact, blast, and fire;
  • durability in severe exposure environments;
  • life cycle assessment;
  • design principles and design guidance; applications of UHPC in bridges and buildings, precast concrete, repair and rehabilitation, seismic retrofit, field-cast connections, nuclear fuel and spent fuel storage and containment, etc.;
  • new predictive models for the behavior of UHPC, and other novel research that pushes the envelope of innovation and application of UHPC.
Prof. Dr. Moncef L. Nehdi
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • ultrahigh-performance concrete
  • rheology
  • early-age behavior
  • microstructure
  • mixture proportioning
  • mechanical load
  • durability
  • severe exposure
  • sustainability
  • life cycle analysis
  • design
  • application

Published Papers (5 papers)

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Research

Article
Elastic Restraint Effect of Concrete Circular Columns with Ultrahigh-Performance Concrete Jackets: An Analytical and Experimental Study
Materials 2021, 14(12), 3278; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14123278 - 14 Jun 2021
Viewed by 594
Abstract
Concrete circular columns are among the most common vertical load-bearing members in structural engineering. Because of the change of service loads or environmental factors, the strengthening of deteriorated members is often demanded to restore and maintain their performance. In view of the limitations [...] Read more.
Concrete circular columns are among the most common vertical load-bearing members in structural engineering. Because of the change of service loads or environmental factors, the strengthening of deteriorated members is often demanded to restore and maintain their performance. In view of the limitations of the traditional strengthening methods and the superior mechanical properties of the new material, ultra-high-performance concrete (UHPC), this study analyzed the stress–strain state of concrete circular columns confined by UHPC jackets under axial compression in the elastic stage. Since elastic analysis is the basis for the service limit state design, the elastic stress solution was derived through the theory of elasticity, and experimental verification of the effectiveness of the UHPC jackets in circular concrete columns was performed. Theoretical bases and references for practical strengthening works are provided. Full article
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Article
Mechanical Behavior of Ultrahigh-Performance Concrete Tunnel Lining Segments
Materials 2021, 14(9), 2378; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14092378 - 03 May 2021
Cited by 3 | Viewed by 564
Abstract
Ultrahigh-performance concrete (UHPC) is a novel material demonstrating superior mechanical, durability and sustainability performance. However, its implementation in massive structures is hampered by its high initial cost and the lack of stakeholders’ confidence, especially in developing countries. Therefore, the present study explores, for [...] Read more.
Ultrahigh-performance concrete (UHPC) is a novel material demonstrating superior mechanical, durability and sustainability performance. However, its implementation in massive structures is hampered by its high initial cost and the lack of stakeholders’ confidence, especially in developing countries. Therefore, the present study explores, for the first time, a novel application of UHPC, incorporating hybrid steel fibers in precast tunnel lining segments. Reduced scale curved tunnel lining segments were cast using UHPC incorporating hybrid 8 mm and 16 mm steel fibers at dosages of 1%, 2% and 3% by mixture volume. Flexural and thrust load tests were conducted to investigate the mechanical behavior of UHPC tunnel lining segments thus produced. It was observed that the flow of UHPC mixtures decreased due to steel fibers addition, yet steel fibers increased the mechanical and durability properties. Flexural tests on lining segments showed that both the strain hardening (multiple cracking) and strain softening (post-peak behavior) phases were enhanced due to hybrid addition of steel fibers in comparison with the control segments without fibers. Specimens incorporating 3% of hybrid steel fibers achieved 57% increase in ultimate load carrying capacity and exhibited multiple cracking patterns compared to that of identical UHPC segments with 1% fibers. Moreover, segments without fibers incurred excessive cracking and spalling of concrete at the base under the thrust load test. However, more stable behavior was observed for segments incorporating steel fibers under the thrust load, indicating its capability to resist typical thrust loads during tunnel lining field installation. This study highlights the potential use of UHPC with hybrid steel fibers for improved structural behavior. Moreover, the use of UHPC allows producing structural members with reduced cross-sectional dimensions, leading to reduced overall structural weight and increased clear space. Full article
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Article
Estimating CO2 Emission Savings from Ultrahigh Performance Concrete: A System Dynamics Approach
Materials 2021, 14(4), 995; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14040995 - 20 Feb 2021
Cited by 3 | Viewed by 601
Abstract
Ordinary Portland cement concrete (OPC) is the world’s most consumed commodity after water. However, the production of cement is a major contributor to global anthropogenic CO2 emissions. In recent years, ultrahigh performance concrete (UHPC) has emerged as a strong contender to replace [...] Read more.
Ordinary Portland cement concrete (OPC) is the world’s most consumed commodity after water. However, the production of cement is a major contributor to global anthropogenic CO2 emissions. In recent years, ultrahigh performance concrete (UHPC) has emerged as a strong contender to replace OPC in diverse applications. UHPC has much higher mechanical strength, and thus less material is used in a structural member to resist the same load. Moreover, it has a much longer service life, reducing the long-term need for repair and replacement of aging civil infrastructure. Thus, UHPC can enhance the sustainability of cement and concrete. However, there is currently no robust tool to estimate the sustainability benefits of UHPC. This task is challenging considering that such benefits can only be captured over the long-term since variables, such as population growth and cement demand per capita, become more uncertain. In addition, the problem of CO2 emissions from cement and concrete is a complex system affected by time-dependent feedback. The System Dynamics (SD) method has specifically been developed for modeling such complex systems. Accordingly, a SD model was developed in this study to test various pertinent policy scenarios. It is shown that UHPC can reduce cumulative CO2 emissions of cement and concrete—over the studied simulation period—by more than 17%. If supplementary cementitious materials are further deployed in UHPC and new technologies permit reducing the carbon footprint per unit mass of cement, emission savings can become more substantial. The model offers a flexible framework where the user controls various inputs and can extend the model to account for new data, without the need for reconstruction of the entire model. Full article
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Article
Predicting Ultra-High-Performance Concrete Compressive Strength Using Tabular Generative Adversarial Networks
Materials 2020, 13(21), 4757; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13214757 - 24 Oct 2020
Cited by 8 | Viewed by 822
Abstract
There have been abundant experimental studies exploring ultra-high-performance concrete (UHPC) in recent years. However, the relationships between the engineering properties of UHPC and its mixture composition are highly nonlinear and difficult to delineate using traditional statistical methods. There is a need for robust [...] Read more.
There have been abundant experimental studies exploring ultra-high-performance concrete (UHPC) in recent years. However, the relationships between the engineering properties of UHPC and its mixture composition are highly nonlinear and difficult to delineate using traditional statistical methods. There is a need for robust and advanced methods that can streamline the diverse pertinent experimental data available to create predictive tools with superior accuracy and provide insight into its nonlinear materials science aspects. Machine learning is a powerful tool that can unravel underlying patterns in complex data. Accordingly, this study endeavors to employ state-of-the-art machine learning techniques to predict the compressive strength of UHPC using a comprehensive experimental database retrieved from the open literature consisting of 810 test observations and 15 input features. A novel approach based on tabular generative adversarial networks was used to generate 6513 plausible synthetic data for training robust machine learning models, including random forest, extra trees, and gradient boosting regression. While the models were trained using the synthetic data, their ability to generalize their predictions was tested on the 810 experimental data thus far unknown and never presented to the models. The results indicate that the developed models achieved outstanding predictive performance. Parametric studies using the models were able to provide insight into the strength development mechanisms of UHPC and the significance of the various influential parameters. Full article
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Article
Mechanical Properties of Ultra-High Performance Concrete before and after Exposure to High Temperatures
Materials 2020, 13(3), 770; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13030770 - 07 Feb 2020
Cited by 17 | Viewed by 1137
Abstract
Compared with ordinary concrete, ultra-high performance concrete (UHPC) has excellent toughness and better impact resistance. Under high temperatures, the microstructure and mechanical properties of UHPC may seriously deteriorate. As such, we first explored the properties of UHPC with a designed 28-day compressive strength [...] Read more.
Compared with ordinary concrete, ultra-high performance concrete (UHPC) has excellent toughness and better impact resistance. Under high temperatures, the microstructure and mechanical properties of UHPC may seriously deteriorate. As such, we first explored the properties of UHPC with a designed 28-day compressive strength of 120 MPa or higher in the fresh mix phase, and measured its hardened mechanical properties at seven days. The test variables included: the type of cementing material and the mixing ratio (silica ash, ultra-fine silicon powder), the type of fiber (steel fiber, polypropylene fiber), and the fiber content (volume percentage). In addition to the UHPC of the experimental group, pure concrete was used as the control group in the experiment; no fiber or supplementary cementitious materials (silica ash, ultra-fine silicon powder) were added to enable comparison and discussion and analysis. Then, the UHPC-1 specimens of the experimental group were selected for further compressive, flexural, and splitting strength tests and SEM observations after exposure to different target temperatures in an electric furnace. The test results show that at room temperature, the 56-day compressive strength of the UHPC-1 mix was 155.8 MPa, which is higher than the >150 MPa general compressive strength requirement for ultra-high-performance concrete. The residual compressive strength, flexural strength, and splitting strength of the UHPC-1 specimen after exposure to 300, 400, and 500 °C did not decrease significantly, and even increased due to the drying effect of heating. However, when the temperature was 600 °C, spalling occurred, so the residual mechanical strength rapidly declined. SEM observations confirmed that polypropylene fibers melted at high temperatures, thereby forming other channels that helped to reduce the internal vapor pressure of the UHPC and maintain a certain residual strength. Full article
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

1. Title: Machine Learning Predictive Model for Properties of Ultra-High Performance Concrete

Authors: Moncef Nehdi and Afshin Marani

2. Title: System Dynamics Model for Sustainability of Ultra-High Performance Concrete

Authors: Moncef Nehdi and Rashid Rehan

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