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19 pages, 2491 KB

Open AccessArticle

Effect of Waste Glass Incorporation Methods on the Physical, Mechanical and Microstructural Properties of Cementitious Binders

by Jurgita Malaiškienė, Karolina Bekerė and Jelena Škamat

Materials 2026, 19(7), 1346; https://doi.org/10.3390/ma19071346 - 28 Mar 2026

Viewed by 433

Abstract

In previous studies, it was established that replacing cement with dispersed glass from various electronic and household devices is challenging due to the formation of agglomerates in the mixture. Therefore, this study addresses this problem by applying different methods for incorporating dispersed glass: [...] Read more.

In previous studies, it was established that replacing cement with dispersed glass from various electronic and household devices is challenging due to the formation of agglomerates in the mixture. Therefore, this study addresses this problem by applying different methods for incorporating dispersed glass: mixing in a conventional Hobart-type mixer, mixing dry components in an intensive Eirich-type mixer, and dispersing the glass particles in water using ultrasonic treatment. Using these 3 glass waste incorporation methods, the properties of hardened cement paste—density, compressive strength, phase composition, and microstructure—were compared. The effects of 4 types of glass (from television screens, washing machines, fluorescent lamps, and solar panels) were analysed. The results showed that lamp glass dispersed in water with ultrasound showed the best performance, while for the other glass types, intensive mixing was more effective. Under these conditions, the compressive strength of the samples increased by up to approximately 24%, and a denser microstructure was obtained compared to other glass incorporation methods. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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16 pages, 3613 KB

Open AccessArticle

Layer Bond Strength in 3D-Printed Concrete: The Role of Interlayer Surface Area and Printing Delay Time

by Nikol Žižková, Josef Válek, Arnošt Vespalec, Jindřich Melichar, Sławomir Czarnecki and Adrian Chajec

Materials 2026, 19(6), 1168; https://doi.org/10.3390/ma19061168 - 17 Mar 2026

Viewed by 575

Abstract

Three-dimensional (3D) printing, also known as additive manufacturing of cementitious materials, appears to be a promising way to build in a way that is more time-efficient, cost-effective and, under certain conditions, environmentally friendly. This technology continues to exhibit significant inhomogeneity, which is frequently [...] Read more.

Three-dimensional (3D) printing, also known as additive manufacturing of cementitious materials, appears to be a promising way to build in a way that is more time-efficient, cost-effective and, under certain conditions, environmentally friendly. This technology continues to exhibit significant inhomogeneity, which is frequently caused by the interlayer area. The presented research aims to clarify the influence of the interlayer surface area and delay time on the bond strength. This study involved reference cast and printed samples with different delay times and cast samples with different interlayer surface areas. Different interlayer surface areas were accomplished through the utilisation of a teeth shaper before casting the second layer. Research has shown that the interlayer surface area has a significant impact on layer bond strength; up to a 70% increase in bond strength can be achieved while increasing the area by 20%. The results show that the increase in strength due to a larger surface area remained constant in terms of percentage, across delay times, with a linear dependency on a specific range of conditions. After the threshold of the surface area increased, the bond strength could be compromised and lowered. This threshold is above a 120% increase in surface area for the used teeth geometry and material. The proposed technology of ejecting teeth to alter the interlayer surface area has the potential to reduce the heterogeneity of mechanical properties in 3D-printed objects, caused by the different delay time between layers, because of the print strategy or material shortage. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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16 pages, 6008 KB

Open AccessArticle

Residual Mechanical and Structural Properties of Non-Calcined Hwangto Concrete After Exposure to High Temperatures

by Taehyung Kim, Wonchang Kim, Hajun Im and Taegyu Lee

Materials 2026, 19(4), 724; https://doi.org/10.3390/ma19040724 - 13 Feb 2026

Viewed by 383

Abstract

This study evaluated the residual mechanical properties of concrete in which Ordinary Portland Cement (OPC) was partially replaced with non-calcined Hwangto (NHT). Specimens were prepared with two water-to-binder (W/B) ratios (0.41 and 0.33) and three NHT replacement levels (0%, 15%, and 30%). The [...] Read more.

This study evaluated the residual mechanical properties of concrete in which Ordinary Portland Cement (OPC) was partially replaced with non-calcined Hwangto (NHT). Specimens were prepared with two water-to-binder (W/B) ratios (0.41 and 0.33) and three NHT replacement levels (0%, 15%, and 30%). The specimens were exposed to elevated temperatures of 20, 100, 200, 300, 500, and 700 °C at a heating rate of 1 °C/min. The results indicated that while the initial compressive strength at room temperature decreased with increasing NHT content, the residual mechanical performance at high temperatures significantly improved. Notably, temporary strength recovery was observed in the 200–300 °C range due to the internal autoclaving effect. At 700 °C, the NHTC (non-calcined Hwangto concrete)-30 series exhibited the highest thermal stability, retaining 28.2% of its initial compressive strength, whereas the Plain (OPC Concrete) and NHTC-15 series retained only 23.6% and 22.4%, respectively. Regarding energy absorption, the dissipated energy varied with the W/B ratio. In the W/B 41 series, the NHTC-30 specimen demonstrated superior ductility and energy dissipation capacity at 700 °C, outperforming the Plain specimen. This enhanced post-peak performance is attributed to the thermal activation of kaolinite into metakaolin, which preserves microstructural integrity by mitigating the severe degradation of hydration products and inhibiting crack propagation. These findings suggest that incorporating NHT effectively enhances the fire resistance and residual structural integrity of concrete, particularly in normal-strength matrices. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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14 pages, 3450 KB

Open AccessArticle

Influence of a Silane Coupling Agent and MWCNTs on the Structural and Durability Performance of CFRP Rebars

by Woo Sung Yum, Do Young Kwon and Yong Sik Chu

Materials 2026, 19(1), 106; https://doi.org/10.3390/ma19010106 - 28 Dec 2025

Viewed by 566

Abstract

This study investigates the influence of silane coupling agents and multi-walled carbon nanotubes (MWCNTs) on the mechanical, durability, and thermal performance of CFRP rebars manufactured using a pilot-scale pultrusion process. The incorporation of additives extended epoxy working time without causing adverse viscosity effects [...] Read more.

This study investigates the influence of silane coupling agents and multi-walled carbon nanotubes (MWCNTs) on the mechanical, durability, and thermal performance of CFRP rebars manufactured using a pilot-scale pultrusion process. The incorporation of additives extended epoxy working time without causing adverse viscosity effects during processing. Silane-modified CFRP rebars exhibited the highest mechanical performance, achieving a tensile strength of approximately 2649 MPa, an elastic modulus of 156 GPa, and improved bond strength with concrete, which is attributed to enhanced fiber–matrix interfacial adhesion. MWCNT-modified rebars showed slightly lower tensile strength but demonstrated superior thermal resistance, retaining the highest proportion of mechanical properties after exposure to 250 °C due to matrix reinforcement and crack-bridging effects. No significant degradation was observed under simulated marine exposure, while gradual reductions (up to ~7%) occurred in alkaline environments, with silane-modified rebars showing the greatest durability. These findings provide mechanistic insights and practical guidelines for optimizing epoxy formulations to enhance the structural and long-term performance of CFRP rebars. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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20 pages, 2271 KB

Open AccessArticle

Utilizing Carbonated Reclaimed Water as Concrete Mixing Water: Improved CO₂ Uptake and Compressive Strength

by Hoon Moon, Muhammad Haseeb Zaheer, Indong Jang, Gi-Joon Park, Jung-Jun Park, Sehee Hong and Namkon Lee

Materials 2026, 19(1), 76; https://doi.org/10.3390/ma19010076 - 24 Dec 2025

Cited by 3 | Viewed by 734

Abstract

This study investigates the carbonation degree of reclaimed water (RW) and its potential use as mixing water for cementitious materials under controlled laboratory conditions using a simplified CO₂ injection method. To reproduce the chemical environment of actual RW, a synthetic reclaimed water [...] Read more.

This study investigates the carbonation degree of reclaimed water (RW) and its potential use as mixing water for cementitious materials under controlled laboratory conditions using a simplified CO₂ injection method. To reproduce the chemical environment of actual RW, a synthetic reclaimed water (SRW) system with a cement-to-sand ratio of 8:2 was prepared and used throughout the evaluation. Thermogravimetric analysis revealed that the cementitious solids suspended in SRW exhibit high reactivity with CO₂, achieving a net CO₂ uptake of 16.8%, equivalent to 8.31 g of CO₂ sequestered per kilogram of RW. The use of untreated RW as mixing water slightly reduced flowability and increased superplasticizer demand compared with distilled water, whereas carbonation treatment of RW improved workability and mitigated the rapid initial setting typically observed with untreated RW. Notably, replacing 3% of the cement with carbonated RW solids did not cause any reduction in compressive strength, indicating that the carbonated solids can be incorporated without compromising mechanical performance. These results confirm that the CaCO₃ formed during RW carbonation remains stably retained within mortar and concrete, demonstrating the feasibility of using carbonated RW as a dual-function material—serving both as mixing water and as a medium for CO₂ sequestration. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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25 pages, 3719 KB

Open AccessArticle

Applying the Life Cycle Assessment to the Use of Biochar from Vine Pruning Waste as an Additive in Mortar

by Jorge Los Santos-Ortega, Javier Ferreiro-Cabello, Esteban Fraile-García and Fátima Somovilla-Gómez

Materials 2025, 18(24), 5573; https://doi.org/10.3390/ma18245573 - 11 Dec 2025

Cited by 2 | Viewed by 624

Abstract

The agricultural industry and corresponding waste materials represent a potential research area for applying circular economy strategies. This research is a life cycle assessment of the addition of different mass percentages (0.47%W, 1.52%W and 2.27%W) of biochar made from vine pruning waste to [...] Read more.

The agricultural industry and corresponding waste materials represent a potential research area for applying circular economy strategies. This research is a life cycle assessment of the addition of different mass percentages (0.47%W, 1.52%W and 2.27%W) of biochar made from vine pruning waste to mortar mixes. The research involves two scenarios. Scenario I is an attributional approach, aligned with the Environmental Product Declaration and Carbon Footprint standards. Scenario II takes a consequential approach, including biochar removals, as well as products and materials avoided as a result of the decision to start using this additive in mortar. The key findings differ substantially. For instance, under the impact category of Potential Global Warming compared to the reference mortar (without biochar additive) (0.58 kg CO₂ eq), Scenario I yields a 56.85% increase in emissions (+2.21 kg CO₂ eq) for the 1.52%W mix. By contrast, under Scenario II, the same alternative mixture yields an environmental benefit with a 76.83% decrease in emissions (−0.45 kg CO₂ eq). This research highlights the environmental benefits of reusing agricultural waste specifically in the construction sector and provides an example of a circular economy study. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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22 pages, 3904 KB

Open AccessEditor’s ChoiceArticle

Sulphate Resistance of Alkali-Activated Material Produced Using Wood Ash

by Yiying Du, Ina Pundiene, Jolanta Pranckeviciene and Aleksandrs Korjakins

Materials 2025, 18(18), 4313; https://doi.org/10.3390/ma18184313 - 15 Sep 2025

Cited by 5 | Viewed by 1270

Abstract

The durability of construction and building materials under sulphate environments is an important indicator to evaluate their service life. In this study, the physical and mechanical behaviours of wood-ash-based alkali-activated materials (AAMs) incorporating coal fly ash, metakaolin, natural zeolite, and calcined phosphogypsum were [...] Read more.

The durability of construction and building materials under sulphate environments is an important indicator to evaluate their service life. In this study, the physical and mechanical behaviours of wood-ash-based alkali-activated materials (AAMs) incorporating coal fly ash, metakaolin, natural zeolite, and calcined phosphogypsum were assessed before and after being subjected to sodium sulphate corrosion cycles via the compressive strength, mass, and volume changes. The microstructure, elemental composition, and phase identification were further analysed using X-Ray Diffraction(XRD) and scanning electron microscope(SEM). The results show that the exposure to sulphate solution caused decalcification and dealumination of hydrates, releasing calcium and aluminium to react with sulphate and forming expansive erosion products, ettringite and gypsum. This contributed to the microstructural damage, leading to mass change, volume expansion, and compressive strength loss of 7.33, 1.29, and 60.42%. The introduction of binary aluminosilicate precursors enhanced the sulphate resistance by forming a well-bonded microstructure consisting of calcium (aluminate) silicate hydrate and sodium aluminate silicate hydrate, with the compressive strength loss decreasing up to 18.60%. The co-usage of calcined phosphogypsum deteriorated the mechanical properties of AAMs but significantly improved the sulphate resistance. The sodium sulphate environment facilitated anhydrate hydration, generating more sulphate hydrates and hemigypsums that co-existed with erosion products, forming a compact microstructure and improving the compressive strength by twofold. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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17 pages, 4491 KB

Open AccessArticle

Effect of Synthesized C-S-H Nanoparticles on the Early Hydration and Microstructure of Cement

by Yoojung Hwang, Suji Woo and Young-Cheol Choi

Materials 2025, 18(14), 3396; https://doi.org/10.3390/ma18143396 - 20 Jul 2025

Cited by 5 | Viewed by 2210

Abstract

Ground granulated blast-furnace slag (GGBS), a waste product generated during steel production, can be added as a substitute for cement in concrete to mitigate the environmental impact of the cement and steel industries. However, the use of GGBS is limited because it decreases [...] Read more.

Ground granulated blast-furnace slag (GGBS), a waste product generated during steel production, can be added as a substitute for cement in concrete to mitigate the environmental impact of the cement and steel industries. However, the use of GGBS is limited because it decreases the early strength development of cement or concrete. This study evaluated the performance of incorporating synthesized C-S-H nanoparticles to enhance the compressive strength, early hydration, and microstructure of cement composite. The synthesized C-S-H nanoparticles were produced at standard atmospheric pressure and room temperature. Heat of hydration, X-ray diffraction, and thermogravimetric analyses were conducted to investigate the hydration and mechanical properties of the cement containing the C-S-H nanoparticles. Further, mercury intrusion porosimetry was conducted to examine the pore structures. The experimental finding demonstrated that adding C-S-H nanoparticles accelerated the early hydration progress in the cement composites, thereby increasing their initial compressive strength. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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21 pages, 3144 KB

Open AccessArticle

The Impact of Superplasticizer Chemical Structure on Reactive Powder Concrete Properties

by Stefania Grzeszczyk, Aneta Matuszek-Chmurowska, Natalina Makieieva, Teobald Kupka and Adam Sudoł

Materials 2025, 18(7), 1646; https://doi.org/10.3390/ma18071646 - 3 Apr 2025

Cited by 1 | Viewed by 1501

Abstract

It is difficult to obtain efficient flowability of reactive powder concrete (RPC) mix due to a low water/binder ratio. The improvement of material flowability could be achieved by using the latest generation polycarboxylate superplasticizers (SPs), as well as by changing the mixing procedure. [...] Read more.

It is difficult to obtain efficient flowability of reactive powder concrete (RPC) mix due to a low water/binder ratio. The improvement of material flowability could be achieved by using the latest generation polycarboxylate superplasticizers (SPs), as well as by changing the mixing procedure. This paper presents two different superplasticizers’ effect on a fresh mix and hardened reactive powder concrete properties. Results of systematic experimental studies (including physicochemical and spectroscopic tests) and molecular modelling suggest that superplasticizer chemical structure plays a key role in shaping the properties of the concrete mix. It has been demonstrated that SP containing more carboxylate salt groups -COO⁻ Me⁺ improves fluidity of the RPC mix and causes its better deaeration. In contrast, hardened concrete exhibits lower porosity and consequently greater strength. On the other hand, a change in ingredients mixing from a three-stage to a four-stage procedure increased the mix flowability and the RPC strength. The chemical structure of SP and the mixing procedure had no significant impact on cement hydration progress. Our results could be useful both from the point of view of the basic science of materials and the applied field of planning of cement composites in construction. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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21 pages, 11170 KB

Open AccessArticle

Compression Dewatering Forming: A Rheology-Driven Approach to Produce Complex-Shaped Prefabricated Cement Products

by Chunlei Xia, Qianping Ran, Xiongfei Zhang and Xiaorong Wang

Materials 2025, 18(7), 1607; https://doi.org/10.3390/ma18071607 - 2 Apr 2025

Viewed by 920

Abstract

With the development of prefabricated buildings, complex-shaped cement products, represented by heating-type elevated floors, have appeared on the market. These cement products can only be produced by the pouring method, with low efficiency and poor precision. Among the existing processing methods for preparing [...] Read more.

With the development of prefabricated buildings, complex-shaped cement products, represented by heating-type elevated floors, have appeared on the market. These cement products can only be produced by the pouring method, with low efficiency and poor precision. Among the existing processing methods for preparing cement products, compression dewatering offers the greatest ability to produce cement products with complex shapes. However, the pressed mixing material comprises a plastic fresh mortar, which inherently lacks fluidity, making it difficult to completely fill the cavity of the shaped mold. Few studies have been conducted on the experimental method and design ratios of mortar for the compression dewatering process in the industry, with no effective solution. To achieve the efficient production of complex-shaped cement products, this study explored the experimental method of testing the strength and flowability of mortar formed through compression dewatering as the forming process. Mortar ratios suitable for producing complex-shaped cement products using the compression dewatering process were determined, the relationship between material rheology and product forming performance was analyzed, and the influence of the compression process on the strength and micro-properties was studied. Finally, a cement-based heating-type elevated floor forming technology was developed, offering a novel approach for the efficient forming of complex-shaped cement products. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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17 pages, 5287 KB

Open AccessArticle

Influence of Pozzolanic Additives on the Structure and Properties of Ultra-High-Performance Concrete

by Jurgita Malaiškienė and Ronaldas Jakubovskis

Materials 2025, 18(6), 1304; https://doi.org/10.3390/ma18061304 - 16 Mar 2025

Cited by 12 | Viewed by 1972

Abstract

The aim of this paper is to analyse the influence of the following different supplementary cementitious materials (SCMs): milled quartz sand, microsilica, waste metakaolin, milled window glass, and a binary additive made of one part waste metakaolin and one part microsilica, on the [...] Read more.

The aim of this paper is to analyse the influence of the following different supplementary cementitious materials (SCMs): milled quartz sand, microsilica, waste metakaolin, milled window glass, and a binary additive made of one part waste metakaolin and one part microsilica, on the properties of ultra-high-performance concrete, and choose the best additive according to the physical, mechanical, and structural properties of concrete. In all mixes except the control mix, 10% of the cement was replaced with pozzolanic additives, and the changes in the physical, mechanical, and structural properties of the concrete were analysed (density, compressive strength, water absorption, capillary water absorption, degree of structural inhomogeneity, porosity, freeze–thaw resistance prediction coefficient Kf values); X-ray diffraction analysis (XRD) and scanning electron microscopy analysis (SEM) results were then interpreted. Concrete with microsilica and the binary additive (microsilica + metakaolin) was found to have the highest compressive strength, density, closed porosity, and structural homogeneity. Compared to the control sample, these compositions have 50% lower open porosity and 24% higher closed porosity, resulting from the effect of pozzolanic additives, with which the highest density and structural homogeneity was achieved due to the different particle sizes of the additives used. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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19 pages, 2451 KB

Open AccessArticle

Effect of Microencapsulated Temperature Rise Inhibitor on the Temperature Rise of Medium-Sized Concrete

by Yingda Zhang, Junru Zhang, Jun Chen, Zhijian Yan, Xinyue Liu and Haojie Zhang

Materials 2025, 18(6), 1230; https://doi.org/10.3390/ma18061230 - 10 Mar 2025

Cited by 4 | Viewed by 1465

Abstract

This study investigates the effect of microencapsulated temperature rise inhibitors (TRIs) on the hydration temperature evolution and crack resistance of medium-sized concrete structures. Unlike mass concrete, medium-sized concrete elements such as beams, slabs, and columns pose unique challenges in temperature control due to [...] Read more.

This study investigates the effect of microencapsulated temperature rise inhibitors (TRIs) on the hydration temperature evolution and crack resistance of medium-sized concrete structures. Unlike mass concrete, medium-sized concrete elements such as beams, slabs, and columns pose unique challenges in temperature control due to their moderate volume, limited heat dissipation, and susceptibility to thermal stress-induced cracking. To address this issue, concrete mixtures with TRI dosages of 0%, 0.05%, 0.1%, and 0.15% were evaluated using a sealed foam box method, allowing for precise monitoring of hydration temperature development under insulated conditions. The results indicate that TRIs effectively suppress peak hydration temperature and delays its occurrence, with higher TRI dosages leading to more pronounced effects. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirm that the hydration suppression is attributed to a controlled-release mechanism, where TRIs gradually dissolve, forming a hydration barrier on cement particles. This slows down calcium hydroxide (CH) crystallization, alters C-S-H gel evolution, and reduces early age heat accumulation, mitigating thermal cracking risks. Furthermore, mechanical property tests reveal that, while early age compressive and tensile strength decrease with TRI addition, long-term strength recovery is achieved at optimum TRI dosages. This study identifies 0.1% TRI as the most effective dosage, striking a balance between hydration heat reduction and long-term mechanical performance. These findings provide a scientific basis for optimizing TRI dosages in medium-sized concrete applications, offering a practical solution for thermal cracking prevention. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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Review

Jump to: Research

49 pages, 2481 KB

Open AccessReview

A Comprehensive Review of Numerical and Machine Learning Approaches for Predicting Concrete Properties: From Fresh to Long-Term

by Nilam Adsul, Yongho Choi and Su-Tae Kang

Materials 2025, 18(15), 3718; https://doi.org/10.3390/ma18153718 - 7 Aug 2025

Cited by 9 | Viewed by 3125

Abstract

The growing demand for innovation and the use of diverse materials in cementitious composites necessitate predictive models that account for material variability. Numerical, code-based, and machine learning (ML) models have been developed to predict various concrete properties. However, their accuracy is significantly influenced [...] Read more.

The growing demand for innovation and the use of diverse materials in cementitious composites necessitate predictive models that account for material variability. Numerical, code-based, and machine learning (ML) models have been developed to predict various concrete properties. However, their accuracy is significantly influenced by factors such as mix design, composition, intrinsic properties, and external conditions. Developing robust models that integrate these variables is essential for improving predictive accuracy and optimizing material performance. This paper presents a comprehensive review of numerical, code-based, and ML modelling techniques for predicting both fresh and long-term concrete properties. Since both numerical and ML models rely on experimental data—either to determine coefficients in numerical approaches or to train ML models—data gathering, preprocessing, and handling are crucial for model performance. Previous studies indicated that data variability significantly impacts accuracy, emphasizing the importance of effective preprocessing. While larger datasets generally improve reliability, some models achieve high accuracy even with very limited data. This review not only demonstrates the superior performance of ML models over traditional numerical approaches but also highlights the relative effectiveness of different ML algorithms based on reported accuracy metrics. ML-based approaches, including both ensemble and non-ensemble models, have exhibited strong predictive capabilities across a wide range of concrete property categories. In contrast, traditional numerical models often yield lower accuracy, although modified versions that incorporate additional parameters have shown improved performance. Furthermore, the integration of optimization algorithms and interpretability tools enhances both predictive reliability and model transparency—critical aspects that are often overlooked. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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39 pages, 4364 KB

Open AccessReview

Bond Behavior of Glass Fiber-Reinforced Polymer (GFRP) Bars Embedded in Concrete: A Review

by Saad Saad and Maria Anna Polak

Materials 2025, 18(14), 3367; https://doi.org/10.3390/ma18143367 - 17 Jul 2025

Cited by 8 | Viewed by 2751

Abstract

Glass Fiber-Reinforced Polymer (GFRP) bars are becoming increasingly common in structural engineering applications due to their superior material properties, mainly their resistance to corrosion due to their metallic nature in comparison to steel reinforcement and their improved durability in alkaline environments compared to [...] Read more.

Glass Fiber-Reinforced Polymer (GFRP) bars are becoming increasingly common in structural engineering applications due to their superior material properties, mainly their resistance to corrosion due to their metallic nature in comparison to steel reinforcement and their improved durability in alkaline environments compared to CFRP and BFRP reinforcement. However, GFRP bars also suffer from a few limitations. One of the main issues that affects the performance of GFRP reinforcing bars is their bond with concrete, which may differ from the bond between traditional steel bars and concrete. However, despite the wide attention of researchers, there has not been a critical review of the recent research progress on bond behavior between GFRP bars and concrete. The objective of this paper is to provide an overview of the current state of research on bond in GFRP-reinforced concrete in an attempt to systematize the existing scientific knowledge. The study summarizes experimental investigations that directly measure bond strength and investigates the different factors that influence it. Additionally, an overview of the analytical and empirical models used to simulate bond behavior is then presented. The findings indicate the dependence of the bond on several factors that include bar diameter, bar surface, concrete strength, and embedment length. Additionally, it was concluded that both traditional and more recent bond models do not explicitly account for the effect of different factors, which highlights the need for improved bond models that do not require calibration with experimental tests. Full article

(This article belongs to the Special Issue Concretes and Cement-Based Composites: Additives/Admixtures, Hydration Process and Durability Research (3rd Edition))

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