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Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures
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Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures

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

Deadline for manuscript submissions: closed (20 January 2022) | Viewed by 51088

Special Issue Editors

Dr. Branko Šavija

E-Mail Website
Guest Editor
Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2628CN Delft, The Netherlands
Interests: multi-scale mechanics of construction materials; additive manufacturing of cementitious composites; concrete durability
Special Issues, Collections and Topics in MDPI journals
Assoc. Prof. Ivan Ignjatovic

E-Mail Website
Guest Editor
University of Belgrade, Serbia
Interests: structural concrete; durability; service life design; recycling and waste materials in concrete
Dr. Ravi A. Patel

E-Mail Website
Guest Editor
Paul Scherer Institute, Switzerland
Interests: concrete durability; transport processes; chemomechanical processes; pore-scale modeling and multiscale modeling

Special Issue Information

Dear Colleagues,

Concrete is a building material of choice for structures in aggressive environmental conditions. Structures that are expected to have a long service life, such as bridges, tunnels, and dams, nuclear power plants, and geological waste disposal facilities, have main components made of concrete. Furthermore, there is a pressing need for extending the service life of existing structures as a more sustainable option compared to buiding new structures. In order to ensure that these structures perform well, it is important to understand time-dependent changes in the material and its interaction with the environment. This is especially critical when new types of concrete, such as alkali-activated concrete, recycled aggregate concrete, or concrete based on suplementary cementitous materials, are considered for application.

This aim of this Special Issue is to cover recent research in time-dependent phenomena
(shrinkage, creep, fatigue), aging, and durability of cementitious materials and reinforced concrete structures, including their service life design. The focus is on measuring, modeling, and monitoring these processes on multiple length scales, ranging from the microscale (pore-scale) all the way up to the macroscale (structural element/structure scale). Transport processess, cracking, damage, reinforcement corrosion, and loss of serviceability are all topics of interest. Furthermore, contributions dealing with the long-term performance of new types of concrete on all length scales are especially encouraged.

With this Special Issue, it is our ambition to circulate the latest knowledge in the long-term performance of cementitious materials and reinforced concrete structures. Excellent contributions will form a basis for new research for both young researchers as well as leading experts in the field.

Assist. Prof. Branko Šavija
Assoc. Prof. Ivan Ignjatovic
Dr. Ravi A. Patel
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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 2600 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

  • Alkali–silica reaction
  • Sulphate attack
  • Calcium leaching
  • Carbonation
  • Chloride ingress
  • Reinforcement corrosion
  • Service life design
  • Transport processes
  • Creep/shrinkage
  • Concrete cracking
  • Serviceability limit state (SLS)
  • Aging

Published Papers (18 papers)

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16 pages, 8696 KiB  
Article
Mechanisms and Critical Technologies of Transport Inhibitor Agent (TIA) throughout C-S-H Nano-Channels
by Qi Luo and Jiale Huang
Materials 2022, 15(2), 515; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15020515 - 10 Jan 2022
Cited by 4 | Viewed by 1369
Abstract
The critical issue of the durability of marine concrete lies in the continuous penetration and rapid enrichment of corrosive ions. Here a new ion transfer inhibitor, as TIA, with calcium silicate hydrate (C-S-H) interfacial affinity and hydrophobicity is proposed through insights from molecular [...] Read more.
The critical issue of the durability of marine concrete lies in the continuous penetration and rapid enrichment of corrosive ions. Here a new ion transfer inhibitor, as TIA, with calcium silicate hydrate (C-S-H) interfacial affinity and hydrophobicity is proposed through insights from molecular dynamics into the percolation behavior of the ion solution in C-S-H nano-channels and combined with molecular design concepts. One side of the TIA can be adsorbed on the surface of the cement matrix and can form clusters of corrosive ions to block the gel pores so as to resist the ion solution percolation process. Its other side is structured as a hydrophobic carbon chain, similar to a door hinge, which can stick to the matrix surface smoothly before the erosion solution is percolated. It can then change into a perpendicular chain shape to reduce the percolation channel’s diameter and thereby inhibit the percolation when ions meet the inhibitor. Therefore, once the erosion solution contacts TIA, it can quickly chelate with calcium ions and erosion ions at the interface to form clusters and compact pores. In addition, the water absorption, chloride migration coefficient, and chloride content of concrete samples decreased significantly after adding TIA, proving that TIA can effectively enhance the durability of cement-based materials. The structure–activity relationship of ion transfer that is proposed can provide new ideas for solving the critical problems of durability of cement-based materials and polymer molecular design. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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18 pages, 4175 KiB  
Article
A Study of the Flexural Behavior of Fiber-Reinforced Concretes Exposed to Moderate Temperatures
by Marta Caballero-Jorna, Marta Roig-Flores and Pedro Serna
Materials 2021, 14(13), 3522; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14133522 - 24 Jun 2021
Cited by 6 | Viewed by 1530
Abstract
The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, [...] Read more.
The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, and one steel fiber was employed as a reference. Three-point bending tests were carried out following an adapted methodology based on the standard EN 14651. This adapted procedure included an insulation system that allowed the assessment of FRC flexural behavior after being exposed for two months at temperatures of 5, 20, 35 and 50 °C. In addition, the interaction of temperature with a pre-cracked state was also analyzed. To do this, several specimens were pre-cracked to 0.5 mm after 28 days and conditioned in their respective temperature until testing. The findings suggest that this range of moderate temperatures did not degrade the behavior of FRCs to a great extent since the analysis of variances showed that temperature is not always a significant factor; however, it did have an influence on the pre-cracked specimens at 35 and 50 °C. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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14 pages, 7126 KiB  
Article
Influence of Natural Weather Conditions in the Long-Term Fracture Energy of Glass Fibre Reinforced Cement (GRC) Modified with Chemical Additions
by Alejandro Enfedaque, Marcos G. Alberti, Jaime C. Gálvez and Shou Mengie
Materials 2021, 14(12), 3355; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14123355 - 17 Jun 2021
Cited by 1 | Viewed by 1319
Abstract
The use of glass fibre-reinforced cement (GRC) in structural elements has been limited due to the reduction in the mechanical properties of the material with aging. Chemical additions have been used to modify the cement mortar formulation in order to minimise such loss, [...] Read more.
The use of glass fibre-reinforced cement (GRC) in structural elements has been limited due to the reduction in the mechanical properties of the material with aging. Chemical additions have been used to modify the cement mortar formulation in order to minimise such loss, but no conclusive results have been obtained yet. Moreover, the application of accelerated aging methods in such modified GRC formulations still poses several uncertainties. An experimental campaign seeking to assess the reduction in the fracture energy of two GRCs manufactured with modified matrixes after five years of exposure to natural environment was performed. Furthermore, a comparison with results from the literature that used accelerated aging methods was performed. The results show that the use of the chemical additives might be capable of maintaining to a notable extent the mechanical properties of GRC after five years of natural aging. Regarding the accelerated aging method by means of immersion in hot water tanks, it seemed that the equivalences applied in previous research accurately match the degradation of the material after natural exposure to weather. Additionally, a digital image correlation analysis showed that aged GRCs seemed to distribute damage in a smaller area than young GRCs. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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15 pages, 9831 KiB  
Article
Determination of Loss of Reinforcement Due to Corrosion through X-ray Computer Micro-Tomography
by Fernando França de Mendonça Filho, Oguzhan Copuroglu, Erik Schlangen and Branko Šavija
Materials 2021, 14(4), 893; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14040893 - 13 Feb 2021
Cited by 2 | Viewed by 1648
Abstract
X-ray computer scanning tomography (CT scan) is an increasingly more available technique, which has been applied to material sciences for years. Although most of its use is qualitative for gaining insights on material behavior, quantitative analysis for estimations of deterioration rates is possible. [...] Read more.
X-ray computer scanning tomography (CT scan) is an increasingly more available technique, which has been applied to material sciences for years. Although most of its use is qualitative for gaining insights on material behavior, quantitative analysis for estimations of deterioration rates is possible. This paper describes an unbiased, straightforward method to determine the amount of reinforcement lost to corrosion through the use of X-ray tomography without the need to remove the concrete cover. Other methods of assessment such as gravimetric analysis, half-cell potential, resistivity of mortar cover, corrosion current, and scanning electron microscopy (SEM) are used in the same samples for comparison. While the electrical and electrochemical tests are valuable to describe the state of the samples, those demonstrated poor capacity of determining the stage of corrosion of the reinforcement in terms of amount of material lost. Electron microscopy could determine how much of the reinforcement corroded with high accuracy; however, these results are deficient in representativity, being based on a single plane of the steel. X-ray tomography, while suffering from sample size limitation, could provide quantitative information on the total volume of material lost for each sample with far higher accuracy than indirect techniques, which is significant for the forensic determination of remaining life service of structures. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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23 pages, 5816 KiB  
Article
Long-Term Creep and Shrinkage Behavior of Concrete-Filled Steel Tube
by Doan-Binh Nguyen, Wei-Sheng Lin and Wen-Cheng Liao
Materials 2021, 14(2), 295; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14020295 - 08 Jan 2021
Cited by 12 | Viewed by 2225
Abstract
A concrete-filled steel tube (CFT) combines the advantages of concrete and steel in construction and structural applications. However, research on the time-dependent deformation of the CFT under long-term sustained loading are still limited, particularly for stress transfer between the steel tube and concrete [...] Read more.
A concrete-filled steel tube (CFT) combines the advantages of concrete and steel in construction and structural applications. However, research on the time-dependent deformation of the CFT under long-term sustained loading are still limited, particularly for stress transfer between the steel tube and concrete due to creep. This study investigated the creep behavior of CFT over a long period of 400 days. The creep and shrinkage strain of CFT was significantly lower than those of concrete that was not confined within a steel tube. The vertical strains of the steel tube and concrete core were almost identical, and it was shown that they were well bonded and acted as a composite. The vertical stress of steel increased by 32.7%, whereas the vertical stress of concrete decreased by 15.8% at 375 days. The stress transfer is notable and cannot be neglected in CFT design. Moreover, the results of creep and shrinkage were compared to prediction values of the B4 model and B4-TW model to verify their validity. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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23 pages, 3873 KiB  
Article
Effective and Apparent Diffusion Coefficients of Chloride Ions and Chloride Binding Kinetics Parameters in Mortars: Non-Stationary Diffusion–Reaction Model and the Inverse Problem
by Jerzy J. Jasielec, Jakub Stec, Krzysztof Szyszkiewicz-Warzecha, Artur Łagosz, Jan Deja, Andrzej Lewenstam and Robert Filipek
Materials 2020, 13(23), 5522; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13235522 - 03 Dec 2020
Cited by 15 | Viewed by 2235
Abstract
A non-equilibrium diffusion–reaction model is proposed to describe chloride transport and binding in cementitious materials. A numerical solution for this non-linear transport with reaction problem is obtained using the finite element method. The effective chloride diffusion coefficients and parameters of the chloride binding [...] Read more.
A non-equilibrium diffusion–reaction model is proposed to describe chloride transport and binding in cementitious materials. A numerical solution for this non-linear transport with reaction problem is obtained using the finite element method. The effective chloride diffusion coefficients and parameters of the chloride binding are determined using the inverse method based on a diffusion–reaction model and experimentally measured chloride concentrations. The investigations are performed for two significantly different cements: ordinary Portland and blast furnace cements. The results are compared with the classical diffusion model and appropriate apparent diffusion coefficients. The role of chloride binding, with respect to the different binding isotherms applied, in the overall transport of chlorides is discussed, along with the applicability of the two models. The proposed work allows the determination of important parameters that influence the longevity of concrete structures. The developed methodology can be extended to include more ions, electrostatic interactions, and activity coefficients for even more accurate estimation of the longevity. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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17 pages, 5278 KiB  
Article
A Cracking Model for Reinforced Concrete Cover, Taking Account of the Accumulation of Corrosion Products in the ITZ Layer, and Including Computational and Experimental Verification
by Tomasz Krykowski, Tomasz Jaśniok, Faustyn Recha and Michał Karolak
Materials 2020, 13(23), 5375; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13235375 - 26 Nov 2020
Cited by 9 | Viewed by 2020
Abstract
The paper presents the finite element method model (FEM) which allows the forecasting of the evolution of damage in a concrete cover together with experimental verification of the model. The objective of the model is to define the corrosive volume strain tensor rate [...] Read more.
The paper presents the finite element method model (FEM) which allows the forecasting of the evolution of damage in a concrete cover together with experimental verification of the model. The objective of the model is to define the corrosive volume strain tensor rate effected by corrosion, which comprises the accumulation of corrosion products in pore spaces as well as in micro-cracks which develop at the initial stage of cover degradation. The propagation of damage in the contact zone was captured by taking into account the function describing the degradation of the interface transition zone depending on the cover tightening time–critical time. The method of determining the critical time along with the method of taking into account the effective electrochemical equivalent of iron was also analyzed in this paper. The work presents the experimental verification of the model using an accelerated corrosion test of reinforcement in concrete and strain measurements with optical methods. The conducted tests demonstrate satisfactory compliance of the model with the test results. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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17 pages, 7067 KiB  
Article
Chloride-Induced Corrosion of Steel in Alkali-Activated Mortars Based on Different Precursors
by Antonino Runci and Marijana Serdar
Materials 2020, 13(22), 5244; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13225244 - 20 Nov 2020
Cited by 8 | Viewed by 1972
Abstract
The low environmental impact and high long-term performance of products are becoming imperative for the sustainable development of the construction industry. Alkali-activated materials (AAMs) are one of the available low-embodied-carbon alternatives to Portland cement (OPC). For their application in the marine environment or [...] Read more.
The low environmental impact and high long-term performance of products are becoming imperative for the sustainable development of the construction industry. Alkali-activated materials (AAMs) are one of the available low-embodied-carbon alternatives to Portland cement (OPC). For their application in the marine environment or where de-icing salts are used, it is of utmost importance to demonstrate their equal or better performance compared to OPC. The aim of this study was to compare the corrosion behaviour of the steel in AAMs based on different regionally available by-products with the behaviour of the steel in OPC. The by-products used were fly ash, slag, silica fume, and iron-silica fines. The corrosion process of each system was monitored by the corrosion potential and polarisation resistance during exposure to tap water and chloride solution over a period of almost one year. Certain AAMs showed a higher resistance to chloride penetration compared to OPC, which was attributed to the smaller number of capillary pores and higher gel phase precipitation. The same corrosion resistance compared to OPC was achieved with alkali-activated fly ash and alkali-activated slag mortars. The stability of the systems in tap water and chloride solution was confirmed by the visual assessment of the steel surface at the end of the test period. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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19 pages, 3445 KiB  
Article
The Reinforced Spun Concrete Poles under Physical Salt Attack and Temperature: A Case Study of the Effectiveness of Chemical Admixtures
by Romualdas Kliukas, Arūnas Jaras and Ona Lukoševičienė
Materials 2020, 13(22), 5111; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13225111 - 12 Nov 2020
Cited by 2 | Viewed by 1623
Abstract
The present paper focused on the investigation of the effectiveness of using various chemical admixtures and their effect on the strength and deformability of the reinforced spun concrete members—the supporting poles of the overhead power transmission lines—under the unfavorable long-term combined action of [...] Read more.
The present paper focused on the investigation of the effectiveness of using various chemical admixtures and their effect on the strength and deformability of the reinforced spun concrete members—the supporting poles of the overhead power transmission lines—under the unfavorable long-term combined action of the aggressive salt-saturated groundwater and the temperature changes. According to the long-term experimental program, 96 prismatic spun concrete specimens were subjected to multi-cycle (25-50-75 cycles) processing under the combined aggressive environmental conditions. It has been found that chemical admixtures which decrease the initial water-cement ratio produce a considerable positive effect on the mechanical properties of spun concrete used in hot and arid climates and exposed to physical salt attack (PSA). Superplasticizers decrease the initial water-cement ratio the most, and, due to a unique concrete compaction method used, they produce the most homogeneous and dense concrete structure. They can be recommended as most effective in increasing the durability of spun concrete used under the above-mentioned aggressive environmental conditions. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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15 pages, 2805 KiB  
Article
Corrosion Behavior of AISI 1018 Carbon Steel in Localized Repairs of Mortars with Alkaline Cements and Engineered Cementitious Composites
by Erick Maldonado-Bandala, Noema Higueredo-Moctezuma, Demetrio Nieves-Mendoza, Citlalli Gaona-Tiburcio, Patricia Zambrano-Robledo, Héctor Hernández-Martínez and Facundo Almeraya-Calderón
Materials 2020, 13(15), 3327; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13153327 - 27 Jul 2020
Cited by 3 | Viewed by 2488
Abstract
The selection of materials for repairs of reinforced concrete structures is a serious concern. They are chosen for the mechanical capacity that the repair mortar achieves. However, several important characteristics have been left aside, such as the adhesion of the repair mortar with [...] Read more.
The selection of materials for repairs of reinforced concrete structures is a serious concern. They are chosen for the mechanical capacity that the repair mortar achieves. However, several important characteristics have been left aside, such as the adhesion of the repair mortar with the concrete substrate, the electrical resistivity and—hugely important—the protection against corrosion that the repair material can provide to the reinforcing steel. The aim of this work was to study the corrosion behavior of AISI 1018 carbon steel (CS) in mortars manufactured with alkaline cements, engineered cementitious composites (ECC), and supplementary cementitious materials (SCM). Two types of ordinary Portland cement (OPC) 30R and 40R were used. The constituent materials for the mortars with ECC mixture mortars they use OPC 40R, class F fly ash (FA), silica fume (SF) and polypropylene (PP) fibers. The sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) were used as activating agents in alkali activated cements. The reinforced specimens were immersed in two different electrolytes, exposed to a 3.5 wt % of NaCl and Na2SO4 solutions, for 12 months and their electrochemical behavior was studied by half-cell potential (Ecorr) and linear polarization resistance (LPR) according to ASTM C876-15 and ASTM G59-97, respectively. The results obtained indicated that, the mortar they have the best performance and durability, is the conventional MCXF mortar, with OPC 30R and addition of 1% polypropylene PP fiber improves the behavior against the attack of chlorides and sulfates. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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16 pages, 6558 KiB  
Article
A Peridynamics-Based Micromechanical Modeling Approach for Random Heterogeneous Structural Materials
by Sumeru Nayak, R Ravinder, N M Anoop Krishnan and Sumanta Das
Materials 2020, 13(6), 1298; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13061298 - 13 Mar 2020
Cited by 12 | Viewed by 4344
Abstract
This paper presents a peridynamics-based micromechanical analysis framework that can efficiently handle material failure for random heterogeneous structural materials. In contrast to conventional continuum-based approaches, this method can handle discontinuities such as fracture without requiring supplemental mathematical relations. The framework presented here generates [...] Read more.
This paper presents a peridynamics-based micromechanical analysis framework that can efficiently handle material failure for random heterogeneous structural materials. In contrast to conventional continuum-based approaches, this method can handle discontinuities such as fracture without requiring supplemental mathematical relations. The framework presented here generates representative unit cells based on microstructural information on the material and assigns distinct material behavior to the constituent phases in the random heterogenous microstructures. The framework incorporates spontaneous failure initiation/propagation based on the critical stretch criterion in peridynamics and predicts effective constitutive response of the material. The current framework is applied to a metallic particulate-reinforced cementitious composite. The simulated mechanical responses show excellent match with experimental observations signifying efficacy of the peridynamics-based micromechanical framework for heterogenous composites. Thus, the multiscale peridynamics-based framework can efficiently facilitate microstructure guided material design for a large class of inclusion-modified random heterogenous materials. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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19 pages, 17485 KiB  
Article
Effect of Recycled Iron Powder as Fine Aggregate on the Mechanical, Durability, and High Temperature Behavior of Mortars
by Md Jihad Miah, Md Kawsar Ali, Suvash Chandra Paul, Adewumi John Babafemi, Sih Ying Kong and Branko Šavija
Materials 2020, 13(5), 1168; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13051168 - 05 Mar 2020
Cited by 21 | Viewed by 4035
Abstract
This study evaluates the mechanical, durability, and residual compressive strength (after being exposed to 20, 120, 250, 400 and 600 °C) of mortar that uses recycled iron powder (RIP) as a fine aggregate. Within this context, mechanical strength, shrinkage, durability, and residual strength [...] Read more.
This study evaluates the mechanical, durability, and residual compressive strength (after being exposed to 20, 120, 250, 400 and 600 °C) of mortar that uses recycled iron powder (RIP) as a fine aggregate. Within this context, mechanical strength, shrinkage, durability, and residual strength tests were performed on mortar made with seven different percentages (0%, 5%, 10%, 15%, 20%, 30% and 50%) of replacement of natural sand (NS) by RIP. It was found that the mechanical strength of mortar increased when replaced with up to 30% NS by RIP. In addition, the increase was 30% for compressive, 18% for tensile, and 47% for flexural strength at 28 days, respectively, compared to the reference mortar (mortar made with 100% NS). Shrinkage was observed for the mortar made with 100% NS, while both shrinkage and expansion occurred in the mortar made with RIP, especially for RIP higher than 5%. Furthermore, significantly lower porosity and capillary water absorption were observed for mortar made with up to 30% RIP, compared to that made with 100% NS, which decreased by 36% for porosity and 48% for water absorption. As the temperature increased, the strength decreased for all mixes, and the drop was more pronounced for the temperatures above 250 °C and 50% RIP. This study demonstrates that up to 30% RIP can be utilized as a fine aggregate in mortar due to its better mechanical and durability performances. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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16 pages, 3259 KiB  
Article
Prediction of Chloride Distribution for Offshore Concrete Based on Statistical Analysis
by Qing-feng Liu, Zhi Hu, Xian-yang Lu, Jian Yang, Iftikhar Azim and Wenzhuo Sun
Materials 2020, 13(1), 174; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13010174 - 01 Jan 2020
Cited by 43 | Viewed by 3553
Abstract
Chloride-induced corrosion is the main threat to the service life of concrete structures. In order to better investigate chloride distribution in offshore concrete, this study proposed a new prediction model based on statistical analysis as well as a large body of experimental results [...] Read more.
Chloride-induced corrosion is the main threat to the service life of concrete structures. In order to better investigate chloride distribution in offshore concrete, this study proposed a new prediction model based on statistical analysis as well as a large body of experimental results collected from various sources. A detailed discussion found that the key influential parameters, such as diffusion coefficient ( D ), surface chloride concentration ( C S ) and penetration depth ( x ) are all highly time-dependent. The exposure zone, water–cement ratio and service time were also considered as relevant factors. The proposed model is then validated by two alternative tests and the results suggest that it is feasible in predicting the chloride content and penetration depth of concrete structures in a marine environment under chloride attack. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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20 pages, 7527 KiB  
Article
The Development of Nanoalumina-Based Cement Mortars for Overlay Applications in Concrete Floors
by Jacek Szymanowski and Łukasz Sadowski
Materials 2019, 12(21), 3465; https://0-doi-org.brum.beds.ac.uk/10.3390/ma12213465 - 23 Oct 2019
Cited by 24 | Viewed by 2866
Abstract
This article focuses on the development of nanoalumina-based cement mortars for overlay applications in concrete floors. It focuses on the effect of applying aluminum oxide (Al2O3) nanopowder to the cement mortar used to make the overlay, on the adhesion [...] Read more.
This article focuses on the development of nanoalumina-based cement mortars for overlay applications in concrete floors. It focuses on the effect of applying aluminum oxide (Al2O3) nanopowder to the cement mortar used to make the overlay, on the adhesion of this overlay to concrete substrate and on its functional properties. It was claimed that the addition of 0.5% of Al2O3 nanopowder has a positive effect on the adhesion of the cement mortar used to make the overlay to the substrate made of concrete. The prior studies performed using scanning electron microscopy (SEM) confirmed that the reason for the improvement in adhesion is the fact that cement mortar used to make the overlay with the addition of 0.5% of Al2O3 nanopowder is less porous than the reference mortar within the interphase. The article concurs that the most favorable results, in terms of lower abrasion resistance and higher subsurface tensile strength of the cement mortar used to make the overlay, are mainly brought about by adding 0.5% of Al2O3 nanopowder. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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14 pages, 2568 KiB  
Article
Development of Nano-SiO2 and Bentonite-Based Mortars for Corrosion Protection of Reinforcing Steel
by Venura Kiloshana Karunarathne, Suvash Chandra Paul and Branko Šavija
Materials 2019, 12(16), 2622; https://0-doi-org.brum.beds.ac.uk/10.3390/ma12162622 - 17 Aug 2019
Cited by 20 | Viewed by 3846
Abstract
In this study, the use of nano-silica (nano-SiO2) and bentonite as mortar additives for combating reinforcement corrosion is reported. More specifically, these materials were used as additives in ordinary Portland cement (OPC)/fly ash blended mortars in different amounts. The effects of [...] Read more.
In this study, the use of nano-silica (nano-SiO2) and bentonite as mortar additives for combating reinforcement corrosion is reported. More specifically, these materials were used as additives in ordinary Portland cement (OPC)/fly ash blended mortars in different amounts. The effects of nano-silica and bentonite addition on compressive strength of mortars at different ages was tested. Accelerated corrosion testing was used to assess the corrosion resistance of reinforced mortar specimens containing different amounts of nano-silica and bentonite. It was found that the specimens containing nano-SiO2 not only had higher compressive strength, but also showed lower steel mass loss due to corrosion compared to reference specimens. However, this was accompanied by a small reduction in workability (for a constant water to binder ratio). Mortar mixtures with 4% of nano-silica were found to have optimal performance in terms of compressive strength and corrosion resistance. Control specimens (OPC/fly ash mortars without any additives) showed low early age strength and low corrosion resistance compared to specimens containing nano-SiO2 and bentonite. In addition, samples from selected mixtures were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Finally, the influence of Ca/Si ratio of the calcium silicate hydrate (C-S-H) in different specimens on the compressive strength is discussed. In general, the study showed that the addition of nano-silica (and to a lesser extent bentonite) can result in higher strength and corrosion resistance compared to control specimens. Furthermore, the addition of nano-SiO2 can be used to offset the negative effect of fly ash on early age strength development. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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12 pages, 3064 KiB  
Article
Influence of Flue Gas Injection on the Long-Term Durability of a Natural Draft Concrete Cooling Tower
by Jianmin Du, Wenjuan Zhuang, Guo Li and Pei Zhang
Materials 2019, 12(13), 2038; https://0-doi-org.brum.beds.ac.uk/10.3390/ma12132038 - 26 Jun 2019
Viewed by 2335
Abstract
The article undertakes the very important topic of the long-term durability of concrete in a natural draft concrete cooling tower with flue gas injection. The corrosive conditions, including temperature, relative humidity, and CO2 and SO2 gas concentrations, near the inner wall [...] Read more.
The article undertakes the very important topic of the long-term durability of concrete in a natural draft concrete cooling tower with flue gas injection. The corrosive conditions, including temperature, relative humidity, and CO2 and SO2 gas concentrations, near the inner wall of a cooling tower with flue gas injection were monitored in real time to obtain the long-term durability performance of concrete. The pH and chemical compositions of the condensed liquid that adhered to the tower’s inner face and the macromorphology, compressive strength, and neutralization depth of in situ specimens were tested periodically. In addition, a finite element numerical simulation was conducted to simulate and verify the concentration distributions of CO2 and SO2 in the flue gas in the cooling tower. The results showed that the cleaned flue gas was enveloped, diluted, and uplifted by hot vapor in the cooling tower, and its concentration decreased. Meanwhile, the effective diffusion radius increased gradually as the flue gas rose. With the same elevation in the cooling tower, the concentration of flue gas decreased rapidly from the central point to the surrounding area. The air near the inner surface of the cooling tower was merely dampened air with a low concentration of acidic gas due to the gigantic diameter of the cooling tower. As a result, the injection of cleaned flue gas will not evidently increase the corrosion risk in a natural draft concrete cooling tower. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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Review

Jump to: Research

25 pages, 3631 KiB  
Review
Systematic Review on the Creep of Fiber-Reinforced Concrete
by Nikola Tošić, Stanislav Aidarov and Albert de la Fuente
Materials 2020, 13(22), 5098; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13225098 - 12 Nov 2020
Cited by 28 | Viewed by 4234
Abstract
Fiber-reinforced concrete (FRC) is increasingly used in structural applications owing to its benefits in terms of toughness, durability, ductility, construction cost and time. However, research on the creep behavior of FRC has not kept pace with other areas such as short-term properties. Therefore, [...] Read more.
Fiber-reinforced concrete (FRC) is increasingly used in structural applications owing to its benefits in terms of toughness, durability, ductility, construction cost and time. However, research on the creep behavior of FRC has not kept pace with other areas such as short-term properties. Therefore, this study aims to present a comprehensive and critical review of literature on the creep properties and behavior of FRC with recommendations for future research. A transparent literature search and filtering methodology were used to identify studies regarding creep on the single fiber level, FRC material level, and level of structural behavior of FRC members. Both experimental and theoretical research are analyzed. The results of the review show that, at the single fiber level, pull-out creep should be considered for steel fiber-reinforced concrete, whereas fiber creep can be a governing design parameter in the case of polymeric fiber reinforced concrete subjected to permanent tensile stresses incompatible with the mechanical time-dependent performance of the fiber. On the material level of FRC, a wide variety of test parameters still hinders the formulation of comprehensive constitutive models that allow proper consideration of the creep in the design of FRC elements. Although significant research remains to be carried out, the experience gained so far confirms that both steel and polymeric fibers can be used as concrete reinforcement provided certain limitations in terms of structural applications are imposed. Finally, by providing recommendations for future research, this study aims to contribute to code development and industry uptake of structural FRC applications. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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26 pages, 4462 KiB  
Review
Effect of Fibers on Durability of Concrete: A Practical Review
by Suvash Chandra Paul, Gideon P.A.G. van Zijl and Branko Šavija
Materials 2020, 13(20), 4562; https://0-doi-org.brum.beds.ac.uk/10.3390/ma13204562 - 14 Oct 2020
Cited by 51 | Viewed by 6148
Abstract
This article reviews the literature related to the performance of fiber reinforced concrete (FRC) in the context of the durability of concrete infrastructures. The durability of a concrete infrastructure is defined by its ability to sustain reliable levels of serviceability and structural integrity [...] Read more.
This article reviews the literature related to the performance of fiber reinforced concrete (FRC) in the context of the durability of concrete infrastructures. The durability of a concrete infrastructure is defined by its ability to sustain reliable levels of serviceability and structural integrity in environmental exposure which may be harsh without any major need for repair intervention throughout the design service life. Conventional concrete has relatively low tensile capacity and ductility, and thus is susceptible to cracking. Cracks are considered to be pathways for gases, liquids, and deleterious solutes entering the concrete, which lead to the early onset of deterioration processes in the concrete or reinforcing steel. Chloride aqueous solution may reach the embedded steel quickly after cracked regions are exposed to de-icing salt or spray in coastal regions, which de-passivates the protective film, whereby corrosion initiation occurs decades earlier than when chlorides would have to gradually ingress uncracked concrete covering the steel in the absence of cracks. Appropriate inclusion of steel or non-metallic fibers has been proven to increase both the tensile capacity and ductility of FRC. Many researchers have investigated durability enhancement by use of FRC. This paper reviews substantial evidence that the improved tensile characteristics of FRC used to construct infrastructure, improve its durability through mainly the fiber bridging and control of cracks. The evidence is based on both reported laboratory investigations under controlled conditions and the monitored performance of actual infrastructure constructed of FRC. The paper aims to help design engineers towards considering the use of FRC in real-life concrete infrastructures appropriately and more confidently. Full article
(This article belongs to the Special Issue Long-Term Behavior of Cementitious Materials and Reinforced Concrete Structures)
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