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Zhao H, Yang Y, Shu X, Qiao M, Dong L, Ran Q. Computational Simulations of Adsorption Behavior of Anionic Surfactants at the Portlandite-Water Interface under Sulfate and Calcium Ions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 38335537 DOI: 10.1021/acs.langmuir.3c03914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
The adsorption behaviors of two kinds of anionic surfactants (called HSO4 and HPO4, respectively) with different negatively charged hydrophilic head groups (sulfate and phosphate groups) under different concentrations of sulfate and calcium ions at the portlandite-water interface are investigated by molecular dynamics simulations. Although the adsorption strength of HPO4 is much greater than that of HSO4, the desorption energy of HSO4 is slightly greater at an early stage of desorption due to a more perpendicular orientation and denser packing of hydrophobic tail chains. After adding ions, the sulfate ion has a significant weakening effect due to competitive adsorption, and the negative influence of the calcium ion is weaker, and it even slightly promotes the adsorption at low concentration. Due to the stronger electrostatic interaction of phosphate head groups with the portlandite surface, adsorption strength and adsorption stability for HPO4 are always greater than that of HSO4 under the interference of sulfate ions. The competitive adsorption of the sulfate ion significantly weakens the interaction of hydrophilic head groups with portlandite and the dense packing of two surfactants. The calcium ion with low concentration approaches the portlandite surface and acts as an ion bridge to slightly enhance the adsorption of the surfactant. The ion bridging effect is stronger in the HPO4 system than in the HSO4 system.
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Affiliation(s)
- Hongxia Zhao
- School of Material Science and Engineering, Southeast University, Nanjing, Jiangsu 211189, China
- State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Sobute New Materials Co., Ltd., Nanjing, Jiangsu 210008, China
| | - Yong Yang
- School of Material Science and Engineering, Southeast University, Nanjing, Jiangsu 211189, China
- State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Sobute New Materials Co., Ltd., Nanjing, Jiangsu 210008, China
| | - Xin Shu
- State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Sobute New Materials Co., Ltd., Nanjing, Jiangsu 210008, China
| | - Min Qiao
- State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Sobute New Materials Co., Ltd., Nanjing, Jiangsu 210008, China
| | - Lei Dong
- School of Material Science and Engineering, Southeast University, Nanjing, Jiangsu 211189, China
| | - Qianping Ran
- School of Material Science and Engineering, Southeast University, Nanjing, Jiangsu 211189, China
- State Key Laboratory of High Performance Civil Engineering Materials, Jiangsu Sobute New Materials Co., Ltd., Nanjing, Jiangsu 210008, China
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Tararushkin EV, Pisarev VV, Kalinichev AG. Interaction of Nitrite Ions with Hydrated Portlandite Surfaces: Atomistic Computer Simulation Study. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5026. [PMID: 37512300 PMCID: PMC10383609 DOI: 10.3390/ma16145026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 07/12/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023]
Abstract
The nitrite admixtures in cement and concrete are used as corrosion inhibitors for steel reinforcement and also as anti-freezing agents. The characterization of the protective properties should account for the decrease in the concentration of free NO2- ions in the pores of cement concretes due to their adsorption. Here we applied the classical molecular dynamics computer simulation approach to quantitatively study the molecular scale mechanisms of nitrite adsorption from NaNO2 aqueous solution on a portlandite surface. We used a new parameterization to model the hydrated NO2- ions in combination with the recently upgraded ClayFF force field (ClayFF-MOH) for the structure of portlandite. The new NO2- parameterization makes it possible to reproduce the properties of hydrated NO2- ions in good agreement with experimental data. In addition, the ClayFF-MOH model improves the description of the portlandite structure by explicitly taking into account the bending of Ca-O-H angles in the crystal and on its surface. The simulations showed that despite the formation of a well-structured water layer on the portlandite (001) crystal surface, NO2- ions can be strongly adsorbed. The nitrite adsorption is primarily due to the formation of hydrogen bonds between the structural hydroxyls on the portlandite surface and both the nitrogen and oxygen atoms of the NO2- ions. Due to that, the ions do not form surface adsorption complexes with a single well-defined structure but can assume various local coordinations. However, in all cases, the adsorbed ions did not show significant surface diffusional mobility. Moreover, we demonstrated that the nitrite ions can be adsorbed both near the previously-adsorbed hydrated Na+ ions as surface ion pairs, but also separately from the cations.
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Affiliation(s)
- Evgeny V Tararushkin
- International Laboratory for Supercomputer Atomistic Modelling and Multi-Scale Analysis, HSE University, 101000 Moscow, Russia
| | - Vasily V Pisarev
- International Laboratory for Supercomputer Atomistic Modelling and Multi-Scale Analysis, HSE University, 101000 Moscow, Russia
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412 Moscow, Russia
| | - Andrey G Kalinichev
- Laboratoire SUBATECH, UMR 6457-Institut Mines Télécom Atlantique, Nantes Université, CNRS/IN2P3, 44307 Nantes, France
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González-Caro Á, Merino-Lechuga AM, Fernández-Ledesma E, Fernández-Rodríguez JM, Jiménez JR, Suescum-Morales D. The Effect of Acanthocardia tuberculata Shell Powder as Filler on the Performance of Self-Compacting Mortar. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1734. [PMID: 36837361 PMCID: PMC9964419 DOI: 10.3390/ma16041734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
In this research, the feasibility of using Acanthocardia tuberculata shell waste from the canning industry in the manufacturing of self-compacting mortar (SCM) was tested. The seashells were finely ground to be used as filler instead of the limestone filler normally used in this type of SCM. First, a physicochemical and microstructural characterisation of all raw materials was carried out, including the particle size distribution of both fillers. Subsequently, the self-compactability properties in the fresh state of SCM were evaluated using a total substitution by volume of limestone filler for seashell powder, using different self-compactiblity parameters. The mineralogical phases of all the SCM tested were identified once hardened by means of X-ray diffraction technique, thermogravimetric and differential thermal analysis. In addition, the mechanical properties, water absorption capacity, dry bulk density and accessible porosity of water of hardened mortars at 28 days of curing were analysed. The effect of replacing limestone filler by Acanthocardia tuberculata filler resulted in a decrease in compressive strength of 29.43, 16.84 and 2.29%, respectively. The results indicate that it is possible to completely replace natural limestone filler with Acanthocardia tuberculata shell filler without significantly affecting the mechanical properties of SCM.
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Affiliation(s)
- Ágata González-Caro
- Área de Química Inorgánica, Escuela Politécnica Superior de Belmez, Universidad de Córdoba, 14240 Córdoba, Spain
| | - Antonio Manuel Merino-Lechuga
- Área de Ingeniería de la Construcción, Escuela Politécnica Superior de Belmez, Universidad de Córdoba, 14240 Córdoba, Spain
| | - Enrique Fernández-Ledesma
- Área de Ingeniería de la Construcción, Escuela Politécnica Superior de Belmez, Universidad de Córdoba, 14240 Córdoba, Spain
| | | | - José Ramón Jiménez
- Área de Ingeniería de la Construcción, Escuela Politécnica Superior de Belmez, Universidad de Córdoba, 14240 Córdoba, Spain
| | - David Suescum-Morales
- Área de Ingeniería de la Construcción, Escuela Politécnica Superior de Belmez, Universidad de Córdoba, 14240 Córdoba, Spain
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State-of-the-Art Review of Capabilities and Limitations of Polymer and Glass Fibers Used for Fiber-Reinforced Concrete. MATERIALS 2021; 14:ma14020409. [PMID: 33467581 PMCID: PMC7829961 DOI: 10.3390/ma14020409] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/02/2021] [Accepted: 01/05/2021] [Indexed: 11/16/2022]
Abstract
The concrete industry has long been adding discrete fibers to cementitious materials to compensate for their (relatively) low tensile strengths and control possible cracks. Extensive past studies have identified effective strategies to mix and utilize the discrete fibers, but as the fiber material properties advance, so do the properties of the cementitious composites made with them. Thus, it is critical to have a state-of-the-art understanding of not only the effects of individual fiber types on various properties of concrete, but also how those properties are influenced by changing the fiber type. For this purpose, the current study provides a detailed review of the relevant literature pertaining to different fiber types considered for fiber-reinforced concrete (FRC) applications with a focus on their capabilities, limitations, common uses, and most recent advances. To achieve this goal, the main fiber properties that are influential on the characteristics of cementitious composites in the fresh and hardened states are first investigated. The study is then extended to the stability of the identified fibers in alkaline environments and how they bond with cementitious matrices. The effects of fiber type on the workability, pre- and post-peak mechanical properties, shrinkage, and extreme temperature resistance of the FRC are explored as well. In offering holistic comparisons, the outcome of this study provides a comprehensive guide to properly choose and utilize the benefits of fibers in concrete, facilitating an informed design of various FRC products.
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Liang Y. Mechanical and fracture properties of calcium silicate hydrate and calcium hydroxide composite from reactive molecular dynamics simulations. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.138117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hajilar S, Shafei B. Structure, orientation, and dynamics of water-soluble ions adsorbed to basal surfaces of calcium monosulfoaluminate hydrates. Phys Chem Chem Phys 2018; 20:24681-24694. [PMID: 30187069 DOI: 10.1039/c8cp03872d] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transport of water molecules and chloride ions in nanopores of hydrated cement paste (HCP) is proven to adversely affect the long-term durability of reinforced concrete structures exposed to seawater or deicing salts. The resistance against chloride attack is primarily associated with the chloride binding capacity of the main HCP constituents. Experimental tests revealed that AFm phases of HCP play a central role in binding the chloride ions. However, many aspects of AFm-solution interactions were largely unknown, especially at their interfaces. This was the motivation of the current study, in which the atomistic processes underlying the transport of water-soluble ions are investigated in detail using the classical molecular dynamics (MD) method. To this end, an aqueous layer containing various concentrations of sodium chloride solution is sandwiched between two basal surfaces of calcium monosulfoaluminate hydrate, which is the most abundant phase of AFm. The adsorption mechanisms of water molecules and diffusing ions are then characterized for inner- and outer-sphere distance ranges from the basal surfaces of monosulfoaluminate. It is found that the self-diffusion coefficient of the chloride and sodium ions present in the outer-sphere range are 83% and 47% larger than those residing in the inner-sphere range. With increasing the distance from the solid surface, an increase in the self-diffusion coefficient is captured. This increase in mobility is larger for chloride ions than sodium ions. This can be understood based on the observation that the inner- and outer-sphere complex formation are the governing adsorption mechanisms for the chloride and sodium ions, respectively.
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Affiliation(s)
- Shahin Hajilar
- Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA 50011, USA.
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Fe/starch nanoparticle - Pseudomonas aeruginosa: Bio-physiochemical and MD studies. Int J Biol Macromol 2018; 117:51-61. [DOI: 10.1016/j.ijbiomac.2018.04.191] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/15/2018] [Accepted: 04/30/2018] [Indexed: 12/23/2022]
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Hajilar S, Shafei B. Atomic-scale investigation of physical adsorption of water molecules and aggressive ions to ettringite's surfaces. J Colloid Interface Sci 2018; 513:104-116. [PMID: 29132102 DOI: 10.1016/j.jcis.2017.09.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/31/2017] [Accepted: 09/02/2017] [Indexed: 11/15/2022]
Abstract
The strength and durability of cementitious composite materials are adversely affected by the ingress of water molecules and aggressive ions into their intrinsic meso- and nano-pore spaces. Among various phases of hydrated cement paste (HCP), aluminum-rich phases play an important role in controlling the diffusivity of aqueous solutions, which can contain aggressive ions. To this date, however, there has been no systematic study to understand the adsorption mechanisms and chloride binding capacity of the aluminum-rich phases of HCP. This research gap has been the motivation of the current study to investigate the physical adsorption characteristics of ettringite as the main aluminum-rich phase of HCP and the primary hydrated product of calcium sulfoaluminate cement. Through a set of Molecular Dynamics simulations supported by macro-scale experimental tests, a fundamental insight into the molecular origins of the diffusion of water molecules, as well as sodium and chloride ions, in contact with ettringite is provided. As the primary objective of this study is to evaluate the transport properties at and near solution/solid interfaces, the molecular adsorption mechanisms are characterized for inner- and outer-sphere distances from the solid substrate. With an in-depth understanding of the structure and dynamics of water molecules and aggressive ions in contact with ettringite's surfaces, the outcome of this study provides reliable measures of physical adsorption, binding capacity, and self-diffusion coefficient, which can be further employed to introduce strategies to avoid the degradation of a wide variety of cementitious materials exposed to harsh environmental conditions.
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Affiliation(s)
- Shahin Hajilar
- Department of Civil, Construction and Environmental Engineering, Iowa State University, Ames, IA 50011-1066, United States.
| | - Behrouz Shafei
- Department of Civil, Construction and Environmental Engineering, Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011-1066, United States.
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Hajilar S, Shafei B, Cheng T, Jaramillo-Botero A. Reactive Molecular Dynamics Simulations to Understand Mechanical Response of Thaumasite under Temperature and Strain Rate Effects. J Phys Chem A 2017; 121:4688-4697. [PMID: 28530814 DOI: 10.1021/acs.jpca.7b02824] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the structural, thermal, and mechanical properties of thaumasite is of great interest to the cement industry, mainly because it is the phase responsible for the aging and deterioration of civil infrastructures made of cementitious materials attacked by external sources of sulfate. Despite the importance, effects of temperature and strain rate on the mechanical response of thaumasite had remained unexplored prior to the current study, in which the mechanical properties of thaumasite are fully characterized using the reactive molecular dynamics (RMD) method. With employing a first-principles based reactive force field, the RMD simulations enable the description of bond dissociation and formation under realistic conditions. From the stress-strain curves of thaumasite generated in the x, y, and z directions, the tensile strength, Young's modulus, and fracture strain are determined for the three orthogonal directions. During the course of each simulation, the chemical bonds undergoing tensile deformations are monitored to reveal the bonds responsible for the mechanical strength of thaumasite. The temperature increase is found to accelerate the bond breaking rate and consequently the degradation of mechanical properties of thaumasite, while the strain rate only leads to a slight enhancement of them for the ranges considered in this study.
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Affiliation(s)
- Shahin Hajilar
- Department of Civil, Construction and Environmental Engineering, Iowa State University , Ames, Iowa 50011, United States
| | - Behrouz Shafei
- Department of Civil, Construction and Environmental Engineering, Iowa State University , Ames, Iowa 50011, United States.,Department of Materials Science and Engineering, Iowa State University , Ames, Iowa 50011, United States
| | - Tao Cheng
- Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
| | - Andres Jaramillo-Botero
- Chemistry and Chemical Engineering, California Institute of Technology , Pasadena, California 91125, United States
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