Cement Nanocomposites Research Articles

Study on the Effect of Residual Polymer Superplasticizer on the Properties of Graphene-Cement Composites.

Graphene, renowned for its exceptional mechanical, thermal, and electrical properties, is being explored as a cement nanofiller in the construction field. However, the limited water dispersibility of graphene requires the use of polymer superplasticizers, such as polycarboxylate ether (PCE). Previous studies have investigated the mechanisms by which PCE facilitates the dispersion of graphene within cement nanocomposites. However, such studies have made minimal progress, indicating a lack of understanding of the effect of residual PCE (rPCE) remaining in aqueous solution without binding to graphene. In this study, the effects of rPCE on the dispersion of graphene and the mechanical properties of graphene-cement composites (GCCs) were systematically analyzed. For this purpose, the content of rPCE was accurately measured through the centrifugation process and thermal analysis of graphene dispersion with PCE, and the result was 78.0 wt.% compared to graphene. The optical microscopy, particle size analysis, and contact angle measurement of the graphene dispersions with and without rPCE confirmed that rPCE is crucial for the dispersion of graphene and the enhancement of the interfacial affinity between graphene and cement. Additionally, the compressive strength of GCC with rPCE exhibited a substantial enhancement of approximately 10% (68.36 MPa) compared to plain cement (62.33 MPa). The effectiveness of rPCE in enhancing compressive strength correlated with the uniform dispersion of graphene within GCC and the promotion of cement hydration, as evidenced by field emission scanning electron microscopy and X-ray diffraction, respectively.

Development of cement nanocomposites reinforced by carbon nanotube dispersion using superplasticizers

Development of cement nanocomposites reinforced by carbon nanotube dispersion using superplasticizers

Reinforcement of Cement Nanocomposites through Optimization of Mixing Ratio between Carbon Nanotube and Polymer Dispersing Agent.

Carbon nanotubes (CNTs), known for their exceptional mechanical, thermal, and electrical properties, are being explored as cement nanofillers in the construction field. However, due to the limited water dispersion of CNTs, polymer dispersing agents like polycarboxylate ether (PCE) and sulfonated naphthalene formaldehyde (SNF) are essential for uniform dispersion. In a previous study, PCE and SNF, common cement superplasticizers, effectively dispersed CNTs in cement nanocomposites. However, uncertainties remained regarding the extent to which all dispersing agents interacted efficiently with CNTs. Therefore, this research quantitatively assessed CNT interaction with dispersing agents through dispersion and centrifugation. Approximately 37% of PCE and 50% of SNF persisted compared to CNT after centrifugation. The resulting cement nanocomposites, with optimized mixing ratios, exhibited enhanced compressive strength of about 14% for CNT/PCE (78.13 MPa) and 12.3% for CNT/SNF (76.97 MPa) compared to plain cement (68.52 MPa). XRD results linked strength reinforcement to increased cement hydrate from optimized CNT dispersion. FE-SEM analysis revealed that CNTs were positioned within the pores of the cement. These optimized cement nanocomposites hold promise for improved safety in the construction industry.

Mechanical and smart properties of cement nanocomposites containing nanomaterials: A brief review

Mechanical and smart properties of cement nanocomposites containing nanomaterials: A brief review

Development of isotopically labelled 65Cu embedded PMMA-65CuO nanocomposites for detection and quantification of PMMA bone cement degradation at trace levels

Polymethyl methacrylate (PMMA) bone cement is a popular bone-filling material for biomedical applications. Bone-cement implant failure is a common occurrence, but the consequence of this failure can be prevented/minimised by early detection of degradation. This work utilises a stable isotope labelling approach to monitor PMMA bone cement degradation. Stable isotopically enriched traceable nanoparticles of 65CuO were synthesized and introduced to PMMA bone cement. Accelerated and normal degradation of 65CuO-loaded PMMA bone cement nanocomposite was performed in acetone and simulated body fluid (SBF). 65Cu was detected and quantified upon PMMA bone cement nanocomposite degradation. The results showed a linear correlation between bone cement degradation and tracer release. When the 65CuO-PMMA composite deteriorated by 6.10 ± 3.04% in acetone, 5.6 ± 2.5 µg of tracer was released in 10 min. Similarly, after one week of degradation in SBF, 0.35 ± 0.31 µg of 65Cu tracer was released, translating to a 0.18 ± 0.09% weight loss. The stable isotopic tracer approach allowed us to measure and detect 65Cu under conditions of high background Cu concentration present in the human body upon 0.2% of PMMA nanocomposite degradation. 65CuO nanoparticles addition to PMMA bone cement did not alter the cytocompatibility (proliferation, differentiation, and osteocalcin formation) in MG-63 cells.

Multifunctional performance of core–shell rGO@Fe3O4 on the mechanical, electrical/thermal, EMI, and microstructure properties of cement-based composites

This research study focuses on the development of a multifunctional cement nanocomposite using reduced graphene oxide (rGO) nanosheets. To address the challenges of rGO dispersion, a core–shell structure of rGO@Fe3O4 (rGO@F) was investigated in cement paste. The rGO@F nanohybrid was thoroughly characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The main objectives of this study were to improve the mechanical properties, electrical conductivity, thermal conductivity, and chemical properties of the cement composite through the incorporation of rGO@F. The performance of the cement paste containing rGO0.1@Fe3O4 (0.1 wt% rGO and 1 wt% Fe3O4) was evaluated, and it was found that its toughness and compressive strength were significantly enhanced compared to the reference sample. Furthermore, the addition of rGO@F led to a remarkable increase in the electrical and thermal conductivity of the modified cement composite, attributed to the formation of conductive pathways facilitated by the rGO nanosheets. Comprehensive analyses including XRD, TGA, differential scanning calorimetry (DSC), thermally assisted microscopy (TAM), FTIR, and X-ray photoelectron spectroscopy (XPS) confirmed that the rGO@F nanohybrid had a significant impact on the chemical properties and hydration process of the hardened cement paste. SEM images revealed a more compact microstructure of the cement paste in the presence of rGO@F, demonstrating its role in crack inhibition. Additionally, an increase in the formation of improved hydration crystals such as tobermorite and jennite was observed. The core–shell structure of rGO@F exhibited exceptional electromagnetic wave absorption properties due to its layered configuration, effectively trapping the electromagnetic waves. Overall, this research study highlights the successful fabrication of a multifunctional cement nanocomposite through the incorporation of rGO@F. The findings demonstrate significant improvements in mechanical strength, electrical conductivity, thermal conductivity, chemical properties, crack inhibition, and electromagnetic wave absorption. This research contributes to the advancement of cement-based materials with enhanced performance and opens up avenues for various applications in fields such as construction, infrastructure, and telecommunications.

Effect of graphene oxide and functionalized carbon nanotubes on mechanical and durability properties of high volume fly-ash cement nanocomposite

In the current investigation, the effect of Graphene Oxide (GO) and Functionalized Carbon Nanotubes (FCNTs) on the mechanical and durability properties of High Volume Fly-ash (HVFA) cement nanocomposite. The two control samples are fabricated including OPC-C and HVFA-C, whereas, the GO (0.005, 0.01, 0.02, and 0.04% by weight of binder) incorporated samples are called HVFA-GO-CNCs and for FCNTs (0.005, 0.01, 0.02, and 0.04% by weight of binder) incorporated samples are named as HVFA-FCNT-CNCs. It was observed the addition of 0.02% GO and 0.02% FCNTs in HVFA cement nanocomposite improved compressive (37.21, 27%) and tensile strength (61.71, 41.93%) as compared to the control (HVFA-C) at a curing age of 90 days. Electrical resistivity for all mixes of HVFA-GO-CNCs has been increased with increasing dosages of GO, while in the case of HVFA-FCNT-CNCs decreased with increasing dosages of FCNTs. The capillary water absorption test results observed that incorporating the GO and FCNTs into the HVFA cement nanocomposite decreased water absorption with increasing dosages of GO and FCNTs. After acid attack on HVFA-GO-CNCs and HVFA-FCNT-CNCs, compressive strength was decreased and after sulphate attack on HVFA-GO-CNCs and HVFA-FCNT-CNCs, compressive strength was found to be increased as compared to water cured sample, at 90 days of curing. In this study, GO significantly improves compressive, tensile strength, apparent electrical resistivity, reduces capillary water absorption, and more resistant to acid/sulphate attack of HVFA cement nanocomposite as compared to the FCNTs. So, the current study provides a suitable path for the production of eco-friendly, cost-effective, better mechanical properties, and more durable building materials.

Study on Interfacial Interaction of Cement-Based Nanocomposite by Molecular Dynamic Analysis and an RVE Approach

There is an increased demand for cement nanocomposites in the twenty-first century due to their composition, higher strength, high efficiency, and multiscale nature. As carbon nanotubes (CNTs) possess extremely high strength, resilience, and stiffness, inclusion of carbon nanotubes in small quantities to the concrete mix makes them a multifunctional material. A molecular level understanding is significant to capacitate the macrolevel properties of these composites. In the proposed work, molecular dynamics (MD) simulations are used to understand the behaviour of the composites at the atomic level and continuum mechanics with representative volume element (RVE) homogenization modelling is carried out for interfacial interaction study of composites. The mechanical properties such as Young’s modulus, shear modulus, and poisons are evaluated using previous methods of simulations for different compositions of nanomaterials in cement matrix. The FORCITE module of MD simulation and square RVE model is used to determine the mechanical, electrical properties, and elastic constants of the cement nanocomposite. The MD simulation describes the linking effect of CNT into cement matric, and the RVE modelling study reveals the pull-out effect of CNT from matrix. From experimental and analytical studies, it is found that increase in CNT till 0.5% weight fraction increases the mechanical properties about 12% and further increasing of CNT weight fraction causes a reduction in mechanical properties about 5% due to the agglomeration of nanotubes. The density of states method in MD simulation indicates that mobility of the electrons increases with an increase in carbon nanotube proportion in the composites. The experimental test results substantiate the analytical studies, and the error obtained from both approaches is less than 20%. From the analytical study, the average maximum Young’s modulus, shear modulus, and bulk modulus are obtained as 46 GPa, 31 GPa, and 32 GPa for 0.5% weight fraction of CNT in cement matrix. Hence, it is concluded that 0.5% weight fraction of CNT is considered as optimum dosage to obtain better electrical and mechanical properties.

The effect of foamed cement nanocomposite as counter electrode on the performance of dye‐sensitized solar cell

AbstractImproper interparticle connection between carbon‐based materials, poor interface bonding between the carbon counter electrodes (CEs) and substrate, and low surface area are the main limitations of carbon‐based CEs in dye‐sensitized solar cells. In this study, we utilized foamed cement and binder for adherence and surface area improvement in carbon‐based CEs, such as graphite, multi‐walled carbon nanotubes, and carbon black (CB). The results revealed that incorporating foamed cement into carbon materials improved the resistance, short‐circuit current density, fill factor, and power conversion efficiency of the device. The porous cement/CB nanocomposite CE with a photoconversion efficiency of 5.51% exhibited the best photovoltaic performance. Moreover, this nanocomposite electrode showed an enhancement catalytic activity by high current density in cyclic voltammogram, low charge transfer resistance ) in electrochemical impedance spectroscopy, and high exchange current density in Tafel measurements compared to other electrodes. The porosity of foamed cement has been found to be the main cause of its superior photovoltaic performance, which expands the contact area with the electrode and enables rich ion transport. Additionally, the enhanced performance was due to strong bonding, crack‐free deposited films, superior conductivity, and high catalytic activity.

Implementation of Cement-based nano composite Energy Absorption Damper to improve the damping properties of concrete and monitoring applications

The energy from the moving seismic waves through a building structure is dispersed by means of dampers. Dampers work by converting the kinetic energy into heat energy, dissipating it into the hydraulic fluid. Damper systems are designed and manufactured to protect structural integrity, reduce structural damage, and prevent injury to people by absorbing energy from earthquakes and minimizing structural deformations. The most effective way to achieve good vibration damping is by tailoring the construction materials such as cement with nanomaterials like Silica, Alumina, Graphene, CNTs, etc. This paper focuses on developing a vibration damper, prepared by cement nanocomposite containing MWCNTs and Carbon fibers. The tests, such as the Impact, Flexural, and Compressive strength tests, are conducted to investigate their energy-absorbing capacity, strength, and durability. The microstructural analysis SEM is performed to know the morphology of concrete mix with MWCNTs and Carbon fibers on damping mechanism. Impact test results indicate that the beams without MWCNTs and CFs exhibited an average energy absorption of 248 J, while those with MWCNTs and CFs absorbed an average energy of 262 J which shows almost 15% more energy absorption. Adding nanomaterials in a cement matrix improves concrete’s frictional damping energy consumption ability and increases structures’ energy-absorbing properties, flexural strength, and compressive strength.

The Effect of Carbon Black, MWCNT and Carbon Fiber on Flexural behavior of cement nano composites

One of the most popular and commonly utilised building materials is concrete. The recent studies of materials science explains influence of nano materials on cement composite at the macro, micro or structural level and their application in construction industry. In present study flexural behavior of cement nano composite containing nano materials such such as Multi-walled carbon nanotubes (MWCNTs) and Carbon fibers (CFs) and carbon black (CB) are studied. The various sample are prepared and flexural test is carried out. The flexural responses of plain cement beams and CB-CF- CNTs/cement beams were compared using single point bending tests results. The hybridization of MWCNTs, CFs, and Carbon Black coated with cement indicates improvement in mechanical properties compared to other samples. The SEM indicates the strong bonding between CFs, MWCNTs, and the cement matrix.

Piezo-resistive Properties of Polymer based cement nano composites

The nano technology has potential applications in development self-sensing smart materials. These nano materials is used in cement matrix or polymer base to improve the mechanical and piezo electrical properties of composites. In the present study, the graphene and carbon nano tube are added in matric, which acts as the conductive fibre into polymer cement composites. Cement based polymer composites are prepared by adding carbon fibre, epoxy resin, carbon nano tube and graphene as conductive filler in matrix to prepare the distinctive specimens for experimental investigations. The electro mechanical test are carried out to assess the piezo electrical properties of these composites subjected gradual increase of mechanical loading such as flexural and compression. The present study describes the self-sensing piezo-resistive capability of composite to monitor the strain in structures. The experimental test elucidates the addition of epoxy in cement matrix enhance the mechanical properties while carbon nano tube and graphene proves to be promising smart self-sensing materials in composites by measuring the variation in stress at critical regions. The SEM with EDX analysis shows that epoxy resin act as binding agent which hinder the cracks propagations and improves the mechanical properties of composites.

Comparative effects of nano-silica and graphene oxide on Pozzolana Portland cement nanocomposites

Comparative effects of nano-silica and graphene oxide on Pozzolana Portland cement nanocomposites

Preparation, property determination and bridge health monitoring applications of self-sensing cement nanocomposites

Graphene has local superconductivity, very high electron mobility, good mechanical properties and high stability, and is therefore an excellent filler material for self-sensing cementitious composites. The incorporation of graphene provides a broad application prospect for the development of self-sensing cementitious composites. This work explored the effects of polyethylene (PE) fiber size and surface modifiers on the compressive and tensile properties of ultra-high performance concrete (UHPC). Then, graphene was added on this basis to observe the effect of graphene doping on the electrical properties of UHPC and to select the optimal doping amount. Finally, the mechanical properties and tensile and compressive self-sensing of the UHPC added with graphene were tested. Finally, the bridge with higher stress under self-weight is simulated by finite element to find the location of sensor placement and design a simple bridge health monitoring system.

Portland cement hydration in the vicinity of electrically polarized conductive surfaces

Hardening of Portland cement-based materials in vicinity of electrically conductive surfaces, especially when the surfaces are electrically or galvanically polarized, can lead to both morphological and chemical changes in cement close to the surfaces due to combined electrochemical and electrophysical processes.Cement hydration products close to graphite and steel surfaces being positively (anode) and negatively (cathode) electrically polarized (direct current) were studied. Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy were used to compare structure and atomic composition of cement hydration products on cathode, anode and a reference surface with no electrical polarization.The application of direct current (DC) potential in aqueous Portland G cement dispersion significantly affects cement hydration products close to cathode and anode and different products were found at the anode compared to the cathode surfaces. At the graphite anode, calcium sulphate crystals along with calcium hydroxide were most abundant, while the graphite cathode was mainly covered with calcium hydroxide. The calcium hydroxide carbonated upon exposure to air during drying. When steel electrodes where used, the most significant adsorption occurred at the anode, in contrast to graphite where the largest amount of the adsorbed material was found on the cathode. The observed differences were explained in view of electrophysical (electrophoresis, electroosmosis) and electrochemical (reduction and oxidation) processes occurring at electrode surfaces upon application of DC current.The knowledge gained in this work is important for engineering of electrically conductive cement nano-composites where typically the contact surface of an electrically conductive filler and a cementitious matrix is high.

Fabrication of polyamide-12/cement nanocomposite and its testing for different dyes removal from aqueous solution: characterization, adsorption, and regeneration studies

Polyamide-12/Portland cement nanocomposite was prepared by using the exfoliated adsorption method. The fabricated nanocomposite was applied first time to remove Congo red (CR), brilliant green (BG), methylene blue (MB), and methyl red (MR) from the synthetic wastewater. The polymer nanocomposite was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, Brunauer–Emmett–Teller surface area analysis, and X-ray diffraction. The adsorption was rapid and all the studied dyes were absorbed on the surface of the polymer nanocomposite in 90 min. The point of zero charge was found at pH 5 and the factors such as pH, time, and temperature were found to affect the adsorption efficiency. Freundlich isotherm and pseudo-second-order models well-fitted the adsorption isotherm and kinetics data, respectively. The calculated maximum adsorption capacity was 161.63, 148.54, 200.40, and 146.41 mg/g for CR, BG, MB, and MR, respectively. The mode of the adsorption process was endothermic, spontaneous, and physical involving electrostatic attraction. On an industrial scale, the high percentage of desorption and slow decrease in the percentage of adsorption after every five regeneration cycles confirm the potential, practicality, and durability of the nanocomposite as a promising and advanced adsorbent for decolorization of colored wastewater.

Dispersion of Multi-Walled Carbon Nanotubes into White Cement Mortars: The Effect of Concentration and Surfactants.

Multi-wall carbon nanotubes (MWCNTs) exhibit exceptional mechanical and electrical properties and can be used to improve the mechanical and piezoelectric properties of cement-based materials. In the present study, the effect of different MWCNT concentrations as well as different types of surfactants and a superplasticizer were examined to reinforce, at the nanoscale, a white cement mortar typically used for the restoration of monuments of cultural heritage. It was shown that sodium dodecylbenzenesulfonate (SDBS) and Triton X-100 surfactants slightly decreased the white cement mortars’ electrical resistivity (by an average of 10%), however, the mechanical properties were essentially decreased by an average of 60%. The most suitable dispersion agent for the MWCNTs proved to be the superplasticizer Ceresit CC198, and its optimal concentration was investigated for different MWCNT concentrations. Carboxylation of the MWCNT surface with nitric acid did not improve the mechanical performance of the white cement nanocomposites. The parametric experimental study showed that the optimum combination of 0.8 wt% of cement superplasticizer and 0.2 wt% of cement MWCNTs resulted in a 60% decrease in the electrical resistivity; additionally, the flexural and compressive strengths were both increased by approximately 25% and 10%, respectively.

Machining of Polymethyl-methacrylate (PMMA) bone cement-based nanocomposite using Combined compromise solution (CoCoSo) theory

Polymethyl-methacrylate (PMMA) bone cement has become an effective biomaterial in orthopedic applications due to its outstanding biocompatibility and mechanical properties. A machining test is essential required while using PMMA bone cement nanocomposite in implant applications. Drilling on the prosthetic product is mainly needed when using PMMA to insert bolts for safety and fixation in the human body. The drilling on bone cement-based prostheses is the most often used machining method during bone-grafting and implant interface surgical procedures. Henceforth, this article focus on the relatively new Combined compromise solution (CoCoSo) theory to study the influence of varying process variables on the drilling performance of Graphene Nanoplatelets (GNP) infused PMMA bone cement nanocomposites. The control of process constraints, namely, GNP weight percentage (Wt.%), spindle speed (SPEED), and drill bit tool material (TOOL) such as HSS, Carbide, and TiAlN, is mainly done to achieve the desired value of Surface roughness (SR) and Material removal rate (MRR) during the drilling experimentation. Using the CoCoSo technique, the optimum setting was attained as Wt.% = 4, SPEED = 1428 rpm, and a Carbide drill bit tool. The synthesized sample was also subjected to an XRD examination to validate the appropriate infusion of nanomaterials in PMMA bone cement. The flexural analysis of the developed nanocomposite sample indicates that mechanical property improves significantly due to the supplement of GNP in PMMA. The findings of the proposed nanocomposites material show its feasibility in biomedical functions. Also, the drilling optimization results demonstrate new criteria to control the quality and productivity indices. It can be recommended for multicriteria optimization case studies.

Optimization of the Mechanical Properties and the Cytocompatibility for the PMMA Nanocomposites Reinforced with the Hydroxyapatite Nanofibers and the Magnesium Phosphate Nanosheets.

Commercial poly methyl methacrylate (PMMA)-based cement is currently used in the field of orthopedics. However, it suffers from lack of bioactivity, mechanical weakness, and monomer toxicity. In this study, a PMMA-based cement nanocomposite reinforced with hydroxyapatite (HA) nanofibers and two-dimensional (2D) magnesium phosphate MgP nanosheets was synthesized and optimized in terms of mechanical property and cytocompatibility. The HA nanofibers and the MgP nanosheets were synthesized using a hydrothermal homogeneous precipitation method and tuning the crystallization of the sodium-magnesium-phosphate ternary system, respectively. Compressive strength and MTT assay tests were conducted to evaluate the mechanical property and the cytocompatibility of the PMMA-HA-MgP nanocomposites prepared at different ratios of HA and MgP. To optimize the developed nanocomposites, the standard response surface methodology (RSM) design known as the central composite design (CCD) was employed. Two regression models generated by CCD were analyzed and compared with the experimental results, and good agreement was observed. Statistical analysis revealed the significance of both factors, namely, the HA nanofibers and the MgP nanosheets, in improving the compressive strength and cell viability of the PMMA-MgP-HA nanocomposite. Finally, it was demonstrated that the HA nanofibers of 7.5% wt and the MgP nanosheets of 6.12% wt result in the PMMA-HA-MgP nanocomposite with the optimum compressive strength and cell viability.

Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing.

Cement is the most widely consumed material globally, with the cement industry accounting for 8% of human-caused greenhouse gas emissions. Aiming for cement composites with a reduced carbon footprint, this study investigates the potential of nanomaterials to improve mechanical characteristics. An important question is to increase the fraction of carbon-based nanomaterials within cement matrices while controlling the microstructure and enhancing the mechanical performance. Specifically, this study investigates the fracture response of Portland cement reinforced with one- and two-dimensional carbon-based nanomaterials, such as carbon nanofibres, multiwalled carbon nanotubes, helical carbon nanotubes and graphene oxide nanoplatelets. Novel processing routes are shown to incorporate 0.1–0.5 wt% of nanomaterials into cement using a quadratic distribution of ultrasonic energy. Scratch testing is used to probe the fracture response by pushing a sphero-conical probe against the surface of the material under a linearly increasing vertical force. Fracture toughness is then computed using a nonlinear fracture mechanics model. Nanomaterials are shown to bridge nanoscale air voids, leading to pore refinement, and a decrease in the porosity and the water absorption. An improvement in fracture toughness is observed in cement nanocomposites, with a positive correlation between the fracture toughness and the mass fraction of nanofiller for graphene-reinforced cement. Moreover, for graphene-reinforced cement, the fracture toughness values are in the range of 0.701 to 0.717 MPa. Thus, this study illustrates the potential of nanomaterials to toughen cement while improving the microstructure and water resistance properties.This article is part of a discussion meeting issue ‘A cracking approach to inventing new tough materials: fracture stranger than friction’.