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Research and development of nanocomposites have become a scientific field of interest in the last decade. These are formed from mixtures of polymers and inorganic solids that combine to form a heterogeneous/hybrid material. They are a type of matrix added to nanoparticles to enhance mechanical properties and additional properties such as electrical, physical and optical properties, followed by size repositioning. These matrices are added in a concentration of about 0.5–2% in the nanocomposite structure. Minor changes in structure, composition, interfacial interactions and components or any exclusive properties may instigate the product. Regarding the method of preparation, the biopolymer and inorganic matrix are grown and polymerized in situ to create a nanocomposite material. The use of nanocomposites has increased its share of interest in biomedical and pharmaceutical sciences, as they can be used as a medicinal carrier due to their morphological properties, such as their surface and rheological properties. This comprehensive review aims to discuss the advantages and disadvantages of nanocomposites, their method of preparation, their types and the utility of nanocomposites as a controlled and targeted delivery system, their use to deliver anticancer, antimicrobial, anti-inflammatory, antidiabetic and cardiovascular drugs, including their prospects. [ABSTRACT FROM AUTHOR]

The peculiarities of adsorption removal of the mixture of heavy metal ions Cu, Cd, Co, Zn, and Cr from an aqueous solution using clay-supported nanoscale zero-valent iron (nZVI) composite materials were investigated. As an inorganic matrix for stabilizing nZVI the aluminosilicates kaolinite (K) (1:1), montmorillonite (MMT) (2:1) and palygorskite (Pg) (2:1) were used. Powder X-ray diffraction (XRD), N2 adsorption-desorption, electrochemical methods, and inductively coupled plasma atomic emission spectroscopy were used to characterize the samples. Adsorption experiments were investigated in a wide range рН. The obtained results show that at pH 6, the adsorption of heavy metal ions for modified samples is two to four times higher than for natural clay minerals. The experimental results were analyzed using Freundlich and Langmuir models of adsorption isotherms. The selectivity coefficients for all pairs of heavy metals (HM) were calculated. It shows that the adsorption centers on the surfaces of layer silicates form strong complexes with heavy metal ions, which correspond to the Irving-Williams series of stability of the corresponding complexes in solutions: Cu > Zn > Co > Cd > Cr. The role of the dispersed matrix as a stabilizing component of highly reactive nano-dispersed iron in the composite adsorbent is determined. According to the efficiency of removal of heavy metals from aqueous solutions, composite materials form a sequence: nZVI-montmorillonite ≥ nZVI-palygorskite > nZVI-kaolinite. The results indicated that clay-supported nanoscale zero-valent iron might be an effective material for water purification from the mixture of heavy metal ions. [ABSTRACT FROM AUTHOR]

The pore structure of shale oil reservoirs is complex, and the microscale and nanoscale effect is obvious in the development of shale oil reservoirs. Understanding the oil flow mechanism in shale reservoirs is essential for optimizing the development plan and enhancing the recovery rate of shale oil reservoirs. In this review, we briefly introduce the occurrence status of shale oil and shale oil flow in the inorganic matrix and the organic matrix (including the shrinkage of kerogen, oil diffusion in kerogen, oil transport in the organic pore channels, coupling of diffusion, and fluid transport in the organic matrix). Then, the shale oil microflow simulation and a coupling model of double-porous media for microflow and macroflow in the production process of shale oil are discussed. Finally, we summarize the main conclusions and perspectives on the oil flow mechanism and numerical simulations in shale oil reservoirs. An accurate description of shale oil occurrence status and shale oil flow in the inorganic and organic matrices is crucial for the numerical simulation of shale oil reservoirs. It can provide a basis and reference for the future directions of shale oil flow and numerical simulations during the development of shale oil reservoirs. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation of the mechanical properties of rubberised concrete confined with basalt-fibre textile-reinforced mortar (TRM) jackets. The main aim is to evaluate the effectiveness of the TRM confinement scheme on cylindrical rubberised concrete specimens by examining five different mixtures (rubber content ranging from 10.5% up to 42% of the total aggregate volume), including a plain concrete reference mixture. Unconfined and confined specimens with either one or two TRM layers were subjected to monotonic axial loading. The results indicate a decrease in the compressive strength of unconfined concrete as the rubber content increased. The stress–strain curves of rubberised concrete became smoother at the peak as the rubber content increased, also exhibiting increased axial strain capacity post-peak. Rubberised concrete exhibited less brittle failure than plain concrete, accompanied by increased lateral dilation. Confinement with TRM increased the compressive strength, while also enhanced the performance in terms of toughness and axial deformation capacity compared to unconfined concrete. Overall, it is concluded that there is a promising potential for using TRM-confined rubberised concrete in applications with ductility demands and low environmental footprint specifications. [ABSTRACT FROM AUTHOR]

The pore structure of shale oil reservoirs is complex, and the microscale and nanoscale effect is obvious in the development of shale oil reservoirs. Understanding the oil flow mechanism in shale reservoirs is essential for optimizing the development plan and enhancing the recovery rate of shale oil reservoirs. In this review, we briefly introduce the occurrence status of shale oil and shale oil flow in the inorganic matrix and the organic matrix (including the shrinkage of kerogen, oil diffusion in kerogen, oil transport in the organic pore channels, coupling of diffusion, and fluid transport in the organic matrix). Then, the shale oil microflow simulation and a coupling model of double-porous media for microflow and macroflow in the production process of shale oil are discussed. Finally, we summarize the main conclusions and perspectives on the oil flow mechanism and numerical simulations in shale oil reservoirs. An accurate description of shale oil occurrence status and shale oil flow in the inorganic and organic matrices is crucial for the numerical simulation of shale oil reservoirs. It can provide a basis and reference for the future directions of shale oil flow and numerical simulations during the development of shale oil reservoirs.

This work focuses on the mechanical characterization of the inorganic matrix used for Fiber-Reinforced Cementitious Matrix (FRCM) composites, nowadays widely used to retrofit existing reinforced concrete and masonry structures. While several works in technical literature investigate the experimental behavior of the whole FRCM composite, few information are available on the mechanical characterization of the mortar, which contains polymers and synthetic fibers in its admixture. However, the knowledge of its behavior in tension, especially after crack formation, is an important feature for the calibration of constitutive models to be adopted in the study of structural elements strengthened with FRCM. To this aim, an experimental program was performed on mortar specimens characterized by different shapes and dimensions, tested under direct tension or three-point-bending. From the performed tests, it was possible to characterize inorganic matrix behavior both in the uncracked stage, through the determination of the elastic parameters (elastic modulus and Poissons coefficient), and in the cracked stage. The use of digital image correlation (DIC) technique also allowed the study of the evolution of crack propagation in the specimens. Lastly, a correlation factor between axial and flexural tensile strength is proposed, for both design and numerical modelling purposes.

Six matrices based on alkali-activated aluminosilicate with different amounts of potassium phosphate were prepared for the production of six-layer composite plates. The addition of potassium phosphate in the matrix was 2 wt%, 4 wt%, 6 wt%, 8 wt% and 10 wt% of its total weight. The matrix without the potassium phosphate was also prepared. The aim of this study was to determine whether this addition has an effect on the tensile strength or Young’s modulus of composites at temperatures up to 800 °C. Changes in the thickness and weight of the samples after this temperature were also monitored. Carbon plain weave fabric was chosen for the preparation of the composites. The results show that under normal conditions, the addition of potassium phosphate has no significant effect on the mechanical properties; the highest measured tensile strengths were around 350 MPa. However, at temperatures of 600 °C and 800 °C the addition of potassium phosphate had a positive effect, with the tensile strength of the composites being up to 300% higher than the composites without the addition. The highest measured values of composites after one hour at 600 °C were higher than 100 MPa and after 1 h at 800 °C higher than 85 MPa.

The mineral component of fish otoliths (ear bones), which is aragonitic calcium carbonate (CaCO3), makes this structure the preferred sample choice for measuring biological carbon and oxygen-stable isotopes in order to address fundamental questions in fish ecology and fisheries science. The main drawback is that the removal of otoliths requires sacrificing the specimen, which is particularly impractical for endangered and commercially valuable species such as Atlantic bluefin tuna (Thunnus thynnus) (ABFT). This study explores the suitability of using the first dorsal fin spine bone of ABFT as a non-lethal alternative to otolith analysis or as a complementary hard structure. The fin spines of freshly caught ABFT were collected to identify carbonate ions within the mineral matrix (i.e., hydroxyapatite) and to determine the nature of the carbonate substitution within the crystal lattice, knowledge which is crucial for correct measurement and ecological interpretation of oxygen and carbon stable isotopes of carbonates. Fin spine sections were analyzed via X-ray Photoelectron Spectroscopy (XPS), Raman Spectroscopy, and Fourier Transform InfraRed (FTIR). The XPS survey analysis showed signals of Ca, O, and P (three compositional elements that comprise hydroxyapatite). The Raman and FTIR techniques showed evidence of carbonate ions within the hydroxyapatite matrix, with the IR spectra being the most powerful for identifying the type B carbonate substitution as shown by the carbonate band in the v2 CO32− domain at ∼872 cm−1. The results of this study confirmed the presence of carbonate ions within the mineral matrix of the fin spine bone of ABFT, showing the feasibility of using this calcified structure for analysis of stable isotopes. Overall, our findings will facilitate new approaches to safeguarding commercially valuable and endangered/protected fish species and will open new research avenues to improve fisheries management and species conservation strategies.

This work focuses on the mechanical characterization of the inorganic matrix used for Fiber-Reinforced Cementitious Matrix (FRCM) composites, nowadays widely used to retrofit existing reinforced concrete and masonry structures. While several works in technical literature investigate the experimental behavior of the whole FRCM composite, few information are available on the mechanical characterization of the mortar, which contains polymers and synthetic fibers in its admixture. However, the knowledge of its behavior in tension, especially after crack formation, is an important feature for the calibration of constitutive models to be adopted in the study of structural elements strengthened with FRCM. To this aim, an experimental program was performed on mortar specimens characterized by different shapes and dimensions, tested under direct tension or three-point-bending. From the performed tests, it was possible to characterize inorganic matrix behavior both in the uncracked stage, through the determination of the elastic parameters (elastic modulus and Poisson’s coefficient), and in the cracked stage. The use of digital image correlation (DIC) technique also allowed the study of the evolution of crack propagation in the specimens. Lastly, a correlation factor between axial and flexural tensile strength is proposed, for both design and numerical modelling purposes.

The mineral component of fish otoliths (ear bones), which is aragonitic calcium carbonate (CaCO3), makes this structure the preferred sample choice for measuring biological carbon and oxygen-stable isotopes in order to address fundamental questions in fish ecology and fisheries science. The main drawback is that the removal of otoliths requires sacrificing the specimen, which is particularly impractical for endangered and commercially valuable species such as Atlantic bluefin tuna (Thunnus thynnus) (ABFT). This study explores the suitability of using the first dorsal fin spine bone of ABFT as a non-lethal alternative to otolith analysis or as a complementary hard structure. The fin spines of freshly caught ABFT were collected to identify carbonate ions within the mineral matrix (i.e., hydroxyapatite) and to determine the nature of the carbonate substitution within the crystal lattice, knowledge which is crucial for correct measurement and ecological interpretation of oxygen and carbon stable isotopes of carbonates. Fin spine sections were analyzed via X-ray Photoelectron Spectroscopy (XPS), Raman Spectroscopy, and Fourier Transform InfraRed (FTIR). The XPS survey analysis showed signals of Ca, O, and P (three compositional elements that comprise hydroxyapatite). The Raman and FTIR techniques showed evidence of carbonate ions within the hydroxyapatite matrix, with the IR spectra being the most powerful for identifying the type B carbonate substitution as shown by the carbonate band in the v2 CO32− domain at ∼872 cm−1. The results of this study confirmed the presence of carbonate ions within the mineral matrix of the fin spine bone of ABFT, showing the feasibility of using this calcified structure for analysis of stable isotopes. Overall, our findings will facilitate new approaches to safeguarding commercially valuable and endangered/protected fish species and will open new research avenues to improve fisheries management and species conservation strategies. [ABSTRACT FROM AUTHOR]

This work focuses on the mechanical characterization of the inorganic matrix used for Fiber-Reinforced Cementitious Matrix (FRCM) composites, nowadays widely used to retrofit existing reinforced concrete and masonry structures. While several works in technical literature investigate the experimental behavior of the whole FRCM composite, few information are available on the mechanical characterization of the mortar, which contains polymers and synthetic fibers in its admixture. However, the knowledge of its behavior in tension, especially after crack formation, is an important feature for the calibration of constitutive models to be adopted in the study of structural elements strengthened with FRCM. To this aim, an experimental program was performed on mortar specimens characterized by different shapes and dimensions, tested under direct tension or three-point-bending. From the performed tests, it was possible to characterize inorganic matrix behavior both in the uncracked stage, through the determination of the elastic parameters (elastic modulus and Poisson's coefficient), and in the cracked stage. The use of digital image correlation (DIC) technique also allowed the study of the evolution of crack propagation in the specimens. Lastly, a correlation factor between axial and flexural tensile strength is proposed, for both design and numerical modelling purposes. [ABSTRACT FROM AUTHOR]

Introduction: Thin layer chromatography (TLC) is frequently used to obtain the fingerprint of a plant extract. Although the retardation factor and the response to visualisation give primary information about compound identification, the direct TLC‐mass spectrometry (MS) coupling allows a more detailed characterisation of samples. Objectives: To demonstrate the potential for the flavonoid dereplication using an inorganic matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) method with and without TLC separation. Material and Methods: Samples derived from wine, apple or rose were deposited on an aluminium‐backed silica gel TLC sheet compatible with the MS adapter. Unlike the wine sample, for apple and rose samples compound derivatisation was necessary. These two samples were deposited twice and the plate was cut in two parts. One half was oversprayed with Neu‐Peg reagent to visualise flavonoids while the inorganic matrix was deposited on each flavonoid zone on the second half for MS ionisation. Results: Mass spectra obtained for samples without plate development showed numerous ions corresponding to glycosylated flavonoids. The lower m/z observed could be due either to aglycone flavonoids or to in‐source fragment ions. After plate development, a separation of many spots was observed and each spot was analysed separately leading to a deeper identification of the present flavonoids. Moreover, isobaric flavonoids with different hRf values could be differentiated. Conclusion: TLC‐MALDI‐TOF‐MS using an inorganic matrix enabled the analysis of anthocyanins in positive mode and of flavonols, flavanols, dihydrochalcones and phenolic acids in negative mode, reducing adduct, aggregate forms giving thus simple and reliable spectra for the dereplication approach of flavonoids in complex samples. Flavonoid compounds contained in various plant samples were analyzed using TLC/MALDI‐TOF MS with and without TLC plate development. Ionization of flavonoid was assisted by an inorganic matrix deposited on each spot zone of interest. The use of tis inorganic matrix enables anthocyanin ionization in positive mode whereas the other flavonoid derivatives were analysed in negative mode and reduce formation of adduct, aggregate forms during ionization giving thus simple and reliable MS spectra suitable for compound identification. [ABSTRACT FROM AUTHOR]

Highlights • A new model is proposed for the gas apparent permeability in inorganic nanopores. • Impacts of nanoscale and irreducible water saturation are both considered. • The presence of water reduces gas conductance. • To the contrary, nanoscale effect increases gas conductance. • At high pressures, a higher percentage of nanocapillarys is favorable for gas flow. • At lower pressures, a higher percentage of nanofractures is favorable for gas flow. • The real gas effect can enhance gas flow capacity especially in small pore sizes. Abstract Characterizing fluid flow in shale is challenging due to the existence of small-sized pores, variable wettability conditions, and different pore fluid occupancies. Majority of the sub-irreducible water saturation is stored inside the hydrophilic inorganic material (iOM) nanopores in the form of bound water film or capillary water at initial reservoir condition. During production, gas is transported through nano-pores and nano-fractures where a water film covers iOM’s walls and crevices. That gives rise to the existence of multiphase fluid occupancies in pores and fractures. In this paper, we present an improved gas permeability model by taking into account the impacts of nanoscale (i.e., slippage effect, Knudsen diffusion) and sub-irreducible water saturations. To do so, the gas flow is modeled in hydrophilic iOM consisting of two types of pore networks (i.e., porous matrix and fracture network). We expand gas transport equations for nano-capillaries and nano-slits by taking into account pore size distribution (PSD) and fracture aperture distribution (FAD) using fractal theory. The proposed model is compared against the relevant experimental data and other analytical models available from the literature. The results show that by neglecting the nanoscale effect, the existence of water film could lead to an underestimation of flow capacity while ignoring the PSD/FAD would overestimate the calculated gas conductance. At higher pressures (>10 MPa), the gas apparent permeability rises as we increase the percentage of nano-capillary pores in the pore space. This trend reverses at lower pressures. For all pressures lower than 10 MPa, the apparent permeability decreases with increasing contribution of nano-capillary pores in the pore space. Real gas effect can significantly enhance gas flow capacity in nano-capillaries and nano-slits at higher pressures and lower temperatures. This effect is particularly significant in small pore sizes. [ABSTRACT FROM AUTHOR]

There is an increased use of fiber reinforced polymer composites (FRPC) in a wide area of engineering fields for various reasons including, ease of transportation and installation, high strength to weight ratio and favorable durability in different conditions. On the other hand, the use of this material as confining shells has been an interesting matter for retrofit, strengthening and construction of quasi-structural column systems. In this research, concrete cylinders with 150 mm diameter and 300 mm height were made, and effect of organic (epoxy-based) and inorganic (cementitious-based) matrices on strength behavior and ductility of cylinders wrapped in one and two-ply carbon, basalt and glass fabrics were studied. Results show that compressive strength of wrapped cylinders was 1.11 to 2.42 times higher than unwrapped ones. Also, there was a considerable 10 times increase in cylinders’ ultimate strain. Effects of confinement upgrade (from one to two-ply) were 3% to 26% increase for compressive strength and 17% to 41% for failure strain. Fabrics’ quantity performance was Carbon > Basalt > Glass.

This paper investigates the axial stress–strain response of concrete confined with Steel-Reinforced Grout (SRG) jackets comprising of Ultra High Tensile Strength Steel (UHTSS) textiles embedded in an inorganic binder. Brittle, semi-ductile and ductile stress–strain response curves are identified according to the level of confinement stiffness provided by the SRG jackets. A comprehensive experimental database of 80 SRG-confined columns is developed and used to assess the influence of key design parameters. The results are then used to propose new design-oriented models to predict the strength and ultimate strain of SRG confined concrete columns by taking into account the confinement stiffness of the jackets. [ABSTRACT FROM AUTHOR]

Terbium(III), yttrium(III), and neodymium(III) complexes with 4-aminobenzoic acid have been co-doped into silica matrix. For the samples, the characteristic emissions of terbium(III) increase obviously with the addition of yttrium(III) complex, while the reverse is true with the addition of neodymium(III) complex. Compared with terbium(III) complex doped silica sample, the photoacoustic signal of the ligand decreases for terbium(III)–yttrium(III) complexes co-doped sample, and increases for terbium(III)-neodymium(III) complexes co-doped sample. The fluorescence quantum yields and lifetimes of the samples have been determined. The co-fluorescence mechanism has been discussed from radiative and nonradiative relaxations. The nephelauxetic parameters and photoacoustic branching vectors of neodymium(III) in the silica samples have also been calculated. The spectral result indicates that heteronuclear complexes may form in the silica matrix upon a suitable heat treatment. The co-fluorescence effect found in the inorganic matrix can contribute to the better design and application of rare earths containing fluorescent materials. [ABSTRACT FROM PUBLISHER]

Gas shale was treated as a quintuple porosity system. When the source rock matures, a portion of kerogen or bitumen will be transformed into hydrocarbon, and move to displace the water out from inorganic matrix. When the kerogen is recrystallized to graphite, there will be less dissolved gas left in solid kerogen, which was assumed to be substantial in immature source rock. A series of resistivity tests showed the resistivity of shale decreases with higher vitrinite reflectance value, and proved the graphite do exist in overmature shale. With the role of natural fracture in shale analyzed, the water and hydrocarbon stored in overmature shale was summarized, and the overmature organic-rich gas shale should be treated as two porosity system. To find out which kind of pore may accommodate most of the free gas, a generalized material balance equation was presented, and the volume change with pressure drop in organic matrix and inorganic matrix can be calculated simultaneously. The field case herein proved that new material balance equation can be applied to calculate original free gas and adsorbed gas in shale or sandstone, and it was suggested that while in overmature gas shale there is free gas in inorganic pore, free gas in organic pore and adsorbed gas in kerogen, most of the free gas is in the organic pores. [ABSTRACT FROM AUTHOR]

This paper presents the results of the mechanical characterization of composite materials comprising high strength textiles embedded in inorganic matrices. These materials are commonly termed Textile Reinforced Mortars (TRM) or, when comprising cementitious matrices, Fabric-Reinforced Cementitious Matrix (FRCM – despite the fact that this term is often extended to composites with cement-free matrices). Different types of fibers were employed, namely carbon, glass, and basalt, as well as steel cords, which were embedded in lime- or cement-based matrices. Results of tensile tests on single fiber yarns and composite prismatic specimens with a rectangular cross-section are shown and discussed. The effect of fiber coating and stitch-bonded joints between warp and weft yarns on the tensile behavior observed is studied. The results obtained help to shed light on the different parameters that affect tensile testing of inorganic-matrix composites contributing to the appropriate mechanical characterization of these materials. [ABSTRACT FROM AUTHOR]

Recent calamitous events have shown the fragility of the existing masonry buildings. Many of them are heritage structures, such as churches and monumental buildings. Therefore, optimized strengthening strategies are necessary. Experimental studies performed on masonry elements strengthened with composite systems have shown the performance of these materials. However, further development is necessary to optimize the intervention strategies. In fact, due to the lack of general validity models, the design is usually based on prescriptive approaches according to manufacturers’ broad instructions, often producing systems with low efficiency and overestimations of the amount of reinforcement. In this paper a generalized approach is proposed to assess the flexural behavior of masonry sections strengthened with composites. The proposed theory has allowed performance of a sensitivity analysis assessing the impact both of the mechanical parameters of masonry and of the strengthening system. In particular, the impact of several constitutive relationships of composites (linear, bilinear, or trilinear) have been evaluated in terms of ultimate behavior of the strengthened masonry. For strengthening systems more compatible with the masonry substrate, the form of the stress⁻strain relationship becomes a key aspect. For such cases, the modeling of the reinforcement plays a fundamental role and the form of the relationship is strongly correlated to the type of reinforcement selected, e.g., organic versus inorganic matrix.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with diverse developmental roles, including differentiation of skeletal elements. It is a positive regulatory factor of chondrogenesis and osteogenic differentiation in vitro, but little is known about its in vivo role in bone formation. In our experiments, diaphyses of long bones from hind limbs of PACAP gene-deficient mice showed changes in thickness and increased staining intensity. Our main goal was to perform a detailed morphological and molecular biological analysis of femurs from PACAP knockout (KO) and wild type (WT) mice. Transverse diameter and anterior cortical bone thickness of KO femurs showed significant alterations with disturbed Ca2+ accumulation and collagen type I expression. Higher expression and activity of alkaline phosphatase were also observed, accompanied by increased fragility PACAP KO femurs. Increased expression of the elements of bone morphogenic protein (BMP) and hedgehog signalling was also observed, and are possibly responsible for the compensation mechanism accounting for the slight morphological changes. In summary, our results show that lack of PACAP influences molecular and biomechanical properties of bone matrix, activating various signalling cascade changes in a compensatory fashion. The increased fragility of PACAP KO femur further supports the role of endogenous PACAP in in vivo bone formation.

We report, for the first time, the application of fluorinated hexagonal boron nitride nanosheets (F-BNNs) as an effective inorganic matrix for matrix-assisted laser desorption and ionization mass spectrometry (MALDI-MS) analysis of perfluoroalkyl acids (PFAAs). Fluoride modification of F-BNNs increases both enrichment ability and ionization efficiency. The method was validated using environmental water, milk, human serum samples, and zebrafish imaging that has been previously exposed to PFAAs. The method provided in this work holds considerable promise in term of rapid analysis, sample requirement, and practicability. Fluorinated hexagonal boron nitride nanosheets (F-BNNs) was first used as an inorganic matrix for matrix-assisted laser desorption and ionization mass spectrometry (MALDI MS) analysis of perfluoroalkyl acids (PFAAs) in complex samples in negative reflector mode. [Display omitted] • F-BNNs was used as absorbent and inorganic matrix for MALDI-MS analysis of PFAAs in water, milk, and human serum samples. • Mass imaging of PFAAs in zebrafish was explored using F-BNNs. • The possible ionization mechanism of F-BNNs as matrix was discussed. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experimental study conducted to understand the behavior and stress-transfer mechanism of fiber-reinforced cementitious matrix (FRCM) composites externally bonded to a concrete substrate for strengthening applications. The FRCM composite was comprised of a polyparaphenylene benzobisoxazole (PBO) fiber net embedded within two layers of polymer-modified cement-based mortar. Single-lap shear tests were conducted on specimens with composite strips bonded to concrete prisms. Parameters that varied were bonded length and width of composite. Additionally, the external coating layer of matrix was omitted on a limited number of specimens to examine the interfacial behavior between fibers and matrix and the role of the matrix in the stress transfer. Strain measurements along the composite bonded length were used to investigate the stress-transfer mechanism. Results suggest that the effective bond length of this composite is within the range of 250 to 330 mm (10 to 13 in.). Unlike with fiber-reinforced polymer (FRP) composites, no width effect was observed in terms of the maximum load. Finally, the stress-transfer mechanism at the matrix-fiber interfaces on either side of the fiber net was found to be unequal. [ABSTRACT FROM AUTHOR]