Gutnikov, Sergey I

Popov S.S., Gutnikov S.I.

In this work, the aim was to define the dependence of the strength of basalt fibers (BCF) on their chemical composition, characterized by two parameters: the NBO/T ratio and the acidity modulus Ma. It makes it possible to predict the change in the mechanical parameters of fibers from their composition, since basalt rocks have a significant drawback - the inconstancy of the chemical composition. Fibers of various chemical compositions were obtained based on 14 different basalt deposits. Pearson’s correlation coefficient for NBO/T and ultimate tensile strength was 0.79, and for acidity modulus and tensile strength it was 0.53. The tensile strength of tested fibers from different deposits ranges from 1495 to 3380 MPa. In addition, with the help of the Raman spectra analysis, it was confirmed that tensile strength can be largely determined by the influence of the chemical composition of basalts on their structure.

Guo Z., Xing D., Xi X., Yue X., Liang C., Hao B., Zheng Q., Gutnikov S.I., Lazoryak B.I., Ma P.

The construction of a lunar base is considered to be an important step towards deep-space exploration by humanity, and will rely on the utilisation of in situ lunar resources. In this paper, we discuss the current knowledge on the feasibility of converting lunar soil to high-performance fibres that can be used for the construction of a lunar base. This fibre would be combined with further portions of lunar soil to generate fibre-reinforced composites, which is utilized as multi-functional materials for lunar base construction. We discuss and analyse the latest findings regarding the composition of lunar soil simulants and their fibrisation properties, and techniques for fibre spinning and system integration. Finally, we suggest how the achievements made so far could be applied to the construction of a lunar base.

Xing D., Chang C., Xi X., Hao B., Zheng Q., Gutnikov S.I., Lazoryak B.I., Ma P.

• Morphologies and properties of basalt fibre processed at different temperatures were studied. • Reduction on the strength of fibre upon thermal treatment occurred in three steps. • Thermal treatment led to the formation of crystal on fibre surface. • Crystallization on fibre began with the spontaneous formation of spinel phase. • Spinel crystal was the nucleation site for the formation of pyroxene structure. In this study, the morphologies and properties of basalt fibre (BF) treated at different temperatures in air atmosphere were studied. The results showed that the heat treatment caused the formation of crystals on fibre surface, which resulted in the alteration of BF from the paramagnetic material to the ferromagnetic one. The tensile strength of BF was reduced significantly upon thermal treatment, and such reduction occurred in three temperature ranges: i) Decomposition of organic sizing on fibre surface, which led to the exposure of more defect structures (100–400 °C), and the structural changes of BF may also occur; ii) Simultaneous relaxation of excessive enthalpy and structural anisotropy, which were responsible for the phase separation in the amorphous matrix in the fibre (500–600 °C); iii) Structural modification due to the formation of multifarious crystals in the fibre (700–1000 °C). The crystallization in BF began with spontaneous spinel phase formation, which was favored by the initial phase separation and the oxidation of Fe 2+ . The spinel crystals became nucleation sites for the formation of pyroxene structure, and this process was accompanied by the enrichment of Ca, Mg and Fe on fibre surface. Therefore, the inhibition of crystallization for BF was important to maintain the mechanical performance of filament under the continuous thermal conditions for practical applications.

Lipatov Y.V., Gutnikov S.I., Lazoryak B.I.

• Zr-rich basalt continuous fiber with record values of alkali resistance were obtained. • By adding lanthanum oxide to t the production temperature range increases. • The tensile strength of Zr-rich basalt continuous fibers increases by 15–20%. Zirconium-rich basalt continuous fibers with zirconium oxide content from 5.1 to 8.1 wt% with the addition of 1% lanthanum oxide were obtained in a laboratory facility. The production temperature range were measured. It was shown that lanthanum oxide addition allows to decrease production temperature by 50° and to make wider the production temperature range by 10°. Weight loss and tensile strength loss of fibers after refluxing in alkali solution were determined. The weight loss after boiling in 1 M NaOH and 0.5 M Na2CO3 solution is comparable to the weight loss of zirconium-rich glass fibers (AR glass). The addition of lanthanum oxide leads to an increase in the tensile strength of Zr-rich basalt continuous fibers by 15–20%. Based on the obtained data, it can be concluded that the presented approach will not only improve the alkali resistance of basalt continuous fibers for reinforcing cements and concretes, but also significantly reduce their cost.

Gutnikov S.I., Popov S.S., Efremov V.A., Ma P., Lazoryak B.I.

This paper presents a study of the influence of basalt rocks’ phase composition, acidity modulus, and structural parameter NBO/T on the tensile strength and elastic modulus of basalt continuous fibers (BCFs) derived from them. A series of BCF samples based on 14 different basalt deposits was obtained under equal conditions. The tensile strength and elastic modulus of the BCFs from different deposits vary in the ranges of 1495–3380 MPa and 58.2–78.7 GPa, respectively. Using the original method of quantitative phase analysis based on the Rietveld method, the phase compositions of the 14 deposits were defined. All deposits can be used to obtain BCFs. In the studied natural rocks, the main component is tectosilicates; the mass content of framework aluminosilicates is in the range of 16.5–3.3 mass percent. The second main component is inosilicates; the mass content of chain aluminosilicates is in the range of 6.0–58.0 mass percent. The correlations among phase composition, acidity modulus, ratio of non-bridging oxygens to tetrahedral cations, tensile strength, and elastic modulus of the BCFs from the 14 different basalt deposits were calculated. There were strong positive correlation between tectosilicate minerals mass content and elastic modulus [Pearson correlation coefficient (PCC) of 0.7] and strong negative correlation between content of chain and layered aluminosilicates and elastic modulus (PCC of − 0.74).

Xing D., Chen L., Ma Q., Hao B., Gutnikov S.I., Lazoryak B.I., Mäder E., Ma P.

In this study, the properties of E-glass fiber (GF) (0.5 g) exposed to sulfuric acid (100 mL, c H + =0.1 mol/L) and potassium hydroxide (100 mL, c O H − =0.1 mol/L) solutions were studied. The results showed that after acid treatment, the GF was damaged with decreased tensile strength, and spiral cracks developed on the fiber surface. Acid corrosion of the GF was mainly attributed to the depletion of metal ions in the GF, and the ion-depletion-depth model was proposed to explain the mechanism. In the alkali solution, the Si O Si bonds in the network structure of the GF were degraded by the OH− ions, resulting in the destruction of the glass network. It formed a corrosion layer with sheet-like nanostructures on the fiber surface, which prevented further attack of alkali ions on the fiber. Comparative results of the tensile strength of the treated GF confirmed that the filament was more susceptible to acid attack than alkali attack.

Pastushkov P.P., Gutnikov S.I., Pavlenko N.V., Zheldakov D.Y., Stolyarov M.D.

Abstract In this article, the general information about aerogels as well as application areas of materials based on them are presented. Scientific and technical review on heat conductivity of aerogel-based thermal insulation materials was made. It was determined, that among the Russian studies the results of behaviour of these materials under high temperatures are not presented. Comprehensive studies of thermal characteristics, including heat conductivity values in temperature range of 10–650 °C (where 650 °C is the maximal operating temperature) for the thermal insulation rolled materials based on TiO2-aerogel DRT06-Z (Alison Aerogel) were carried out. The mathematical relationship between heat conductivity and operating temperature in range of 10–650 °C was determined. Using the obtained results, the calculation of thickness of insulation for the studied aerogel-based rolled materials was realized according to the construction rules SP 61.13330.2010, that can be applied for design of high-heat insulation for equipment and pipelines.

Gutnikov S.I., Manylov M.S., Lazoryak B.I.

The present research focuses on the influence of phosphorus oxide additives on the structure and thermal properties of the basalt glasses, produced in the form of fibers, i.e. at very high quenching speed. Basaltic glass fibers with various P2O5 contents were produced in two stages. In the first stage, the bulk glasses were prepared by adding variable amounts of (NH4)4P2O7 to milled natural andesitic basalt in order to obtain samples containing 2, 4, and 6 wt % P2O5. In the second stage, the glass fibers were obtained using a laboratory-scale system. Basalt glass fibers were characterized by Raman spectroscopy to obtain information on the structure of the obtained fibers, and by DSC-TG and XRD analyses to determine the change in crystallization mechanism of basaltic fibers. The hydrostatic weighing was used for the determination of glasses density. An increase in the content of P2O5 to 6 wt % leads to a decrease in the density of glass fibers due to the polymerizing effect of phosphorus oxide. The obtained X-ray diffraction patterns indicate that all samples are X-ray amorphous. The Raman results show that the decrease in the intensity of the line corresponding to vibrations of the structural units Q2 (about 920 cm–1) with respect to the line corresponding to Q3 (about 1125 cm–1) is related to an increase of P2O5 content. This also indicates the increase in polymerization degree of glass structure. DSC and XRD data also found out the change of phase transformations order with an increase of phosphorus oxide. The crystallization in natural and modified basalt glass fibers begins with spontaneous spinel-like phase formations that become nucleation sites for the precipitation of monoclinic pyroxene as a major phase. With an increase in the P2O5 content, there is a tendency to a decrease in the pyroxene at higher temperature, as a result of which, the hematite crystallizes at lower temperatures. That is associated with the activation of liquation processes, accompanied by the formation of amorphous phases with different viscosities with an increase in the concentration of P2O5. In conclusion, all the obtained data indicate the prospect of using the proposed approach to obtain basalt glass fibers with enhanced thermal and mechanical stability.

I. Gutnikov S., S. Zhukovskaya E., S. Popov S., I. Lazoryak B.

This work presents the study of the dependence of the basalt continuous fibers (BCF) tensile strength on their chemical composition. 14 different basalt deposits were used to obtain continuous fibers by a laboratory scale system. Based on the data for more than 15 articles focused on natural basalt continuous fibers (32 different compositions) and experimental data of 14 experimental BCF series, the correlation of the tensile strength, the acid modulus and the NBO/T parameter was calculated. The PCC (pearson correlation coefficient) value of NBO/T and the tensile strength was 0.79, for acidity modulus and tensile strength -0.53.Raman data for experimental BCF confirm the significant influence of the chemical composition of basalts on their structure, which determines their tensile strength. With a decrease in NBO/T, the observed ratio between the Raman bands at low-and high-frequencies gradually increases.

Gutnikov S.I., Lazoryak B.I.

The experimental data presented in this work show the effects of nozzle diameter, drawing speed, and formation temperature on the diameter and strength of basalt filaments and melt flow rate. Several series of basalt continuous fibers were obtained using a specially designed crucible of platinum–rhodium alloy with four nozzles of different diameters (1.5, 2.5, 3.5, and 4.5 mm). The conditions of the process varied in formation temperature (from 1370 to 1450 °C) and winding speed (from 300 to 1200 m/min). Melt flow rate was almost independent of the winding speed, indicating laminar flow of the melt through the nozzles and the Newtonian nature of the liquid. The results show strict correlations between fiber diameter, nozzle diameter, and winding speed. The diameter of the fibers had a significant effect on their strength. The tensile strength of the obtained basalt fibers varied from 550 to 3320 MPa depending on the formation conditions. The results of this work could be useful not only for scientists, but also for technologists seeking the optimal conditions for technological processes.

Gutnikov S.I., Pavlov Y.V., Zhukovskaya E.S.

The influence of low-frequency vibrational treatment on the crystallization of basalt wool fibers was studied. In this work, three series of samples were investigated. The first sample set was only one-sided heated at temperatures from 300 °C to 900 °C for 24 h. The second sample set was after only vibrational treatment with a frequency of 50 Hz and oscillations amplitude of 1 mm for 6–48 h. The third sample set was after simultaneous treatment of one-sided heating and vibration at temperatures from 300 °C to 600 °C with a frequency of 50 Hz and oscillations amplitude of 1 mm for 24 h. It is shown that at temperatures close to the glass transition temperature, vibration can influence on the relaxation processes in glasses and accelerate them. Mechanism of glass structure transformation in the basalt fiber does not change, but it starts at a slightly lower temperature. That is a consequence of an additional low-energy vibrational treatment. The vibrational treatment intensifies the crystallization process in basalt fibers and decreases the service temperature of the material by at least 40–50 °C.

Kuzmin K.L., Gutnikov S.I., Zhukovskaya E.S., Lazoryak B.I.

In the present research the dependence of compositional variations on the basaltic glass fibers mechanical properties was explored. Addition of 15 mol % MgO or 5 mol % ZnO led to enhanced for tensile strength up to 43% and 47% and for modulus up to 13% and 25% respectively. The structure of basaltic glass fibers with varying MgO and ZnO contents was investigated by solid-state 29 Si and 27 Al nuclear magnetic resonance with magic angle spinning (MAS-NMR) and infrared (IR) spectroscopy. It was indicated that the increase of MgO and ZnO contents slightly decreased the degree of network polymerization. 27 Al MAS NMR exhibit a peak consistent with tetrahedral aluminum units AlO 4 . The noticeable fraction peaks of narrow octahedral aluminum units AlO 6 are observed. Presence of aluminum cations in coordination 4 and 6 was confirmed by IR spectroscopy. In order to study their crystallization ability the glasses were heated at various temperatures for various time periods with following self-cooling. The crystalline phases were identified by X-ray diffraction analysis. Obtained results have shown the possibility to increase mechanical properties of continuous fibers and composites on their base by 50–60%.

Kuzmin K.L., Timoshkin I.A., Gutnikov S.I., Zhukovskaya E.S., Lipatov Y.V., Lazoryak B.I.

Abstract The present study explains the role of surface modification of constituent materials on composite material performance. The influence of silane and nano-hybrid coatings on mechanical properties of basalt fibers and composite materials on their base was investigated. Infrared spectroscopy indicated that modification of basalt fiber surface and nano-SiO2 was successfully applied. The surface modification leads to the significant increase in the tensile strength of basalt fibers compared to the non-coated fibers. The tensile strength of silane-treated fibers was established 23% higher than the non-coated fibers, indicating that silane plays a critical role in the strength retention of basalt fibers. Also it was pointed out that silane coupling agents can be used for the preparation of the nano-hybrid coating. Addition of SiO2 nanoparticles into the fiber surface was incorporated to enhance the interfacial bonding of basalt fiber reinforced epoxy composite.

Manylov M.S., Gutnikov S.I., Lipatov Y.V., Malakho A.P., Lazoryak B.I.

Deferrized glass was produced by the reduction smelting of basalt batch in a graphite crucible at a high temperature. The deferrized continuous fiber has higher glass transition and drawing temperatures, lower crystallization ability and enhanced thermal stability in comparison with those of the original basalt fiber.

Kuzmin K.L., Zhukovskaya E.S., Gutnikov S.I., Pavlov Y.V., Lazoryak B.I.

Basaltic glass fibers with different lithium oxide (6–14 mol%) and sodium oxide (2–14 mol%) contents were prepared. The influence of Li2O and Na2O content on the process of fiber manufacturing was investigated. Addition of alkali oxides reduced the forming temperature and substantially expanded the fiber‐forming temperature ranges. The obtained thermal data from differential thermal analysis revealed a decline in glass transition temperature (Tg) of fibers against the compositional changes. The inclusion of Li2O and Na2O in the glass network led to a reduction in its thermal stability. The obtained X‐ray diffraction patterns and IR spectra of Li‐rich and Na‐rich basaltic glass fibers confirmed the formation of highly polymerized structures such as LiAl(Si2O6) and (Na,K)(AlSiO4), respectively, and relatively depolymerized silicate anions. The effects of potassium–lithium and potassium–sodium ion exchange on the mechanical properties of basaltic glass fibers were investigated. As‐received Li‐rich and Na‐rich basaltic glass fibers were ion‐exchanged in potassium nitrate for different exchange times, and their mechanical properties were measured before and after chemical tempering. The measured tensile strength and Young's modulus values of the fibers showed an increase after treatment in molten salt.

Yang X., He M., He Y., Ou Z.

Tian L., Wang L., Xian G.

Xiang D., Tian H., Ma J., Harkin-Jones E., Li Y., Wang M., Liu L., Wu Y., Cheng J., Li D.

Han R., She Z., He P., Guo Y., Wang Z., Li G., Zhang S.

Capolupo F., D’Alessandro C., De Maio D., Di Giamberardino F., Palmieri V.G., Anacreonte A.V., Russo R., Musto M.

Wang Y., Zhang D., Shi H., Niu C., Huyan C., Liu D., Chen F., Zhang L.

Wang Y., Dou H., Li H., Bai J., Bai Z., Li W.

AbstractDuring fabrication of basalt fiber, one critical procedure is the homogenization of melt, which typically lasts over 10 h at ∼1500°C. However, the changes in composition and structure of basalt melt during the homogenization process remain poorly understood. In this study, basalt melts were held at 1550°C for various durations and then rapidly quenched to form basalt glasses, enabling analyses of their compositional and structural evolution. Compositions of glasses were analyzed using chemical titration, energy dispersive X‐ray, and inductively coupled plasma optical emission spectrometry methods. The crystallization process was examined through differential scanning calorimetry analysis, while structural evolution was investigated via Raman and X‐ray photoelectron spectroscopy O1s spectroscopy. The results showed that the primary composition change during homogenization was the valence transition from Fe3+ to Fe2+. The O2‐ produced with the valence transition gradually converted the Q3 units into the Q2 units. The homogenization process reached the stability of composition and structure after 8 h. A high proportion of Q2 units will align along the fiber axis, enhancing the melt spinnability and reinforcing the basalt fiber.

Agrawal M., Durai Prabhakaran R.T., Mahajan P.

AbstractBasalt fibers (BFs) are considered an environmentally friendly alternative to glass fibers (GFs). In this article, the basalt fiber and glass fiber surface were modified using hybrid sizings consisting of silane coupling agent (3‐Glycidoxypropyl)trimethoxysilane and MWCNTs. The existing sizings were removed from the fiber surface using acetone treatment, and the hybrid sizings were applied to the fiber surface using the dip coating method. The sizings were characterized using SEM‐EDS and AFM. The composites were fabricated using as‐received and hybrid‐sized fibers using vacuum‐assisted resin infusion molding (VARIM). The quasi‐static tensile, flexural, short beam shear and fatigue tests were performed on BF/epoxy, GF/epoxy, and hybrid fiber BF/GF epoxy composites. The results showed that the static and fatigue properties were improved by adding multi‐walled carbon nanotubes in the sizings and the matrix. The fatigue life improved by a factor of 2–3 due to matrix or fiber modifications. However, the matrix modifications were more effective in static performance, but the interface design showed better properties in fatigue loading. As in both the treatments, the static and fatigue properties are improved, and the findings obtained could be useful to enhance the life of wind turbine blades or other composite structures which are susceptible to fatigue damage.Highlights The fibers were coated successfully with the GPMS/MWCNT hybrid sizings. SEM‐EDS and XPS characterization showed CNTs adhered to fiber surface. Matrix modification with MWCNTs showed a better tensile strength of epoxy. The static and fatigue properties were improved significantly. Better interfacial bonding in the case of modified matrix and fibers.

Zhu Z., Li N., Yang X., Liu Q., Bai Z., Fan K., Yang Y., Wang P., Li K., Zhong F., Li Y., Zhan Y., Feng W.

AbstractThe application of basalt fiber‐reinforced polymer composite (BFRP) is largely restricted by the poor interfacial interaction between BF and matrix due to the intrinsic incompatibility. Herein, the current study reported the enhancement of interfacial bonding in BF/phthalonitrile (PN) composite through in‐situ growth of iron phthalocyanine on BF surface using a liquid bio‐based PN monomer (BCPN). BCPN was first synthesized, characterized, and used to initiate the complexation reaction from iron in BF and CN groups in BCPN, resulting in the increased roughness of BF surface. Consequently, the flexural strength, flexural toughness, tensile strength, tensile toughness, and interlaminar shear strength (ILSS) of BCPN‐treated BF/benzoxazine–functional phthalonitrile (BZPN) composites were improved in comparison with those of BF/BZPN composite, with an increment of 36.6%, 72.6%, 36.2%, 96.9%, and 64.9%, respectively. Meanwhile, these BFRPs show high mechanical retention rates after thermal exposure of 300°C/1 h. Due to the compatibility/co‐curing between iron phthalocyanine on BF surface and BZPN resin, physical entanglement and chemical anchoring obviously improved the interfacial bonding of BF and BZPN, thereby leading to a higher stress transfer efficiency. This work will enrich the interface construction methods of BFRPs and also provide references for the practical applications of high‐performance BF/PN composites.Highlights In‐situ reaction of Fe in BF and CN in PN induced iron phthalocyanine onto BF. Flexural strength, tensile strength, and ILSS of BF/PN composite were improved by 36.6%, 36.2%, and 64.9%, respectively. Interfacial bonding was enhanced via well compatibility/co‐curing reactions of BF and PN.

Hamada H.M., Abed F., Al-Sadoon Z.A., Hassan A.

Abstract Concrete is widely used in construction due to its remarkable compressive strength and durability. However, its performance can deteriorate when exposed to harsh environmental conditions, such as acidic or alkaline surroundings. There has been considerable interest in incorporating both basalt and steel fibers (B&SFs) to enhance the resilience of concrete in such challenging settings. This study presents a comprehensive examination of the influence of B&SFs on the strength and microstructure of concrete, utilizing desert sand as a fine aggregate and subjecting it to exposure to acidic and alkaline environments. Employing a systematic experimental approach, this research assesses concrete samples with varying B&SFs proportions. The study encompasses density and compressive strength tests, complemented by microstructural analyses using scanning electron microscopy (SEM) and X-ray diffraction (XRD), to analyze the performance of the concrete under diverse environmental conditions. Initial findings indicate that including B&SFs results in a substantial improvement in concrete strength. The role of basalt fibers (BFs) in enhancing the concrete's resistance to acidic environments by mitigating deleterious effects on microstructural integrity is particularly noteworthy. Notably, when exposed to acidic conditions, concrete mixtures containing 0.5% BFs demonstrated the least strength loss. When B&SFs are synergized, their positive effects are amplified, yielding concrete with exceptional resistance to alkaline environments. Microstructural analysis reveals that incorporating fibers refines and strengthens the interconnected matrix of cementitious products, thereby enhancing cohesion and overall strength. Furthermore, this study underscores that desert sand can be a viable alternative to traditional fine aggregates without compromising concrete resistance if it is appropriately reinforced with fibers. In conclusion, this research sheds light on the promising role of B&SFs in augmenting the strength and microstructure of concrete containing desert sand.

Wang Z., Zheng Z., Jiang L., Qin Y., Zhu J., Zhou Y., Xiao L., Zhou C., Ding L.

Huang S., Xiang Z., He S., Yin L., Zhang S., Chen C., He K., Lu C.

Abstract (Mg,Fe)SiO3 is primarily located in the mantle and has a substantial impact on geophysical and geochemical processes. Here, we employ molecular dynamics simulations to investigate the structural and transport properties of (Mg,Fe)SiO3 with varying iron contents at temperatures up to 5000 K and pressures up to 135 GPa. We thoroughly examine the effects of pressure, temperature, and iron content on the bond lengths, coordination numbers, viscosities, and electrical conductivities of (Mg,Fe)SiO3. Our calculations indicate that the increase of pressure leads to the shortening of the O–O and Mg–O bond lengths, while the Si–O bond lengths exhibit the initial increase with pressure up to 40 GPa, after which they are almost unchanged. The coordination numbers of Si transition from four-fold to six-fold and eventually reach eight-fold coordination at 135 GPa. The enhanced pressure causes the decrease of the diffusion coefficients and the increase of the viscosities of (Mg,Fe)SiO3. The increased temperatures slightly decrease the coordination numbers and viscosities, as well as obviously increase the diffusion coefficients and electrical conductivities of (Mg,Fe)SiO3. Additionally, iron doping facilitates the diffusion of Si and O, reduces the viscosities, and enhances the electrical conductivities of (Mg,Fe)SiO3. These findings advance fundamental understanding of the structural and transport properties of (Mg,Fe)SiO3 under high temperature and high pressure, which provide novel insights for unraveling the complexities of geological processes within the Earth’s mantle.

Khan M.B., Houda M., Zada N.S., Imran M., Benjeddou O.

R. K., K.R. P., Bheemappa S.

Liu C., Wu H., Zhang H., Shi Q., Li H., Kang Q., Tao L.

Wang Q., Zhang Q., Luo L., Yan T., Liu J., Ding L., Jiang W.

• The tensile strengths of BFs at high temperatures were studied • BFs with higher IRIs retained better tensile strengths at high temperatures • A CaO-based crystal layer was formed on the surface of BFs • BFs with lower IRIs formed more ferric tetrahedral structures at high-temperature Iron plays an important role in enhancing the tensile strength of basalt fibers (BFs); however, the origins of tensile-strength variation at high temperatures are not well understood. In this work, we prepared BFs with different iron reduction indices (IRI = Fe 2+ /Fe total ) and explored the effects of high temperature and IRI on tensile strength. The results show that BFs with higher IRIs retained better tensile strength after high-temperature treatment at 600°C for 1 h. The surface morphology was analyzed by scanning electron microscopy to observe the nanocrystalline layers on the surface of BFs with higher IRIs, and the main composition of the crystals was CaO. The formation of nanocrystalline layers increased the tensile strength of the BFs. Moreover, results from transmission 57 Fe Mössbauer spectroscopy and Fourier transform infrared spectroscopy indicate that BFs with lower IRIs formed more ferric tetrahedral structures (Fe 3+ (tet)) after high-temperature treatment, which depolymerized Si(Al)-O-Si(Al) tetrahedral structures, resulting in lower tensile strength. A better understanding of the origin of microstructures in different iron coordination states and the tensile strength of BFs at high temperatures will assist in the development of advanced iron-bearing glass fiber products suitable for high-temperature environments.

Huang Z., Chen W., Tran T.T., Pham T.M., Hao H., Chen Z., Elchalakani M.

The application of fiber-reinforced-polymer (FRP) bars to reinforce concrete structures could mitigate the corrosion-induced damage of steel reinforcements. No study has been reported in open literature on flexure-critical or shear-critical concrete beams reinforced with Basalt FRP (BFRP) bars under impact loads. In this study, six BFRP bars reinforced concrete beams were tested under quasi-static and impact loads. The test results showed the flexure-critical beams experienced the failure mode changing from flexure-governed under quasi-static loads to flexure-shear combined under impact loads. The shear-critical beams still failed in diagonal shear under impact loads, but experienced severer concrete spalling and more critical diagonal cracks on both sides of the beams. The impact performance of concrete beams with higher strength concrete may not be necessarily superior to that of beams with normal strength concrete due to the increased brittleness. Moreover, a numerical model of the tested beams under impact loads was developed and calibrated in LS-DYNA. Numerical results showed increasing tension reinforcement ratio could change the failure mode from flexure-governed to flexure-shear combined along with the reduced maximum midspan deflection. The BFRP bars reinforced concrete beams had comparable impact resistant performance with the conventional steel reinforced concrete beams

Meng Y., Liu J., Xia Y., Liang W., Ran Q., Xie Z.

Continuous basalt fibres (CBFs) produced directly from natural basalt seldom achieve adequate performance with high tensile strengths. Thus, formulation optimization is a key component of technological innovation in the field of CBFs. From this perspective, a series of experiments were designed to prepare a type of CBF using two natural forms of basalt. The average tensile strength of the fabricated CBF was 4111 MPa. Moreover, it is found that the amount of glass network modifier (Na 2 O + K 2 O) has a negative correlation with the tensile strength of CBF. By combining our results with past studies, two empirical formulas were proposed to quantify the relationship between viscosity (η) and viscosity modulus (Mη) for basalt melts at 1300 °C and 1400 °C: η(1300 °C) = −91.22971 + 16.06614e 1.25983Mη and η(1400 °C) = −30.57462 + 6.32023 e 1.18491 Mη . It was found that a value of Mη ranging between 2.2 and 2.6 is optimum for CBF production. We also established an important correlation between η, Mη and mix compositions, which could be an essential criterion to evaluate the characteristics and production technology of CBF, including basalt beneficiation and formulation optimization.

Chang C., Yue X., Hao B., Xing D., Ma P.

This paper reported the preparation of a hierarchical structure consisting of micro-scale basalt fiber fabric and nano-scale carbon nanotubes (CNTs). The developed fabric was employed as reinforcement to develop nanocomposites with multi-layer structures for electromagnetic interference shielding. Different techniques were employed to study the morphologies and properties of the fabric and corresponding nanocomposites. The results showed that by optimizing the experimental conditions, CNTs with controlled content and quality were grown on the surface of basalt fiber. These properties significantly affected the electromagnetic interference shielding performance of corresponding nanocomposites. The novelty of this study lies in the direct growth of nanotubes on basalt fiber by utilizing the in-situ generated mineral nanoparticles on fiber surface as a catalyst, and a spontaneous infusion of uncured polymer into the fabric, which eliminates the problems associated with the dispersion and re-agglomeration of CNTs during the preparation of nanocomposites.

Lilli M., Rossi E., Tirillò J., Sarasini F., Di Fausto L., Valente T., González C., Fernández A., Lopes C.S., Moscatelli R., Bemporad E., Sebastiani M.

This article presents an experimental investigation to quantify the effects of high temperature exposure (400–600 °C) on the mechanical properties of single basalt fibres. To this purpose, a combination of single edge notch tension and nanoindentation micro-pillar splitting methods was used to provide an assessment of the fracture toughness of as-received and thermally treated basalt fibres. Similar values were obtained by the two different methods, and interestingly both highlighted an increase in K I c after heat treatment, up to 22% after exposure at 600 °C for 1h ( 1.59 ± 0.06 M P a m ). The increase in K I c suggests that microstructural changes occur in the fibres, as confirmed by high-speed nanoindentation mapping. Local radial heterogeneity in the fibre structure and elastic modulus and, possibly, the loss of defect orientation originally induced during the fibre drawing process are envisaged to control the decay of basalt fibres tensile strength during high temperature exposure, mimicking a thermal recycling process for composites.

Lilli M., Sarasini F., Fausto L.D., González C., Fernández A., Lopes C.S., Tirillò J.

The disposal of fibre reinforced composite materials is a problem widely debated in the literature. This work explores the ability to restore the mechanical properties of thermally conditioned basalt fibres through chemical treatments. Inorganic acid (HF) and alkaline (NaOH) treatments proved to be effective in regenerating the mechanical strength of recycled basalt fibres, with up to 94% recovery of the strength on treatment with NaOH. In particular, HF treatment proved to be less effective compared to NaOH, therefore pointing towards a more environmentally sustainable approach considering the disposal issues linked to the use of HF. Moreover, the strength regeneration was found to be dependent on the level of temperature experienced during the thermal treatment process, with decreasing effectiveness as a function of increasing temperature. SEM analysis of the fibres’ lateral surfaces suggests that surface defects removal induced by the etching reaction is the mechanism controlling recovery of fibre mechanical properties. In addition, studies on the fracture toughness of the regenerated single fibres were carried out, using focussed ion beam (FIB) milling technique, to investigate whether any structural change in the bulk fibre occurred after thermal exposure and chemical regeneration. A significant increase in the fracture toughness for the regenerated fibres, in comparison with the as-received and heat-treated basalt ones, was measured.

Song L., Xu J., Tang H., Liu J., Liu J., Li X., Fan S.

Lunar regolith in-situ utilization receives increasing attentions due to development of lunar exploration research. The complex composition of lunar regolith leads to its complicated phase reaction and composition evolution at high temperature, whereas few studies focus on the alteration of physicochemical properties for simulated lunar regolith at high temperature. This paper focuses on physicochemical variation characteristics and magnetic transformation for high-Ti type basalt lunar regolith simulant CLRS-2 during vacuum sintering process. Importantly, the effect of heat-treatment on magnetic properties of CLRS-2 and the magnetic properties difference between high-Ti and low-Ti type basalt lunar regolith simulant have been investigated. The results would help us understand how the micro-morphology and chemical composition of ilmenite change in lunar regolith during sintering process. What can be inferred is that the ions substitution between ilmenite and other minerals or amorphous phase would occur during sintering process of lunar regolith at high temperature in vacuum, which would lead to the evaporation of Fe-containing components. Besides, the results of micro-hardness indicate that the ilmenite content difference between CLRS-1 and CLRS-2 have no influence on the micro-hardness of the sintered samples, while the density of samples and the sintering condition such as temperature have a greater influence. • First demonstration of unique micro-morphology variation of high-Ti type basalt lunar soil simulant. • First demonstration of weak ferromagnetic property for vacuum sintered basalt lunar regolith simulants. • First certification of the effect of ilmenite amount on composition evolution for lunar soil simulants. • First demonstration of small influence by ilmenite amount on micro-hardness of sintered samples.

Cui S., Xu X., Yan X., Chen Z., Hu C., Liu Z.

Abstract Bonding performance of basalt fiber reinforced cementitious composites (BFRCC) was studied through analyses on pull-out tests and scanning electron microscope (SEM) results. It is concluded that: (1) The rupture failure occurred for dispersed and flexible-type fibers, the pull-out failure controlled cluster-type fibers, and failure modes of alkali-resistant fibers are related to their embedded lengths (le). (2) As le increases, peak pull-out load (Npmax) increases and then becomes unchanged. Appropriate le is within 15–18 mm. (3) As specimen ages, Npmax first increases and starts to decrease at 7-day. (4) Comparisons of bonding strength among different fiber types: dispersed > flexible > alkali-resistant > cluster. (5) SEM analyses are consistent with the macro bonding performance of BFRCC.

MA P., LIANG C., XI X., CHEN T., WANG R., GU Y., XING D., YUE X., GUO Z., HAO B.

The construction of a lunar base is considered to be a giant step for the deep-space exploration by human beings. The in situ utilization of lunar resource is essential for the realization of this ambitious plan. In this study, the composition, crystal structure, melting, and fiberization behaviors of lunar soil simulant were investigated in an effort to develop a continuous fibre to address the material requirements for building a lunar base. The results showed that the chemical and mineral composition of the lunar soil simulant were similar to those of basalt roes on the Earth, and the material could be completely melted at 1332°C. The crystal structure of the simulant was homogenized and transformed into the amorphous glass state when the melted material was quenched by water. Using a fibre spinning facility, continuous filaments were obtained using the melted lunar soil simulant as the raw material. The obtained fibre showed the tensile strength of more than 1400 MPa, which is comparable with that of a commercial basalt fibre. These results confirmed the feasibility of using lunar soil to prepare a continuous fibre for the construction of a lunar base.

Jin E., Wang Z., Hu Q., Li M., Yuan J.

Warp sizing is considered as the most important process of weaving preparation in the textile field. The quality of sized warp yarns is directly determined by the permeation and coating of sizing paste into/on warp yarns. However, many significant flaws of the current method of permeability and coating property of sizing paste, such as low accuracy and narrow variety adaptability for sizing agents and warp yarns, have emerged in the evaluation process. In order to eliminate the inherent flaws in the current method, the investigation chose chitosan (CS) as a representative of common sizing agents, introduced various amounts of perylene units onto molecular chains of the CS, and prepared a new functional sizing agent—fluorescent CS with different labeling degrees of perylene. Furthermore, PVA-perylene was synthesized to evaluate the permeability and coating property of PVA sizing paste. Then, three indexes to indicate the permeability and coating property of sizing paste, i.e. permeation percentage, coating percentage and integrity percentage of sizing film, were evaluated using the CS-perylene and PVA-perylene derivatives prepared. Due to the fluorescence emitted by the perylene units, the three indexes can be determined accurately and conveniently depending on only fluorescent microscope and common image processing software. The investigation efficiently solves the difficult problem of evaluating permeation and coating property of the pastes of both bio-based and petroleum-based sizing agents with appropriate degrees of labeling and has a significant guiding function on accurate determination of the quality of sized yarns.

Miao Y., Xing D., Xi X., Yue X., Bai Y., Ma P.

In this paper, polymer nanocomposites made from epoxy and carbon nanotubes were developed and used as a sizing for basalt fibre. Full-scale experiment (two-factor and four-level combination) with quantitative analysis on the stability, wettability, conductivity, and morphology of liquid was applied to obtain the optimum formulation of sizing. The surface, electrical and mechanical properties of basalt fibre before and after sizing were studied. The results showed that nanocomposite sizing was deposited on the fibre surface during the fibre spinning process. The sizing gave significant increases on the electrical and tensile strength of basalt fibre, revealing the effectiveness of nanocomposites as a multi-functional material. The application of conducting sizing was a simple and effective way to enhance the technique value of insulating basalt fibre.

Lima L.F., Mantas P.Q., Segadães A.M., Cruz R.C.

In this work, basalt from the Serra Geral Formation, Brazil, was used to prepare a glass frit from which glass-ceramics were produced by the sinter-crystallization process. After different heat treatments in an inert atmosphere, properties were evaluated, as well as their relationship with the obtained microstructure. The results show that bulk density, hardness and crystallinity index increased with the treatment time up to the final temperature, with highest values for the longest heat treatment (6.5 h), respectively 2.39 g/cm3, 74.8% and 9.81 GPa. However, a shorter heat treatment (2.5 h) at the same final temperature resulted in comparable values (respectively, 2.38 g/cm3, 72.3% and 9.68 GPa). As such, isothermal steps at intermediate crystallization temperatures have no relevant influence on the final microstructure. Thus, for this basalt, nucleation is a very fast process and crystal growth is likely rather limited and little improved by intermediate crystallization heat treatment steps.

Xing D., Xi X., Qi M., Zheng Q., Ma P.

Sizing, a liquid mixture consisting of film former, coupling agent, antistatic and lubricant agents, is normally applied onto the surface of basalt fiber (BF) immediately after the filament was dra...

Yonggui W., Shuaipeng L., Hughes P., Yuhui F.

Abstract In this study, basalt fibre and nano-silica were used to reinforce recycled concrete, to enhance the elevated temperature performance of the recycled concrete and expand its application space. The mechanical properties and microstructures at 25, 200, 400, and 600 °C were studied using a static load test, scanning electron microscopy and X-ray diffraction. The results indicate that with an increase in temperature, the compressive strength and splitting tensile strength decrease, the mortar matrix gradually loosens, the properties of the interface transition zone and the bonds of the mortar to the fibres deteriorate, the influence of the replacement ratio on the compressive strength is weakened, and the influence of the nano-silica on the compressive strength is enhanced. At elevated temperatures, basalt fibre is beneficial to the improvement of the compressive strength of the recycled concrete, and basalt fibre has a more significant effect on the splitting tensile strength than the replacement ratio and nano-silica content. The relative residual splitting tensile strength increases as the basalt fibre content increases. Nano-silica is generally beneficial to the improvement of the compressive strength at different temperatures. The results indicate that basalt fibre and nano-silica contribute to the improvement of the interface transition zone performance and to the elevated temperature performance of the recycled concrete.

Li M., Gong F., Wu Z.

Abstract The alkali resistant basalt fiber (ABF), which are the modified basalt fiber with the property of the alkali resistant, has potential application in concrete. This study investigated the alkali resistance of ABF and the unmodified basalt fiber (BF) by soaking the fibers into the simulated alkaline solution of concrete. The effects of BF and ABF on the mechanical properties of concrete were studied. The results showed that, the compressive strength, flexural strength and splitting tensile strength of the concrete with the addition of 0.1% ABF were increased by 2.5%, 17.2% and 12.1%, respectively. The measurements of mercury intrusion porosimeter (MIP) and scanning electron microscopy (SEM) indicated that the addition of ABF improved the pore size distribution of concrete. Moreover, the bonding between the fibers and the matrix of concrete was enhanced.