Basaltic Glass Research Articles

Structure, crystallization behavior and chemical stability analysis of Nd3+-basaltic glasses for immobilizing simulated trivalent actinides

The Nd3+-basaltic glass was prepared by melt-heat treatment method using Nd3+ to simulate trivalent actinides. The structure, thermal stability and leaching characteristics of basaltic glass with different contents of Nd2O3 were investigated. XRD and SEM-EDX results show that the simulated waste loading of Nd2O3 in basaltic glass can be up to ∼30 wt.%, and oxy-silicate apatite (Ca2Nd8(SiO4)6O2) precipitates when Nd2O3 content reaches 32 wt.%. Raman results indicate that the addition of Nd2O3 breaks some of Si-O-Si bond, but overall there is not much effect on the glass network structure. DSC results show the Tg of the glasses increases and the thermal stability first increases and then decreases with the increase of Nd2O3 content. The leaching resistance of samples was evaluated by the ASTM Product Consistency Test (PCT) Method, which shows that all the samples have good leaching resistance. Among them, the standard mass loss of Na is the greatest after 28 days. The NLNd is 4∼5 orders of magnitude lower than other elements.

Dissolution mechanisms of water in depolymerized silicate (peridotitic) glasses based on infrared spectroscopy

The dissolution of water changes the chemical and physical properties of melts. The effect of water dissolution depends on the bulk H2O content and dissolution mechanisms. Previous research mainly focused on relatively polymerized glasses, whereas dissolution mechanisms of water in highly depolymerized glasses have not been well studied. We investigated three sets of hydrous (up to 5 wt% H2O), highly depolymerized glasses using Fourier transform infrared spectroscopy. The three suites of glasses can be classified as tephritic (non-bridging oxygens to tetrahedral cations, NBO/T ≈ 0.9), basanitic (NBO/T ≈ 1.5), and peridotitic (NBO/T ≈ 2.5). The comparison of infrared spectra indicated four prominent features. First, the combination band related to molecular H2O at ∼ 5200 cm−1 decreases in relative intensity with increasing depolymerization. At 2 wt% bulk H2O, the proportion of H2O molecules decreases from the tephritic through basanitic to peridotitic glasses, where the proportion of H2O molecules is below 10 %. At 5 wt% bulk H2O, the proportion of H2O molecules in the peridotitic glass is around 20 %, whereas it is around 50 % in the basaltic glass with the same H2O content. Second, a second peak appears at 4270–4180 cm−1, next to the (Si,Al)OH combination peak (network hydroxyl), with increasing CaO and MgO contents in basanitic (∼25 wt% CaO) and peridotitic (∼40 wt% MgO) glasses, respectively. We assign this peak to the (Mg,Ca)OH group (free hydroxyl); this is the first identification of this group based on infrared spectroscopy. This assignment is also supported by IR data on Mg(OH)2 and Ca(OH)2 crystalline phases from the literature. Third, the ratio of (Si,Al)OH and (Mg,Ca)OH peak absorbances remains nearly constant with increasing water content in basanitic and peridotitic glasses, suggesting no effect of water on polymerization of extremely depolymerized melts. Fourth, the (Si,Al)OH peak shifts to lower wavenumbers with increasing depolymerization. As a result, the (Si,Al)OH peak position could potentially be used to evaluate the degree of melt polymerization in general, and the effect of water on melt polymerization in particular.

Physical and mechanical properties of gypsum-based composites reinforced with basalt, glass, and PVA fibers

The purpose of this experiment is to investigate the influence of basalt fibers (BF), glass fibers (GF), and Polyvinyl alcohol (PVA) fibers on the properties of fiber-reinforced gypsum-based composites including setting time, extended diameter, water absorption, and flexural strength. In this study, the change of experimental results was obtained by selecting the fiber type, length, volume, and surface treatment as influencing factors; the mechanisms of change in the context of existing research was explained. Moreover, the scanning electron microscope was further analyzed, and analysis models of different factors on the fiber reinforced gypsum matrix were depicted. The results indicated that, with the increase in fiber length and volume, the setting time and fluidity will decrease and water absorption will increase. Compared with control group, the optimal ratios of three selected fibers were all 10 mm and 1.0%; in addition, the flexural strength can be increased by more than 50%. Moreover, the setting time, fluidity, and water absorption can increase by HCl, NaOH, and KH550 silane coupling agent treatments on the BF surface, with an improvement effect within 5%. The HCl and NaOH treatments can form pit etching on the fiber surface through an oxide reaction, while a hairy transmission stress interface layer between the BF and gypsum can be formed by the KH550 silane coupling agent treatment, where the strength lifting effect is better.

The effect of using CaCO3 and lime glass in the probability of pore structure forming on a ceramic glass based on scoria basalt rocks

With the development of technology lately, the technology for making lightweight materials is also growing, where the goal is to reduce the total weight of the material without reducing its mechanical strength. Several parameters that influence the manufacture of lightweight materials are the number of pores, materials weight, and physical resistance. One commonly used method is mixing ceramic glass with a foaming agent. In this study, basalt rock from East Lampung, Indonesia, and lime glass was used as a ceramic glass material mixed with CaCO3, which melted down at a temperature of 1200 0C. Variations in composition were carried out by mass comparison between basalt and lime glass, namely A sample (100:0), B sample (70:30), C sample (50:50), and D sample (30:70) with 50%wt CaCO3 added for each sample and heated up to 1200 0C. Treatment variations (annealed and normalized) are also applied to see the phenomena occur. Based on the characterization results, the best sample obtained is in B sample with normalized treatment, whose has porosity value of 53.2% and density value of 1.08 gr/cm3. Based on the results of the SEM test, the pores with a size ≤ 0.5µm are 95%, and ≥ 0.5µm are 5%, where the crystals formed are pyroxene and calcite with the compositions of CaO and SiO2, respectively 39.46% and 41.90%.

Structure and stability analysis of basaltic glasses for immobilizing simulated actinides Nd, Ce and La

Taking a power reactor in China as the object, the simulated actinides basaltic glasses were prepared by the solid-state melt method using Nd, Ce and La to simulate the actinides Am, Np and U. The XRD, SEM-EDX, XPS, Raman and DSC results show that the loading of the simulated actinides in basaltic glass can be up to 36 wt.%, and excess simulated actinides lead to oxyapatite crystals precipitation in the glasses; about half of Ce4+ in basaltic glasses is reduced to Ce3+; the simulated actinides may break Si-O bonds in glass networks, but overall there were no serious effects; the thermal stability of the basaltic glasses with the simulated actinides content increased first, and reduce when the content of more than 25 wt.%. All the samples have good leaching resistance and the leaching rates of Nd, Ce and La are 4 orders of magnitude lower than Si and Na.

Quantification of amorphous Si, Al, and Fe in palagonitic Mars analogs by chemical extraction and X-ray spectroscopy

Data collected by orbiters and landers have consistently shown abundant amorphous materials on Mars. Developing analytical techniques that target amorphous materials in terrestrial analogs can help determine the environmental conditions under which the amorphous assemblages on Mars were formed. However, the inherent short-range order, chemical heterogeneity, and nanoscale phase interactions create challenges in characterizing these phases. This study is aimed to overcome these challenges by combining chemical dissolution rate analysis with spectroscopy-based mass balance calculations (MBC) to characterize different pools of amorphous materials in terrestrial analogs. The differences in dissolution rates between rapidly dissolving Si, Al, and Fe amorphous materials and the slowly dissolving crystalline minerals were modeled to predict amorphous composition in five palagonitic samples from Hawaii (Mauna Kea) and four hyaloclastite tuffs from the subglacial volcanoes in southwest Iceland. These samples were selected as potential analogs because of their spectral and compositional resemblance to Mars's surface materials.The amorphous Si, Al, and Fe compositions from both sites varied based on the degree of aqueous alteration, grain size, and location. The amorphous fractions of the unconsolidated palagonitic analogs from Hawaii are composed of alteration products such as opal CT and ferrihydrite with minor amounts of unaltered basaltic glass. In contrast, the amorphous fractions of the cemented Icelandic samples were composed mainly of unaltered glass and mixed Fe(II, III) iron phases. Amorphous compositions of the loose Hawaiian and the consolidated Icelandic palagonites are comparable with the Martian modern and ancient aeolian materials respectively. The amorphous compositions in the Hawaiian sample, HWMK101, closely resemble the amorphous materials in Rocknest, a modern aeolian material from the sand shadow, and the Icelandic samples are comparable to the ancient aeolian materials from the Stimson formation. Our analysis indicates the presence of hydrated secondary alteration products such as ferrihydrite and allophane in Rocknest, and a mixture of reduced iron phases and silicate glass outlined with finer altered opaline silicates in Greenhorn. The chemical extraction analysis combined with MBC can be used to characterize amorphous phases in terrestrial analogs to better constrain the formation and characterization of the abundant amorphous materials on Mars.

Solubility of water in peridotite liquids and the prevalence of steam atmospheres on rocky planets

Atmospheres are products of time-integrated mass exchange between the surface of a planet and its interior. On Earth and other planetary bodies, magma oceans likely marked significant atmosphere-forming events, during which both steam- and carbon-rich atmospheres may have been generated. However, the nature of Earth's early atmosphere, and those around other rocky planets, remains unclear for lack of constraints on the solubility of water in liquids of appropriate composition. Here we determine the solubility of water in 14 peridotite liquids, representative of Earth's mantle, synthesised in a laser-heated aerodynamic levitation furnace. We explore oxygen fugacities (fO2) between −1.9 and +6.0 log units relative to the iron-wüstite buffer at constant temperature (2173 ± 50 K) and total pressure (1 bar). The resulting fH2O ranged from nominally 0 to 0.027 bar and fH2 from 0 to 0.064 bar. Total H2O contents were determined by transmission FTIR spectroscopy of doubly-polished thick sections from the intensity of the absorption band at 3550 cm−1 and applying the Beer-Lambert law. The mole fraction of water in the liquid is found to be proportional to (fH2O)0.5, attesting to its dissolution as OH. The data are fitted by a solubility coefficient of 524 ± 16 ppmw/bar0.5, given a molar absorption coefficient, ε3550, of 6.3 ± 0.3 m2/mol for basaltic glasses or 647 ± 25 ppmw/bar0.5, for a preliminary ε3550=5.1±0.3 m2/mol for peridotitic glasses. These solubility constants are roughly 10 - 25% lower than those for basaltic liquids at 1623 K and 1 bar. Higher temperatures result in lower water solubility in silicate melts, wholly offsetting the greater depolymerisation of peridotite melts that would otherwise increase H2O solubility relative to basaltic liquids at constant temperature. Because the solubility of water remains high relative to that of CO2, steam atmospheres are rare, although they may form under moderately oxidising conditions on telluric bodies, provided sufficiently high H/C ratios prevail.

Orbital and In Situ Investigation of the Bagnold Dunes and Sands of Forvie, Gale Crater, Mars

AbstractThe Bagnold linear dune field investigated by Curiosity at Mount Desert Island (MDI) is north of the ∼5.5 km high Aeolis Mons mound in Gale crater. False‐color images (RGB: 2.496, 1.802, and 1.237 μm, respectively) generated from Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) data show the dune field has a reddish‐brown color. The Sands of Forvie (SoF), located ∼2.5 km to the southeast of MDI, is darker and lacks the reddish‐brown color. Single scattering albedo (SSA) spectra retrieved at 12 m/pixel using along‐track oversampled CRISM observation FRT00021C92 show a long wavelength (1.7–2.5 μm) increase in albedo for MDI dunes. For the same wavelength interval, SoF is characterized by a broad ∼2.2 μm absorption feature, consistent with color differences between the two deposits. Checkerboard un‐mixing of the SSA image cube was used to isolate spectral endmembers within the MDI and SoF deposits. Radiative modeling of these CRISM spectral endmembers using Hapke (2012, https://doi.org/10.1017/CBO9781139025683) theory implies finer grain sizes, more pigeonite, plagioclase, and olivine, and less basaltic glass and augite for MDI as compared to the SoF deposit. These results are consistent with Curiosity‐based observations that MDI contains smaller ripples with overall finer grains, whereas SoF has large ripples with coarser grains on the crests. Although these sand deposits are only located ∼2.5 km away from one another, wind and local topographic controls are interpreted to have modulated grain sizes and mineralogy.

Experimental investigation on the bond performance of sea sand coral concrete with FRP bar reinforcement for marine environments

The world is rich in marine resources, and the use of seawater, sea sand and coral instead of fresh water, river sand and gravel can solve problems such as the scarcity of traditional materials for marine engineering construction. Additionally, fibre-reinforced polymer (FRP) bars have demonstrated excellent corrosion resistance performance, which can effectively solve the problem of the corrosion of steel in harsh marine environments. To study the bond performance between FRP bars and sea sand coral concrete (SSCC), 72 specimens of direct Pull-out were designed, and relevant tests were carried out to explore the effects of fibre types, bar diameters, bond lengths and SSCC strength grades. The results show that the bond strength between carbon fibre-reinforced polymer (CFRP) bars and SSCC was higher than that of basalt fibre-reinforced polymer (BFRP) bars and glass fibre-reinforced polymer (GFRP) bars. The splitting damage pattern occurred in most of the specimens; the bond strength between FRP bars and SSCC decreased with increasing diameter and bond length of FRP bars but increased with increasing SSCC strength grade. As a result, by fitting the bond-slip curves obtained from the tests, the bond-slip constitutive relationship between FRP bars and SSCC specimens was obtained, which clearly and precisely represents the bond failure process of SSCC with FRP bar reinforcement.

Experiments on the reactivity of basaltic minerals and glasses in Venus surface conditions using the Glenn Extreme Environment Rig

AbstractClimate models for Venus rely heavily on theoretical modeling and laboratory experimentation due to the extreme surface conditions of the planet and limited in situ surface data. To better explore the relative importance of reactions between the surface and the atmosphere on Venus, we exposed representative volcanic glasses and basaltic minerals to a large‐scale simulation of Venus surface conditions with a realistic atmospheric composition. This study consistend of two experiments of 42 and 80 days that replicated both physical conditions and atmosphere composition derived from available in situ near‐surface data using the Glenn Extreme Environment Rig (GEER) at the NASA Glenn Research Center. These experiments revealed significant reactivity of common Ca‐bearing pyroxenes (diopside and augite) to form anhydrite. Olivine and labradorite showed minimal reactivity. Volcanic glasses, including both natural and synthetic samples, were exceptionally reactive, rapidly forming both anhydrite and thénardite (Na2SO4), as well as transition metal sulfates (i.e., Cu, Cr), halite (NaCl), and sylvite (KCl). Our results document chemical and textural alteration of sample surfaces and provide sufficient evidence for an active sulfur sink on multiple samples, with sulfates as the dominant secondary mineralogy. These experiments suggest likely surface mineralogies and solid phases present on Venus' surface with significant implications for upcoming missions and provide new data for comparison to high‐temperature mineral–gas reactions prevalent on Venus, Earth, and Io.

Finite Element Simulation of FRP-Strengthened Thin RC Slabs

This study aims to investigate the flexural behavior of high-strength thin slabs externally strengthened with fiber-reinforced polymer (FRP) laminates through a numerical simulation. A three-dimensional (3D) finite element (FE) model is created to simulate the response of strengthened reinforced concrete (RC) slabs under a four-point bending test. The numerical model results in terms of load-deflection behavior, and ultimate loads are verified using previously published experimental data in the literature. The numerical results show a good agreement with the experimental results. The FE model is then employed in a parametric study to inspect the effect of concrete compressive strength on the performance of RC thin slabs strengthened with different FRP types, namely carbon fiber-reinforced polymers (CFRP), polyethylene terephthalate fiber-reinforced polymers (PET-FRP), basalt fiber-reinforced polymers (BFRP) and glass fiber-reinforced polymers (GFRP). The results showed that the highest strength enhancement was obtained by the slab that was strengthened by CFRP sheets. Slabs that were strengthened with other types of FRP sheets showed an almost similar flexural capacity. The effect of concrete compressive strength on the flexural behavior of the strengthened slabs was moderate, with the highest effect being a 15% increase in the ultimate load between two consecutive values of compressive strength, occurring in the CFRP-strengthened slabs. It can thus be concluded that the developed FE model could be used as a platform to predict the behavior of reinforced concrete slabs when strengthened with different types of FRP composites. It can also be concluded that the modulus of elasticity of the composite plays a major role in determining the flexural capacity of the strengthened slabs.

Phase separation and properties of glasses of the system MgO–CaO–Fe <sub>2</sub>O<sub>3</sub>–Al<sub>2</sub>O<sub>3</sub>–В<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub>

The synthesis and study of model glasses of the MgO–CaO–Fe2O3–Al2O3–SiO2 system, which is the base for obtaining continuous basalt fiber, has been carried out. Systematized data on the effect of components on the glasses structure and the sequence of phase separation processes occurring during their heat treatment have been obtained. It is shown that during phase separation, crystalline phases are separated in the following sequence: magnetite–pyroxene–plagioclase with a predominance of the anorthite component. Glasses of the MgO–CaO–Fe2O3–Al2O3–SiO2 system were modified by adding B2O3, and the active role of this component in the processes of glass formation and crystallization was shown. The ratio of glass-forming and modifying components of model glasses is established, at which an increase in the strength of glasses from 110 to 180 MPa is achieved. Based on the study of the technological properties of model glasses and strength characteristics, components were determined for modifying basalt glasses in order to increase the strength of the fiber.

Geochemistry of impact glasses in the Chang’e-5 regolith: Constraints on impact melting and the petrogenesis of local basalt

Lunar impact glasses can provide important information on the bulk compositions of their sources and the impact history of the Moon. Here, we report the chemical composition of fifty-four clean glass spherules containing neither relict clasts nor crystals from the Chang’e-5 (CE5) regolith. They can be subdivided into three compositional groups: (1) mid-Ti basaltic (TiO2 = 4.1 ∼ 6.5 wt%), (2) low-Ti basaltic (TiO2 = 1.3 ∼ 3.9 wt%), and (3) high-Al (Al2O3 > 15 wt%). Fifty-one glasses (∼94 %) are mid-Ti basaltic, which form a loose compositional cluster for most major and trace elements. These glasses exhibit considerable variations in SiO2 (35.3 ∼ 45.3 wt%). Their TiO2, Al2O3, MgO and CaO show negative correlations with SiO2, while the Na2O, K2O and P2O5 positively correlate with SiO2, also yielding a positive correlation between the CIPW normative plagioclase and olivine. These variations likely result from differential vaporization of SiO2, strongly suggesting an impact origin of these glasses. Their major and trace element compositions are averagely similar to the bulk-rock, in turn indicating that they were formed from the local regolith. The remaining three glasses, including two low-Ti basaltic and one high-Al variety, exhibit distinct major and trace elements from the regolith, indicating an exotic source. In addition, the mid-Ti basaltic glasses provide another approach for estimating the average composition of the CE5 basalt other than directly measuring the small basalt fragments assuming that the exotic materials in the CE5 regolith were limited. This estimation reveals critical trace element characteristics of the CE5 basalt, e.g., it has higher La/Yb (3.71), Sm/Yb (1.76), Sr/Yb (31.6), and (Eu/Eu*)N (0.45) than KREEP, indicating that CE5 basalt must derive from a non-KREEP source. Chemical modeling indicates that the contribution of KREEP-rich materials in the mantle source should be less than 0.3 %. The trace element characteristics of the CE5 basalt can be reproduced by extensive (80 %) fractional crystallization after low-degree (2 %) melting. We propose that this fractional crystallization process might occur at depth, implying vast igneous underplating (7,250 ∼ 11,750 km3) beneath the CE5 landing area. This study also suggests that the high Th concentration (5.43 ppm) is an inherent property of the CE5 basalt resulting from extensive fractional crystallization. Thus, high Th detected by remote sensing may not be associated directly with a KREEP component but rather with highly fractionated basalts.

Simulated Lunar Surface Hydration Measurements Using Multispectral Lidar at 3µm.

Accurately measuring the variability of spectroscopic signatures of hydration (H2O + OH) on the illuminated lunar surface at 3 μm as a function of latitude, lunar time of day, and composition is crucial to determining the generation and destruction mechanisms of OH species and understanding the global water cycle. A prime complication in analysis of the spectroscopic feature is the accurate removal of thermal emission, which can modify or even eliminate the hydration feature depending on the data processing methods used and assumptions made. An orbital multispectral lidar, with laser illumination at key diagnostic wavelengths, would provide uniform, zero‐phase geometry, complete latitude and time of day coverage from a circular polar orbit, and is agnostic to the thermal state of the surface. We have performed measurement simulations of a four‐wavelength multispectral lidar using spectral mixtures of hydrated mid‐ocean‐ridge basalt (MORB) glasses and lunar regolith endmembers to assess the lidar performance in measuring hydration signatures on the lunar surface. Our results show a feasible system with wavelengths at 1.5 μm, 2.65 μm, 2.8 μm, and 3.1 μm can measure lunar hydration with a precision of 52 ppm (1σ) or better. These results, combined with the uniform measurement capabilities of multispectral lidar make it a valuable spectroscopic technique for elucidating mechanisms of OH/H2O generation, migration, and destruction.

Numerical geochemical modelling of basalt-water interaction under subcritical conditions

A comprehensive hydrothermal-geochemical model was built in TOUGHREACT™ to match a detailed laboratory simulation of the interaction between tholeiitic basalt from the Elvarpahraun flow of the Svartsengi volcanic system in the Reykjanes Peninsula, Iceland and distilled de-oxygenated water. The experiment was done under subcritical conditions (350 °C and 490 bar), conditions associated with seafloor spreading centres and mid-ocean ridges.This modelling study was used to develop methodologies for building reactive transport models in TOUGHREACT™ with a particular focus on the parameters for reaction thermodynamics and reaction kinetics at high temperature and pressure conditions. The validation and update of geochemical assumptions are also integral to the methodology. Equilibrium constants for mineral and aqueous reactions were estimated using SUPCRTBL by Zimmer et al. (2016). Mineral dissolution rates were primarily adopted from Palandri and Kharaka (2004), while precipitation rates were estimated following the work of Horiuti (1957). Justifications for the modelling decisions made are presented in detail.Based on the model, precipitation rates are generally higher than expected rates from the estimated kinetic parameters and mineral surface area estimates, while there is agreement in terms of dissolution rates. Mineral solid solutions dissolved stoichiometrically, except bytownite, whose albite component was preferentially dissolved. The volume of basalt glass in the sample was higher than experimental estimates, based on the silica concentration trends. Sulfide inclusions in the glass also significantly affected the observed sulfate and sulfide trends while the glass dissolved. The potassium concentration trends in the effluents indicate the presence of K-feldspar. Lastly, based on the model results, the bulk flow rates were observed to affect the overall reaction rates.

A Raman Spectroscopic and Microimage Analysis Perspective of the Chang'e‐5 Lunar Samples

AbstractThe Chang'e‐5 (CE‐5) materials represent the youngest returned lunar samples. We performed a detailed Raman spectroscopic survey (1259‐point Raman modal analysis) to evaluate the mineralogical characteristics of CE‐5 soils, constraining the source materials and shock effects of these unique samples. The mineral chemistry (e.g., Mg#3‐60 for mafic minerals) and modal abundance (first distinguishing basaltic and feldspathic glasses) of CE‐5 mare soils are different from those of Apollo high‐ and low‐Ti basalts, possibly representing an intermediate‐Ti mare basalt. The occurrence of minor Mg‐rich materials (Mg# > 70) provides evidence of contamination from ∼5% to 7% exogenous materials, possibly related to Mg‐suite rocks. The microimage analyses suggest that the CE‐5 soils are fine‐grained, mature, and unimodal particle‐size distribution, highlighting that micrometeorite reworking dominates the CE‐5 regolith evolution with minor mixing from nonmare materials. The pressure‐sensitive minerals (quartz and maskelynite) indicate that 17–25.8 GPa shock pressures might be the higher limit in a relatively young lunar terrain.

Performance of Glass Fiber, Basalt Fiber: Subjected to Fire

Abstract— Over the decades, there was a widespread increase in the use of fiber in concrete for improving its properties such as tensile strength and ductility. The fiber reinforced concrete is also used in retrofitting existing concrete structures. Dispersed fiber reinforcement of concrete improves specific properties and one of them is fire resistance. In numerous research was proven that glass fiber and basalt fiber can inhibit or partly prevent concrete from explosive spalling. New kind of fiber may be be used as dispersed reinforcement are chopped basalt fiber (BF) and glass fiber with ability to improve not only physical and mechanical properties of concrete but also to resist fire . Basalt is rock with suitable properties for resistance to high temperatures, as low coefficient of thermal expansion and stability up to 600 °C to 700 °C. Glass fiber has benefits of getting higher tensile strength and fire resistant properties, thus reducing the loss of damage during fire accident of concrete structures. Concrete mixes with various doses of cement and chopped basalt fiber and glass fiber had been investigated in this study. Properties of fresh and hardened concrete had been examined and evaluated temperatures.Due to large damages of concrete structure it was not possible to measure changes of porous system evaluated by spacing factor after thermal load. Compressive strength was examined before and after thermal load. Special thermal regimes with maximum temperature 200 °C, 300 °C,400˚C and 500 °C were applied. Results showed that chopped basalt fiber and glass fiber have positive impact not only on mechanical properties of concrete but also on its fire resistance. Two specific doses of chopped basalt fiber and glass fiber were tested but further research is in progress. Many studies are under way in this modern world in construction fields and seen that use of fiber reinforced concrete can lead to more effective and efficient construction material. Keywords— Chopped basalt fiber (BF), Glass fiber, Thermal load, fire resistance, spacing factor.

Bulk compositions of the Chang’E-5 lunar soil: Insights into chemical homogeneity, exotic addition, and origin of landing site basalts

Lunar soil is a fine mixture of local rocks and exotic components. The bulk-rock chemical composition of the newly returned Chang’E-5 (CE-5) lunar soil was studied to understand its chemical homogeneity, exotic additions, and origin of landing site basalts. Concentrations of 48 major and trace elements, including many low-concentration volatile and siderophile elements, of two batches of the scooped CE-5 soil samples were simultaneously obtained by inductively coupled plasma mass spectrometry (ICP-MS) with minimal sample consumption. Their major and trace elemental compositions (except for Ni) are uniform at milligram levels (2–4 mg), matching measured compositions of basaltic glasses and estimates based on mineral modal abundances of basaltic fragments. This result indicates that the exotic highland and KREEP (K, rare earth elements, and P-rich) materials are very low (<5%) and the bulk chemical composition (except for Ni) of the CE-5 soil can be used to represent the underlying mare basalt. The elevated Ni concentrations reflect the addition of about 1 wt% meteoritic materials, which would not influence the other bulk composition except for some highly siderophile trace elements such as Ir. The CE-5 soil, which is overall the same as the underlying basalt in composition, displays low Mg# (34), high FeO (22.7 wt%), intermediate TiO2 (5.12 wt%), and high Th (5.14 µg/g) concentrations. The composition is distinct from basalts and soils returned by the Apollo and Luna missions, however, the depletion of volatile or siderophile elements such as K, Rb, Mo, and W in their mantle sources is comparable. The incompatible lithophile trace element concentrations (e.g., Ba, Rb, Th, U, Nb, Ta, Zr, Hf, and REE) of the CE-5 basalts are moderately high and their pattern mimics high-K KREEP. The pattern of these trace elements with K, Th, U, Nb, and Ta anomalies of the CE-5 basalts cannot be explained by the partial melting and crystallization of olivine, pyroxene, and plagioclase. Thus, the mantle source of the CE-5 landing site mare basalt could have contained KREEP components, likely as trapped interstitial melts. To reconcile these observations with the initial unradiogenic Sr and radiogenic Nd isotopic compositions of the CE-5 basalts, clinopyroxene characterized by low Rb/Sr and high Sm/Nd ratios could be one of the main minerals in the KREEP-bearing mantle source. Consequently, we propose that the CE-5 landing site mare basalts very likely originated from partial melting of a shallow and clinopyroxene-rich (relative to olivine and orthopyroxene) upper mantle cumulate with a small fraction (about 1–1.5 %) of KREEP-like materials.

Crystallization Kinetics of Basalt Glass-Ceramics Produced from Olivine Basalt Rock

Glass-ceramics acquired from the melting of rocks have a vast application marketplace. In this study, an olivine basalt rock from Zhangjiakou in China was selected as a raw material to prepare basalt glass-ceramics, and the crystallization kinetics of olivine basalt glass was investigated using differential thermal analysis. Polarizing microscope and X-ray diffraction (XRD) analysis results revealed that the main mineral compositions of olivine basalt are plagioclase, pyroxene, olivine, and iron oxide(s). Three crystallization peaks were observed in the DSC curve of the olivine basalt glass. The Avrami exponent (n), apparent activation energies for the crystallization, and glass transition of basalt glass were determined using the Owaza method based on data obtained from isothermal measurements. The crystallization activation energies (E) of the three crystallization peaks of olivine basalt glass were 314.20 kJ/mol, 1232.49 kJ/mol, and 696.89 kJ/mol, respectively. In addition to this, the crystal growth index indicated that the crystallization mode in the olivine basalt glass was surface crystallization. The crystallization phases and microstructure of the olivine basalt glass heated at 860 °C, 1100 °C, and 1180 °C were also studied. The conclusions obtained offer some useful information for the preparation of basalt glass-ceramics from olivine basalt rocks.

Obsidian and mafic volcanic glasses from the Philippines and Vietnam found in the Paris Museum Australasian tektite collection

AbstractDuring the systematic magnetic susceptibility survey of the Paris Museum Australasian tektite collection, we identified three previously overlooked occurrences of volcanic glass that resembles tektites, based on anomalous magnetic properties, high water content, the presence of microcrystals, and anomalous chemical composition. These occurrences are from the Phu Yen province in south‐central Vietnam (two rhyolitic glass fragments) and from the Philippines: one from northern Luzon Island (a basaltic rounded etched glass), one from Santa Mesa near Manilla (a dozen small rounded rhyolitic gravels). The two occurrences in the Philippines are quite similar to previously described volcanic glasses from the nearby Pagudpod and Nagcarlan localities, respectively. The rhyolitic glass specimens from the Phu Yen province are the first documentation of a geological occurrence of obsidian in Vietnam. This work is a warning note that glass samples with anomalous properties found among tektite collections may correspond to volcanic pseudotektites instead of real tektites with anomalous composition. The basaltic glass sample from the Philippines locally shows microcrystalline quench textures previously unknown in natural samples. These findings may also be of interest for archeologists involved in glass artifacts sourcing.