The complex failure behavior of ice under cyclic loading holds significant relevance for understanding the behavior of nearshore sea ice cover, ice shelves, and ice pavements or runways. Experimental evidence demonstrates that the strength of freshwater ice, whether in compression or flexure, can either increase or decrease after cyclic loading. To explore this further, new cyclicmonotonic loading experiments were conducted on snow-sintered ice using four-point bending and unconfined compression tests subjected to various temperatures, monotonic strain rates, and cycling conditions. The results show that the average non-cycled flexural and compressive strength of snow-sintered ice at -10 degrees C is higher than that of water-frozen freshwater ice. The cycled flexural and compressive strength of snow-sintered ice under cyclic loading is highly sensitive to strain rate and accumulated strain. Notably, brittle failure was delayed under cyclic compressive loading at strain rates as high as 10-1 s-1. However, as the number of cycles increases, accumulated strain leads to a decrease in strength. Cyclic loading altered the ductile-tobrittle transition rate and secant modulus, shedding light on the mechanisms behind high-strainrate, low-cycle strengthening effects in ice.

The lunar base establishing is crucial for the long-term deep space exploration. Given the high costs associated with Earth-Moon transportation, in-situ resource utilization (ISRU) has become the most viable approach for lunar construction. This study investigates the sintering behavior of BH-1 lunar regolith simulant (LRS) in a vacuum environment across various temperatures. The sintered samples were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), along with nanoindentation, uniaxial compression, and thermal property tests to evaluate the microstructural, mechanical, and thermal properties. The results show that the sintering temperature significantly affects both the microstructure and mechanical strength of the samples. At a sintering temperature of 1100 degrees C, the compressive strength reached a maximum of 90 MPa. The mineral composition of the sintered samples remains largely unchanged at different sintering temperatures, with the primary differences observed in the XRD peak intensities of the phases. The plagioclase melting first and filling the intergranular pores as a molten liquid phase. The BH-1 LRS exhibited a low coefficient of thermal expansion (CTE) within the temperature range of - 150 degrees C to 150 degrees C, indicating its potential for resisting fatigue damage caused by temperature fluctuations. These findings provide technical support for the in-situ consolidation of lunar regolith and the construction of lunar bases using local resources.

The exploration of the Moon necessitates sustainable habitat construction. Establishing a permanent base on the Moon requires solutions for challenges such as transportation costs and logistics, driving the emphasis on In-Situ Resource Utilization (ISRU) techniques including Additive Manufacturing. Given the limited availability of regolith on Earth, researchers utilize simulants in laboratory studies to advance technologies essential for future Moon missions. Despite advancements, a comprehensive understanding of the fundamental properties and processing parameters of sintered lunar regolith still needs to be studied, demonstrating the need for further research. Here, we investigated the fundamental properties of lunar regolith simulant material with respect to the stereolithography-based AM process needed for the engineering design of complex items for lunar applications. Material and mechanical characterization of milled and sintered LHS-1 lunar regolith was done. Test specimens, based on ASTM standards, were fabricated from a 70 wt% (48.4 vol %) LHS-1 regolith simulant suspension and sintered up to 1150 degrees C. The compressive, tensile, and flexural strengths were (510.7 +/- 133.8) MPa, (8.0 +/- 0.9) MPa, and (200.3 +/- 49.3) MPa respectively, surpassing values reported in previous studies. These improved mechanical properties are attributed to suspension's powder loading, layer thickness, exposure time, and sintering temperature. A set of regolith physical and mechanical fundamental material properties was built based on laboratory evaluation and prepared for utilization, with the manufacturing of complex-shaped objects demonstrating the technology's capability for engineering design problems.

In-Situ Resource Utilization (ISRU) approaches hold significant importance in plans for space colonization. This work explores a different ISRU concept applying fast-firing, a robust and well-known industrial process, to Mars regolith simulant (MGS-1). The fast-fired specimens were compared to the ones obtained by conventional sintered under low heating rates. When the holding time at the firing temperature is longer than 15 min, fast-fired specimens exhibited higher density and flexural strength (> 35 MPa) than conventional sintering. For both processes, the bulk density values and the mechanical properties of the regolith compacts were enhanced with increasing dwell time. This was attributed to higher heating rates changing the densification/crystallization kinetics involving the basalt glass in the regolith composition. Specifically, high heating rate promotes sintering over crystallization. On these bases, fast firing can be considered a potential candidate for ISRU on Mars.

The technology of 3D printing, referred to as additive manufacturing, is widely acknowledged as a transformative innovation that has the potential to supplant traditional processing methods in numerous domains. The present study showcases a quantitative assessment of the mechanical properties of moon dust, also known as Lunar Regolith Simulants (LRS), printed through vat polymerization. In this study, we conduct a thorough investigation and explore the effects of layer height [LH] (LH = 10 mu m, 20 mu m, 30 mu m, 40 mu m, 50 mu m, 60 mu m]), exposure time [ET] (ET = 3000 ms, 5000 ms, 7000 ms, 11,000 ms), and sintering impact [1075 degrees C, 1082 degrees C, 1083 degrees C, 1085 degrees C, 1086 degrees C, 1087 degrees C, 1090 degrees C] on the mechanical properties of printed structures. Herein, we utilize a 55 % volume suspension of LRS to print rod and block configurations via digital light printing [DLP] that are subsequently consolidated through sintering in ambient air. This 55 % LRS via vat polymerization approach has not been previously reported. The morphology of the simulant powders exhibited irregular and angular features. Our experimental results show that a 30 um (LH) with (ET) 11,000 ms exhibits maximum compressive and flexural strength of 330 MPa and 100 MPa at 1085 degrees C. The sintering atmosphere greatly affects the microstructure, macroscopic features, and mechanical strength of 3D-printed LRS, which reveals diverse chemical compositions and underlying reaction mechanisms. This sintering process improves particle bonding, resulting in densification and reduced voids within the 3D-printed structure. It is essential to optimize the annealing parameters to achieve the desired strength while avoiding excessive sintering that may cause dimensional distortions or structural defects. This innovative approach opens new possibilities for future space exploration and extraterrestrial construction.

In-Situ Resource Utilisation (ISRU) is increasingly being seen as a viable and essential approach to constructing infrastructure for human habitation on the moon. Transporting materials and resources, from Earth to the Moon, is prohibitively expensive and not sustainable for long-term, large-scale development. Various fabrication technologies have been investigated in recent years, designed for extra-terrestrial exploration and settlement. This review presents a comprehensive study on the development of several sintering techniques of lunar regolith simulant to demonstrate its feasibility for ISRU on the moon. Various critical processing parameters are evaluated in pursuit of creating a structural material that can withstand the extreme lunar environment. Key outcomes are summarised and assessed to provide insight into their viability. Finally, current challenges are addressed and potential improvements, and avenues for further research, suggested.

The mechanical and thermal properties of the fabricated structures composed of lunar regolith are of great interest due to the urgent demand for in situ construction and manufacturing on the Moon for sustainable human habitation. This work demonstrates the great enhancement of the mechanical and thermal properties of CUG-1A lunar regolith simulant samples using spark plasma sintering (SPS). The morphology, chemical composition, structure, mechanical and thermal properties of the molten and SPSed samples were investigated. The sintering temperature significantly influenced the microstructure and macroscopic properties of these samples. The highest density (similar to 99.7%), highest thermal conductivity (2.65 W.m(-1).K-1 at 1073 K), and the best mechanical properties (compressive strength: 370.2 MPa, flexural strength: 81.4 MPa) were observed for the SPSed sample sintered at 1273 K. The enhanced thermal and mechanical properties of these lunar regolith simulant samples are attributed to the compact structure and the tight bonding between particles via homogenous glass.

Molybdenum ore tailings, iron ore tailings and waste glass powders are important industrial solid wastes, mainly composed of silicate minerals and quartz, which are expected to become alternative resources for inorganic nonmetal industrial materials. In this paper, the ultra-lightweight ceramsite was prepared by the synergistic sintering of molybdenum ore tailings, iron ore tailings and waste glass powders according to their characteristics of silicate minerals. The physical and mechanical properties were investigated when the sintering temperature was between 1100 and 1140 degrees C. The evolution of mineral phases and formation mechanism of pore structure during sintering were studied by XRD, FT-IR, SEM, TG-DSC and HSM. The results showed that in the sintering process, the waste glass powders and the pargasite in iron ore tailings first melted to produce the initial liquid phases. Then the anorthoclase and the quartz in molybdenum ore tailings melted to produce a large amount of liquid phases. These liquid phases covered the gas generated by the oxidation of SiC, thus forming a rich pore structure. At the same time, the [Si2O64-] and Ca2+, Mg2+ in the liquid phases derived from quartz and pargasite melting recrystallized to form diopside, which was conducive to the improvement of mechanical properties of ceramsite. When the raw material ratio of molybdenum ore tailings, iron ore tailings and waste glass powders was 6:2:2 and the sintering temperature was 1120 degrees C, the pore structure of the ceramsite as prepared was uniform and rich and mostly closed. The density was low and the mechanical propertities were excellent. It has a good application prospect in the field of building thermal insulation and sound insulation.

Establishing a base on the Moon is one of the new goals of human lunar exploration in recent years. Sintered lunar regolith is one of the most potential building materials for lunar bases. The physical, mechanical and thermal properties of sintered lunar regolith are vital performance indices for the structural design of a lunar base and analysis of many critical mechanical and thermal issues. In this study, the HUST-1 lunar regolith simulant (HLRS) was sintered at 1030, 1040, 1050, 1060, 1070, and 1080 C. The effect of sintering temperature on the compressive strength was investigated, and the exact value of the optimum vacuum sintering temperature was determined between 1040 and 1060 C. Then, the microstructure and material composition of vacuum sintered HLRS at different temperatures were characterized. It was found that the sintering temperature has no significant effect on the mineral composition in the temperature range of 1030-1080 C. Besides, the heat capacity, thermal conductivity, and coefficient of thermal expansion (CTE) of vacuum sintered HLRS at different temperatures were investigated. Specific heat capacity of sintered samples increases with the increase of test temperature within the temperature range from -75 to 145 C. Besides, the thermal conductivity of the sintered sample is proportional to density. Finally, the two temperatures of 1040 and 1050 degrees C were selected for a more detailed study of mechanical properties. The results showed that compressive strength of sintered sample is much higher than tensile strength. This study reveals the effects of sintering temperature on the physical, mechanical and thermal properties of vacuum sintered HLRS, and these material parameters will provide support for the construction of future lunar bases. (c) 2024 Published by Elsevier B.V. on behalf of China University of Mining & Technology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Addressing the challenges of wet and soft loess foundations is crucial in geotechnical engineering due to their inherent low strength and high compressibility. High-temperature sintering technology is a leading method for enhancing loess foundations, known for its fast processing and effective reinforcement. This paper focuses on the effects of saturation on the compressibility of sintered loess, using results from saturation and compression tests. It highlights how saturation influences loess differently under various sintering conditions. Particularly, loess sintered at 200 degrees C breaks down after saturation, losing its resistance to deformation. By contrast, loess sintered at other conditions retains some deformative resistance, but its compressibility still increases. The study finds an inverse relation between sintering temperature and the increase in compressibility after saturation. Additionally, it examines changes in compressibility indices, which include the compression coefficient, compression index, and modulus of compressibility. These are analyzed based on different saturation times, establishing a law that links saturation time to the compressibility of sintered loess.