This study aims to investigate the effect of fine aggregate lithology on the performance of rubberized asphalt mixtures. SEM, XRD, and contact angle tests were used to analyze the microscopic physical and chemical properties of 0–3-mm grain-size diabase and limestone. The performance characteristics of two types of ARAC-13 rubberized asphalt mixtures (with the diabase coarse aggregates and diabase fine aggregates, and diabase coarse aggregates and limestone fine aggregates, respectively) were then compared through conventional high-temperature water stability performance tests, uniaxial penetration tests, and accelerated loading abrasion tests. The results show that the surface roughness, chemical composition, and surface adhesion properties of limestone are better than those of diabase, and the surface roughness of limestone is 13.9% higher than that of diabase, and the surface adhesion energy is 6.4% higher. However, the results show relatively small differences between the asphalt mixtures with the diabase coarse aggregates and diabase fine aggregates and those with diabase coarse aggregates and limestone fine aggregates in the conventional water stability performance test and the high-temperature performance test. Furthermore, the strength reaches 90% when cured for 8 h for limestone and 12 h for diabase, with the curing rate being faster for limestone. The anti-abrasion performance of diabase specimens is superior to that of limestone specimens, but the anti-abrasion decay performance is the opposite. In summary, it can be observed that limestone fine aggregate shows better adhesion performance with asphalt than diabase fine aggregate, and it was recommended that diabase coarse aggregate and limestone fine aggregate be used to improve the asphalt–aggregate interface and enhance the road performance of the asphalt pavement.

Investigating the intrusion behavior of buffer/backfill materials is a critical aspect in the design of high-level radioactive waste (HLW) disposal repositories. This study proposes an intrusion model that accounts for the influence of the accessory-mineral ring and refines it by incorporating the specimen saturation process. The results show that the model demonstrated good agreement with the measured values after 30 days, but less accurate prior to this time. After incorporating a correction for the specimen’s saturation process, the model could well predict the measured values throughout the whole intrusion process. Additionally, the study suggests that predictions under parallel montmorillonite plates may be lower compared to non-parallel plates. The accessory-mineral ring significantly inhibits bentonite intrusion, and its restraining effect increases with the ring’s width. Compared to the smooth acrylic fissures, the irregular fractures in actual disposal repositories further limit bentonite intrusion. Fracture water seepage restricts bentonite intrusion in the upper part of the specimen while promoting it in the lower part, and also enhances the inhibiting effect of the accessory-mineral ring. The extent of this effect depends on the water flow velocity. Furthermore, increasing temperature promotes bentonite intrusion.

Bio-based plastics represent an opportunity to reduce the impact of petroleum-based plastics on the environment, leading to harmful effects on both terrestrial and marine ecosystems. Nevertheless, the plant origin of bio-based plastics does not necessarily imply better management of their end of life. However, when recycling is impossible, the biological degradation of bio-based plastics would be an effective method to reduce their environmental impact. Polylactic acid (PLA) is one of the most produced biopolymers currently among the bio-based plastics already developed for several years. Thus, the objective of this article is to provide a state of the art on the biodegradation of bio-based plastics based on PLA. In particular, the microorganisms catalyzing the different biochemical reactions and the main biodegradation mechanisms are reviewed according to aerobic and anaerobic conditions. Moreover, different microorganisms involved in the degradation of PLA are summarized. Furthermore, a special attention is paid to the analytical methods to evaluate the biodegradation of polylactic acid and to the different existing biodegradation test methods, because this subject has rarely been reviewed in the literature. In the end, several promising topics for the future research are proposed, such as enzyme engineering technology as a recently emerging method for PLA degradation and a new common testing method to collect as much data as possible on the biodegradability to compare different studies.

An erratum on: Prediction and analysis of strength and economic feasibility of filling materials under the influence of mix proportion and curing age. By Zhang Y, Liang H, Fei S, Zhang A, Yu J and Qin X (2024). Front. Mater. 11:1428859. doi: 10.3389/fmats.2024.1428859Error in FigureDue to a production error, there was a mistake in Figure 1 as published. The corrected Figure 1 appears below. The publisher apologizes for this mistake.The original version of this article has been updated.

Additive manufacturing (AM or 3D printing) holds the potential to revolutionize the ceramic industry by offering fresh avenues for manufacturing complicated ceramic components directly from digital models without the need for costly tooling. This advancement can lead to decreased production costs and lead times, while also enhancing design flexibility and tolerance for imperfections. Thus, there is an increasing interest in utilizing AM techniques to produce advanced ceramic components and explore their wide-ranging applications. This special issue consists of several articles from renowned groups worldwide, presenting their insights and recent progress in AM of advanced ceramic materials and applications. These articles discuss advances across various topics including novel materials, innovative techniques, and emerging applications, which broaden the understanding of the capabilities, challenges, future perspectives and implementation of AM of advanced ceramic materials. The collections in this special issue have attracted review and research articles addressing diverse aspects of the AM-fabricated advanced ceramic materials and applications. Fiume et al. (fmats.2023.1242480) discussed the vat-photopolymerization of ceramic materials and explored the state-of-the-art of the applications in advanced multidisciplinary fields including biomedicine, energy, environment, space and aerospace, with a special focus on current trends and project-specific requirements. Pan et al. (fmats.2020.00054) formed high-resolution, defect-free alumina ceramics using stereolithography-based 3D printing technology, which provides a rapid and cost-effective manner to produce ceramic cores used in astronautics engineering and material engineering fields related to high-temperature environments. Yan et al. (fmats.2023.1239692) introduced a hybrid approach methodology that combines experimental rheology with Finite Element simulations to determine the printability of ceramic-polymer ink formulations which aids in optimizing low-temperature extrusion 3D printing of novel inks for bone tissue engineering. Heise et al. (2024.1441812) presented the design and use of an inline mid-infrared optical coherence tomography (MIR-OCT) system combined with deep learning for classification and in-process feedback as a versatile tool for at-line and inline quality control in lithography-based ceramic manufacturing. This special issue has a strong focus on AM-fabricated advanced ceramic materials and their applications. The exceptional dimensional/chemical stability over a wide temperature range, along with high corrosion resistance and lower density in comparison to metal-based components, have made ceramic materials highly intriguing for space and aerospace applications, thus have becoming a fascinating research area. Fiume et al. (fmats.2023.1242480) summarized relevant outcomes and final considerations of various classes of AM-fabricated advanced ceramics used in space and aerospace industry, including both oxide- and non-oxide ceramics and ceramic composites. Pan et al. (fmats.2020.00054) discussed the influence of high-temperature sintering conditions on microstructure and properties of 3D-printed alumina ceramics and obtained high-performance intricate alumina ceramic cores essential for crafting high-temperature hollow turbine blades. Tissue engineering applications are another subfield where AM of bioceramics finds tremendous potential. Fiume et al. (fmats.2023.1242480) highlighted how the scientific community is devoting considerable efforts to the transfer of stereolithography-based 3D printing technology of bioceramic materials into clinical practice in various fields of application, such as orthopedics and dentistry. Yan et al. (fmats.2023.1239692) established a framework for streamlining the design of inks for extrusion 3D printing of ceramic-polymer scaffolds for bone tissue engineering. They evaluated the compressive properties of printed hydroxyapatite-polycaprolactone scaffolds and characterized the effects of ceramic content and component ratio ratio on the hyperelasticity observed in response to compressive deformations.In recent years, artificial intelligence (AI) has emerged as one of the most active subfields of AM. This is also reflected in AM of advanced ceramic materials. AI has been suggested in AM of ceramics for classification between accurately 3D-printed and ceramics specimens with failures at the micron scale. Specifically, deep learning methods involving convolutional neural networks or residual neural networks that have enabled easy training and model generation for image data are chosen. Deep learning plays a crucial role in advancing AM by enabling more efficient processes, better quality control, and innovative material and design solutions. Heise et al. (2024.1441812) highlighted the potential of MIR-OCT coupled with AI-based identification methods for inline process monitoring and quality control in additive ceramic manufacturing machinery. They integrated the OCT measurement head in a 3D ceramic printer that enables direct layer growth monitoring, geometry verification, and real-time defect development monitoring, providing immediate user alerts when misprints are produced. Such monitoring enhances production efficiency by promptly detecting potential defects, reducing the time and cost commitments, and minimizing resource consumption.As mentioned earlier, AM of advanced ceramic materials and its applications constitute a vibrant and rapidly evolving field. While the contents of this special issue may encompass just a fraction of the outstanding research efforts in progress, our aspiration is to offer fellow researchers a glimpse into the dynamic and swiftly evolving landscape of this field.

Magnesium phosphate cement (MPC) is known as a high-performing rapid repair material for concretes in practice, and has also become a fast-moving research area for other applications, although its application has not yet reached its full potential. MPC has been utilized as a repair material in certain applications, although it is still less commonly used/recommended than the most popular and standardized repair materials. Therefore, it is important to systematically investigate the suitability of this material in the construction sector as a repair material. This review provides an in-depth summary of the engineering properties of magnesium potassium phosphate cements (MKPCs), as a particular example of MPCs that do not suffer from the undesirable release of ammonia which is observed in some other MPC formulations. Key properties relevant to the use of MKPCs as repair materials, from the fresh state to the hardened state are systematically examined. On this basis, the suitability of MKPC as a potential repair material is explored, highlighting the state-of-the-art practices, challenges and drawbacks in engineering applications, and future perspectives.

To investigate the effect of power density on the residual stress distribution on the surface of 17-7 PH stainless steel welded joints during laser shock process, we utilized ABAQUS finite element software for analyzing its distribution under different laser shock power densities. The material was tested for residual stress using an X-ray stress diffractometer to verify the accuracy of the simulation results and lay the foundation for finding the optimal process parameters. The simulation results show that when the laser power density is 2.79 GW/cm2, the maximum residual compressive stress value on the surface of the sample after laser shock peening is −37.2 MPa; When the laser power density is 2.79 GW/cm2, the maximum residual compressive stress value on the surface of the sample is −94.1 MPa; When the power density reaches 5.17 GW/cm2, the maximum residual stress value on the surface of the laser shock peening sample is −144.8 MPa, and residual stress cavity is formed. The experimental results show that when the laser power density is 2.79 GW/cm2, the maximum residual compressive stress on the surface of the sample is −37.3 MPa; When the power density is 3.98 GW/cm2, the uniformity of compressive stress distribution on the surface of the sample is optimal, with a maximum residual compressive stress value of −99.0 MPa; When the power density is 5.17 GW/cm2, the maximum residual compressive stress value is −146.1 MPa, and residual stress cavity is formed on the material surface. The simulation results are close to the experimental results, and the model error ranges from 0.2% to 4.9%. The simulation results are accurate and reliable.

New geomaterials and technologies are involved in a wide range of applications in all areas of civil engineering, including slope stabilization, coastal engineering, landfill containment, hydraulic engineering, highway and bridge construction, underground storage facilities, post-disaster reconstruction and tunnel support. The projects cover not only common materials for infrastructure construction, as well as the disposal of hazardous geomaterials, resource utilization of industrial waste, development of geopolymer materials and new materials for the treatment of contaminated soils related to geo-environmental engineering. Along with the increasing complexity of the external environment, newly developed geotechnical materials are associated with the coupling of several disciplines, including physics, mechanics, chemistry and even biology. Recently, although scholars have achieved certain research results, there is still a lack of sufficient awareness of many new materials and their performance under complex environmental conditions.The Research Topic intends to gather the latest research results and review articles on new synthetic materials, disaster soil reinforcement and engineering security in complex environments. A total of six articles are presented on this research topic, including theoretical analyses, laboratory experiments, numerical simulations and field tests. This topic provides a significant reference for infrastructure design, stability assurance and environmental protection in geotechnical engineering. The submission for this research topic has been closed. More extensive and in-depth research in the field of hazardous geomaterials and engineering environment is looked forward to development.In the future, the researches on hazardous geomaterials will be gradually developed in the direction of more intelligent, sustainable and multidisciplinary integration driven by advanced technology and environmental awareness. All of the selected contributions help reveal innovative concepts and cutting edge technologies in this broad field. The editors would like to thank all reviewers and authors for the highly effective contributions.

The research aims to investigate the effects of proportion and age of maintenance on the strength and economy of filling materials, in order to provide theoretical guidance and technical support for the management of coal mined-out area. Firstly, adjustments are made to the proportioning and maintenance age of the fill materials, and experiments are conducted to explore the strength performance of materials under different proportions. Secondly, GANs is utilized to expand the dataset, and an MLP-LSTM network is constructed to predict the strength of materials experiencing different maintenance ages under various proportions. Finally, integrating practical engineering applications, an economic viability prediction analysis is conducted to examine the cost of fill materials under different proportions and maintenance ages, along with their influencing factors. The results indicate that appropriate adjustments to proportioning can effectively enhance the strength of fill materials, whereas excessively high or low proportions may lead to unstable or surplus strength. Extending the maintenance age can to some extent improve the material’s strength, but it also increases maintenance costs, necessitating a comprehensive balance in terms of economic viability. Consequently, this research offers a theoretical foundation and practical guidelines for optimizing mixture proportions and selecting appropriate curing ages, providing valuable insights for enhancing the efficiency and cost-effectiveness of coal mined-out area filling treatments.

To study the damage characteristics and damage model of reinforced concrete slabs under explosive impact, the failure modes of reinforced concrete slabs under near-field and contact explosion were first studied through on-site experiments. A coupled model was established based on the Coupled Eulerian-Lagrangian (CEL) method using AUTODYN finite element software. The reliability of the model was verified by comparing the numerical simulation results with experimental results. Based on this, a fully coupled model of Carbon Fiber Reinforced Polymer (CFRP) reinforcement for reinforced concrete slabs under contact explosion was established, and the influence of different CFRP thicknesses and reinforcement methods on the blast resistance performance of reinforced concrete slabs was discussed. The research results indicate that under the action of near-field explosions, the front face of reinforced concrete slabs mainly experiences slight peeling damage, and the central area of the back face forms seismic collapse and peeling damage, with damage cracks diverging from the center to the surrounding areas; Under the action of contact explosion, the front face of the reinforced concrete slab produces blast pits, the back face forms a seismic collapse zone, and peeling damage occurs; The CFRP reinforcement layer can improve the blast resistance performance of reinforced concrete slabs; There is an optimal thickness when using CFRP to enhance the blast resistance of reinforced concrete slabs.