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The strength of cemented tailings backfill (CTB) is influenced by multiple factors, with the type of cementitious material playing a crucial role in determining the strength of the backfill. To investigate the influence of two different cementitious materials on the strength of CTB, based on the fundamental physicochemical properties of tailings, flow characteristic tests and uniaxial compressive strength (UCS) tests of the backfill were conducted using a cementitious backfill slurry prepared from tailings. Representative proportioned backfill specimens were selected for X-ray diffraction (XRD) and scanning electron microscope (SEM) microstructural analysis to study the evolution patterns of backfill strength influenced by cementitious material type, cement-to-tailing (c/t) ratio, and slurry concentration. The results indicate that the tailings exhibit favorable gradation but unstable continuity. Furthermore, a high content of clay minerals such as kaolinite, along with the presence of fluorine (F) and phosphorus (P), adversely affects the strength of fillers. In terms of slurry flowability, the fluidity of cementation powder filling slurry is generally superior to that of cemented filling slurry. In identical conditions, the strength of cementation powder fillers at all ages is significantly higher than that of cement. As the c/t ratio decreases, the strength advantage of cementation powder fillers becomes even more prominent. Compared to cemented fillers, the hydrated product calcium silicate hydrate gel (C-S-H gel) in cementation powder fillers is more abundant, while the hydrated product calcium aluminate hydrate (CAH) is coarser. This microscopic structural difference explains the strength characteristics of the fillers.

Bone cement implantation syndrome (BCIS) has been characterized by hypotension and/or hypoxia during cementation of a prosthesis; however, the casual link between cement and the pathophysiology of BCIS is unclear. This study aimed to determine if there is an association between cement and the incidence of BCIS by comparing cemented versus non-cemented hip arthroplasties in a modern series of patients who had a femoral neck fracture. A single-institution multi-surgeon retrospective review of 428 patients who underwent either hemi-arthroplasty (HA) or total hip arthroplasty (THA) for acute femoral neck fracture between May 2017 and December 2024 was performed. Data including American Society of Anesthesiologists (ASA) classification, co-morbidities, type of anesthesia, operative time, and use of cement for fixation were recorded. Intraoperative anesthesia records were manually reviewed for hypoxia and hypotension, and the grade of BCIS was calculated where applicable. Data were then analyzed using multivariate logistic regressions, analyses of variances (ANOVA), t-tests, and Chi-square analyses. Of the 428 patients, 301 (70%) had a cemented arthroplasty (211 HA and 90 THA), whereas the remaining 127 (30%) had cementless implants (18 HA and 109 THA). Of patients who met BCIS criteria, 219 (51%) were grade I and 83 (19%) were grade II. There were no patients who were grade III (cardiovascular collapse requiring cardiopulmonary resuscitation). Of patients who met BCIS criteria, there was no statistical association with cemented versus cementless fixation. In the multivariate analyses, only the type of anesthesia (spinal versus general) was associated with BCIS grade I or II (odds ratio (OR) = 2.37 (95% confidence interval (CI): 1.55 to 3.61), P < 0.001). There were no other recorded variables that reached statistical significance. In this modern series of patients undergoing arthroplasty for femoral neck fracture, no association was found between intraoperative BCIS and the use of cement fixation. Prior assumptions regarding BCIS may need to be reconsidered given contemporary surgical and anesthetic techniques.

Wollastonite is a natural meta-silicate mineral material with fibrous characteristics. In this paper, wollastonite with different aspect ratios obtained after grinding was used as a mineral admixture to replace cement for preparing ultra-high-toughness cement-based composites (UHTCCs). The effects of wollastonite on the fluidity, compressive strength, flexural strength, and tensile properties of UHTCCs were investigated, and the crack morphology and micro-topography of the tensile specimens after fracture were observed. The experimental results show that when the wollastonite replacement ratio exceeds 4%, it exerts a negative effect on the fluidity of UHTCCs, and wollastonite with a larger aspect ratio has a more significant negative impact. Relying on the bridging effect, replacing cement with wollastonite can significantly improve the flexural strength and compressive strength of UHTCCs. However, when the replacement ratio exceeds 6%, the strength enhancement effect of wollastonite with a larger aspect ratio begins to decrease. When the cement replacement ratio of wollastonite is up to 6%, it can increase the initial cracking strength, tensile strength and tensile strain of UHTCCs. At the same replacement ratio, wollastonite with a larger aspect ratio shows a better reinforcing effect. According to the observation of post-fracture crack morphology, the cracks of UHTCCs change from the original smooth cracks to tortuous ones after cement is partially replaced by wollastonite. Replacing a part of cement with wollastonite optimizes the performance relationship among PE fibers, the matrix, and the PE fiber-matrix interface, and it enhances their synergistic effect. This not only raises the initial tensile cracking strength of UHTCCs but also improves its tensile strain. In particular, wollastonite with a larger aspect ratio exhibits a more pronounced reinforcing effect.

The incorporation of plastic waste into cement-based materials offers a promising strategy for improving sustainability; however, it is often associated with reduced mechanical performance due to weak interfacial bonding. This study investigates the effect of metakaolin on the interfacial transition zone (ITZ) and mechanical properties of cement mortars modified with polyethylene terephthalate (PET) flakes used for the partial replacement of natural sand. Mortars containing 10 and 50 wt% metakaolin (as cement replacement) and 5 vol.% PET flakes (as sand replacement) were prepared and tested after 28 days of curing. Compressive and flexural strength were evaluated, and microstructural analysis was conducted using scanning electron microscopy (SEM) with a focus on the ITZ. The results indicate that the incorporation of PET flakes leads to a reduction in mechanical properties due to the formation of a porous and weak ITZ. However, the addition of 10 wt% metakaolin significantly improved mechanical properties, enabling PET-modified mortars to achieve strength comparable to the reference mix. SEM observations revealed that metakaolin contributed to the refinement of the microstructure and reduction in ITZ porosity, which enhanced interfacial bonding and improved stress transfer between PET particles and the cement matrix. These findings demonstrate that metakaolin can effectively mitigate the negative effects associated with PET incorporation by improving the microstructural characteristics of the ITZ, thereby enhancing the performance of sustainable cement-based composites.

Cementum is a specialized mineralized tissue that covers the tooth root surface and anchors the tooth to the surrounding periodontal ligament. The cervical acellular cementum (AC) is indispensable for periodontal attachment and represents a key target for periodontal regenerative therapies. However, the developmental origin and molecular identity of AC-forming cementoblasts remain poorly understood. Here, through an integrated spatial and single-cell transcriptomic analysis, we identify AC-forming cementoblasts as a distinct population of noncanonical mineralizing cells enriched for cell-matrix organization and Wnt signaling signatures, distinguishing them from cellular cementum-forming cementoblasts localized in the apical portion. Lineage tracing using a Wnt inhibitory factor 1 (Wif1-creER) demonstrates that AC-forming cementoblasts originate exclusively from peri-epithelial apical Wif1+ cells of the elongating tooth root via canonical Wnt signaling activation. Collectively, our findings uncover the unique ontogeny and molecular signature of acellular cementum, providing insights into the formation and maintenance of the periodontal attachment apparatus.

Nano-hydroxyapatite and silica incorporation into glass ionomer cements (GICs) have been proposed to enhance their physical and biological properties. In paediatric dentistry, the Hall technique relies heavily on the sealing ability of luting cements used for stainless steel crown (SSC) placement. This study aimed to compare the microleakage of nano-hydroxyapatite-silica incorporated glass ionomer cement (nano-HA-silica GIC) with conventional GIC and resin-modified glass ionomer cement (RMGIC) when used as luting agents for SSCs placed using the Hall technique. Thirty extracted human primary molars were randomly allocated into three groups (n = 10). Stainless steel crowns were cemented using conventional GIC, nano-HA-silica GIC, or RMGIC following the Hall technique protocol. Specimens were immersed in 2% methylene blue dye, sectioned longitudinally, and evaluated under a digital microscope to assess dye penetration. Microleakage values were statistically analysed using one-way ANOVA followed by the Games-Howell post hoc test. Statistically significant differences in microleakage were observed among the three groups (p < 0.001). RMGIC demonstrated significantly lower microleakage compared with both conventional GIC (mean difference = 1.568) and nano-HA-silica GIC (mean difference = 2.290). No statistically significant difference was observed between conventional GIC and nano-HA-silica GIC (mean difference = 0.722). Nano-hydroxyapatite-silica incorporated GIC exhibited comparable sealing ability to conventional GIC; however, RMGIC demonstrated superior resistance to microleakage when used as a luting cement for SSCs placed using the Hall technique. Further studies are required to evaluate the long-term clinical performance of nano-HA-silica modified GIC.

Morbidly obese patients undergoing cemented primary total knee arthroplasty (TKA) have demonstrated higher revision incidence. Cementless TKA implants have demonstrated good five-year results in this patient population. The purpose of this study was to review 10-year results of primary TKA in morbidly obese (body mass index [BMI] &#x2265; 39.5) patients using a highly porous, cementless tibial baseplate. This is a retrospective study of 114 TKAs in morbidly obese patients who underwent primary cementless TKA with a minimum 10-year follow-up. There were 25 lost to follow-up, leaving 89 TKAs in 74 patients who had a mean follow-up of 124.7 months (range, 116.9 to 141.9). The average age was 57 years (range, 36 to 73), and the average BMI was 46.1 (range, 39.5 to 63.9). Clinical results, patient-reported outcome measures, radiographs, and complications were reviewed. There were nine revisions, including two for tibial component aseptic loosening (2.3%), two for instability (2.3%), two for deep infection (2.3%), two for extensor mechanism rupture (2.3%), and one for patellar dislocation (1.1%). The two aseptic loosening cases occurred within eight months of the index TKA. Knee Society Score (KSS) improved from a mean of 36.2 to 88.3, 86.5, and 90.4 at 2-, 5-, and 10-year follow-up, respectively. The KSS function score improved from a mean of 41.5 to 68.7, 75.3, and 80.4 at 2-, 5-, and 10-year follow-up, respectively. Survivorship was 97.8% with aseptic loosening as the endpoint at 12 years and 89.9% for all-cause revision. Cementless TKA using a highly porous tibial baseplate in morbidly obese patients demonstrated excellent results with 97.8% survivorship at 12 years with aseptic loosening as the endpoint. Cementless TKA with the benefit of at least 10 years of biologic fixation can be an alternative mode of fixation compared to cement fixation in this challenging patient population.

With the requirement for reducing carbon footprint in engineering construction, porous vegetation concrete is increasingly receiving attention for use in completed slope restoration. Cemented soil is introduced after the completion of porous vegetation concrete stabilization and functions mainly as a revegetation substrate. An important consideration for cemented soil in this application is its ability to maintain strength and water stability and possess moisture retention capacity, without causing much increase in alkali release or diffusion. This present study investigated a newly developed twofold stabilization system involving both cement binders and organic waterborne epoxy resin to meet the requirements of synthetically enhancing slope stabilization and restoration. Changes in the unconfined compressive strength and water stability were analyzed, whilst mineralogical composition and microstructure characteristics were investigated. The results indicated that moderate incorporation of triethylenediamine (TETA)-cured epoxy resin (1-2% by soil mass) moderately reduced strength and increased water stability with controlled alkali release in cemented soil. Mineralogical and microstructural analysis revealed that TETA-cured epoxy resin retarded cement hydration and refined particle bonding, exhibiting less consolidated pore structure characteristics. The twofold stabilization was exceptional in enhancing structural stability exposed to repeated humidity variation, albeit it yielded increased strength reduction rate from <7% to 9-16% under UV irradiation. Potentials of calcium sulfoaluminate cement and Portland slag cement were also investigated. A pilot-scale vegetation trial with representative plant species gave general agreement with effects observed in the laboratory in alkali reduction and moisture retention. The results provided an ecological approach for better restoring completed slopes that were stabilized using porous vegetation concrete.

Heavy metal contamination in soils poses serious threats to the environment and human health. Cement-based solidification/stabilization (S/S) is a common method for treating heavy metal-contaminated soils due to its simplicity and effectiveness. However, the immobilization efficiency of conventional cement systems is limited. In this study, low-cost and highly dispersible novel carbon nanodots (CNDs) are synthesized from citric acid and urea by a microwave-assisted method and added to cement systems to improve the immobilization of Pb and Cd. Leaching results show that, with 15 wt.% cement, the addition of 0.4 wt.% (by weight of cement) CNDs reduces the leaching concentrations of Pb and Cd by 77.3% and 71.8%, respectively. Leaching results and Tessier analyses show that CNDs promote the transformation of Pb and Cd from exchangeable to stable forms and improve chemical stability. XRD, FTIR, DTG, and SEM results show that CNDs accelerate cement hydration and promote the formation of C-S-H gels, which enhances physical encapsulation. FTIR, UV-Vis, and adsorption results further indicate that oxygen- and nitrogen-containing groups on CNDs complex with Pb2+ and Cd2+ and strengthen chemical immobilization. This study provides a cost-effective nanomaterial for improving the immobilization of Pb and Cd in cement-based systems and offers new directions for the application of CNDs in sustainable environmental materials.

Orthodontically induced inflammatory root resorption (OIIRR) is a prevalent complication driven by excessive mechanical force, yet the underlying mechanisms linking mechanotransduction to osteoclast activation remain elusive. Here, we identify a novel signaling axis wherein sphingosine kinase 1 (SphK1) in cementocytes translates heavy orthodontic force into a pro-osteoclastogenic signal via mitophagy-mediated mitochondrial transfer. In vivo, heavy force induced OIIRR and upregulated mitophagy markers in cementocytes. In vitro, heavy compression force triggered SphK1-dependent mitophagy in IDG-CM6 cementocytes, as evidenced by increased mitophagosome formation, co-localization of mitochondria with lysosomes, and elevated PINK1/PARKIN signaling. Inhibition of SphK1, either pharmacologically or genetically, suppressed this mitophagic response. Conditioned media from force-loaded cementocytes enhanced osteoclast differentiation and glycolytic metabolism, effects that were abolished by SphK1 inhibition and rescued by a mitophagy agonist. Crucially, we demonstrated that heavy force promotes the transfer of mitochondria from cementocytes to osteoclast precursors, a process dependent on mitophagy. This transferred mitochondrial cargo functioned as a metabolic subsidy, boosting osteoclast bioenergetics and resorptive activity. Our findings unveil the SphK1-mitophagy-mitochondrial transfer axis as a fundamental mechanism of cementocyte-osteoclast communication, positioning SphK1 as a promising therapeutic target to prevent OIIRR.

Island reef road construction faces a complex marine service environment characterized by high salinity and high humidity. Meanwhile, rapid construction and prompt subgrade repair are urgently required, creating a strong demand for novel calcareous-sand-based stabilization materials that combine excellent mechanical performance with resistance to seawater erosion. To this end, this study developed an early-strength cemented calcareous-sand reinforcement material for road base construction. Sulfoaluminate cement (SAC) and ferrite-aluminate cement (FAC), both featuring rapid setting/early strength development and superior corrosion resistance, were used to cement calcareous sand (CS) and to investigate its mechanical and microstructural characteristics under different water environments. Unconfined compressive strength tests (UCS) showed that SC-CS and FC-CS could meet subgrade requirements at 1 d and 7 d, with SC-CS and FC-CS reaching 3.12 MPa and 3.44 MPa at 1 d, and 3.26 MPa and 3.67 MPa at 7 d, respectively, under seawater SS conditions. Seawater mixing and immersion were found to promote the early strength and stiffness development of both SC-CS and FC-CS, with a more pronounced effect observed for FC-CS. Based on experimental results, a damage model for the stabilized specimens was established with a fitting accuracy of R2 > 0.97. This constitutive model accurately describes the stress-strain relationship of the material and quantitatively characterizes its damage evolution. Microscopic XRD and SEM analyses indicated that the main hydration product in freshwater-cured specimens was ettringite, and the interparticle connection of CS was dominated by bridging through rod-like ettringite. In contrast, under seawater conditions, the ettringite content decreased, while hydrotalcite and calcium aluminate hydrate increased, forming massive and lamellar bridging products. Compared with SC-CS, the bridging structure in FC-CS was denser. Moreover, the compactness of the bridging structure not only affected its mechanical properties but also governed the movement mode of CS particles, thereby influencing the damage evolution and failure mode of the specimens. The findings provide theoretical support for the construction needs of island road.

Lithium slag (LS), a by-product of lithium-ion battery recycling, contains hazardous contaminants that pose potential environmental risks during disposal. The LS used in this study contained 7.46&#xa0;mg&#xa0;kg-1 thallium (Tl) and 2.56&#xa0;wt% fluorine (F) based on initial material characterization. This study investigates low-dosage cement-based stabilization systems using ordinary Portland cement (OPC) or composite Portland cement (CPC) combined with CaO for the simultaneous immobilization of Tl and F in lithium slag. Four formulations with LS:binder:CaO ratios of 20:(0.30-0.75):0.10 were evaluated over 28 days of curing. Leaching behavior was assessed using the toxicity characteristic leaching procedure (TCLP), and microstructural evolution was examined using X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS). Untreated LS exhibited significant contaminant mobility, with TCLP leachate concentrations of 13.24&#xa0;mg&#xa0;L-1 F and 89&#xa0;&#x3bc;g&#xa0;L-1 Tl. Cement-CaO stabilization substantially reduced contaminant release. The optimized low-OPC formulation (20:0.30:0.10) reduced Tl concentration to 0.17&#xa0;&#x3bc;g&#xa0;L-1 (>99 % reduction) and F concentration to 3.39&#xa0;mg&#xa0;L-1 (&#x223c;74 % reduction). Microstructural observations indicated progressive matrix densification associated with the formation of C-S-H gel and Ca-rich hydration products. XRD and SEM-EDS results suggest that Tl retention is mainly associated with adsorption or incorporation within C-S-H phases, while fluoride stabilization is related to the formation of Ca-F phases (e.g., CaF2) under alkaline conditions. The optimized formulation achieved regulatory compliance with an estimated material cost of approximately 11 RMB t-1 (&#x223c;1.5 USD t-1) and a carbon footprint of 16.5&#xa0;kg CO2 t-1, representing a 54 % reduction compared with higher-binder systems. These results indicate that low-dosage cement stabilization provides a potentially cost-effective strategy for reducing contaminant mobility in lithium slag, although further long-term durability assessments are required.

Increasing numbers of spine surgery cases and an aging society led to challenges during revision surgery with osteoporotic bone. Safe and stable operative techniques are required. In this ex vivo study, human lumbar vertebrae were prepared and then screened for assessing bone density. Eighteen donors (65 vertebrae) with osteoporotic conditions were included. Primary dorsal instrumentation was performed using either standard pedicle screws (6.35&#xa0;mm diameter; Group A, n&#x2009;=&#x2009;50) or vertebroplasty screws (VT, 6.35&#xa0;mm; Group B, n&#x2009;=&#x2009;15). This was followed by a standardized pull-out test cycle, after which the vertebrae of group A exhibited pedicle perforations replicating revision conditions. Subsequently, 50 vertebrae from Group A were reassigned to simulate revision conditions and divided into two subgroups (n&#x2009;=&#x2009;25 each): Group A1 received conventional pedicle screws with an increased diameter (7.5 mm), while Group A2 was treated with cement-augmented pedicle screws (VT, 6.35 mm). A second pull-out test was performed, and statistical analysis was conducted. The specimens with conventional screws had a lower mean pull-out strength compared to primarily cement-augmented screws during the first pull-out cycle 662.8&#x2009;&#xb1;&#x2009;365.1 N vs. 1066.1&#x2009;&#xb1;&#x2009;213.7 N. In the revision model, cement-augmented screws (Group A2) demonstrated a significant higher median pull-out strength compared to larger-diameter conventional screws (Group A1) (687.5 N [IQR: 448.8-1137.5 N]; vs. 486.5 N [IQR: 338.8-605.0 N]). In this ex vivo revision model of osteoporotic bone, increasing screw diameter alone resulted in reduced pull-out strength compared to primary instrumentation, whereas cement-augmented pedicle screws consistently demonstrated superior fixation in both test cycles. These findings highlight the limited effectiveness of increasing screw diameter under revision conditions and support cement augmentation as a biomechanically advantageous strategy in osteoporotic bone, while clinical validation remains necessary.

Cephalomedullary nails (CMNs) are commonly used to treat proximal femur fractures. The Trochanteric Fixation Nail Advanced (TFNA, DePuy Synthes) is a CMN system, introduced in 2015, featuring significant design modifications compared to its predecessors. These include a new Ti-15Mo alloy and a fenestrated lag screw that permits cement augmentation of the femoral head. Nevertheless, device-specific failures have emerged. We report a unique mode of failure: breakage of the lag screw through a cement fenestration. An 81-year-old woman with an AO/OTA 31-A2.1 pertrochanteric fracture underwent long TFNA fixation (130&#xb0;, 10&#xa0;&#xd7;&#xa0;400 mm) with a 90-mm lag screw positioned center-center in dynamic mode. At 7.5&#xa0;months, she developed severe atraumatic hip pain and imaging demonstrated non-union, autodynamization, and lag screw breakage. Retrieval of the broken implant demonstrated a fracture through the first cement fenestration of the lag screw. She subsequently underwent conversion to total hip arthroplasty. There have been several reports of increased implant breakage associated with the TFNA in a distinctive "stepped propagation" pattern of metal cracking. These typically occur at the lag screw aperture. However, fenestrations in the lag screw also appear to act as stress risers when cement is not used. In non-union, stress is concentrated at the first fenestration, initiating crack propagation and implant failure. TFNA lag screws are vulnerable to fatigue fracture in the setting of non-union. Fenestrated head elements should be reserved for cases in which cement augmentation is planned. Patients treated with TFNA implants should be monitored closely for delayed union to mitigate the risk of fatigue failure.

This study investigates the valorization of dredged sludge as a sustainable subgrade fill material through stabilization with a nano-calcium carbonate-cement composite. Unconfined compressive strength (UCS) tests were systematically conducted to determine the optimal dosage of nano-CaCO3 as a supplementary additive at a fixed cement content of 8% by dry soil mass. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and quantitative pore structure analysis were employed to elucidate the underlying solidification mechanisms. The results demonstrate that the addition of 2% nano-CaCO3 yields the highest 28-day UCS of 721 kPa, representing a statistically significant 21% improvement over the cement-only reference (596 kPa) and a more than threefold increase relative to untreated sludge (213 kPa). Conversely, increasing the nano-CaCO3 dosage to 2.5% leads to a significant strength reduction, attributed to nanoparticle agglomeration and hindered cement hydration. Microstructural characterization reveals that the optimal nano-CaCO3 dosage accelerates early-age hydration through a nucleation effect, promotes the consumption of portlandite, and enhances the formation of calcium silicate hydrate (C-S-H) gel. Semi-quantitative XRD analysis further confirms the conversion of less stable monosulfate (AFm-SO4) into stable monocarboaluminate (AFm-CO3) phases. These synergistic mechanisms-nucleation, physical pore filling, and chemical reaction-result in a densified matrix with a refined pore structure, reduced total porosity, and a more homogeneous pore-size distribution. The findings provide a robust theoretical basis for the resource-oriented utilization of dredged sludge and the design of low-carbon composite stabilizers for soft soil treatment.

Percutaneous vertebroplasty is a commonly used, minimally invasive therapeutic intervention to relieve pain caused by vertebral compression fractures, which are becoming more prevalent due to the aging population. Although the procedure is generally safe, complications such as cement leakage into the bloodstream can occur. We present the case of a 67-year-old female with a history of advanced osteoporosis and multiple vertebroplasty procedures who developed dyspnoea 5 months after her most recent surgery. Imaging revealed an intracardiac cement embolism extending from the inferior vena cava through the right atrium and tricuspid valve into the right ventricle. This rare complication of vertebroplasty, caused by cement leakage, resulted in tricuspid valve regurgitation and pulmonary hypertension. This case highlights the importance of recognizing and managing the rare complications of vertebroplasty by using a multimodality imaging approach, especially in patients with a history of multiple procedures.

Thaumasite sulfate attack (TSA) under elevated water pressure has important implications for the durability of deep underground concrete structures, yet the deterioration process and the coupled effect of water pressure and carbonate supply remain insufficiently understood. In this study, laboratory pressurized sulfate exposure tests were conducted to investigate the evolution of macroscopic performance and microstructure of cement mortars with different limestone powder contents (0%, 15%, and 30%) under water pressures of 0, 2.5, and 5.0 MPa. The results show that elevated water pressure promotes sulfate ingress into the mortar and accelerates later-stage strength loss; this interpretation is supported by the depth-dependent distribution of soluble SO42- measured in mortars without limestone powder. Two-way ANOVA indicates that both water pressure and limestone powder content have significant effects on compressive strength, and their interaction becomes statistically significant at 120 d. XRD, FT-IR, and SEM/EDS results show that, under elevated water pressure and high limestone powder content, the corrosion products gradually evolve from gypsum-related products to ettringite- and thaumasite-related products, with a certain spatial differentiation. Specifically, the gray-white, mud-like surface products are consistent with thaumasite-rich assemblages, whereas the needle- and column-like crystals in the interior are consistent with ettringite-rich assemblages. Overall, elevated water pressure mainly promotes sulfate transport, while limestone powder mainly increases carbonate availability. These two factors may jointly intensify TSA deterioration in mortar through a pathway involving transport enhancement, carbonate supply, corrosion product evolution, and aggravated macroscopic damage. This study provides a reference for understanding the sulfate deterioration mechanism of limestone powder-containing cement-based materials in deep underground environments under elevated water pressure.

The present study aimed to evaluate the surface roughness (SR) and color stability of conventional restorative glass ionomer cements (GICs) modified with the addition of red propolis ethanolic extract (RPEE) as an antimicrobial agent. Four GICs (Riva, Maxxion, Vidrion, and Ketac) were used with the addition of RPEE at concentrations of 11% and 20%. For the control groups, the GICs were manipulated according to the manufacturers' instructions. SR was assessed using a surface profilometer. For the color variation analysis, the specimens' colors were measured in the CIE Lab* color space using a spectrophotometer. The Kruskal-Wallis test, followed by Dunn's test, was used to evaluate statistical significance. The addition of RPEE did not negatively affect the SR of Riva, Maxxion, and Ketac GICs (p = 0.796, p = 0.111, and p = 0.858, respectively). By contrast, a significant reduction in SR was observed in Vidrion GIC with the addition of RPEE (p = 0.009). When comparing the different GIC brands, Riva and Ketac exhibited the lowest SR, with significant differences relative to Vidrion (p = 0.008) and Maxxion (p = 0.006). Both RPEE concentrations (11% and 20%) caused major color changes in all GICs tested, with no statistical differences between the two concentrations (p = 1.000), nor among the different GIC brands (p = 0.071). The incorporation of RPEE into conventional GIC did not increase SR, though in the case of Vidrion cement, it resulted in a significant reduction of this parameter. Conversely, the addition of red propolis at both 11% and 20% concentrations caused significant and clinically unacceptable color changes in all tested cements, regardless of brand or concentration.