Search Results (101)

The Böhme abrasion test (EN 14157) is widely used to evaluate the wear resistance of natural stones; however, the abrasive powder specified by TS 699 requiring 70–80 wt.% crystalline Al₂O₃ is not commercially available in the Turkish market. Commercially supplied abrasives deviate substantially from both the prescribed chemical composition and the grain-size distribution of TS 699, introducing a recognized but unresolved source of variability in Böhme abrasion measurements. This study evaluates the influence of abrasive type and particle-size distribution on Böhme abrasion performance with the aim of identifying which available abrasive material yields the most reliable and reproducible test results. The emphasis is therefore metrological—on test repeatability and standardization—rather than on ranking the abrasion resistance of the stones. Six natural stones representing contrasting lithologies—four crystalline marbles, one limestone, and one granite—were tested using five abrasive powders: two locally produced natural emery abrasives (Emery-1 and Emery-2), silicon carbide (SiC), white corundum, and brown corundum. Each abrasive was evaluated under both standardized graded conditions prepared in accordance with TS 699 and heterogeneous ungraded conditions reflecting common industrial practice. Chemical analyses confirmed that both emery abrasives deviate markedly from TS 699 specifications, with Al₂O₃ contents (~57.7 wt.%) well below the required range and Fe₂O₃ (~24 wt.%) considerably exceeding the standard limit. Sieve analyses further revealed substantial particle-size deviations in several commercial abrasives. One-way ANOVA demonstrated that abrasive type exerts a statistically significant influence on abrasion performance (F = 8.99, p < 0.05, η² = 0.297). SiC consistently produced the highest abrasion values, followed by corundum-based abrasives, while emery abrasives showed comparatively lower but stable performance. Independent-samples t-tests showed that particle-size grading significantly affected abrasion performance only for brown corundum (p < 0.05), attributable to its markedly elevated coarse particle fraction. Petrographic analysis, XRD, and SEM–EDS characterization of the investigated rocks confirmed that abrasion response is additionally modulated by rock mineralogy and microstructure. Under standardized grading conditions, SiC provided the most consistent and reproducible results across all lithologies, supporting its suitability as the reference abrasive for inter-laboratory Böhme testing. Locally produced emery abrasives, despite their chemical non-compliance with TS 699, yielded stable and reproducible outcomes under controlled grading, supporting their potential as cost-effective alternatives for routine testing. Full article

Sandstone–marble waste powder concrete composite structures serve as common load-bearing systems in tunnels, underground caverns, and similar engineering projects, where the interface roughness characteristics directly govern their overall stability and service safety. To investigate the influence of interface roughness on the failure behavior of the composite, four groups of sandstone–concrete composite specimens made with marble waste powder concrete were prefabricated with different joint roughness coefficients (JRC = 0, 7.84, 17.99, 20.79). The concrete matrix was prepared with marble waste powder incorporated at 25 wt% of the total binder, corresponding to 20.45 wt% of the total mixture, and the water-to-binder ratio was 0.20. Uniaxial compression tests were conducted with synchronous acoustic emission (AE) and digital image correlation (DIC) monitoring to examine the roughness-dependent mechanical response, energy evolution, damage activity, and strain localization of the composites. The results show that the peak stress and elastic modulus of the composite increase continuously with increasing JRC. When JRC increases from 0 to 20.79, the peak stress increases by 170.3% and the elastic modulus increases by 201.1%. The energy evolution mechanism transitions from progressive damage with gradual energy dissipation at low roughness to a three-stage mode at high roughness, characterized by initial frictional energy dissipation, intermediate energy storage, and rapid elastic energy release and dissipated energy increase near failure. DIC results further reveal that increasing interface roughness suppresses interfacial shear slip and promotes tensile-dominated strain localization, whereas excessive roughness may induce local stress concentration around asperities and increase the tendency toward abrupt post-peak instability, the failure mode changes from mixed tensile–shear failure with obvious interfacial slip to tensile-dominated failure. Full article

Since tires from end-of-life vehicles are not entirely biodegradable and pose a serious environmental problem, their disposal has become a significant global environmental concern. One technique to decrease these environmental issues is incorporating waste rubber to make sustainable green concrete. This study examined the usage of waste supplementary cementitious materials (SCMs) such as fly ash (FA), metakaolin (MK), marble powder (MP), slag (SL), and silica fume (SF) for surface precoating of crumb rubber (CR) to improve the mechanical properties of the produced crumb rubber concrete (CRC) by strengthening the bond between CR and cement paste in the interfacial transition zone (ITZ). The CR replaced (0, 15%, and 25%) of sand by weight in the preparation of CRC mixtures. A total of eleven CRC mixes were cast to investigate the fresh properties, compressive strength, and splitting tensile strength. In addition, the compressive stress-strain curve was investigated, and peak stress, peak strain, energy absorption, toughness, and modulus of elasticity have been evaluated. The outcomes showed that precoating CR using FA, followed by MK, has the strongest effect on increasing CRC compressive performance. The 25% substitution of sand with FA-treated CR increased compressive strength after 28 days, splitting tensile strength, peak stress, toughness, and modulus of elasticity by 34.7%, 23.7%, 34.8%, 26.1%, and 25.2%, respectively, in comparison to the same percentage of untreated CR. The proposed approach demonstrates a viable pathway for integrating waste materials and SCM-based technologies to develop high-performance, sustainable cementitious composites. Full article

Bergamot essential oil (BEO) has demonstrated antidepressant potential, but its oral application is limited by poor water solubility and undesirable organoleptic properties. In this study, a BEO-loaded beverage was developed based on a whey protein-stabilized oil-in-water emulsion system. The optimal formulation, determined via single-factor experiments combined with orthogonal optimization, consisted of inulin (0.5 g/50 g), milk powder (2.0 g/50 g), sucralose (0.008 g/50 g), and sodium carboxymethyl cellulose (0.04 g/50 g). The resulting beverage remained stable without visible phase separation during 4 months of storage at 4 °C. In a chronic corticosterone treatment (CCT)-induced mouse model of depression, oral administration of the BEO beverage increased activity in the central area of the open field test and exploratory behavior in the elevated plus maze, while reducing repetitive stereotyped behaviors in the marble burying test. At the molecular level, the BEO beverage was associated with reduced levels of interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and corticosteroid (CORT), and increased levels of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), serotonin (5-HT), dopamine (DA), and norepinephrine (NE). Additionally, the BEO beverage was associated with observed alleviation of neuronal damage in the hippocampal CA3 region, upregulation of brain-derived neurotrophic factor (BDNF), improved gut microbial diversity, and altered host metabolic profiles. Collectively, these findings suggest that the BEO emulsion beverage is a feasible intervention for alleviating depression-like behaviors in the mouse model, and provide initial associative evidence supporting its potential as a functional food for mood management. Full article

This study investigates the influence of bottom ash (BA) and marble dust powder (MD) as partial replacements for Ordinary Portland Cement (OPC) on the physical, mechanical, and mass loss performance of cement pastes under cyclic seawater exposure and their economic feasibility. Mixtures containing 0–20% BA and 0–20% MP were tested to evaluate their workability, strength, porosity, durability, and cost efficiency. The results indicate that BA reduces workability, which is reflected in the lower slump values of mixtures with a higher BA content, whereas MD enhances fluidity by filling the voids between particles and improving the packing density of the mixture, which results in better workability. The optimal composition, which was 15% bottom ash and 10% marble dust powder, achieved a superior mechanical performance, with compressive strength (CS) and flexural strength (FS) increases of 2.2% and 38.7%, respectively, at 28 days compared to the control. Increasing the BA and MD content up to a total of 35% of the binder generally led to a moderate reduction in early-age strength, while mixtures with 20% replacement exhibited comparable or improved long-term strength at 90 days. This led to decreased porosity and improved long-term mass loss performance under cyclic seawater exposure. The incorporation of BA and MD also reduced water absorption, indicating enhanced durability, with these beneficial effects becoming more pronounced at later ages. Economically, cement substitution with BA and MD reduced production costs by up to 39.6%. In summary, moderate incorporation of BA and MD enhances performance, reduces cost, and supports the sustainable utilization of industrial waste in cementitious materials. The mixture proportions investigated in this study offer a promising alternative binder for use in the sustainable building sector. Full article

This study investigates the effects of artificial plate powders with different compositions on the durability, physical, mechanical, and microstructural properties of self-compacting mortar (SCM). Waste quartz-based composite plate fragments and waste cultured marble pieces were ground into fine powders, and the resulting quartz-based plate powder (WQP) and cultured marble powder (WMP) were used as filler materials to partially replace cement at replacement levels of 0%, 5%, 10%, 15%, 20%, and 25% by mass. The workability of fresh mortars was evaluated using the mini slump flow test in accordance with EFNARC guidelines, while hardened specimens were tested for porosity, capillary water absorption, abrasion resistance, flexural strength, and compressive strength. In addition, specimens with a 25% replacement ratio that were exposed to temperatures of 300 °C, 600 °C, and 900 °C underwent mechanical testing, and their microstructures were analyzed using SEM and XRD. The results indicated that increasing replacement ratios generally reduced workability and mechanical strength, while increasing porosity and water absorption. However, low replacement levels slightly enhanced flexural strength due to the filler effect. SEM and XRD analyses revealed that the quartz in WQP maintained high thermal stability, and mortars containing WQP exhibited a denser, more coherent, and more homogeneous microstructure. Overall, the findings demonstrate that waste-based plate powders can serve as sustainable fillers in SCM, offering environmental benefits while maintaining acceptable mechanical and microstructural performance. Full article

This study aimed to evaluate the technical and environmental feasibility of producing concrete paver blocks and pervious concrete paver blocks by incorporating marble waste to evaluate its filler effect within the cementitious matrix. The methodology included the characterization of marble waste, the production of test specimens with the control (0%), 10%, 20%, and 30% of cement replacement, and the execution of performance tests, supplemented by statistical analyses. The results indicated that marble waste replacement significantly impacted the properties. In terms of pervious concrete paver block permeability, the highest rates were observed in the control and 30% treatments. For water absorption, concrete paver blocks showed higher values at a maximum of 20%, while pervious concrete paver blocks maintained statistically analogous values for 10% and 20%. Regarding compressive strength, the concrete paver block formulation with 10% marble waste was statistically compatible with the control. It is concluded that the incorporation of marble waste into concrete and pervious concrete paver blocks is environmentally advantageous as it valorizes an industrial waste. However, mix design optimization is essential, given that excessive replacement (above 10%) resulted in a reduction in compressive strength. Full article

This study is part of a broader conservation and restoration project of the 17th-century statue “Santissimo Salvatore” attributed to the Bolognese sculptor Gabriele Brunelli (1615–1682). This sculpture was traditionally classified as a marble statue, i.e., primarily composed of calcium carbonate. However, the careful diagnostic analyses conducted during the present work of restoration revealed that, instead, the sculpture is made of gypsum alabaster, a material predominantly composed of calcium sulphate hydrate (CaSO₄·2H₂O). In the present research, a multi-analytical investigation was carried out using X-Ray Powder Diffraction (XRPD), Field Emission Environmental Scanning Electron Microscopy (FE-ESEM) with Energy-Dispersive X-ray Spectroscopy (EDS), and confocal Raman microspectrometry. Here, we report detailed and updated analytical data of the material constituting the “Santissimo Salvatore” statue by Gabriele Brunelli. These data were found extremely useful to plan and accomplish the restoration work in detail: (i) the suitable conservation project of the artwork, (ii) the reassessment of the knowledge on the artist’s sculptural production, and (iii) gaining more information about the material used in the 17th-century Bolognese sculptural context. Full article

This paper examined the effect of marble powder (MP) on air-cured cement-based materials when subjected to sulfuric acid (H₂SO₄) attack. Four MP replacement levels were tested: 0%, 5%, 10%, and 15% by weight of cement. The prepared samples were cured for 90 days prior to being exposed to H₂SO₄. Macroscopic tests for apparent density and compressive strength along with microstructural characterization using X-ray diffraction (XRD) and scanning electron microscopy (SEM) were performed to determine the effect of MP on the properties of the materials. The Rietveld method was used to analyze the amounts of different crystalline phases and amorphous calcium silicate hydrate (C-S-H). The obtained results indicate that 5% MP in air-cured cement -based materials exhibited the best behavior with acceptable resistance to acid attacks. This level of MP replacement was found to optimize the filler effect, improve the hydration process, and enhance the matrix density, which in turn reduces the permeability of the material and increases acid resistance. This is attributed to the balanced contribution of MP to phase formation, particularly calcite, which helps to counteract acid-induced dissolution, while also preserving the stability of C-S-H phases. This study provides a new perspective of the role of MP in influencing phase content (crystalline and amorphous phases) and their possible impacts on macroscopic properties such as apparent density and compressive strength. MP behaved as a filler, to improve hydration and resistance to acid attacks. Additionally, using MP as a replacement for ordinary Portland cement (OPC) offers a sustainable alternative by reducing waste and promoting the recycling of marble industry by-products, thereby contributing to environmental sustainability. It is recommended that, 5% MP is the optimal replacement content to enhance durability and mechanical properties in air-cured cement-based materials in aggressive environments, as it is both practical and achievable for infrastructure to be subjected to the aggressive environment. Full article

Waste stone powder is a major solid waste byproduct of stone operations. This study developed a novel “alkali activation-calcination” process that efficiently converts waste stone powder into high-value-added silicon-based materials (SSM). This study elucidated the morphological evolution of silicon during the conversion process and revealed the formation mechanism of active silicon. Through further integration of batch adsorption experiments and multi-technique characterization analysis, the immobilization efficacy of this material for heavy metals cadmium/lead was elucidated, revealing both direct and indirect interfacial reaction mechanisms. The results demonstrate that in-creasing the calcination temperature, alkali activator concentration, and calcination duration enhances the reactive silica content in SSM. NaOH as activator, the calcination process significantly reduces both the thermal decomposition temperature of raw materials and the initial temperature required for silicon conversion. Under optimized conditions (WG:MD:activator = 1:0.8:0.32, temperature = 800 °C, time = 1 h), the reactive silica content reached 24.30%. The generation rate of reactive silica is governed by the combined effects of interfacial chemical reactions and solid-phase product layer diffusion. Under idealized laboratory conditions, the maximum adsorption capacities (Qm) of SSM were determined to be 57.40 mg/g for cadmium and 496 mg/g for lead, which are significantly higher than those of many other adsorbents. Continuous desorption experiments and characterization analyses confirm that Cd and Pb adsorption by SSM is primarily driven by electro-static interactions, complexation, precipitation, and coordination, while ion ex-change plays a secondary role. Highly reactive silica facilitates interactions between Cd/Pb and oxygen-containing functional groups (e.g., -OH, ≡Si-OH, Si-O-Si), promoting precipitate formation for effective heavy metal removal. This work offers theoretical guidance for valorizing silica-rich waste rock powder. It is important to note, however, that while the adsorption capacity of SSM is encouraging, its practical implementation requires resolving key issues identified during the lab-to-application transition. Full article

Portland cement is widely used in construction, but it contributes significantly to global CO₂ emissions. This study evaluates the potential use of construction and demolition waste (CDW) and marble powder (MP) as supplementary cementitious materials, in line with circular economy goals. Both wastes were ground finer than cement and characterised chemically and physically. Binary and ternary blends with 5% and 10% replacement were tested in pastes and mortars for fresh properties, mechanical performance, and durability. Setting time, soundness, and workability remained within standard limits. Compressive strength decreased moderately, with 28-day activity indices between 82 and 88%, confirming the low reactivity of the supplementary cementitious materials. Sorptivity decreased in all mixes, and chloride resistance improved in the 10CDW and 10MP blends. However, the ternary mix showed increased chloride migration. Carbonation depth increased in all mixes, indicating the need for protective measures in carbonation-prone environments. Replacing 10% of cement with CDW or MP can avoid 70–80 kg of CO₂ per tonne of binder and reduce landfill waste. These materials can be used as low-carbon fillers in cement-based systems, provided that their durability limitations are considered in design. Full article

The rapid development in building construction has stimulated the replacement of cement in concrete with construction waste materials such as marble waste powder (MWP) and granite waste powder (GWP) to reduce the negative impact of cement production and to save natural resources. Therefore, the inclusion of these materials in concrete contributes to environmental sustainability by reducing cement consumption and promoting the reuse of industrial waste. The present study employs Response Surface Methodology (RSM) and, for the first time in a comparable context, the Neural Network Algorithm (NNA) as an advanced optimization and predictive tool to evaluate the synergistic effect of using GWP and MWP as partial cement replacements in concrete exposed to elevated temperatures. The study involved four independent variables: replacement level of GWP up to 9%, replacement level of MWP up to 9%, the degree of temperature (T) up to 800 °C, and the exposure duration (D) up to 2 h, while the dependent variable (output) was the compressive strength (CS). The ANOVA results revealed that the quadratic model outperformed the linear model in predicting the CS of concrete. The Quadratic model, derived from RSM, demonstrated superior performance in predicting CS values. However, the NNA model also showed high predictive accuracy (R² = 0.949; RMSE = 1.5297 MPa), effectively capturing the complex and nonlinear relationships among temperature, duration, and the cement replacement levels with GWP and MWP. The optimization results revealed that the maximum compressive strength of 39.4 MPa can be achieved at 8.92% GWP, 1.89% MWP, T of 247 °C, and D of 0.64 h with a desirability of 1. The proposed models provided valuable insights into the synergistic effects of granite and marble waste powders, supporting the design of sustainable, high-performance concrete with reduced environmental footprint and improved resource efficiency. Full article

This study evaluates the physical, mechanical, durability, and environmental properties of geopolymer mortars (GMs) produced using waste tire steel fibers (WTSFs), hemp fibers (HFs), waste marble powder (WMP), and recycled fine aggregates (RFAs). Within the scope of this study, fibers were incorporated as single and hybrid types at 0.5% and 1% by volume. The addition of HFs generally reduced dry unit weight, as well as compressive and flexural strength but increased fracture energy by nearly three times. The addition of WTSFs improved compressive and flexural strengths by up to 42% and enhanced fracture energy by 840%. Hybrid fibers increased the strength values by 21% and the fracture energy by up to four times, demonstrating a clear synergistic effect between HFs and WTSFs in enhancing crack resistance and structural stability. In the durability tests conducted within the scope of this study, HFs burnt at 600 °C, while WTSFs showed signs of corrosion under freeze–thaw and acid conditions; however, hybrid fibers combined the benefits of both materials, resulting in an effective preservation of internal structure. The fact that the materials used in the production of GM samples were waste or recycled products reduced the total cost to 188 USD/m³, and thanks to these materials and the carbon-negative properties of HFs, CO₂ emissions were reduced to 338 kg CO₂/m³. The presented study demonstrates the potential of using recycled and waste materials to create sustainable building materials in the construction industry. Full article

Rapid urbanization and industrialization have increased atmospheric pollution, particularly via sulfur oxides (SO_x) that form sulfuric acid and accelerate the degradation of cementitious materials. While Portland-cement systems have been widely studied, less is known about the acid resistance of geopolymer mortars. This study investigates the durability and microstructural evolution of metakaolin–red mud geopolymer mortars incorporating limestone, marble, and basalt powders as partial sand replacements (5, 10, and 15 wt %). Specimens were immersed in 3% H₂SO₄ for 30, 60, and 90 days, with performance evaluated via compressive and flexural strength, weight loss, and ultrasonic pulse velocity (UPV), alongside scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). After 90 days, the optimal basalt-filled mix (15 wt %) retained 84% of its initial compressive strength (46.8 MPa), compared with 61% for the control; mass loss decreased from 6.4% (control) to 3.2%, and UPV degradation was reduced by 35%. Microstructural analyses indicate denser gel phases and reduced microcracking in basalt- and marble-filled mixes. These results demonstrate that industrial by-product fillers can significantly improve sulfuric-acid resistance while supporting more sustainable binder technology. Full article

The construction industry increasingly integrates technological advancements to enhance efficiency and meet technical, environmental, and economic requirements. Self-compacting mortars are gaining popularity due to their superior fluidity, optimized compaction, and improved mechanical properties. This study explores the potential of statistical mix design methodology to optimize self-compacting mortars’ fresh properties and strength development by replacing up to 20% of cement with pozzolana, limestone, and marble powder. A self-compacting mortar repository was used to develop robust models predicting slump flow, compressive strength at 28 days, water absorption, and capillary absorption. Results indicate that marble powder mixtures exhibit superior slump flow, up to 9% higher than other formulations. Compressive strengths range from 50 MPa to 70 MPa. Pozzolana and marble-based mortars show 15% and 12% strength reductions compared to the limestone-based mix, respectively. Water absorption increases slightly for mortars with marble (+2%) or pozzolana (+3%). The mortar containing marble powder has the lowest sorptivity coefficient due to its high specific surface area. The statistical analysis was conducted using a mixture design approach based on a second-order polynomial regression model. ANOVA results for the studied responses indicate that the calculated F-values exceed the critical thresholds, with p-values below 0.05 and R-squared values above 0.83, confirming the robustness and predictive reliability of the developed models. Life cycle assessment reveals that cement production accounts for over 80% of the environmental impact. Partial replacement with pozzolana, limestone, and marble powder reduces up to 19% of greenhouse gas emissions and 17.22% in non-renewable energy consumption, demonstrating the environmental benefits of optimized formulations. Full article