Search Results (634)

Natural fibres, both bio-based and mineral-derived, are increasingly investigated for use in mortar as a means of improving technical efficiency while potentially reducing reliance on synthetic fibres where performance and durability are adequate. This review synthesises mortar-focused evidence across cement-based binders, air lime and natural hydraulic lime binders, gypsum-based binders and clay-based binders, with emphasis on mix designs, fibre–matrix interactions, durability-related behaviours and engineering applications. Across binder systems, the most consistently reported benefit of fibre incorporation is improved crack control and post-crack integrity, provided that fibre dispersion, dosage, and workability are adequately controlled. Some formulations also exhibit reduced measured drying shrinkage, whereas changes in compressive and flexural strength are inconsistent, reflecting the effects of fibre type and content, water demand, density, pore structure and matrix–fibre bonding. Durability is strongly binder- and exposure-dependent. For cement-based mortars, alkaline and calcium-rich pore solution remain key limits for many plant fibres, especially under wetting–drying exposure. For lime-based, gypsum-based and clay-based mortars, chemical attack is generally less severe, but performance and property retention remain sensitive to moisture history, curing path and conditioning. Hygrothermal and hygric effects are conditional and should be considered alongside density, moisture state, pore structure and water uptake. Overall, natural fibres are most convincing when crack control, post-crack integrity, compatibility or moisture-related performance are required, rather than for universal strength or durability improvement. For that, further studies and optimisation are needed. Full article

Magnesium oxychloride (MOA) adhesive plywood represents a novel inorganic matrix panel technology that eliminates organic volatile compounds from the adhesive system and avoids high-temperature hot pressing, potentially offering significant carbon footprint advantages. This study presents a comparative life cycle carbon footprint assessment of conventional urea–formaldehyde (UF) plywood and MOA plywood manufactured in China, using 1 m³ of a finished panel as the functional unit under a cradle-to-grave system boundary, comprising the production stage (Modules A1–A3)—explicitly including forestry operations (silviculture, felling, extraction/forwarding, loading and log haulage) and veneer manufacture within Module A1, now reported as a disaggregated inventory and delimited in a system boundary diagram—and the end-of-life stage (Modules C2–C4), evaluated across three end-of-life (EOL) scenarios: incineration, landfill, and mechanical recycling. Foreground data (process energy, adhesive formulation, transport distances) are metered/primary data collected over a full production year at a single large-scale plywood plant in Suqian, Jiangsu; background data are from ecoinvent v3.9.1 (cut-off), characterised with IPCC AR6 GWP100. Results indicate that MOA plywood generates approximately 253 kg CO₂-e/m³ at the production stage (A1–A3), compared with 301 kg CO₂-e/m³ for UF plywood, a reduction of 15.8% (47.5 kg CO₂-e/m³). Contribution analysis attributes virtually the entire gap to process energy (steam 65.7%, electricity 34.3%), while adhesive raw materials and inbound transport cancel to within rounding, demonstrating that the advantage is a process energy rather than a green chemistry phenomenon. A parameter-specific one-at-a-time analysis and a 200,000-run Monte Carlo simulation with triangular distributions show no reversal of the UF–MOA ranking in any of the 200,000 realisations within the adopted uncertainty ranges, with an approximately 56 kg CO₂-e/m³ median advantage (5th–95th percentile of about 31–85). Under EOL incineration, MOA plywood retains a substantial advantage even after the newly quantified burden of flue gas HCl neutralisation (13.3 kg CO₂-e/m³) and inorganic residue management (0.9 kg CO₂-e/m³) arising from the chloride content of the Sorel cement binder are charged to the MOA system. Under landfill, both products behave similarly, as wood carbon dynamics dominate. A break-even analysis shows that the service life of MOA plywood would have to fall below 25.3 years (against a 30-year reference) for its cradle-to-gate advantage to be erased. These findings clarify the lifecycle trade-offs of inorganic adhesive plywood and provide actionable data for environmental product declarations and procurement frameworks. Full article

This single-site industrial case study compares a leased diesel shunting locomotive with a battery-electric shunting locomotive used for the same class of in-plant railway tasks at the Seza Cement Plant. The evidence base comprises plant leasing and fuel records, equipment specifications, site-reported electricity indicators, operator-reported operational observations, direct CO₂ calculations, and documented occupational safety and health (OSH) functions; it is not a controlled or statistically replicated time–motion experiment. The diesel system incurred a monthly lease cost of USD 10,000 and consumed approximately 1800 L/month, equivalent to 21,600 L/year. Cross-checking the direct CO₂ calculation with 2.692 and 2.683 kg CO₂/L factors gives 58.1 and 58.0 t CO₂/year, respectively. The approximately 24-month payback is treated as a plant-reported investment indicator and evaluated through a normalized sensitivity model because disaggregated costs for locomotive purchase, charging infrastructure, battery replacement, and historical maintenance are not available in the case-study dataset. Operational evidence is reported descriptively: the 20–40% reduction in task time is an operator-reported range rather than a statistical mean; the 7–9 min value refers to the complete 10-wagon weighing maneuver; and 25 loaded wagons (approximately 1450 t) represents the maximum documented field movement rather than a manufacturer-rated capacity. A force-balance check shows that this maximum movement is feasible only if total equivalent resistance remains below approximately 5.41 N/kN, using the 77 kN catalog tractive effort as an upper bound. The battery-electric locomotive produces no local exhaust emissions at the point of use and incorporates SIL 2 remote-control functions, a deadman function, emergency-stop controls, camera support, lighting, and warning systems; these features indicate risk-control capability but do not constitute a measured accident-rate reduction. The study therefore contributes facility-scale, evidence-bounded information for low-speed, repetitive industrial shunting within a defined operating area rather than a general proof of battery-electric superiority across railway applications. Full article

Corrosion of reinforcing steel remains a major cause of premature deterioration in concrete infrastructure, motivating the development of inhibitors with lower toxicity and reduced environmental impact. This review critically examines recent advances in green and bio-based corrosion inhibitors for reinforced concrete, including plant extracts, agro-industrial residues, naturally occurring organic compounds, proteins, polysaccharides, bio-based coatings, hybrid formulations, and microbial systems. The available evidence is synthesized in terms of chemical functionality, delivery route, adsorption and film-forming mechanisms, electrochemical response, compatibility with cementitious materials, and durability under chloride- and carbonation-related exposure. Many formulations provide substantial inhibition under optimized laboratory conditions through interfacial adsorption, coordination with iron species, passive-film stabilization, suppression of anodic and cathodic reactions, and restriction of aggressive-species transport. However, reported efficiencies are not directly comparable because experimental scale, exposure conditions, dosage, steel preparation, and calculation methods vary considerably. Moreover, long-term reinforced-concrete and field studies remain scarce, while extract standardization, cement compatibility, toxicity, biodegradability, and life-cycle performance are frequently insufficiently addressed. Green and bio-based inhibitors therefore represent a promising but heterogeneous technology class. Their practical implementation requires chemically reproducible formulations, complementary electrochemical and surface evidence, concrete-scale durability assessment, environmental validation, and stage-gated progression toward monitored field applications. Full article

The transition to lower-clinker binders in heavy precast concrete is constrained by the need to combine rapid production cycles, high early-age strength, self-compacting performance, durability and measurable environmental benefits. The scientific gap addressed in this study is the limited integrated evidence comparing these criteria under conditions that are representative of industrial heavy precast production, particularly for CEM II/A-S 52.5 R and CEM II/B-V 42.5 R. Four concretes were assessed: CEM I 52.5 R, CEM II/A-S 52.5 R, CEM II/B-V 42.5 R, and a 50:50 CEM I/CEM II/B-V binder. The experimental programme included slump-flow, a plant-specific 600 mm flow-time indicator, compressive strength development, hardened density, water absorption, water penetration under pressure and freeze–thaw resistance. Environmental performance was evaluated using the manufacturers Environmental Product Declarations (EPDs) for the cement component within a cradle-to-gate boundary. All mixtures corresponded to at least strength class C50/60 at 28 days, while CEM I, CEM II/A-S and the 50:50 blend corresponded to C55/67. CEM II/A-S reduced water absorption from 5.49% to 4.29% and water penetration from approximately 61 to 23 mm relative to CEM I, but its freeze–thaw strength loss was 26.80% compared with 4.50% for CEM I. CEM II/B-V provided the lowest cement-related GWP, approximately 154 kg CO₂-eq/m³, about 25% below CEM I, whereas the 50:50 blend reduced this indicator by approximately 12% while achieving the highest 28-day compressive strength (approximately 78 MPa). The results show that cement selection for heavy precast concrete cannot be based on clinker content or strength alone. CEM II/A-S offered the most balanced technological and transport-property performance, whereas CEM II/B-V offered the greatest GWP reduction but requires consideration of its lower strength class and slower early-age development. Long-term durability and full life-cycle impacts remain to be verified. Full article

Water treatment sludge (WTS) is a by-product of water treatment plants, which is often landfilled and risks contaminant leakage into the environment. However, it is rich in aluminosilicate content, which suggests potential suitability as a supplementary cementitious material (SCM), offering a sustainable approach for waste recycling and carbon emission reduction in cement production. While prior reviews have broadly addressed WTS reuse across construction materials, the mechanisms governing its pozzolanic performance as a cement replacement remain insufficiently synthesized, including its emerging use in alternative binders. This systematic review addresses this gap by synthesizing literature from 2010 to 2026 on WTS as a partial cement replacement in cement-based materials (CBMs), in both binary and ternary blends. Findings show that WTS can exhibit high pozzolanic reactivity after grinding and calcination at 600–800 °C, though performance varies depending on source and composition and processing. Partial replacement of cement with 10% calcined WTS was most frequently identified as the optimal substitution level, improving mechanical properties by promoting C-S-H and C-A-S-H formation, although some studies report favourable long-term strength at higher substitution. However, most studies reported that further increasing WTS content in the mix (beyond 10%) leads to a decrease in performance due to the dilution effect, which limits the formation of C-S-H. This review further discusses the durability aspects and environmental impact of using WTS, which remain underexplored in the literature, and highlights areas for future investigations. Full article

Despite the shift toward cleaner energy, coal-fired power plants remain a significant source of global energy, generating excess fly ash that accumulates in large stockpiles—often persisting for decades even after the plants are decommissioned. The study investigated the physicochemical properties and suitability of fly ash recovered from seven ash dams for use in cement-based applications. The recovered ash was beneficiated by drying, breaking agglomerates, and sieving to meet specifications for use as a cementitious material. Subsequently, analyses were conducted for particle size, pH, density, loss on ignition, scanning electron microscopy, oxide composition, X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy, and the compressive strength of mortar samples. The results indicate that the samples are Class F fly ashes, containing amorphous aluminosilicates, with a comparable physical, chemical, and mineralogical composition, and that they meet specifications for use in cement-based materials. This remains true despite a slight increase in sulphur-bearing phases in the Kusile ash associated with the plant’s desulfurization technology. Furthermore, the compressive strength results show that, compared with the reference Portland cement mortar, fly-ash-blended mortars exhibit higher strength gain at later ages, indicating good pozzolanic reactivity, though the degree of strength gain depends on each ash’s fineness, amorphous content, and mineralogy. Full article

Vertical Roller Mills (VRMs) are extensively used in the cement industry for their high energy efficiency. Nonetheless, the start-up phase remains a critical operational challenge due to its pronounced sensitivity to changing process conditions. Such variations frequently induce excessive vibrations, which can trigger unplanned shutdowns, mechanical damage, and diminished throughput. The underlying cause lies in the intrinsic variability of raw materials, particularly in parameters such as moisture, particle size distribution, and hardness, which exert a direct influence on the mill’s dynamic response during the transition to steady-state operation. This study presents the real-world implementation of an Expert System designed to automate the start-up sequence. By applying logical reasoning to key process setpoints, the system enables a controlled and gradual ramp-up, minimizing transient instabilities. Seamlessly integrated into the plant’s control infrastructure, it facilitates remote unattended operation, enhancing process reliability and operational efficiency. The proposed architecture addresses a key challenge in cement production and enables advanced control and intelligent optimization. Full article

The cement industry, responsible for 26% of industrial CO₂ emissions and 8% of global emissions, is under growing pressure to reduce its environmental footprint while maintaining profitability. In this context, optimizing grinding processes is essential to enhance both the efficiency and sustainability of cement production. This study presents the development of a self-adaptive expert system for closed-loop control, integrating symbolic Artificial Intelligence (AI) and Advanced Process Control (APC) techniques. The system dynamically adjusts operational parameters in real time to minimize the specific energy consumption of cement grinding while meeting quality targets. Notably, it enables autonomous plant operation without direct human supervision, thereby reallocating personnel to higher-value tasks and maintaining optimal performance continuously. The benefits observed following industrial implementation are discussed, alongside an analysis of the key factors influencing grinding performance and productivity. Furthermore, the integration of Artificial Neural Networks (ANNs) and genetic algorithms is proposed as a future enhancement, complementing the expert system through neuro-symbolic approaches. This fusion represents a significant step toward the digital transformation of industrial operations. Full article

Amid shifting urban renewal approaches and industrial restructuring in China, small and medium-sized cities face the challenge of conserving industrial heritage through adaptive reuse. Drawing on gazetteers, planning documents, and interviews, this paper examines the transformation of the Anqing Baiqitun Cement Plant into a cultural and creative park across environmental, social, economic, and governance dimensions. The case is significant as a typical heavy industrial heritage in a smaller city, while the enterprise’s restructuring and relocation have produced a rupture in collective memory and identity. The study finds that minimal intervention in the heavy industrial remains achieved carbon sequestration and emission reduction, succeeded in ecological restoration, and attained financial viability by leveraging local markets and intangible assets. However, the industrial past has been selectively reconstructed, creating a divide between the former industrial community and the present one, partly due to an over-reliance on Authorised Heritage Discourse logic and insufficient collaboration with the existing enterprise. Participatory governance, driven mainly by government coordination and market capital, proved efficient but lacked public engagement. The paper argues that regenerating industrial heritage in small and medium-sized cities requires not only physical upgrading but also social mechanisms that enable public participation in conservation. Full article

The reuse of the finest fraction derived from recycled aggregate washing has been investigated for the manufacture of mortars. This practice contributes to the circular economy and lowers CO₂ emissions in the manufacturing of construction materials. A distinction was made between concrete-rich residues (RH) and mixed concrete–ceramic wastes (RHM). Chemical and mineralogical analyses of samples collected over a two-year period revealed consistent homogeneity over time. The RH residues are richer in CaO, primarily as calcite. Conversely, higher ceramic content in the waste correlates with increased SiO₂, Al₂O₃, and K₂O concentrations, predominantly as phyllosilicates and feldspars. Ettringite and portlandite occur in trace amounts. DTA-TG analysis reveals the presence of minor contents of portlandite and C-S-H gel. Mortars were prepared by replacing 10%, 20%, and 30% of Portland cement (OPC) with concrete-derived (RH) and mixed concrete–ceramic (RHM) wastes. At 10% and 20% substitution, both wastes yielded similar strengths, confirming their high potential for masonry mortars without prior treatment. However, at 30% replacement, RH provided markedly higher compressive and flexural strengths than RHM, likely due to a greater presence of the C-S-H gel phase in concrete waste. While 10% and 20% replacements successfully meet the 70% Strength Activity Index (SAI) threshold, a 30% limit severely reduces strength. Consequently, substitutions of 30% or higher require mechanical or thermal activation to enhance CDW reactivity. Given the minimal performance gap between RH and RHM, processing mixed CDW streams uniformly is recommended to maximize economic viability and ensure batch homogeneity in industrial washing plants. Full article

This study reviewed 187 articles based on systematic review guidelines to evaluate pollution controls through a novel analytical multimedia framework that bridges air, water, soil, and acoustic compartments, alongside emerging digital and circular economy paradigms. With 5–7% of worldwide CO₂ emissions originating in the cement industry, fugitive particulate matter constitutes more than 90% of a plant’s emissions. The results show that the cement sector has considerable potential for decarbonization, though highly context-dependent. Under optimal conditions, clinker substitution coupled with alternative fuels could reduce direct emissions by up to 50% and total energy usage by 44%, constrained by regional material availability. Fully integrated carbon capture systems (TRL 7–9) could reduce exhaust emissions by up to 90%, contingent upon overcoming significant energy penalties. Engineering controls in dry-process mills reduced daily occupational noise exposure from 102.9 to 88.3 dB(A). Regarding soil pollution, cement kiln dust increased the unconfined compressive strength of native soils up to 9.9 times for geotechnical stabilization. In water management, hybrid biological systems removed 94.5% of particulate matter and reduced oxygen demand by over 87%, while advanced biomonitoring decreased effluent toxicity by over 90%. The significance of this study lies in overcoming traditional siloed assessments by introducing a holistic multimedia framework that maps biogeochemical interconnectivity alongside Industry 4.0 paradigms. Ultimately, this review provides a vital sociotechnical road map for stakeholders to align localized ecological risk mitigation with stringent 2026 global market mechanisms, such as the carbon border adjustment mechanism and mandatory environmental, social and governance disclosures, ensuring both industrial competitiveness and environmental stewardship. Full article

Waste tires as an alternative fuel in the cement industry offer multiple advantages, including reduced CO₂ emissions and decreased reliance on fossil fuels. In this study, a comparative life cycle assessment (LCA) was conducted for cement clinker production with coal (CPC) as fuel and with waste tires as an alternative fuel (CPCT). The study adopted a “gate-to-gate” scope, with a functional unit of 1 ton of clinker. Environmental impacts were evaluated using the IMPACT 2002 + method. Global warming and non-renewable energy were the dominant impacts in cement clinker production. Compared to the CPC scenario, the CPCT scenario reduced the endpoint damage to resources, climate change, and human health by 19.91%, 2.30%, and 0.70%, respectively. However, the damage to ecosystem quality increased by 11.53%. When the waste tires substitution ratio increased from 5% to 20% according to scenario simulation results, the impacts on non-renewable energy and global warming dropped by 16.23% and 8.59%, respectively. Conversely, this higher substitution ratio exacerbated terrestrial acid/nutri (+10.75%), aquatic acidification (+9.70%), and respiratory inorganics (+5.76%). The results indicated a trend toward reduced reliance on coal and lower CO₂ emissions in the cement clinker production process through the substitution of waste tires. Nevertheless, the trade-off involved higher emissions of certain pollutants, most notably NO_x, leading to increased ecosystem-related impacts. Full article

A data-driven and industrially applicable framework was developed to predict the 28-day compressive strength of cement using routine quality control data from the SEZA Cement Plant. Since 28-day strength is obtained only after a substantial delay, the proposed framework was designed to support earlier decision-making during production. To improve predictive capability, 7-day compressive strength was incorporated as an explanatory variable together with plant quality control parameters, thereby linking early-age mechanical response to later-age performance. Before modeling, the dataset was systematically preprocessed through column standardization, numeric type conversion, removal of incomplete observations, and elimination of age-related strength variables other than the target to avoid information leakage. For comparative evaluation, CatBoost, XGBoost, LightGBM, Random Forest, and Extra Trees were implemented. In addition, a hybrid model, termed the ‘Early-Age-Strength-Supported Weighted Dual-Boosting Ensemble’ (EYD-AIBE), was proposed by combining the optimized predictions of CatBoost and XGBoost using fixed weights. Model performance was assessed under both random split and time split schemes in order to evaluate not only overall pattern-learning capacity but also temporal generalizability. Hyperparameter optimization was performed for CatBoost and XGBoost using Optuna. The results showed that EYD-AIBE achieved the best performance in both evaluation settings. Under random split, it yielded R² = 0.535, RMSE = 0.988 MPa, and MAE = 0.785 MPa, whereas under time split, the model achieved R² = 0.405, RMSE = 1.148 MPa, and MAE = 0.900 MPa. These findings indicate that the proposed hybrid framework provides a feasible, reliable, and methodologically robust tool for cement quality control, production monitoring, process optimization, and early decision support. Full article

The extreme environment characterized by repeated freeze–thaw cycles poses a severe challenge to the stability and durability of loess in engineering applications. This study systematically investigates the improvement of Weinan loess using a plant-based bio-cement (BC) combined with fly ash (FA) under extreme freeze–thaw environments. Through unconfined compressive strength tests, permeability tests, calcium carbonate content measurements, and microscopic analyses (SEM and XRD), the mechanical properties, microstructural evolution, and crack development characteristics of the improved loess were comprehensively evaluated. The results demonstrate that BC-FA modification significantly enhances the mechanical strength and impermeability of loess. The unconfined compressive strength of the 7% FA-amended specimen increased by 201.6% compared to untreated loess, while the permeability coefficient decreased by 61.58%. Freeze–thaw-induced deterioration predominantly occurred within the first five cycles, with a maximum peak strength reduction of 33.29%, after which the soil structure gradually stabilized beyond ten cycles. Microscopic observations revealed that biomineralized calcium carbonate crystals (calcite, aragonite, and vaterite) filled pores and bridged soil particles, forming a continuous cementation network. Furthermore, a novel Crack Identification Method Based on Multi-Feature Mechanical Responses (CIMBMFMR) was proposed, which establishes a quantitative mapping between mechanical degradation, micro-damage, and crack evolution, offering superior accuracy and physical interpretability over traditional image-based techniques. The BC-FA system exhibits notable low-carbon and eco-friendly advantages, providing a promising green solution for loess reinforcement in seasonally frozen regions. Full article