Hasil untuk "Cement industries"

M. Saadi, Alianna Maguire, Neethu T. Pottackal et al.

Additive manufacturing (AM) has gained significant attention due to its ability to drive technological development as a sustainable, flexible, and customizable manufacturing scheme. Among the various AM techniques, direct ink writing (DIW) has emerged as the most versatile 3D printing technique for the broadest range of materials. DIW allows printing of practically any material, as long as the precursor ink can be engineered to demonstrate appropriate rheological behavior. This technique acts as a unique pathway to introduce design freedom, multifunctionality, and stability simultaneously into its printed structures. Here, a comprehensive review of DIW of complex 3D structures from various materials, including polymers, ceramics, glass, cement, graphene, metals, and their combinations through multimaterial printing is presented. The review begins with an overview of the fundamentals of ink rheology, followed by an in‐depth discussion of the various methods to tailor the ink for DIW of different classes of materials. Then, the diverse applications of DIW ranging from electronics to food to biomedical industries are discussed. Finally, the current challenges and limitations of this technique are highlighted, followed by its prospects as a guideline toward possible futuristic innovations.

S. Governo, E. Rossi, S. Azad et al.

X-ray computed tomography (XCT) provides unique opportunities to investigate steel corrosion in reinforced concrete, the primary degradation mechanism compromising infrastructure durability and safety. Its non-destructive nature, combined with high-resolution three-dimensional imaging and time-lapse capabilities, allows for detailed insights into corrosion processes without altering the specimen. However, applying XCT to reinforced concrete remains challenging due to recurring methodological issues, such as selecting appropriate tube voltage and current, defining pre-filtering combinations, mitigating imaging artefacts, and balancing image resolution with sufficient X-ray transmission. These challenges are particularly pronounced when imaging systems with components of widely differing X-ray attenuation, such as steel, concrete, air, and water.This paper proposes a systematic guideline for designing XCT acquisitions tailored to the study of corrosion in reinforced concrete specimens, integrating theoretical considerations with practical examples. The guideline is supported by dedicated charts and design criteria, which guide researchers in selecting acquisition parameters, specimen configurations, and imaging strategies to achieve high-quality and reproducible results. This approach is built upon a critical review of previous studies, highlighting past limitations and identifying future research opportunities for the application of XCT to study corrosion in steel-concrete systems.By providing a coherent framework for experimental design, this paper allows researchers to fully exploit the potential of XCT for studying in-situ steel corrosion and to advance understanding of reinforced concrete degradation, thereby addressing an important challenge in engineering.

Richa Jain, Harshit Jain, Ashish Nim

New building materials that required and produced less energy are need of today’s infrastructure development. The ability of such building materials to promote sustainable development always puts its demand in active mode. With huge consumption of naturally occurring materials in building construction, the problem related to environment degradation is now common for world. Along with this, world is also facing the problem of reuse, recover and scientifically approved disposal of non-biodegradable wastes. Blast furnace slag (BFS) is one of those steel industry wastes that are abundantly available and their disposal arises as prime challenge for industries. This research work makes an efiort to reuse BFS in the form of fine aggregates by replacing it with river sand in cement mortar. A partial to full proportion of river sand was replaced with crushed BFS to form mortar specimens. As per the experimental investigations, a significant change in compressive strength was recorded. The 28th day compressive strength was found 200% more with full replacement of river sand to BFS as compare to reference sample. No significant changes in strength were examined against action of acid and salt. Rapid decrease in strength at elevated temperature was recorded. Results for rebound hammer and UPV were also showed identical concern between actual and predictive strength characteristics. Experimental results were also validated through regression models shows that the models are identically feasible and depicted good relationship between actual and predicted data.

Kenan Muhammad Ryansyah, Resti Ayu Lestari, Vera Surtia Bachtiar et al.

The cement industry is one of the strategic industries that has positive and negative impacts. One of the negative impacts is noise pollution. This research aimed to compare the sound pressure level (SPL) to the standard, analyzed the meteorological influence on SPL, and conducted noise level mapping. The noise measurement according to SNI 7231 of 2009. The SPL data was collected by using a Sound Level Meter at 36 points. Additionally, questionnaires were distributed to workers at the PT Semen Padang Teluk Bayur Packing Plant Unit. Measurement of noise used the grid method with sampling points spaced 20-40 meters apart, then analyzed the correlation and influence of meteorological on SPL, and noise mapping with Surfer 27. The results showed that the highest SPL came from the compressor engine at 85.7 dBA, and the lowest SPL was in the office area at 58.1 dBA. The SPL in this study was influenced by meteorological conditions such as temperature, air humidity, wind speed, and air pressure. There was a correlation between temperature and SPL with a value (r) of 0.9936 (very strong) and a correlation between air humidity and SPL with a value (r) of 0.9962 (very strong).

Kenedy Geofrey Fikeni, Xueyu Pang, Yukun Zhao et al.

During offshore cementing at shallow depth, the low-temperature environment at the bottom of the sea and the low-density requirement of the cement slurry significantly hinder the strength development of oil well cement systems. Hence there is always a strong need to take various measures to enhance the strength development of low-density oil well cement systems. During this study, potential synergistic effects of silica fume, nanomaterials (C-S-H nano-seeds, nano-silica, nano-alumina), and inorganic salts (CaCl2, NaCl, Na2SiO3) to improve the strength of low-density well cement slurry were investigated. Water-to-cement ratio (w/c) was varied between 1.04 and 1.28 to obtain a constant slurry density of 1.5 g/cm3. Test results revealed that the addition of silica fume altered the rheology and flow behavior of low-density cement slurries, resulting in flat rheology profiles at high shear rates. The Bingham plastic model can describe the rheological behavior of cement slurries without silica fume, whereas the Power-law model is more suitable to cement slurries with silica fume. High-dosage silica fume (30 %) is shown to have similar acceleration capability as the strongest nanomaterial accelerator (i.e. C-S-H nano-seeds) at 2 % dosage. However, adding nanomaterials to silica-fume-enriched slurries cannot further increase the hydration rate of cement (i.e. no synergistic effect), possibly due to their similar acceleration mechanism. In contrast, adding chloride-based inorganic salts to silica-fume-enriched slurries further increased the hydration rate of cement significantly, exhibiting a strong synergistic effect. Based on the 7-day compressive strength test results at 15°C, the addition of silica fume or nanomaterials individually can increase the strength of neat cement by up to 92 %, while the combined addition of silica fume and NaCl can increase its strength by 306 %.

Esraa Khalil, Mohamed AbouZeid

Recent global strategies highlight the urgency of addressing greenhouse gas (GHG) emissions, particularly CO₂ from energy-intensive industries such as cement production. Studies show that the cement industry contributes around 8% of the global CO₂ emissions, emphasizing the need for innovative and structural mitigation strategies. While advancements in carbon capture technologies, LC3 cement, alternative raw materials, and renewable energy integration are critical for achieving the net zero emissions (NZEs) goal, the challenge lies in having a structured and comprehensive approach for systematically categorizing, prioritizing, and assessing various CO₂ improvement measures within cement plants. To address this gap, this study introduces a structured assessment model designed to evaluate and rate proposed CO₂ improvement measures based on their alignment with the global NZE targets and plant-specific milestones, providing an overall cement plant performance score. The assessment tool developed in this study provides a quantitative scoring system for assessing the implementation level and impact of various CO₂ improvement measures within cement plants. The framework integrates the cleaner production concept and the 5Cs approach to the decarbonization of the cement industry, offering a systematic yet flexible method for cement industry decarbonization. To validate the assessment tool, two cement plants with different production scales and located at different geographical locations were analyzed. Plant A achieved an overall performance score of 3.315, while plant B scored 3.68. The assessment identified a potential CO₂ reduction of 20–30% through targeted improvements, highlighting that even well-established cement plants have opportunities for emissions reduction and efficiency enhancement. This study advances existing assessment methodologies by providing an adaptable, data-driven, systematic, and scalable tool that enhances decision-making, strategic modifications, and resource allocation for achieving NZE targets. Additionally, this assessment tool bridges the gap between global targets and plant-level implementation, ensuring effective transition towards sustainability in the cement industry.

Rui Shi, Jianyu Kou, Lei Guo et al.

The construction of zero-carbon parks has become an urgent priority. Electric load forecasting plays a decisive role in enabling the efficient operation of industrial parks; however, the complexity of electric load features within the parks has limited the accuracy of electric load forecasting. A novel electric load forecasting framework with feature extraction (TPE-AVMD-BiLSTM with feature extraction) is proposed to improve the forecasting accuracy. This framework combines feature extraction, decomposition with TPE optimization, and BiLSTM prediction. Together, these components work to remove the influence of irrelevant or redundant features. To verify the superiority of the proposed model, ablation experiments were carried out. The annual hourly electric load (8760 h) of typical industries was predicted within the park, including a data center, chemical manufacturing company, residence, shopping mall, cement manufacturing plant, and hospital. The results showed that the proposed model achieved high accuracy for all typical industries (R² > 0.9891, E_MAE < 0.3714, E_RMSE < 0.4694), indicating that the forecasting has excellent coverage performance. The performance of the proposed model over the feature-free baseline confirms that incorporating more correlated features enhances prediction stability. The framework presents a viable solution for achieving accurate electric load forecasting within zero-carbon parks.

Ali Zia Noor, Muhammad Atif, Sadia Bibi et al.

Sustainability and environmental protection are reshaping industries, including construction, where sustainability plays a crucial role in its influence on global resource consumption and waste management. The current study has developed a reusable cement material by photo-chemical surface modification of marble powder, achieved by reacting glycidyl methacrylate with carbonate functionality. This innovative modified marble powder boosts the reusability of construction materials, unlocking new possibilities for sustainable building practices. By transforming waste into valuable resources, we minimize raw material consumption, foster recycling, and advance circular economy principles in the construction industry. The difference in unmodified (22.9 nm) and modified (23–27 nm) marble powder particle sizes was used to assess the effectiveness of surface modification technique. Compared to non-reusable counterpart (20.34 MPa), the reusability has come at the cost of a decrease in compression stress (11.30 MPa, 10.89 MPa, and 10.57 MPa). Overall, photochemically modified marble powder for its reusability is a groundbreaking approach that offers substantial environmental, economical, and technical advantages, making it an appealing choice for the construction industry.

A.T.M. Alberda van Ekenstein, H.M. Jonkers, M. Ottelé

The clinker in cement largely determines the environmental footprint of concrete. Therefore, concrete recycling should focus on retrieving high-quality cementitious fractions to replace clinker. This requires a shift from current traditional recycling techniques towards innovative recycling methods, enabling recovery of not only clean secondary aggregates, but also residual cementitious fines (RCF), potentially eliminating the carbon dioxide emissions associated with them. The production and upcycling of RCF offer new implementation routes that were previously deemed unfeasible. However, the properties of RCF may vary based on their origin, affecting their replacement and upcycling potential. Consequently, assessing the original concrete quality, with a focus on the binder type, before demolition is important. A handheld x-ray fluorescence technique appears promising for this purpose. To achieve effective separation of clean secondary aggregates from the original cementitious content, innovative crushing and separation techniques are needed. Additionally, electrostatic separation shows significant research potential for further optimizing RCF.

Mohammad Teymouri, Mahmoud Shakouri

As sustainable construction practices become more popular, researchers are looking into using readily available and inexpensive agricultural waste materials as a supplementary cementitious material. This study investigates the impact of various pretreatment methods on the chemical composition, crystal structure, morphology, and cost of producing pretreated corn stover ash collected from four different sources in the U.S. This study also evaluates the performance of mortars and pastes containing treated corn stover ash through tests such as compressive strength, flow measurement, calorimetry, and thermal analysis. In addition, thermodynamic modeling is used to predict the phase composition, chemical composition of the pore solution, pH, and electrical resistivity of pastes made with selected pretreated corn stover ashes. The results suggest that acid pretreatment is the most effective and economical method for improving the quality of corn stover ash and that it removes a significant amount of alkalis from the raw material. The simulation of the reaction between cement and the pretreated corn stover ash was confirmed by the experimental results, indicating a marked enhancement in the pozzolanic activity and chemical and physical characteristics of the system.

Julia T. Sonntag, Ravi A. Patel, David Alós Shepherd et al.

This study investigates the resistance against alkali-silica reaction (ASR) of two alternative binder systems, alkali-activated slag (AAS) and Celitement (Celite). Experimental studies on expansion and mechanical strength are carried out. Coupled kinetic and equilibrium thermodynamic modeling is used to clarify the role of binder chemistry on ASR. It was observed that under accelerated conditions OPC based mortars were more susceptible to ASR compared to AAS and Celite-based mortars. Based on experimental and modeling results, a correlation is shown between the dissolution of silica and the degree of expansion, but no correlation was found between the predicted amount of ASR products and the measured degree of expansion. Finally, the expansion degree could only be correlated with the reduction in compressive and flexural tensile strength for ASR-exposed samples.

Saeid Darab Molkabadi

The current research aims to answer the question as to by which channels the oil shock is transmitted to the stock market and how it spreads in the stock market. In this regard, the Factor-Augmented VAR approach, and also the global price index of commodity groups, macroeconomic variables, indices of large listed industries, and the total index of the Tehran Stock Exchange (for the period 2004-2016) have been used. Hence, the action-reaction functions are extracted in order to study the transmission mechanism of the oil price shock and its propagation in the stock market of Iran as an oil-exporting country. The findings show the impact of the oil shock on the stock market through three channels: (a) direct channels (b) global commodity price channels and (c) macroeconomic channels. Furthermore, based on the effects of the oil shock, the way of reaction from these channels is different. Accordingly, in the process of spreading the oil price shock in the stock market, the index of the group of petroleum products, chemical products, basic metals, metal ore extraction, multidisciplinary industrial, banking, and cement sectors, and consequently the total stock market index, increases significantly and steadily.

Asiya Alawi, Abdalrhman Milad, Diego Barbieri et al.

Portland cement (PC) is a common material used in civil infrastructure engineering. Cement production emits roughly 2.2 billion tons of CO₂ per year, contributing 8% of global emissions in 2016. This contributes to almost half of the calcination process, and together with thermal combustion, clinker generation could be responsible for 90% of the sector’s emissions. One effective technique for dealing with these industrial by-product wastes is to employ them to make cement replacements such as concrete and mortar, which can be used in a variety of applications. As a result, the purpose of this research is to review the current advancements, challenges, and future perspectives on the utilization of agro-industrial waste (AIW) produced around the world in cement-based products. Geopolymers (GPs), on the other hand, reduce carbon dioxide emissions and have the potential to be a complete or partial replacement for PC in the construction sector. The GP technology enables the use of AIW in combination with an alumina–silicate (A–S) phase with minimal environmental impact. GP-cement is mostly produced by activating alkali silicates or alkali sols with secondary raw materials such as calcined clays, fly ash (FA), zeolite, metakaolin, etc. Mixing various resource materials, including additives, A–S, and alkali sols, alkali concentrations, optimizing the curing temperature, the SiO₂/Na₂O ratio, microstructural behavior, and other factors, results in GP-cement with outstanding mechanical and durability characteristics. The review concludes that AIW-based geopolymer composites have shown promising results in terms of their mechanical properties, durability, and environmental sustainability, which makes them emerge as promising future building materials with applications in a wide range of industries.

Prasanth Alapati, Mehdi Khanzadeh Moradllo, Neal Berke et al.

Alternative cementitious materials (ACMs) may exhibit superior mechanical properties and durability to certain environments, and that also may be produced with relatively less environmental impact compared to traditional portland cement. Differences in ACM composition, reaction products, and microstructure produces variations in their performance, including their resistance to fluid and ion and to corrosion of embedded steel. Understanding relationships between composition, structure, and corrosion performance in ACM systems is essential for designing durable reinforced concrete from these materials. Here, five commercially available ACMs are evaluated and compared against ordinary portland cement (OPC). The five ACMs include one calcium aluminate cement (CAC); one ternary blend of calcium aluminate, portland cement, and calcium sulfate (CACT); one calcium sulfoaluminate cement (CSA) as well as the same CSA cement with polymer-modification (CSAP); and one activated aluminosilicate binder system (AA). Water sorption, chloride ion ponding, bulk conductivity, formation factor measurements, and accelerated corrosion tests were performed to evaluate the porosity, mass transport, chloride ion binding capacity, and resistance to corrosion of embedded reinforcement. The results demonstrate that mixtures with high pore structure interconnectivity and low binding capacity (such as CSA and CAC investigated in this paper) or mixtures with significantly low binding capacity (such as AA investigated in this paper) should be avoided to minimize damage due to chloride-induced corrosion. Polymer addition could be an important strategy to improve the corrosion resistance of mixtures that have high interconnectivity. Overall, one ACM, CACT, evaluated in this study showed the best corrosion resistance among the materials considered – including OPC.

Ljajsjan Zajceva, Ekaterina Lucyk, Tat’jana Latypova et al.

The development and implementation of “green” technologies in the construction sector, which ensure natural resource conservation, reduce harmful emissions and provide utilization of industrial waste, are key issues in material engineering of the XXI century. Extensive research has been devoted to solving these issues, including research in the field of concrete science. Still, the issue of developing concrete compositions with increased corrosion resistance remains much less studied. At the same time, reactive aggregates from industrial waste can have positive effect on durability of concrete, and the best result can be achieved by means of modification of a concrete mixture with highly effective additives. The article presents the research data in two lines—the study of applicability of reactive aggregates from waste products of nonmetallic and ceramic industries, mineral wool production and concrete scrap for production of corrosion-resistant concretes, as well as the assessment of possibility of Portland cement quantity reduction in a concrete mixture on local raw materials due to the introduction of additives based on polycarboxylates. The article presents the research evidence of the effect of dust and clay particles content on the quality of concrete with a polycarboxylate additive. The article describes the studies of corrosion resistance of concrete samples based on production wastes in sulfate environments and under the influence of carbon dioxide. The developed concrete compositions with waste use can be recommended for widespread application, rational use of resources, and production of durable high-quality concretes. The application of additives based on polycarboxylates makes it possible to produce concretes with the reduction of cement consumption in the mixture by 10–20% and decrease in the mode of thermo-wet treatment by two times.

Hans Böhm, Markus Lehner, Thomas Kienberger

Energy-intensive industries still produce high amounts of non-renewable CO2 emissions. These emissions cannot easily be fully omitted in the short- and mid-term by electrification or switching to renewable energy carriers, as they either are of inevitable origin (e.g., mineral carbon in cement production) or require a long-term transition of well-established process chains (e.g., metal ore reduction). Therefore, carbon capture and utilization (CCU) has been widely discussed as an option to reduce net CO2 emissions. In this context, the production of synthetic natural gas (SNG) through power-to-methane (PtM) process is expected to possess considerable value in future energy systems. Considering current low-temperature electrolysis technologies that exhibit electric efficiencies of 60–70%el, LHV and methanation with a caloric efficiency of 82.5%LHV, the conventional PtM route is inefficient. However, overall efficiencies of &gt;80%el, LHV could be achieved using co-electrolysis of steam and CO2 in combination with thermal integration of waste heat from methanation. The present study investigates the techno-economic performance of such a thermally integrated system in the context of different application scenarios that allow for the establishment of a closed carbon cycle. Considering potential technological learning and scaling effects, the assessments reveal that compared to that of decoupled low-temperature systems, SNG generation cost of &lt;10 c€/kWh could be achieved. Additional benefits arise from the direct utilization of by-products oxygen in the investigated processes. With the ability to integrate renewable electricity sources such as wind or solar power in addition to grid supply, the system can also provide grid balancing services while minimizing operational costs. Therefore, the implementation of highly-efficient power-to-gas systems for CCU applications is identified as a valuable option to reduce net carbon emissions for hard-to-abate sectors. However, for mid-term economic viability over fossils intensifying of regulatory measures (e.g., CO2 prices) and the intense use of synergies is considered mandatory.

Luiz A. Pereira-de-Oliveira, João Castro-Gomes, P. Santos

Mattia De Colle, Pär Jönsson, Andrey Karasev et al.

Recycling of steelmaking slags has well-established applications, such as their use in cement, asphalt, or fertilizer industries. Although in some cases, such as the electric arc furnace (EAF) high-alloyed stainless-steel production, the slag&#8217;s high metal content prevents its use in such applications. This forces companies to accumulate it as waste. Using concepts such dematerialization, waste management, industrial symbiosis, and circular economy, the article drafts a conceptual framework on the best route to solving the landfilling issue, aiming at a zero-waste process re-design. An experimental part follows, with an investigation of the use of landfill slag as a substitute of limestone for the neutralization of acidic wastewater, produced by the rinsing of steel after the pickling process. Neutralization of acidic wastewater with both lime and slag samples was performed with two different methods. Two out of four slag samples tested proved their possible use, reaching desired pH values compared to lime neutralizations. Moreover, the clean waters resulting from the neutralizations with the use of both lime and slag were tested. In terms of hazardous element concentrations, neutralization with slag yielded similar results to lime. The results of these trials show that slag is a potential substitute of lime for the neutralization of acidic wastewater.