Hasil untuk "Cement industries"

M. Juenger, R. Siddique

J. Garcia, Verónica Collado Ciprés, A. Blomqvist et al.

Abstract Cemented carbides cover a wide range of applications in many relevant industries, i.e. as cutting tools (turning, milling, drilling) for machining of metal components in the automotive and/or aerospace industry, as components of drill bits or road headers in the rock tools and mining area or as wear parts in wire drawing dies or punch tools. In this review selected cemented carbide and cermet microstructures are presented. The focus is on microstructures, both those that are already established in the cemented carbide industry and those which have drawn scientific attention due to new potential applications. Cemented carbides are here divided in four groups based on microstructure and chemistry: WC morphology and chemistry, cubic carbide containing cemented carbide and cermets, functionally graded cemented carbides, and binder design of cemented carbides. Furthermore, this review covers some historical background that motivated the microstructure design as well as the status of each class of materials nowadays. The paper aims at categorising cemented carbides in a structured way and to serve as an introduction to cemented carbide microstructures for engineers, researchers and scientists.

J. Provis, S. A. Bernal

Y. H. M. Amran, Rayed Alyousef, Hisham Alabduljabbar et al.

The incessant production of cement has increased the amount of CO2 being released into the atmosphere; thus, aggravating the issue of global warming which has an adverse effect on the environment. Therefore, a more sustainable approach and a careful review of the existing admixtures used to replace conventional concrete have become highly imperative. To this end, many investigations on geopolymer concrete (GeoPC), which exhibit similar or better durability and high strength when compared to conventional concrete, have been carried out by various researchers. GeoPC concrete has the advantage of cement replacement with supplementary cementitious materials that are combined with alkali activated solutions. GeoPC is a relatively new, innovative and sustainable engineering material with many advantages over ordinary concrete. For example, it exhibits higher early strength, lower natural resource consumption, low cost and ability to form various structural shapes. GeoPC is an essential material that can be used for concrete building repairs, maintenance of road transport infrastructure and reducing the negative environmental effects. Therefore, this paper presents a comprehensive review of GeoPC material, its constituents, production techniques, curing regimes, properties and its potential applications in the construction industry.

Kelvin O. Yoro, M. Daramola

Abstract This chapter discusses the concepts of CO2 emission, global warming, and climate change with an emphasis on their environmental impacts. Specifically, the chapter reviews different sources of atmospheric CO2 emissions and recent advances in the implementation of carbon capture and storage (CCS) technology to mitigate greenhouse gas emissions. In this chapter, the intricate relationship between CO2 emission, global warming, and climate change was explicitly explained, and CO2 mitigation strategies in selected industrial sectors such as power, cement, iron, and steel as well as the petrochemical industry were presented. An overview of process integration concepts for energy minimization in environmental sustainability studies was highlighted. The current state of research in this field was reviewed, while future prospects in the application of process synthesis techniques to decrease the high energy and material requirement during CO2 capture were suggested. Finally, CO2 emission trend since the beginning of the first industrial revolution was discussed alongside current international treaties, limitations, and forecasts about greenhouse gas emission.

Y. Cho, Jaekwon Kim, W. Yang et al.

C. Shi, B. Qu, J. Provis

Abstract The development of low-carbon binders has been recognized as a means of reducing the carbon footprint of the Portland cement industry, in response to growing global concerns over CO2 emissions from the construction sector. This paper reviews recent progress in the three most attractive low-carbon binders: alkali-activated, carbonate, and belite-ye'elimite-based binders. Alkali-activated binders/materials were reviewed at the past two ICCC congresses, so this paper focuses on some key developments of alkali-activated binders/materials since the last keynote paper was published in 2015. Recent progress on carbonate and belite-ye'elimite-based binders are also reviewed and discussed, as they are attracting more and more attention as essential alternative low-carbon cementitious materials. These classes of binders have a clear role to play in providing a sustainable future for global construction, as part of the available toolkit of cements.

J. Ahmad, K. Kontoleon, Ali Majdi et al.

In the last few decades, the concrete industry has been massively expanded with the adoption of various kinds of binding materials. As a substitute to cement and in an effort to relieve ecofriendly difficulties linked with cement creation, the utilization of industrial waste as cementitious material can sharply reduce the amount of trash disposed of in lakes and landfills. With respect to the mechanical properties, durability and thermal behavior, ground-granulated blast-furnace slag (GGBS) delineates a rational way to develop sustainable cement and concrete. Apart from environmental benefits, the replacement of cement by GGBS illustrates an adequate way to mitigate the economic impact. Although many researchers concentrate on utilizing GGBS in concrete production, knowledge is scattered, and additional research is needed to better understand relationships among a wide spectrum of key questions and to more accurately determine these preliminary findings. This work aims to shed some light on the scientific literature focusing on the use and effectiveness of GGBS as an alternative to cement. First and foremost, basic information on GGBS manufacturing and its physical, chemical and hydraulic activity and heat of hydration are thoroughly discussed. In a following step, fresh concrete properties, such as flowability and mechanical strength, are examined. Furthermore, the durability of concrete, such as density, permeability, acid resistance, carbonation depth and dry shrinkage, are also reviewed and interpreted. It can be deduced that the chemical structure of GGBS is parallel to that of cement, as it shows the creditability of being partially integrated and overall suggests an alternative to Ordinary Portland Cement (OPC). On the basis of such adjustments, the mechanical strength of concrete with GGBS has shown an increase, to a certain degree; however, the flowability of concrete has been reduced. In addition, the durability of concrete containing GGBS cement is shown to be superior. The optimum percentage of GGBS is an essential aspect of better performance. Previous studies have suggested different optimum percentages of GGBS varying from 10 to 20%, depending on the source of GGBS, concrete mix design and particle size of GGBS. Finally, the review also presents some basic process improvement tips for future generations to use GGBS in concrete.

Anastasija Komkova, Sophie Krog Agergaard, Birgitte Holt Andersen et al.

Global objectives to mitigate climate change, minimise waste, and ensure the efficient use of resources require urgent actions in multiple sectors, including construction and buildings. Currently, rock wool and glass wool are widely used as insulation materials in the building stock across Europe, while in multiple countries are still landfilled at their end-of-life. Within a recent research project, mineral wool waste has proved to be recyclable as a precursor in an alternative binder to carbon-intensive conventional cement, such as alkali-activated materials (AAMs). This open-loop recycling of mineral wool in AAMs is associated with the creation of new value chains within the circular economy that can trigger symbiotic relationships between urban areas and industries. Stakeholders who produce mineral wool waste–based alkali-activated construction materials at a pilot scale in 5 European countries were interviewed to evaluate their environmental, economic and social performance using selected circular economy indicators. Strengths, weaknesses, opportunities, and threats (SWOT) analysis was applied to identify common trends across pilot-scale productions and potential industrial up-scales. While common barriers include limited economic viability at the pilot scale, which can be addressed through industrial upscaling with optimised supply chains, there is also variability in consumer acceptance of waste-based materials across countries. Finally, potential solutions to the identified barriers along each step of the value chain are proposed. The results show that combined actions of industry, cities, and policymakers are required to overcome barriers and nudge the transition towards a circular economy. This can be achieved by using economic incentives to enhance the cost-competitiveness of alternative construction materials, promoting green public procurement, and raising public awareness.

Moutaman M. Abbas

Increased industrialization has resulted in a shortage of natural building materials, thus increasing awareness of sustainable approaches by construction companies. This research explains how waste materials—Ceramic Waste Powder, Waste Glass Powder, Waste Granite Dust, Waste Marble Powder, and Waste Brick Powder—can be employed as environmentally friendly cement alternatives in concrete mixtures. The objective is to study the mechanical characteristics of these supplementary cementitious materials with continuous industrial waste recycling for environmentally sustainable development. In addition to experimental findings, a neural network model was developed to predict the compressive strength of concrete containing these materials, trained on data collected from the literature. The model successfully demonstrated its ability to replicate trends in compressive strength results across varying replacement levels, validating the findings and enhancing the study’s reliability. Tests were carried out for replacement levels of cement by the materials in concrete, from 5 % to 50 %, on compressive and tensile strengths at various curing periods. The test results show that a 10–15 % replacement level is within the optimum range for most of the waste materials. It is also observed that compressive and tensile strength improvement tends to be maximum around 28 days of curing. Increases in dosage lead to a loss in mechanical properties, indicating limited viability for higher replacement percentages. The present review, supported by machine learning predictions, highlights the potential of these materials to improve sustainable practices in the building industries, toward manufacturing Supplementary Cementitious Materials (SCMs) with low environmental impact coupled with resource efficiency.

Kumar G. Prasanna, Saranya D. Sai, Hariksari A. et al.

Concrete is the mostly used material in all the construction activities and thus resulted in scarcity of raw materials for future infrastructure development. The entire problematic condition is balanced by utilization of different alternatives such as by products from various industries resulting towards sustainable development. Hence in order to develop an innovative concrete with improved properties, granite dust and alccofine are used in this present study. Conplast SP550 is used as super plasticizer for workability. M40 grade concrete is considered as reference concrete mix. In the first phase, cement is replaced with granite dust by 10, 20, 30, 40 and 50% and followed by second phase where alccofine is also utilized as an alternative for cement by 5, 10, 15, and 20 % respectively. In the final phase, an innovative concrete with improved compressive strength at 7, 14, 28 and 56 days curing periods is obtained by replacing cement with optimum contents of granite dust and alccofine at 20 % and 15 % respectively. Non-destructive testing such as rebound hammer test is also performed on the concrete mixes. The use of materials such as alccofine and granite dust has shown enhancement of strength resulting in development of new sustainable concrete.

Lan QIAO, Naifu DENG, Shiji MA et al.

The metal mining industry is the second-largest carbon emitter in China, followed by the power industry. The metal mining industry is closely intertwined with six major industries that prioritize emission reduction, including steel, nonferrous metals, and building materials. The construction of mine shafts and drifts plays a pivotal role in the initial development and construction of the metallurgical mining industry, and its carbon emissions are integral to the advancement of the industry under the “dual carbon” strategy. This study delves into the distinctive characteristics of budget quota preparation for metal mine shaft and drift construction projects during the construction period. This study proposes a carbon emission assessment framework and model based on the dual assessment path of direct and auxiliary systems. Carbon emissions from ten key projects and seven auxiliary projects are calculated at each level within each carbon assessment path. Furthermore, a comprehensive analysis of the list of substances in the smallest unit processes at various levels is conducted through multilevel dissection. This analysis culminates in the development of a carbon emission factor database specific to the mine shaft and drift construction projects, which is achieved by searching and analyzing global lists of carbon emission substances across different industries. Based on the carbon emission assessment framework presented in this study, the fundamental data for the top ten carbon emissions in metal mine shaft and drift construction projects are established using the MySQL database, with each database labeled by a unique identifier. Subsequently, an efficient indexing and scheduling mechanism is implemented for the top ten basic data tables using the MATLAB App Designer. This mechanism facilitates the application of a comprehensive dual-path carbon emission measurement model for detailed carbon emission calculation and analysis of metal mine shaft and drift construction projects. Case analysis reveals that, in main shaft construction, the primary carbon emitters are associated with the use of cement, macadam, and electrically driven equipment, accounting for approximately 70%–80% of carbon emissions. From an emission source perspective, major carbon emitters result from material usage, generating approximately two to three times the carbon emissions of machinery energy consumption. From an emission pathway perspective, major carbon emitters are predominantly concentrated in the shaft body construction phase, constituting approximately 92% of carbon emissions within this segment of the main shaft project. Further analysis indicates that electricity consumption is the primary source of carbon emissions from machinery and equipment, representing approximately one-fourth to one-third of the total carbon emissions. By contrast, cement consumption serves as the principal source of carbon emissions from material use, accounting for approximately one-fifth to one-fourth of the total carbon emissions. Accordingly, energy-saving and emission-reduction techniques should prioritize the optimization of the material preparation process, such as cement, and the utilization of electrically driven equipment. The outcomes of this study can provide methodological foundation and data support for detailed carbon assessment and concrete implementation of low carbon emission-reduction policies for mine shaft and drift construction projects in China.

Xiangbo SU, Ruike LYU, Hongye GUO et al.

In the context of future high penetration of new energy, the uncertainty of supply-demand balance gradually increases. Demand response is an important means of ensuring the balance of power and electricity in the system by tapping into user-side flexible resources. When power sector works on demand response, historical data is needed for an initial assessment of load response potential, so as to select the users with high potential and initiate mobilization efforts. This article focuses on defining and providing a mathematical expression for load step that represents the energy consumption characteristics of industrial users. And then a user selection method for industrial demand response based on load step is proposed. Firstly, an index system for the potential of industrial users' demand response across multiple time scales based on load step is proposed. And then, a user selection model is established to conduct an initial evaluation of different users' response potential, and the k-means algorithm and the nearest neighbor propagation algorithm are used to divide groups, allowing for user selection across different time scales. Finally, a case study is presented based on actual load data from several industrial users in industries such as cement and paper, illustrating the user selection results for industrial demand response using the proposed method.

Yasaman Abdolvand, Mohammadhossein Sadeghiamirshahidi

The demand for sustainable ground improvement methods is rising as urban development expands into areas with challenging soil conditions. Traditional approaches, mostly reliant on cement and lime, contribute significantly to anthropogenic greenhouse gas emissions. Researchers, therefore, are constantly searching for new environmentally friendly stabilization methods to improve the engineering properties of soils. One alternative material used for this purpose is gypsum in its hydrated and dehydrated (hemihydrate/anhydrate) states. Not only can natural gypsum be used for ground improvement but also industrial waste and by-products (e.g. used or waste plasterboard, phosphogypsum, flue gas desulfurization gypsum, titanium dioxide production gypsum by-product) can be recycled, and used. Successful application of these materials could lower the carbon footprint of the construction industries (by reducing the consumption of cement and lime) as well as other industries (by recycling their waste and by-products). However, using gypsum presents challenges due to its moderate water solubility, the formation of swelling clay minerals under certain conditions, and the tendency of dehydrated gypsum to swell upon exposure to water, to name a few. Furthermore, the mechanisms leading to the improved behavior of the gypsum-treated soils are complicated, which has resulted in some seemingly contradictory results reported in the literature. This study presents a systematic and extensive review of the observed behavior of gypsum-treated soils and the different mechanisms causing the observed behavior. The research gaps and the required future steps to address these gaps have been identified and reported. A summary of the effect of gypsum treatment on the mechanical and engineering properties of soils, including unconfined compressive strength (UCS), California Bearing Ratio (CBR), swell potential, Atterberg limits, optimum moisture content (OMC), maximum dry density (MDD), durability, and environmental effects has also been presented.

Farzaneh Elyasigorji, Habib Tabatabai

Reductions in cement use have essential benefits in reducing the embodied energy in concrete and CO2 emissions. Hence, effective assessment of potential pozzolanic materials is highly desirable to facilitate usage as sustainable supplementary cementitious materials (SCMs). However, assessment of pozzolanic reactivity using conventional experimental tests is typically time-consuming and expensive. Pozzolanic reactivity is mainly related to the chemical and physical characteristics of various pozzolans, such as amorphous silica and alumina contents and specific surface area. This study develops and presents an equation that can predict the strength activity index (SAI) as an indirect method for the assessment of potential pozzolans and their strength outcome using their chemical and physical properties. The development of a prediction equation not only saves time and resources but also helps with designing optimized and improved pozzolanic SCMs. The strength activity index (SAI) of seven different materials with varying pozzolanic properties was measured at an age of 90 days. The powdered test materials included pottery cull, brick powder, lightweight aggregate fines, glass powder, silica fume, dolostone, and Class C fly ash. In the second stage, correlation analyses were performed to find parameters (based on chemical and physical properties) that were highly correlated with SAI. An equation was then developed as a function of the chemical and physical properties of raw pozzolanic materials using an optimization tool. Consequently, an equation predicting SAI was derived which had a high degree of correlation (R = 0.972) with measured SAI.

Rayed Alyousef, Wasim Abbass, Fahid Aslam et al.

Although the dumping of waste generated by industries in the environment poses a hazard, it is feasible to use waste and unused materials to manufacture high-performance concrete. By recycling these wastes in binary and ternary blends, sustainable and durable concrete mixtures can be created, resulting in the development of sustainable concrete structures. Therefore, a research project was undertaken to develop high-performance concrete (HPC) using available supplementary and waste materials, such as fly ash (FA), silica fume (SF), Quartz filler (QF), and limestone powder (LSP), as partial replacements for cement in binary and ternary blends under various curing conditions. Different percentages (5, 8, 10, 15, 20%) of the supplementary materials were mixed in binary and ternary combinations to determine the optimal dosage for high-performance concrete. The fresh and hardened properties of the concrete were evaluated using various tests, including slump, compressive strength, rapid chloride ion permeability, porosity, and drying shrinkage tests. The prepared concrete specimens were tested using various concentrations of binder replacement in binary, ternary, and quaternary combinations. The results showed that incorporating quartz filler as a partial replacement of cement up to 8% yielded positive results regarding mechanical properties. However, all mixtures containing different dosages of SF, QF, FA, and LSP demonstrated significant improvement in durability-related properties under normal and high-temperature curing conditions. Interestingly, the porosity of mixtures incorporating fly ash and LSP showed a slight increase compared to identical specimens under normal curing conditions. Moreover, the drying shrinkage behavior of ultrafine fillers (QF, SF, LSP, FA) indicated that their incorporation led to an increase in the shrinkage of high-performance mixtures under normal and high-temperature curing conditions. Binary and ternary blends incorporating QF, LSP, and SF showed an increase of around 5–8% in shrinkage under high-temperature curing compared to identical specimens under normal curing conditions. Therefore, it can be concluded that QF, LSP, SF, and FA can be efficiently used to produce high-performance cementitious composites, leading to sustainable concrete material.

Sam Adu-Amankwah, Leon Black, Liu Xianfeng et al.

Ground granulated blast furnace slag (GGBS) is an important supplementary cementitious material (SCM) for producing low carbon and durable concrete. There are however questions around the early age reactivity of GGBS and the factors that influence this. To elucidate the fundamental mechanisms controlling the early age reactivity and particularly the influence of anionic species, simplified systems comprising GGBS and calcium hydroxide were examined in the presence of limestone, anhydrite, or both at 4:1 SCM-to-activator ratio. Limestone and GGBS were considered as SCMs, but calcium hydroxide and anhydrite were considered as activators. Multiple techniques, including isothermal calorimetry, thermogravimetry, X-ray diffraction, electron microscopy, mass balance calculation and mercury intrusion porosimetry were used to study hydration and microstructure. The results show that GGBS hydration commences immediately in the alkaline media provided by calcium hydroxide. Sulphates and limestone influence hydration through reactions with aluminates to form ettringite and carboaluminates, but prevalence of macro-capillary pores in sulphate containing binders sustains diffusion-controlled hydration. Consequently, optimization of the alumina to sulphate and carbonate ratios is essential for exploiting the pore solution and space filling effects in composite cements.

Qingsen Zeng, Xiaoming Liu, Zengqi Zhang et al.

Granulated blast furnace slag (GBFS) is widely used in cement and concrete industries due to its excellent hydration properties. However, there is a huge capacity gap between the steel industry and the cement industry, and hence, the supply of GBFS can hardly meet the demand. At present, few studies have focused on the preparation of cementitious materials with GBFS-like properties, and a detailed summary of the mechanisms is lacking. This review summarizes the physical and chemical properties of GBFS and comprehensively discusses the hydration process in cement. In addition, the synergistic effects between GBFS and solid wastes (red mud, steel slag, gypsum and fly ash) were analyzed in detail. Based on the analysis of this work, there are four synergistic mechanisms among them. Moreover, a method for using solid wastes as raw materials to produce composite GBFS is proposed. It is beneficial to valorize various industrial solid wastes, promote cross-industry cooperation and alleviate the demand of the cement industry for high-quality GBFS. Although it is a theoretically possible method, there are still some problems that need to be solved, such as the lack of uniform quality and environmental standards. This work can provide useful advice for the preparation of composite GBFS.

Michael Ebie Onyia, Chijioke Christopher Ikeagwuani, Michael Chinwe Egbo

The effect of the incorporation of treated waste pressed palm oil fruit fibre (PPOFF) as additives on the mechanical properties of sandcrete masonry blocks (SMBs) was investigated in this study. Taguchi-grey relational analysis (T-GRA) optimization technique was employed to optimize the applied process parameters that involved treated PPOFF, water to cement (W/C) ratio and mould volume (MV). The percentages of PPOFF added were 0.00%, 0.25 %, 0.50 %, 0.75 % and 1.00 % of the cement mass. The treated PPOFF was assigned four levels, while W/C ratio and MV were assigned two levels each in the L8 (4^1x2^2) Taguchi mixed level orthogonal array chosen for the design of experiment. The results obtained with the T-GRA optimization technique showed that the peak response values of the evaluated properties of the produced SMBs, which included compressive strength (CS), bulk density (BD) and water absorption capacity (WAC), were 4.58 N/mm2, 2066 kg/m3 and 4.12 % respectively. The optimal parameter level combination that gave the peak response values in the evaluated properties was found at A1B2C1. This represents 0.25 % treated PPOFF, 0.65 W/C ratio and 0.0101 m3 MV. These values indicate that the produced SMBs are of high quality and can be used as load bearing walls in building industries. The scanning electron microscope images of the produced SMB samples revealed that there was tight PPOFF-cement matrix bonding quality. These imply that the inclusion of the treated PPOFF in the production of SMBs greatly improved its properties. Lastly, the predictive models developed and assessed statistically for the evaluated properties were found to be good and reliable for predicting the properties of such blocks within the range of data considered in this study.