1,720,996 research outputs found
Recent advances in utilizing industrial wastes for enhanced concrete performance
No full textOwing to the torrent of growth and development, accelerated industrial activities have turned the consumption patterns that lead to a rigorous change in consumer needs and demands. These industrial activities account for generating tons of waste in the form of hazardous and nonhazardous components that may include solid waste, liquid waste, or greenhouse gases. The waste created is a liability to humankind but can be turned into an asset if embarked on the construction industry. With these wastes outflowing into the atmosphere, the concept of waste management emphasizes the goals of sustainability. This chapter will explore various types of industrial waste generated across different sectors, highlighting the challenges and opportunities associated with their management. The potential application of industrial waste in cementitious materials will be presented. It will discuss the techniques that can be used to tailor the properties of waste and enhance the performance of concrete. The heart of the chapter involves the methods and strategies for effectively incorporating industrial wastes into cementitious materials, including cement, concrete, and mortar. This may reduce the burden on raw materials, save costs, and boost the circular economy. The study concludes with the potential future trends, emerging technologies, and sustainable practices that give directions to policymakers. It will be a benefit to researchers, engineers, policymakers, and anyone interested in promoting sustainability and waste reduction in the construction industry. The chapter emphasizes the need for sustainable alternatives. The real-world case studies will be discussed from different regions and industries, offering valuable insights into successful waste utilization projects
Holistic review of agricultural wastes used as supplementary cementitious materials in cement-based materials
No full textConcrete is the most consumed construction material owing to its vast applicability, durability, and low cost. However, the carbon footprint of cement, the main binder in concrete, is concerning. Hence, the need for low-carbon substitutes is urgent. Agricultural waste materials that can serve as supplementary cementitious materials have been identified as a possible option. In this chapter, a holistic overview of the characteristics, properties, and performance of agricultural waste materials serving as supplementary cementitious materials in cement-based materials, such as mortar and concrete, is presented. Agro-waste materials covered are sugarcane bagasse ash, rice husk ash, corn-cob ash, palm oil fuel ash, paper pulp ash, groundnut husk ash, bamboo leaf ash, coconut shell ash, cassava peel ash, and wood/sawdust ash. The performance of cement-based materials at optimum content is presented. If the agro-wastes are well processed, they could serve as supplements for cement in cement-based materials with comparable performance to the control concrete mixture.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mechanical performance of engineered cementitious composites incorporating recycled glass powder
Full text linkEngineered cementitious composite (ECC) is conventionally made up of high content fly ash (FA) combined with Portland cement (PC) as a binder. However, the growing call for sustainability is leading to continuous decommissioning of various coal power plants around the world thereby limiting the supply of fly ash available for ECC production. Therefore, it is of high importance to find alternative materials that can be incorporated into ECC as a partial replacement of the conventional binders. This experimental investigation was carried out to investigate the feasibility of incorporating glass powder (GP) as binder into ECC mixtures. The mechanical performance in terms of its compressive, tensile, and flexural properties was evaluated. Results from this study showed that 25% FA can be replaced with GP without any significant reduction in the mechanical performance of ECC mixtures. Microstructural investigations of the mixtures incorporating GP show good bonding between the cementitious matrix and the fibres.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Overview of the Mechanical Properties of Concrete Incorporating Waste From the Concrete Industry as Aggregate
Full text linkMillions of tons of construction and demolitions wastes (CDW) are generated annually by the concrete industry, and these wastes most times end up in landfills where they contaminate the environment. As the global demand for concrete increases with a consequential increase in the consumptions of its components, the use of alternative materials as components in concrete will create a pathway to meet the future demand for concrete. One of the sustainable way forward is replacing the most voluminous component of concrete (i.e. aggregates) with CDW. However, in order to use CDW as aggregate, it needs to undergo processing which turns it into recycled aggregate. Mechanical properties of concrete are greatly affected by the components in concrete, and the replacement of natural aggregates with processed CDW is expected to alter the resulting properties of concrete. Though there are several contradicting conclusions in the literature which might be as a result of different sources and properties of CDW (i.e. recycled aggregate) used. This overview showed that processed CDW can be used successfully as aggregate in concrete to achieve similar/higher strength compared to those made with natural aggregate. But the proper treatment of the recycled aggregate and/or additions such as incorporation of supplementary cementitious materials have to be made. Also, the use of alternate binders such as alkali-activated materials with recycled aggregate can be used to achieve enhanced mechanical properties. In conclusion, the use of these wastes as aggregates in concrete will help to prevent more exploitation of natural deposits of aggregates alongside with reducing the overall cost of the concrete
Use of Rice Husk in Concrete: Review of Mechanical Properties
Full text linkRecently, there has been huge interest in the use of supplementary cementitious materials (SCMs) as a partial replacement for ordinary Portland cement (OPC) in concrete. This urge to replace OPC is due to the high carbon dioxide emitted into the environment during its production. Rice husk ash (RHA) is one of the types of SCM that can be used to replace OPC in concrete, and it is the waste product of rice production. This paper presents a detailed and recent review of the mechanical properties reported by various studies. It was concluded that with the right proportion of RHA incorporated into concrete, enhanced mechanical properties can be achieved. In addition, the use of RHA in concrete reduces the overall embodied carbon of the concrete, while reducing cost and utilizing waste generated by the agricultural industry
Sustainability and Performance Improvement of Engineered Cementitious Composites
Full text linkEngineered cementitious composites (ECCs) are special types of fibre-reinforced cementitious composites (FRCC) with higher strain capacity which can be achieved with low fibre volume as low as 2% and total elimination of coarse aggregates. Due to the outstanding performance of ECCs, they are suitable for various construction and repair applications. However, in order for ECCs to achieve their properties; a high amount of binder which is primarily composed of Portland cement (PC) is used alongside a special type of ultrafine silica sand (USS) which is different from the conventional natural fine aggregates. The production of PC is known to be detrimental to the environment due to its high carbon dioxide emissions coupled with the high consumption of natural resources. Thus, the high use of PC content in ECCs posed a sustainability threat. Similarly, the USS used in ECCs are not readily available everywhere and are expensive. The processing of the USS coupled with its transportation over long distances would also increase the cost and embodied carbon of ECCs. Hence, in order to promote more development and applications of ECCs for various applications; this dissertation aims to provide innovative ways to improve the sustainability of ECCs and their performances. This dissertation offers four solutions to improve the sustainability of ECCs which are (i) use of unconventional industrial by-products as partial replacement of PC (ii) total replacement of PC in ECCs with alternative sustainable binders (iii) replacement of USS in ECCs with recycled materials and (iv) the use of supplementary cementitious materials to replace a high volume of PC. The findings from this study revealed sustainable ECCs with acceptable mechanical and durability performance can be achieved with the use of alternative binders or replacement of the conventional USS used in ECC mixtures. The sustainability and cost assessment of the ECCs indicated that the incorporation of industrial by-products such as blast furnace slag (BFS) especially at higher content is beneficial to reducing the negative environmental impact and economic burden associated with ECCs compared to the conventional ECC. The sustainability index and cost index of the ECCs further showed that the use of BFS is more beneficial when the sustainability and cost of the ECCs are compared with the corresponding performance. Similarly, the use of recycled materials as an alternative to USS was found to result in a significant reduction in the embodied carbon and cost of ECCs. The use of recycled materials such as expanded glass (EG) as aggregates in ECCs was also found to improve the thermal insulation properties of ECCs making such ECC suitable for the production of building envelope elements
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