Properties of Self-Compacting Geopolymer Concrete

2014 ◽  
Vol 803 ◽  
pp. 99-109 ◽  
Author(s):  
Muhd Fadhil Nuruddin ◽  
Fareed Ahmed Memon
Keyword(s):  
Construction Industry ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Raw Materials ◽  
Construction Material ◽  
Construction Materials ◽  
Cement Production ◽  
Cement Manufacture ◽  
The Moment ◽  
The Impact

Concrete has been used in the construction industry since long times. It is probably the most widely used construction material in the world, largely due to the abundance of the raw materials for cement manufacture, low relative cost and the versatility and adaptability of concrete in forming various structural shapes. Massive production of concrete and the associated substantial manufacture of cement have however been observed to have a very negative impact. One of the biggest issues of growing concern at the moment faced by concrete industries is the impact of cement production on the environment. The production of cement not only depletes significant amount of natural resources, but also liberates a considerable amount of carbon dioxide (CO2) and other greenhouse gases into the atmosphere as a result of decarbonation of limestone and the combustion of fossil fuels. In addition, cement is among the most energy intensive construction materials, after aluminium and steel [1].

scholarly journals Impact of the COVID-19 Pandemic on the Patient’s Decision about Bariatric Surgery: Results of a National Survey

Medicina ◽  
2021 ◽  
Vol 57 (8) ◽  
pp. 756
Author(s):  
Maciej Walędziak ◽  
Anna Różańska-Walędziak ◽  
Paweł Bartnik ◽  
Joanna Kacperczyk-Bartnik ◽  
Andrzej Kwiatkowski ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Online Survey ◽  
Negative Impact ◽  
Weight Loss Surgery ◽  
General Information ◽  
Open Questions ◽  
Increased Risk ◽  
Bariatric Patients ◽  
The Moment ◽  
The Impact

Background: the COVID-19 pandemic and the implemented restrictions have changed the functioning of healthcare systems worldwide. The purpose of the study was to evaluate the impact of the present epidemiological situation on patients’ decisions about undergoing weight loss surgery. Methods: data were collected from 906 bariatric patients by the means of a national online survey, the majority of whom were women (87.9%). The survey started on 9 April 2020 and was open until 28 April 2020. The questionnaire included multiple choice and open questions, divided into three chapters: general information about the patient, life during the COVID-19 pandemic, and bariatric care during the COVID-19 pandemic. Results: despite the pandemic and the associated risk of COVID-19 infection, 443 responders (48.9%) would have decided to undergo bariatric surgery. Awareness of the negative impact of obesity on the course of COVID-19 illness had only marginable impact on patients’ decision-making (76.6% vs. 75.3%; p < 0.80). Contact with COVID-19 prior to the survey had a negative impact on the willingness to undergo bariatric surgery (3.0% vs. 4.4%; p < 0.55). There was a positive correlation between the BMI and preference for bariatric surgery in the time of the pandemic (37.4 ± 9.0 vs. 34.9 ± 8.7; p < 0.001). Conclusions: the level of awareness about the advantages of operative treatment of obesity is high among bariatric patients. The majority of patients awaiting bariatric surgery at the moment of the survey were positive about undergoing bariatric surgery despite the increased risk of a serious course of COVID-19 infection. Therefore, a large proportion of patients was determined to have bariatric treatment even during the pandemic, being aware of the increased risk of worse pace of COVID-19 disease in case of obesity and related diseases.

scholarly journals Bio-based construction materials for a sustainable future

2019 ◽  
Author(s):  
Rijk Block ◽  
Barbara Kuit ◽  
Torsten Schröder ◽  
Patrick Teuffel
Keyword(s):  
Construction Industry ◽  
Structural Engineering ◽  
Building Materials ◽  
Raw Materials ◽  
Construction Materials ◽  
Flax Fibres ◽  
The Past ◽  
Natural Building ◽  
Paris Climate Agreement ◽  
Primary Materials

<p>The structural engineering community has a strong responsibility to contribute to a more efficient use of natural resources. Nowadays the construction industry is by far the most resource intense industry sector, approximately 40-50% of all primary raw materials are used, which raises the question about the architects and engineer’s accountability. In this context and as a result of the Paris Climate agreement the Dutch government defined the program “Nederland Circulair in 2050”, which states the ambition to use 50% less primary materials in 2030 and to have a full circular economy in 2050.</p><p>One possible approach to achieve these ambitious goals is the application of renewable, bio-based materials in the built environment and to replace traditional, typically cement-based, materials. Already in the past natural building materials, such as timber and bamboo have been used widely, but in recent years new materials came up and provide new opportunities to be used in the construction industry. The authors explored various alternatives, such as hemp and flax fibres, mycelium and lignin-based fibres for composite materials, which will be described with various experimental and realised case studies.</p>

Mediterranean Cropping Systems: The Importance of Their Economic and Environmental Sustainability

2021 ◽  
Vol 2 (4) ◽  
pp. 1-1
Author(s):  
Maria Pergola ◽  
◽  
Assunta Maria Palese ◽  
Alessandro Persiani ◽  
Pasquale De Francesco ◽  
...  
Keyword(s):  
Environmental Sustainability ◽  
Fossil Fuels ◽  
Raw Materials ◽  
Cropping Systems ◽  
Olive Tree ◽  
Well Being ◽  
C Sequestration ◽  
Agricultural Systems ◽  
The World ◽  
The Impact

The COVID-19 pandemic has drastically changed the lives of people, as well as the production and economic systems throughout the world. The flow of raw materials and products, the supply of labor and manpower, and the purchasing power have all been changed to the detriment of individual health and well-being. Such a situation requires placing even more emphasis on the search for virtuous agricultural systems compatible with the goals of economic and environmental development so clearly defined at the world level in the last decades. The present study aimed to assess the environmental and economic performance of some typical Mediterranean crops grown under different agronomical management regimes, such as strawberry, hazelnut, apricot tree, kiwifruit, peach, olive tree, and grapevine, to emphasize the importance of the mentioned issues even in the current pandemic situation. Life cycle assessment (LCA) was used to investigate the environmental profile of the studied crops, while lifecycle costing (LCC) was performed to assess and compare the economic aspects. From the environmental perspective, the hobby-organic olive systems were the most eco-friendly cropping systems, emitting 0.031 to 0.105 kg CO2eq per kg olives, while the organic hazelnut system had the greatest impact (1.001 kg of CO2eq per kg). Apricot, kiwifruit, and peach systems used N and P inputs most effectively, while strawberry systems efficiently used fossil fuels. Olive HO-2, kiwifruit, and peach cropping systems had the lowest budgets, with the costs amounted to 0.12 € kg-1 per fruit for Olive HO-2 and 0.28 € kg-1 per fruit for both kiwifruit and peach. On the contrary, organic strawberry cultivation was the most expensive (4.77 € kg-1). The variability in results due to the large differences between contexts, such as landscape, technical knowledge, and crop management, characterized the studied agricultural systems. To easily identify sustainability classes and to diminish the impact of farming practices, a considerable effort should be expended to combine LCA with LCC, C sequestration estimates, and some other useful indicators for the environmental quality evaluation.

scholarly journals An econometric analysis of the impact of the RDP on the demand for construction materials in South Africa

1999 ◽  
Vol 2 (3) ◽  
pp. 509-522
Author(s):  
Charles C. Okeahalam
Keyword(s):  
Construction Industry ◽  
South African ◽  
Econometric Model ◽  
Construction Materials ◽  
Efficient Production ◽  
Allocation Of Resources ◽  
African Government ◽  
Construction Activity ◽  
Supply Capacity ◽  
The Impact

The Reconstruction and Development Programme (RDP) is an attempt by the South African government to redress the imbalances of apartheid. It has many facets. One of these involves the provision and distribution of infrastructure to citizens who hitherto have been neglected. This calls for significant construction effort particularly for housing, water, roads and other social construction. This will require efficient production, and allocation of resources to ensure that there is adequate supply of materials to meet the likely increase in demand. This paper examines the expected demand for construction materials, assesses the supply capacity of South African suppliers of construction materials, and develops an econometric model which can be used to evaluate the impact that growth of the internal construction activity will have on construction industry suppliers.

scholarly journals The Durability of Concrete Modified by Waste Limestone Powder in the Chemically Aggressive Environment

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1693 ◽  
Author(s):  
Maja Kępniak ◽  
Piotr Woyciechowski ◽  
Paweł Łukowski ◽  
Justyna Kuziak ◽  
Rafał Kobyłka
Keyword(s):  
Negative Impact ◽  
Raw Materials ◽  
Desirability Function ◽  
Chloride Ion ◽  
Production Costs ◽  
Limestone Powder ◽  
Fine Aggregate ◽  
Concrete Technology ◽  
The Impact ◽  
Durability Of Concrete

The idea of sustainable development assumes that natural resources must be treated as limited goods and that waste must be managed rationally. This idea and the constant striving to reduce production costs make the use of waste materials as substitutes for traditionally used raw materials from non-renewable sources increasingly popular. In cement concrete technology, there are many possibilities to use waste as components of mortars and concretes. The subject of this paper is a fine-grained material, obtained as a by-product during the preparation of aggregate for mineral-asphalt mixtures. The aim of the research was to test the suitability of the selected type of powder, namely limestone powder, as a component of cement composites. The paper presents an evaluation of the potential of using the limestone powder as a substitute for the fine aggregate, focusing on the impact of such a modification on aspects of durability. The sulfate degradation and chloride ion diffusion in concrete were investigated. The overall desirability function has been determined. It was demonstrated that the satisfactory value of the general desirability can be attributed to most of the investigated concretes. Positive test results support the potential of replacing part of natural fine aggregate with the tested waste limestone dust without a negative impact on the durability of concrete.

EXPERIMENTAL STUDY ON RECYCLED CONCRETE WITH STEEL FIBERS AS A SUSTAINABLE BUILDING MATERIAL

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Olivia Mirza ◽  
Dane Wigg ◽  
Won Hee Kang ◽  
Sepani Senaratne ◽  
Vivian Tam ◽  
...  
Keyword(s):  
Natural Resources ◽  
Construction Industry ◽  
Construction Material ◽  
Experimental Studies ◽  
Recycled Concrete ◽  
Steel Fibers ◽  
Future Research ◽  
Sustainable Solutions ◽  
Structural Reinforcement ◽  
The Impact

The global demand for construction aggregate exceeds 26 billion tons per year. With global policy attention directed towards climate change, environmental and economic sustainability, changes are required to the Australian construction industry regarding the extraction of natural resources. In particular, the concrete industry requires seeking innovative, sustainable solutions for reducing the impact of construction and maintenance on the environment. The majority of structures in Australia use reinforced concrete. Therefore, using environmentally and economically sustainable materials such as recycled concrete in construction would preserve natural resources and reduce construction waste and overall costs. There is considerable research available on the use of recycled concrete as a construction material and the use of steel fibers as structural reinforcement has been studied since the 1960’s. However, there is very little research on the combination of the two as a construction material for concrete structures. This study focused on secondary beams made of recycled concrete with the incorporation of steel fibers. This combination offers a structurally sound material that will provide a durable and sustainable solution to Australian Construction Industry. Experimental studies were conducted to validate the performance of the new material in a structural application. Based on the results of the study, recommendations for future research and design applications using these materials are made.

Comparison of Mechanical Properties of Fly Ash Artificial Geopolymer Aggregates with Natural Aggregate

2015 ◽  
Vol 754-755 ◽  
pp. 290-295 ◽  
Author(s):  
Alida Abdullah ◽  
Ku Amirrul Rahman Ku Yin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin ◽  
Mien Van Tran
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Specific Gravity ◽  
Water Absorption ◽  
Raw Materials ◽  
Construction Materials ◽  
High Water ◽  
Natural Aggregate ◽  
Materials Used ◽  
The Impact

This study was conducted to compare the mechanical properties of fly ash artificial geopolymer aggregates with natural aggregate (rock) in term of its impact strength, specific gravity and water absorption.The raw materials used were fly ash, sodium hydroxide, sodium silicate and natural aggregate. After the artificial geopolymer aggregate has been produced, its water absorption, specific gravity and aggregate impact test has been done. All results obtained were compared to natural aggregate. The result shows that the fly ash geopolymer aggregate are lighter than natural aggregate in term of its specific gravity. The impact value for fly ash artificial geopolymer aggregate slightly high compared to natural aggregate while it has high water absorption value compared to natural aggregate. As conclusion, the fly ash artificial geopolymer aggregate can be used as one of the construction materials in concrete as an alternative for coarse aggregate besides natural aggregate with more lightweight properties.

Reuse of Municipal Wastewater Sludge for Construction Material

2010 ◽  
Vol 156-157 ◽  
pp. 939-942 ◽  
Author(s):  
Deng Ling Jiang ◽  
Guo Wei Ni ◽  
Guan Yi Ma
Keyword(s):  
Municipal Wastewater ◽  
Raw Materials ◽  
Construction Material ◽  
Construction Materials ◽  
Matter Content ◽  
Wastewater Sludge ◽  
Dry Matter Content ◽  
Sludge Disposal ◽  
Paper Wastewater ◽  
Feasible Alternative

Treatment of municipal wastewater results worldwide in the production of large amounts of sewage sludge. The major part of the dry matter content of this sludge consists of nontoxic organic compounds, in general a combination of primary sludge and secondary (microbiological) sludge. The sludge also contains a substantial amount of inorganic material and a small amount of toxic components. The large volume of wastewater sludge generated requires enormous landfill space for disposal. Diverting the wastewater sludge from landfill would alleviate the shortage of landfill sites. Thus alternative applications have to be considered for the wastewater sludge diverted away from the landfills. The use of wastewater sludge for the production of construction materials is reviewed in this paper. Wastewater sludge can be used as raw materials for making bricks, concrete filler and concrete aggregates. The study reveals that the reuse of wastewater sludge as construction materials offers a technically feasible alternative for sludge disposal.

scholarly journals Mutual effect of labour market development and COVID-19 pandemic progression

2021 ◽  
Vol 83 (1) ◽  
pp. 421-428
Author(s):  
N. V. Shishkina ◽  
E. A. Mamistova ◽  
T. V. Sabetova
Keyword(s):  
Labor Market ◽  
Negative Impact ◽  
Mutual Effect ◽  
The State ◽  
Social Consequence ◽  
Staff Retention ◽  
Current Events ◽  
The Moment ◽  
High Level ◽  
The Impact

This paper tackles the economic impacts of COVID-19 pandemic on the labor markets and human capital. Specifically, it looks into the issues the pandemic brought upon the human resources and personnel during coronavirus lockdowns. The high level of globalization characteristic of the modern economy has only exacerbated the negative impact of the pandemic. At the moment, it remains impossible to assess the qualitative and quantitative parameters of the damage caused to the economies of countries and regions by this event. However, it is possible to identify the main directions of analysis of the consequences of the pandemic, including in terms of the impact on the state of the labor market, which was the main goal of this study. In particular, the authors highlight a number of consequences, the work on overcoming which is still to be done by the Russian socio-economic system. The most obvious of them is the growth of unemployment, the release of part of the employed and the reduction in the number of jobs, and this is observed extremely unevenly across the sectors of the economy. Nevertheless, the authors point out that the problem of staff release is aggravated by the size of the share of informal employment in the labor market, especially in the sectors of public catering, leisure and tourism that have been most affected by the pandemic. As the second important problem, the authors point to ineffective staff reduction, the dismissal of useful and valuable employees of some organizations while maintaining an unnecessarily bloated staff of others. It also mentions the reasons and forms of staff retention, some of which, being either forced or economically and technologically attractive, give rise to additional problems. The authors call an important social consequence of the pandemic a reduction in the number and level of personal contacts in society, in particular, in working groups. As a result, the author's vision of the long-term consequences of current events for the state of the labor market, employment of the population and the economy as a whole is proposed.)

scholarly journals Metode Menentukan Klor dalam Sludge Oil: Perbandingan Metode Wet dan Metode Jena

2021 ◽  
Vol 10 (1) ◽  
pp. 1-7
Author(s):  
Herliati Rahman ◽  
Akhirudin Salasa
Keyword(s):  
Environmental Sustainability ◽  
Alternative Fuels ◽  
Negative Impact ◽  
Raw Materials ◽  
Cement Industry ◽  
Raw Material ◽  
Chlorine Content ◽  
Cement Production ◽  
Average Accuracy ◽  
The Difference

Currently, the use of alternative fuels and raw materials (AFR) in the cement industry is very attractive. This is driven by demands for environmental sustainability and the efficiency of fuel and raw material costs. One of the materials that can be used as AFR is sludge oil. However, it needs to be ensured that the chlorine content in the sludge oil does not exceed the threshold so that it does not have a negative impact during the cement production process. It is known that if the chlorine content is more than the threshold, it can cause blocking or clogging of the separator and the kiln. This study aims to determine the performance of the Jena Multi EA 4000 instrument in determining the chlorine content in sludge oil quickly and accurately. Analytic Jena Multi EA 4000 is an Atomic Absorption Spectrometers (AAS) instrument that can be used for analysis of samples in the form of solids or slurries containing chlorine. As validation of the resulting analysis, the wet method is used, which as usual, to determine chlorine levels. From the statistic analysis, namely the F-test and T-test, We found that F-count equal to 0.0080 and F-table equal to 4.2839. it shows that F-count < F-table, indicating the difference in the variance of the two methods H0: s12 = s22 is accepted because there is no difference to the variability of these two tests and the value of T-count = -3.9717 and T-table = 2.1788 so that T-count <T-table is accepted because there is no difference in the average accuracy of the two methods H0: M1 = M2.  

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