scholarly journals Reliability of Unconventional Concrete: Improvement in Mix Design and Addition of Bacterial Admixture

2021 ◽  
Vol 9 (11) ◽  
pp. 136-149
Author(s):  
Burhan Afzal
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Bacillus Subtilis ◽  
Silica Fume ◽  
Carbon Dioxide Emissions ◽  
Substantial Reduction ◽  
Bacillus Sphaericus ◽  
Industrial Wastes ◽  
Engineering Properties ◽  
Environmental Damage

Abstract: Portland cement is used by the construction industries, which is known to be a heavy contributor of carbon dioxide emissions and environmental damage. Adding of industrial wastes like demolished old concrete OF structures, silica fume (SF) fly ash (FA) as additional cementing materials (SCMs) could result in a substantial reduction of the overall Carbon dioxide trace marks of the final concrete product. Use of these additional materials in construction industry especially in the making of concrete is highly challenging. Remarkable research efforts are needed to study about the engineering properties of concrete incorporating such industrial wastes. Present research is an effort to study the properties of concrete adding industrial wastes such as demolished concrete, FA and SF The improvement of properties of RCA concrete with the incorporation of two ureolytic-type bacteria, Bacillus subtilis and Bacillus sphaericus to improve the properties of RCA concrete. The experimental investigations are carried out by experts evaluate the improvement of the compressive strength, capillary water absorption and drying shrinkage of RCA concrete adding bacteria. Seven concrete mixes are manufactured using Portland slag cement (PSC) partially changed with SF ranging from 0 to 30%. The mix proportions were obtained as per Indian standard IS: 10262-2009 with 10% extra cement when SF is taken as per the above the construction practice by experts. Optimal dosages of SF for maximum values of compressive strength, tensile splitting strength and flexural strength at 28 days are determined. Keywords: Bacillus subtilis, Bacillus sphaericus, RCA, PSC, Silica Fume.

scholarly journals Drivers of CO2-Emissions in Fossil Fuel Abundant Settings: (Pooled) Mean Group and Nonparametric Panel Analyses

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3956 ◽  
Author(s):  
Elkhan Richard Sadik-Zada ◽  
Wilhelm Loewenstein
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Environmental Kuznets Curve ◽  
Fixed Effects ◽  
Fossil Fuel ◽  
Substantial Reduction ◽  
Resource Curse ◽  
Time Interval ◽  
Kuznets Curve ◽  
Per Capita

The present inquiry addresses the income-environment relationship in oil-producing countries and scrutinizes the further drivers of atmospheric pollution in the respective settings. The existing literature that tests the environmental Kuznets curve hypothesis within the framework of the black-box approaches provides only a bird’s-eye perspective on the long-run income-environment relationship. The aspiration behind this study is making the first step toward the disentanglement of the sources of carbon dioxide emissions, which could be employed in the pollution mitigation policies of this group of countries. Based on the combination of two strands of literature, the environmental Kuznets curve conjecture and the resource curse, the paper at hand proposes an augmented theoretical framework of this inquiry. To approach the research questions empirically, the study employs advanced panel cointegration techniques. To avoid econometric misspecification, the study also employs for the first time a nonparametric time-varying coefficient panel data estimator with fixed effects (NPFE) for the dataset of 37 oil-producing countries in the time interval spanning between 1989 and 2019. The empirical analysis identifies the level of per capita income, the magnitude of oil rents, the share of fossil fuel-based electricity generation in the energy mix, and the share of the manufacturing sector in GDP as essential drivers of carbon dioxide emissions in the oil-rich countries. Tertiarization, on the contrary, leads to a substantial reduction of emissions. Another striking result of this study is that level of political rights and civil liberties are negatively associated with per capita carbon emissions in this group of countries. Furthermore, the study decisively rejects an inverted U-shaped income-emission relationship and validates the monotonically or exponentially increasing impact of average income on carbon dioxide emissions.

Development of Geopolymer Mortar from Metakaolin Blended with Agricultural and Industrial Wastes

2018 ◽  
Vol 766 ◽  
pp. 305-310 ◽  
Author(s):  
Chayanee Tippayasam ◽  
Sarochapat Sutikulsombat ◽  
Jamjuree Paramee ◽  
Cristina Leonelli ◽  
Duangrudee Chaysuwan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Chemical Properties ◽  
Cement Industry ◽  
Industrial Wastes ◽  
Engineering Properties ◽  
Alkali Solutions ◽  
Physical And Chemical

Geopolymer is a greener alternative cement produced from the reaction of pozzolans and strong alkali solutions. Generally, the cement industry is one of largest producers of CO2that caused global warming. For geopolymer mortar usage, Portland cement is not utilized at all. In this research, geopolymer mortars were prepared by mixing metakaolin, various wastes (fly ash, bagasse ash and rice husk ash) varied as 80:20, 50:50 and 20:80, 15M NaOH, Na2SiO3and sand. The influence of various parameters such as metakaolin to ashes ratios and pozzolans to alkali ratios on engineering properties of metakaolin blended wastes geopolymer mortar were studied. Compressive strength tests were carried out on 25 x 25 x 25 mm3cube geopolymer mortar specimens at 7, 14, 21, 28 and 91 air curing days. Physical and chemical properties were also investigated at the same times. The test results revealed that the highest compressive strength was 20% metakaolin - 80% fly ash geopolymer mortar. When the curing times increases, the compressive strength of geopolymer mortar also increases. The mixing of metakaolin and bagasse ash/rice husk ash presented lower compressive strength but higher water absorption and porosity. For FTIR results, Si-O, Al-O and Si-O-Na+were found. Moreover, the geopolymer mortar could easily plastered on the wall.

scholarly journals Composition and selected properties of low pH mortars and concretes for radioactive waste repositories

2020 ◽  
Vol 322 ◽  
pp. 01033
Author(s):  
An Cheng ◽  
Wei-Ting Lin ◽  
Sao-Jeng Chao ◽  
Hui-Mi Hsu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Silica Fume ◽  
Spent Nuclear Fuel ◽  
Cementitious Materials ◽  
Low Ph ◽  
Engineering Properties ◽  
Filling Materials ◽  
Radioactive Waste Repositories ◽  
Waste Repositories

Conventional cementitious materials as tunnel supporting materials are utilised in the construction of the final repository for spent nuclear fuel. However, the use of cementitious material releases alkaline ions from pH12 to pH13 plumed into groundwater. Such a high pH is detrimental to the performance of the bentonite functioning, which may possibly enhance the dissolution and alteration of the fracture buffer and filling materials. Instead, low-pH cementitious materials are being developed for use in geological repositories. This study is aimed at evaluating the usability of low-pH cementitious materials containing 40% silica fume or composites blended with 20% silica fume and 40% fly ash. Engineering properties were analysed and verified through experimental research using the flow, compressive strength, pH measurement and hydraulic conductivity. Test results show that the replacement level with 40% of silica fume or 20% of silica fume and 40% of fly ash was suitable for the mixture of low-pH cementitious. Compared to the compressive strength and water permeability of ordinary cementitious, those of low-pH cementitious enhanced better engineered performances at the age of 91 days. The information is contributed us to establish the long-term durability and environmental requirements of disposal repositories in Taiwan.

scholarly journals Social Roots of Global Environmental Change: A World-Systems Analysis of Carbon Dioxide Emissions

2003 ◽  
pp. 277-315 ◽  
Author(s):  
J. Timmons Roberts ◽  
Peter E. Grimes ◽  
Jodie L. Manale
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Fossil Fuels ◽  
Global Climate ◽  
Global Environmental Change ◽  
Ordinary Least Squares ◽  
Environmental Damage ◽  
Least Squares Regression ◽  
Economic Output ◽  
Stratification System

Carbon dioxide is understood to be the most important greenhouse gas believed to be altering the global climate. This article applies world-system theory to environmental damage. An analysis of 154 countries examines the contribution of both position in the world economy and internal class and political forces in determining a nation's CO, intensity. CO, intensity is defined here as the amount of carbon dioxide released per unit of economic output. An inverted U distribution of CO, intensity across the range of countries in the global stratification system is identified and discussed. Ordinary Least Squares regression suggests that the least efficient consumers of fossil fuels are some countries within the semi-periphery and upper periphery, spe-cifically those nations which are high exporters, those highly in debt, nations with higher military spending, and those with a repressive social structure.

An Experimental Study on the Compressive Strength of Alccofine with Silica Fume Based Concrete

2016 ◽  
Vol 857 ◽  
pp. 36-40 ◽  
Author(s):  
Kumar S. Rajesh ◽  
Amiya K. Samanta ◽  
Dilip K. Singha Roy
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Industrial Waste ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Industrial Wastes ◽  
Cement Replacement ◽  
Cement Manufacture ◽  
Good Improvement ◽  
Compressive Strength Of Concrete

This investigation is focused on the physical and mechanical properties of Alccofine (AF) incorporating silica fume (SF) on M20 grade concrete. Normally, these industrial wastes (SF) are disposed off in landfill. The use of these industrial waste in concrete could reduce waste in the environment as well helps the environment against pollution as it is known that one ton of cement manufacture released one ton of carbon dioxide to the environment .Alccofine is a new replacement material on which very limited research has been done, its effect with flyash has been studied. The current study is a new experimental research undertaken to study the effect of alccofine on SF based concrete. Alccofine was varied in percentages of 0, 5, 10 and 15%, Silica fume was varied in percentages of 0, 5, 10, 15 % The aim of the investigation was to see the effect of alccofine on compressive strength of concrete and do a comparison on 7, and 28 days strength.The results showed that the cement replacement by 10% of alccofine gives higher values when compared with all other mix. The cement replacement by 10% alccofine gave a good improvement in compressive strength. Alccofine has the better performance when compare to the other slag material. It is helpful to make concrete workable

Drying Shrinkage of Fly Ash Mortar Mixed with Seawater

2015 ◽  
Vol 802 ◽  
pp. 118-123 ◽  
Author(s):  
John Wilmer Bautista ◽  
John Benedict Crockett ◽  
Beatrice Ann Liu ◽  
Timothy John Obra ◽  
Cheryl Lyne Roxas
Keyword(s):  
Carbon Dioxide ◽  
Compressive Strength ◽  
Fly Ash ◽  
Carbon Dioxide Emissions ◽  
Drying Shrinkage ◽  
Water Shortage ◽  
Ash Content ◽  
Partial Substitution ◽  
Partial Replacement ◽  
Micro Cracks

Drying shrinkage in mortar produces cracks and micro-cracks which affect the durability of a structure. The effects of seawater as a substitute to freshwater and fly ash as a partial replacement for cement were investigated in this study in order to address the predicted water shortage by 2025 and the increasing carbon footprint from carbon dioxide emissions worldwide. Moreover, these materials are also more economical alternatives to freshwater and cement. Rectangular prism specimens with varying fly ash content (10%, 15%, 20%, 25%, and 30%) were cast to measure the drying shrinkage in mortar while 50-mm cube mortar specimens were prepared to determine the compressive strength. This study investigated whether the addition of fly ash and seawater reduced the drying shrinkage of mortar. From the results, it was found that mortar specimens with 20% fly ash replacement achieved the highest early and late strengths. Partial substitution of fly ash would result to shrinkage in mortar while substitution of seawater to freshwater counteracts the effects of fly ash, thus producing less shrinkage. Fly ash content between 20%-25% combined with seawater produces the least shrinkage value without compromising the minimum required compressive strength.

scholarly journals Geopolymer Cements and Their Properties: A Review

2015 ◽  
Vol 61 (2) ◽  
pp. 85-100 ◽  
Author(s):  
Vladimír Živica ◽  
Martin T. Palou ◽  
Martin Križma
Keyword(s):  
Carbon Dioxide ◽  
Portland Cement ◽  
Carbon Dioxide Emissions ◽  
Construction Material ◽  
Industrial Sector ◽  
Engineering Properties ◽  
Cement Clinker ◽  
Chemical Action ◽  
Cement Production ◽  
Geopolymer Cements

Abstract Concrete is the world's most versatile, durable and reliable construction material. Next to water, concrete is the second most used substance on earth and it requires large quantities of Portland cement. The industrial sector is the third largest source of man-made carbon dioxide emissions after the transportation sector as the major generator of carbon dioxide, which pollutes the atmosphere. Ordinary Portland cement (OPC) production produces the largest amount of carbon dioxide amongst all industrial processes. In addition to that a large amount of energy is also consumed for the cement production. The production of OPC not only consumes a huge amount of the natural resources i.e. limestone and fossil fuels but also produces almost 0.9 t of CO2 for 1t of cement clinker production. Thus, the world cement production generates 2.8 billion tons of manmade greenhouse gas annually. Hence, it is inevitable to find an alternative material to the existing most expensive, most resource and energy consuming Portland cement. Geopolymer cements are innovative binders which can be produced by the chemical action of aluminosilicate materials plenty available worldwide. They are rich in silica and alumina reacting with alkaline solution and producing aluminosilicate gel that acts as the binding material for the concrete. Geopolymers are synthesized by polycondensation reaction of geopolymeric precursor and alkali polysilicates. The paper presents data on the important engineering properties of geopolymer cements showing that these cements offer an alternative to, and potential replacement for, OPC. Geopolymer technology also has the potential to reduce global greenhouse emissions caused by OPC production. Due to the high level of mechanical properties of geopolymer cements and their environmentally beneficial technology they appear as a prospective construction material for the future.

scholarly journals Study on Strength Properties of Concrete with Ceramic Waste Aggregate and Silica Fume Admixture

2018 ◽  
Vol 7 (3.12) ◽  
pp. 831
Author(s):  
Suresh G ◽  
Harishankar S
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Silica Fume ◽  
Coarse Aggregate ◽  
Strength Properties ◽  
Industrial Wastes ◽  
Conventional Concrete ◽  
Ceramic Waste ◽  
Compressive Strength Of Concrete

The ceramic waste is used as a coarse aggregate replacement in concrete is a two way beneficial process that involves minimization of resources for construction and processing of hazardous industrial wastes that cannot be recycled. The ceramic waste obtained from waste dismantled building were used as coarse aggregate 10%, 20%, 30%, 40% and 50% replacement.  To improve the mechanical properties silica fume is added as admixture in the concrete. The optimum percentage replacement was obtained considering the strength as well as the objective of using ceramic waste aggregate. The compressive strength of concrete cubes were tested . The compressive strength of aggregate replaced concrete has been compared to that of conventional concrete and the results are evaluated. 

scholarly journals A Systematic Review on the Performance Characteristics of Sustainable, Unfired Admixed Soil Blocks for Agricultural and Industrial Waste Management

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Tarun Sharma ◽  
Sandeep Singh ◽  
Parteek Singh Thind ◽  
Jasgurpreet Singh Chohan ◽  
Raman Kumar ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Systematic Review ◽  
Energy Consumption ◽  
Carbon Dioxide Emissions ◽  
Carbon Dioxide Emission ◽  
Performance Characteristics ◽  
Industrial Wastes ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Pull Out

Unfired admixed soil blocks are composed of standard soil and a stabilizer or reinforcement material in the form of binder and fiber. This literature review systematically examines the performance characteristics of unfired admixed soil blocks made by using binders such as cement, lime, and other agricultural and industrial wastes available in the form of fibers and ash. A systematic search was carried out on Web of Science and SCOPUS using different keywords, and 313 records were found. After the screening and eligibility process as per PRISMA guidelines, 36 papers were eligible and hence selected to be reviewed and analyzed. This paper examines the performance characteristics of the blocks in terms of physical properties, mechanical properties, durability, microstructural evaluation, statistical analysis, cost analysis, energy consumption, and carbon dioxide emission. It was found that of the total 9 parameters considered for discussion, most of the studies using different admixtures (binder and fibers) in soil blocks were focused on compressive strength testing of blocks, water absorption, and durability by wetting drying cycles. However, other parameters like bulk density, maximum dry density and optimum water content, thermal conductivity, tensile strength, and flexural strength examined in recent studies are also reported in this paper. This systematic review proposes some research problems to be worked on various additional parameters like linear shrinkage, pull out test, erosion test, sorptivity test, porosity, efflorescence, water permeability, freeze/thaw test, and analysis of energy consumption and carbon dioxide emissions during the manufacturing of unfired admixed soil blocks using various binders and fibers for further study which the current literature lacks.

scholarly journals The relationship of economic growth and carbon-dioxide emissions: an application on member countries of Organization of Islamic Cooperation

2021 ◽  
Vol 20 (4) ◽  
pp. 813-833
Author(s):  
Muhammed Veysel Kaya ◽  
Suat Serhat Yilmaz ◽  
Mehmet Gökhan Özdemir
Keyword(s):  
Economic Growth ◽  
Carbon Dioxide ◽  
Natural Resources ◽  
Carbon Dioxide Emissions ◽  
Carbon Dioxide Emission ◽  
Environmental Damage ◽  
Homogeneity Test ◽  
Annual Data ◽  
Causality Analysis ◽  
The Relationship

Motivation: Humanity has benefited from natural resources in production activities throughout history and this pressure on natural resources has increased even more with the efforts of industrialization. In this process, people benefited heavily from fossil fuels in their production and distribution activities, thereby damaging the environment and the atmosphere to a large extent. With the destruction of the environment, it has become important for the countries and the academic circles to measure environmental damage with the increase of economic activities in order to take various measures. Aim: At this point, in this study, the relationship between economic growth and carbon-dioxide emissions was examined within the scope of 50 countries that are members of the Organization of Islamic Cooperation (OIC). In this process, annual data of the countries concerned between 1995 and 2017 were used; Pedroni Cointegration Analysis, Granger Causality Analysis, Pooled Mean Group Estimator (PMGE) and Mean Group Estimator (MGE) methods were used to measure and estimate the relationship between these two variables. The causality analysis shows that the economic growth is the Granger cause of carbon-dioxide emissions in the country group studied. In addition, the coefficients obtained in PMGE and MGE analyzes were found as 0.43 and 0.33 and were statistically significant and positive. Then, with the help of Hausman Homogeneity Test, it was decided between the two estimators, and it concluded that PMGE Estimator is the more reliable estimator. Results: The results obtained with the PMGE estimator indicate that the 1% increase in economic growth increased carbon dioxide emission by 0.43%.

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