scholarly journals Optimal Cement Mixtures Containing Mineral Admixtures under Multiple and Conflicting Criteria

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Nitza M. García ◽  
Hildélix L. Soto-Toro ◽  
Mauricio Cabrera-Ríos ◽  
Oscar Marcelo Suárez
Keyword(s):  
Decision Making ◽  
Fly Ash ◽  
Construction Industry ◽  
Mineral Admixtures ◽  
Optimization Strategy ◽  
Objective Functions ◽  
Performance Measurements ◽  
Sustainable Concrete ◽  
Combined Use ◽  
Nanostructured Silica

In modern construction industry, fabrication of sustainable concrete has turned the decision-making process into a challenging endeavor. One alternative is using fly ash and nanostructured silica as cement replacements. In these modern mixtures, proper concrete bulk density, percentage of voids, and compressive strength normally cannot be optimized individually. Hereby, a decision-making strategy on the replacement of those components is presented while taking into account those three performance measurements. The relationships among those components upon concrete fabrication required a design of experiments of mixtures to characterize those mineral admixtures. This approach integrates different objective functions that are in conflict and obtains the best compromise mixtures for the performance measures being considered. This optimization strategy permitted to recommend the combined use of fly ash and nanosilica to improve the concrete properties at its early age.

Strength and microstructure behaviour of high calcium fly ash based sustainable geo polymer concrete

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vijaya Prasad B. ◽  
Arumairaj Paul Daniel ◽  
Anand N. ◽  
Siva Kumar Yadav
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Building Material ◽  
Polymer Concrete ◽  
Content Type ◽  
Sustainable Concrete ◽  
Binding Material ◽  
High Calcium ◽  
High Calcium Fly Ash

Purpose Concrete is a building material widely used for the infrastructural development. Cement is the binding material used for the development of concrete. It is the primary cause of CO2 emission globally. The purpose of this study is to develop sustainable concrete material to satisfy the present need of construction sector. Geopolymer concrete (GPC) is a sustainable concrete developed without the use of cement. Therefore, investigations are being conducted to replace the cement by 100% with high calcium fly ash (FA) as binding material. Design/methodology/approach High calcium FA is used as cementitious binder, sodium hydroxide (NaOH) and sodium silicates (Na2SiO3) are used as alkaline liquids for developing the GPC. Mix proportions with different NaOH molarities of 4, 6, 8 and 10 M are considered to attain the appropriate mix. The method of curing adopted is ambient and oven curing. Workability, compressive strength and microstructure characteristics of GPC are analysed and presented. Findings An increase of NaOH in the mix decreases the workability. Compressive strength of 29 MPa is obtained for Mix-I with 8 M under ambient curing. A polynomial relationship is obtained to predict the compressive strength of GPC. Scanning electron microscope analysis is used to confirm the geo-polymerisation process in the microstructure of concrete. Originality/value This research work focuses on finding some alternative cementitious material for concrete that can replace ordinary portland cement (OPC) to overcome the CO2 emission owing to the utilisation of cement in the construction industry. An attempt has been made to use the waste material (high calcium FA) from thermal power plant for the production of GPC. GPC concrete is the novel building material and alternative to conventional concrete. It is the ecofriendly product contributing towards the improvement of the circular economy in the construction industry. There are several factors that affect the property of GPC such as type of binder material, molarity of activator solution and curing condition. The novelty of this work lies in the approach of using locally available high calcium FA along with manufactured sand for the development of GPC. As this approach is rarely investigated, to prove the attainment of compressive strength of GPC with high calcium FA, an attempt has been made during the present investigation. Other influencing parameter which affects the strength gain has also been analysed in this paper.

scholarly journals Experimental Programme on FRC with OPC only and FRC with OPC and Mineral Admixtures

2019 ◽  
Vol 8 (4) ◽  
pp. 522-526
Keyword(s):  
Global Warming ◽  
Fly Ash ◽  
Construction Industry ◽  
Research Work ◽  
Mineral Admixtures ◽  
Fine Aggregate ◽  
River Sand ◽  
Natural Sand ◽  
Cement Production ◽  
Granulated Blast Furnace Slag

Due to urbanization and population growth, the Construction industry is increasing rapidly over a few decades at the same time leads to increase in global warming too. In the construction, the main ingredient, Concrete which contains large amount as cement which act as a binder and Natural sand(River sand) as fine aggregate .During the cement production large co2 emits, which is mainly responsible for global warming as well as natural sand leads to Environmental degradation. So, in order to minimize this phenomenon's as well as to enhance advancements in construction industry an attempt is made in this research work to replace the cement partially with supplementary materials known as mineral admixtures. The mineral admixtures such as Fly ash, Ground granulated blast furnace slag (GGBS) and Metakaolin which are by products of industries which usage in concrete as cement replacer decrease the co2 emissions as well as disposal problems of industries and replacing natural sand with M-sand Strength as well as durability properties of FRC (@1% steel fiber by weight of binder) made with 100% OPC with different water binder ratios and concrete grades M25 and M40 were found. And then FRC made with OPC and mineral admixtures up to 45% with fly ash, Metakaolin and GGBS in different combinations were tested for strength and subjected to durability tests. For comparison durability and strengths were performed on M40 grade mix without fibres. It is observed during the analysis of tests FRC with mineral admixtures has performed better than that of FRC made with 100% OPC.

Simulation Tool for Assignment Models: SIMASI

2014 ◽  
Vol 13 (8) ◽  
pp. 4723-4728
Author(s):  
Pratiksha Saxena ◽  
Smt. Anjali
Keyword(s):  
Optimization Procedure ◽  
Simulation Tool ◽  
Optimization Strategy ◽  
Performance Measurements ◽  
Integrated Simulation ◽  
Assignment Model ◽  
Classical Models ◽  
Simulation Results ◽  
User Friendly ◽  
Assignment Models

In this paper, an integrated simulation optimization model for the assignment problems is developed. An effective algorithm is developed to evaluate and analyze the back-end stored simulation results. This paper proposes simulation tool SIMASI (Simulation of assignment models) to simulate assignment models. SIMASI is a tool which simulates and computes the results of different assignment models. This tool is programmed in DOT.NET and is based on analytical approach to guide optimization strategy. Objective of this paper is to provide a user friendly simulation tool which gives optimized assignment model results. Simulation is carried out by providing the required values of matrix for resource and destination requirements and result is stored in the database for further comparison and study. Result is obtained in terms of the performance measurements of classical models of assignment system. This simulation tool is interfaced with an optimization procedure based on classical models of assignment system. The simulation results are obtained and analyzed rigorously with the help of numerical examples. 

scholarly journals Effect of Mineral Admixtures on the Performance of Low-Quality Recycled Aggregate Concrete

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 596
Author(s):  
Yasuhiro Dosho
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mineral Admixtures ◽  
Structural Concrete ◽  
Aggregate Concrete ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could be improved by varying the replacement ratio of the recycled aggregate and using appropriate mineral admixtures such as fly ash and ground granulated blast-furnace slag. The results show the potential for the use of low-quality aggregate in structural concrete.

scholarly journals Uptake of Childcare Arrangements—Grandparental Availability and Availability of Formal Childcare

2021 ◽  
Vol 10 (2) ◽  
pp. 50
Author(s):  
Naomi Biegel ◽  
Karel Neels ◽  
Layla Van den Berg
Keyword(s):  
Decision Making ◽  
Informal Care ◽  
Regression Models ◽  
Local Level ◽  
Formal Care ◽  
Multinomial Regression ◽  
Contextual Data ◽  
Care Arrangement ◽  
Combined Use ◽  
Formal Childcare

Grandparents constitute an important source of childcare to many parents. Focusing on the Belgian context, this paper improves our understanding of childcare decision-making by investigating how formal childcare availability and availability of grandparents affect childcare arrangements. By means of multinomial regression models we simultaneously model uptake of formal and informal childcare by parents. Combining linked microdata from the Belgian censuses with contextual data on childcare at the level of municipalities, we consider formal childcare availability at a local level, while including a wide array of characteristics which may affect grandparental availability. Results indicate that increasing formal care crowds-out informal care as the sole care arrangement, whereas combined use of formal and informal care becomes more prevalent. Characteristics indicating a lack of grandmaternal availability increase uptake of formal care and inhibit to a lesser extent the uptake of combined formal and informal care. While increasing formal care substitutes informal care use, the lack of availability of informal care by grandparents may be problematic, particularly for those families most prone to use informal care.

scholarly journals Significance of properly proportioned fly ash based blended cement for sustainable concrete structures of tannery industry

Structures ◽  
2021 ◽  
Vol 29 ◽  
pp. 1898-1910
Author(s):  
Samira Mahmud ◽  
Tanvir Manzur ◽  
Samina Samrose ◽  
Tafannum Torsha
Keyword(s):  
Fly Ash ◽  
Concrete Structures ◽  
Blended Cement ◽  
Sustainable Concrete ◽  
Tannery Industry

scholarly journals Effect of Fly Ash on Compressive Strength, Drying Shrinkage, and Carbonation Depth of Mortar with Ferronickel-Slag Powder

2021 ◽  
Vol 11 (3) ◽  
pp. 1037
Author(s):  
Se-Jin Choi ◽  
Ji-Hwan Kim ◽  
Sung-Ho Bae ◽  
Tae-Gue Oh
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Bituminous Coal ◽  
Raw Materials ◽  
Drying Shrinkage ◽  
The Other ◽  
Test Results ◽  
Slag Powder ◽  
Ferronickel Slag

In recent years, efforts to reduce greenhouse gas emissions have continued worldwide. In the construction industry, a large amount of CO2 is generated during the production of Portland cement, and various studies are being conducted to reduce the amount of cement and enable the use of cement substitutes. Ferronickel slag is a by-product generated by melting materials such as nickel ore and bituminous coal, which are used as raw materials to produce ferronickel at high temperatures. In this study, we investigated the fluidity, microhydration heat, compressive strength, drying shrinkage, and carbonation characteristics of a ternary cement mortar including ferronickel-slag powder and fly ash. According to the test results, the microhydration heat of the FA20FN00 sample was slightly higher than that of the FA00FN20 sample. The 28-day compressive strength of the FA20FN00 mix was approximately 39.6 MPa, which was higher than that of the other samples, whereas the compressive strength of the FA05FN15 mix including 15% of ferronickel-slag powder was approximately 11.6% lower than that of the FA20FN00 mix. The drying shrinkage of the FA20FN00 sample without ferronickel-slag powder was the highest after 56 days, whereas the FA00FN20 sample without fly ash showed the lowest shrinkage compared to the other mixes.

scholarly journals An Alternative to Clay in Building Materials: Red Mud Sintering Using Fly Ash via Taguchi’s Methodology

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Suchita Rai ◽  
Dilip H. Lataye ◽  
M. J. Chaddha ◽  
R. S. Mishra ◽  
P. Mahendiran ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Industry ◽  
Red Mud ◽  
Morphological Analysis ◽  
Building Materials ◽  
Sintering Temperature ◽  
Bauxite Residue ◽  
Significant Parameter ◽  
Alkaline Waste ◽  
Free Caustic Soda

“Red mud” or “bauxite residue” is a highly alkaline waste generated from alumina refinery with a pH of 10.5–12.5 which poses serious environmental problems. Neutralization or its treatment by sintering in presence of additives is one of the methods for overcoming the caustic problem as it fixes nearly all the leachable free caustic soda present in red mud. In the present study, feasibility of reducing the alkaline nature of red mud by sintering using fly ash as an additive via Taguchi methodology and its use for brick production, as an alternative to clay, is investigated. The analysis of variance (ANOVA) shows that sintering temperature is the most significant parameter in the process. A pH of 8.9 was obtained at 25–50% of red mud and 50–75% fly ash with water and temperature of . Alternatively 50% of red mud can be mixed with 50% of fly ash with water at temperature of to get a pH of about 8.4. The mechanism of this process has been explained with also emphasis on chemical, mineralogical, and morphological analysis of the sintered red mud. The results would be extremely useful in utilization of red mud in building and construction industry.

Effects of Fly Ash and Granular Blast-Furnace Slag on Development Rate of Strength of Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 371-375
Author(s):  
Ji Wei Cai ◽  
Si Jia Yan ◽  
Gong Lei Wei ◽  
Lu Wang ◽  
Jin Jin Zhou
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Development Rate ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Conventional Concrete ◽  
Enhancing Effect ◽  
Substitution Content ◽  
Furnace Slag

Fly ash (FA) and granular blast-furnace slag (GBFS) are usual mineral admixtures to conventional concrete, and their contents substituted for Portland cement definitely affect development rate of strength of concrete. C30 and C60 concrete samples with FA and/or GBFS were prepared to study the influence of substitution content of the mineral admixtures on 3 d, 7 d and 28 d strength. The results reveal that the development rate of strength in period from 3 d to 7 d gets slow with increasing content of mineral admixtures except for concrete with only GBFS less than 20%. In the case of substituting FA as the only mineral admixture for part of cement, the development rate of strength of C30 concrete in period from 7 d to 28 d keeps roughly constant even that of C60 concrete increases. When substituting mineral admixtures in the presence of GBFS for cement within experimental range, the development rate of strength in period from 7 d to 28 d gets fast with increasing substitution content. The enhancing effect of combining FA and GBFS occurs in period from 7 d to 28 d for both C30 and C60 concretes (FA+GBFS≤40%), even occurs in period from 3 d to 7 d for C60 concrete. Based on 7 d strength and the development rate, 28 d strength of concrete can be predicted accurately.

Alternative Concrete – Geopolymer Concrete

2021 ◽  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Industry ◽  
Building Material ◽  
Construction Materials ◽  
Raw Material ◽  
Geopolymer Concrete ◽  
Sustainable Solutions ◽  
New Construction ◽  
Alkali Activated

Concrete is the most versatile, durable and reliable material and is the most used building material. It requires large amounts of Portland cement which has environmental problems associated with its production. Hence, an alternative concrete – geopolymer concrete is needed. The general aim of this book is to make significant contributions in understanding and deciphering the mechanisms of the realization of the alkali-activated fly ash-based geopolymer concrete and, at the same time, to present the main characteristics of the materials, components, as well as the influence that they have on the performance of the mechanical properties of the concrete. The book deals with in-depth research of the potential recovery of fly ash and using it as a raw material for the development of new construction materials, offering sustainable solutions to the construction industry.

Sign in / Sign up

Export Citation Format

Share Document