scholarly journals Optimizing the usage of fly ash in concrete mixes

2017 ◽  
Author(s):  
◽  
Sabelo N. F. Zulu
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
South African ◽  
Drying Shrinkage ◽  
Cost Comparison ◽  
Ordinary Concrete ◽  
Air Content ◽  
Cement And Concrete ◽  
One Year ◽  
The Cost

Improving on our construction practices to promote sustainable development in engineering and to promote eco-friendly living is vital in the fight against global warming and associated problems. This study looked at one of the ways in which engineering can contribute to this fight through promoting the recycling of waste by-products such as fly ash (FA), on a larger scale in the cement and concrete industry, by utilizing the FA to the optimum. In this study concrete mixes of 25 MPa, 35 MPa and 50 MPa with FA partially substituting the cement at 30%, 40%, 50% and 60% were produced and numerous tests were performed to determine the optimum amount of FA that can be used and still obtain better or comparable concrete to ordinary concrete. Testing for concrete properties was conducted under laboratory conditions over a period of one year. In addition, a cost comparison between ordinary concrete and FA concrete was undertaken. The results obtained show that the increase in FA content influenced the rheological properties of fresh concrete favorable. The recorded slump increased with the increase of FA content. Increasing the FA content prolonged the setting of concrete, with the ordinary concrete taking 1 hour 45 min to set, compared to more than 2 hours for FA mixes. The FA increase had negligible effects on the air content of the concrete mixes. The drying shrinkage of concrete increased with the increase of FA content, with the strain ranging from 0,045% to 0,56%. The compressive strength results show that the control mixes with 30% FA content attained the highest compressive strength over a year. In some cases, the 40% FA strength was compatible to the 30% FA strength. The durability index results showed the control mix of 30% FA attaining better results for Oxygen Permeability Index and Sorptivity Index, with the 40% FA mix following closely. The higher FA content mixes (50% and 60%) attained better Chloride Conductivity results than the lower FA content mixes. Increasing the FA content does affect the performance of the concrete at early stages, however concrete with acceptable strength and good durability qualities can be produced even with 50% FA volume. Increasing the FA content can also significantly reduce the cost of producing and working with concrete. The practice of utilizing higher FA content in concrete can be beneficial for the South African cement and concrete industry without compromising the quality of the cement products concrete structures.

scholarly journals Valorization of Crushed Glass as a Potential Replacement for Sand in Cement Stabilized Fly Ash Bricks

2019 ◽  
Vol 15 (1) ◽  
pp. 48-57 ◽  
Author(s):  
R. Saraswathy ◽  
Jijo James ◽  
P. Kasinatha Pandian ◽  
G. Sriram ◽  
J. K. Sundar ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Optimal Combination ◽  
Maximum Strength ◽  
Cost Comparison ◽  
Fine Aggregate ◽  
Control Specimen ◽  
The Cost ◽  
Sand Stabilized

AbstractThe present study involved the utilization of crushed glass as an auxiliary additive in the manufacture of cement stabilized fly ash (CSF) bricks. The bricks were made with 1:1 proportion of fly ash and sand stabilized with 20 % cement. Crushed glass was used as replacement for the fine aggregate in increments of 10 % up to 40 % wherein the sand was completely replaced with crushed glass. The various mix proportions were then moulded into bricks with the addition of water by hand moulding method of forming the bricks and sun dried followed by sprinkle curing over a period of 21 days. The bricks were then subjected to compressive strength, water absorption and efflorescence tests to gauge its performance. The investigation revealed that the addition of crushed glass to the brick mix resulted in an increase in strength of the bricks, however, the maximum strength achieved could not achieve the strength of the control specimen. But the strength was higher than the minimum strength recommended by Bureau of Indian Standards (BIS) for stabilized blocks as well as burnt bricks. It also reduced the water absorption marginally while no efflorescence was seen in any of the combinations. A cost comparison revealed that the optimal combination with crushed glass was able reduce the cost of the brick by 20 %.

Research on Improving the Durability of Fly Ash Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 626-629
Author(s):  
Hong Zhu Quan
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Drying Shrinkage ◽  
Drying Process ◽  
Air Drying ◽  
Damage Resistance ◽  
Fly Ash Concrete ◽  
Air Content ◽  
Binder Ratio ◽  
Freeze Damage

The purpose of this study was to improve the durability of fly ash concrete. As a result, by making fly ash concrete into non-air-entraining type and using durability improving admixture, the compressive strength of fly ash concrete increases 10%~30%, reducing initial compressive strength defects; drying shrinkage is controlled at 60% compared to when the mixture is not added; carbonation of fly ash concrete can be considered roughly proportional to water-cement ratio regardless of water-binder ratio or fly ash replacementratio; the freeze damage resistance improves for 2 weeks curing in air (drying process). Finally, by making fly ash concrete from non-air entraining type and using durability improving admixture, the difficulty of controlling air content in fly ash concrete is reduced and quality management is simplified.

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.

Effects of Elevated Temperatures on the Compressive Strength of HFCC

2011 ◽  
Vol 261-263 ◽  
pp. 416-420 ◽  
Author(s):  
Fu Ping Jia ◽  
Heng Lin Lv ◽  
Yi Bing Sun ◽  
Bu Yu Cao ◽  
Shi Ning Ding
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Relative Strength ◽  
Ordinary Concrete ◽  
Residual Compressive Strength ◽  
Fly Ash Concrete ◽  
The Relationship

This paper presents the results of elevated temperatures on the compressive of high fly ash content concrete (HFCC). The specimens were prepared with three different replacements of cement by fly ash 30%, 40% and 50% by mass and the residual compressive strength was tested after exposure to elevated temperature 250, 450, 550 and 650°C and room temperature respectively. The results showed that the compressive strength apparently decreased with the elevated temperature increased. The presence of fly ash was effective for improvement of the relative strength, which was the ratio of residual compressive strength after exposure to elevated temperature and ordinary concrete. The relative compressive strength of fly ash concrete was higher than those of ordinary concrete. Based on the experiments results, the alternating simulation formula to determine the relationship among relative strength, elevated temperature and fly ash replacement is developed by using regression of results, which provides the theoretical basis for the evaluation and repair of HFCC after elevated temperature.

scholarly journals PEMANFAATAN LIMBAH FLY ASH DARI PEMBAKARAN BATUBARA PADA PEMBUATAN SEMEN PCC (PORTLAND COMPOSITE CEMENT) DI PT SEMEN XYZ LAMPUNG

2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Dwi Septiyana Sari ◽  
◽  
Susanti Sundari
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Raw Materials ◽  
Testing Machine ◽  
Technical Aspect ◽  
Raw Material ◽  
Physical Test ◽  
Composite Cement ◽  
The Difference ◽  
The Cost

Abstract This study discusses the use of fly ash waste from coal burning on the manufacture of PCC (Portland composite cement) at PT. XYZ Lampung. The purpose of this research is to look at the technical studies and the efficiency of raw materials in the use of fly ash in cement making, in this case PCC cement (Portland Composite Cement). The steps taken in analyzing the data in this study were viewed from a technical aspect by means of a physical test, namely the cement compressive strength test at the age of 3 days, 7 days, and 28 days using the Compression Testing Machine. This test was conducted to see the comparison of the compressive strength of PCC cement using limestone and fly ash as raw materials, then calculate the difference in raw material costs in the year before and after the replacement of limestone with fly ash. The results showed that cement with the addition of fly ash after 3 days, 7 days and 28 days had an increased compressive strength value, which increased 21.69%, 16.07% and 8.05% respectively of the compressive strength of cement using limestone. The use of fly ash as a substitute for limestone has an effect on the cost of raw materials, where the difference between the cost of raw materials in 2019 and the cost of raw materials in 2018 is Rp. 39,440,952,074.

scholarly journals USE OF ZEOLITE IS ACTIVATED AS SUBSTITUTION OF CEMENT FOR PRICE AND COST

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Ahmad Nurfiki Alwi ◽  
Arif Rahman Setiaji ◽  
Abdurrohim Kurnia Agung ◽  
Abdul Halim
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Hypothesis Testing ◽  
Building Materials ◽  
Production Costs ◽  
Light Weight ◽  
Residential Community ◽  
High Production ◽  
The Cost ◽  
Cement Compounds

The number of economic needs is one of the fundamental aspects to support the survival of every individual in an area.  If seen in general, the cost of building the building and residential community still use building materials and installation costs are relatively higher.  With the advancement of technology has found a lightweight brick that has better strength, lighter, faster installation and environmentally friendly, so many people began to switch to using lightweight bricks.  For now the price of lightweight brick is still expensive, but this deficiency is covered with the speed of mounting and light weight so overall lightweight brick usage on certain patterns is very profitable.  The use of cement on lightweight bricks leads to high production costs.  With the above problems we have a breakthrough to replace the cement by using zeozolites containing silica compounds that resemble one of the cement compounds.  In this research, cement replacement with Zeolite is 20%, 40% and 60%.  Before use Zeolite was first activated using Fly Ash ratio of 65% Zeolite: 35% Fly Ash and 50% Zeolite: 50% Fly Ash, also activated using Ca (OH) 2 ratio 65% Zeolite: 35% Ca (OH) 2  And 50% Zeolite: 50% Ca (OH) 2.  Thus, there are 15 compositions including the control composition, each composition will be made up of 10 specimens.  Hypothesis testing using two way anova, tested is the effect of cement change treatment with Zeolite and comparison of Zeolite composition with Fly Ash and Ca (OH) 2 to compressive strength, absorption and cost. Keywords: Zeolite, Cement, compressive strength, Cost

scholarly journals Ultra-high-performance concrete with local high unburned carbon fly ash

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Unburned Carbon ◽  
High Tech ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Cost

Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.

scholarly journals Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Hong-zhu Quan ◽  
Hideo Kasami
Keyword(s):  
Fly Ash ◽  
Experimental Studies ◽  
Drying Shrinkage ◽  
Replacement Ratio ◽  
Fly Ash Concrete ◽  
Air Content ◽  
Carbonation Resistance ◽  
Binder Ratio ◽  
Water Binder Ratio

In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

scholarly journals 2694. Incidence of Pneumocytis jiroveci (PJP) Infection with 3-Month Prophylaxis of Aerosolized Pentamidine (AP) in Autologous Hematopoietic Stem Cell Transplantation (HSCT)

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S947-S947
Author(s):  
Sarah Perreault ◽  
Dayna McManus ◽  
Rebecca Pulk ◽  
Jeffrey E Topal ◽  
Francine Foss ◽  
...  
Keyword(s):  
Cost Savings ◽  
Cost Comparison ◽  
High Dose ◽  
Potential Cost ◽  
Hematopoietic Stem ◽  
Increased Risk ◽  
One Year ◽  
Relapsed Disease ◽  
The Cost ◽  
Autologous Hsct

Abstract Background HSCT patients are at an increased risk of developing PJP after transplant due to treatment induced immunosuppression. Given the risk of cytopenias with co-trimoxazole, AP is utilized as an alternative for PJP prophylaxis. A prior study revealed a 0% (0/19 patients) incidence when AP prophylaxis was given for one year post autologous HSCT. Current guidelines recommend a duration of 3 – 6 months for PJP prophylaxis in autologous HSCT. The primary endpoint of this study was to assess the incidence of PJP infection within one year post autologous HSCT in patients who received 3 months of AP. Secondary endpoint was a cost comparison of 3 months compared with 6 months of AP. Methods A single-center, retrospective study of adult autologous HSCT patients at Yale New Haven Hospital between February 2013 and December 2017 was performed. Patients were excluded if: <18 years of age, received < or >3 months of AP, changed to alternative PJP prophylactic agent or received no PJP prophylaxis, received tandem HSCT, deceased prior to one year post-transplant from a non PJP-related infection, HIV positive, or lost to follow-up. Pentamidine was given as a 300 mg inhalation monthly for 3 months starting Day +15 after autologous HSCT. Results A total of 288 patients were analyzed, no PJP infections occurred within one year post HSCT. Additionally, 187 (65%) patients received treatment post HSCT with 135/215 (63%) receiving maintenance immunomodulatory drugs for myeloma and 40/288 (14%) patients developing relapsed disease. 43% of the chemotherapy regimens for relapsed disease included high dose corticosteroids. The cost difference of using 3 months vs. 6 months of AP is $790, reflecting the cost of drug and its administration. Applying our incidence of 0%, potential cost savings of 3 months vs. 6 months of AP would be $330,000 over 5 years or $66,000 per year. Conclusion Three months of AP for PJP prophylaxis in autologous HSCT patients is safe and effective as well as cost-effective compared with a 6 month regimen. Disclosures All authors: No reported disclosures.

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