scholarly journals Mass Concrete Placement of the Offshore Wind Turbine Foundation: A Statistical Approach to Optimize the Use of Fly Ash and Silica Fume

Author(s):  
Mien Van Tran ◽  
Vinh Ngoc Chau

AbstractThe experimental program investigated concrete with a large amount of fly ash (FA) with silica fume (SF) to replace Portland cement on the results of semi-adiabatic test, compressive strength test, and the rapid chloride permeability test (RCPT). The replacement ratios of cement by a combination of FA and SF were 30%, 35%, and 40% by mass. The percentages of SF to replace cement were 0%, 4%, and 8% by mass. Three different water-to-binder ratios (W/B) of 0.34, 0.36, and 0.38 were also investigated. Multiple linear regression was applied to construct the predicted equations (models) for the semi-adiabatic temperature rise test and the compressive strength test. Models were assessed statistically and were used to solve the concrete mixture design optimization problems. The mixture with W/B of 0.36, 31% FA, and 5% SF was found to optimally satisfy the multi-objective problem: 28-day compressive strength of 50 MPa, low heat of hydration, and very low chloride penetrability classification. Field test on the actual wind turbine foundation of the optimal mixture revealed the maximum temperature rise was 74.8 °C and the maximum temperature differential was 21.9 °C.

2020 ◽  
Vol 165 ◽  
pp. 03029
Author(s):  
Jiangong Yang

Through comparatively analyzing the impermeability and compressive strength test data of nano CaCO3 concrete with different content, this paper puts forward the method of optimizing the durability of nano CaCO3 concrete, and studies the influence of the content of fly ash on the durability of nano CaCO3 concrete on this basis, so as to provide a reference for improving the durability of concrete, so as to improve the recycling and reusing efficiency of building materials, and accelerate the practical application of nano CaCO3 concrete in engineering.


Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3344 ◽  
Author(s):  
Zhiyuan Zhou ◽  
Massoud Sofi ◽  
Elisa Lumantarna ◽  
Rackel San Nicolas ◽  
Gideon Hadi Kusuma ◽  
...  

To address sustainability issues by facilitating the use of high-volume fly ash (HVFA) concrete in industry, this paper investigates the early age hydration properties of HVFA binders in concrete and the correlation between hydration properties and compressive strengths of the cement pastes. A new method of calculating the chemically bound water of HVFA binders was used and validated. Fly ash (FA) types used in this study were sourced from Indonesia and Australia for comparison. The water to binder (w/b) ratio was 0.4 and FA replacement levels were 40%, 50% and 60% by weight. Isothermal calorimetry tests were conducted to study the heat of hydration which was further converted to the adiabatic temperature rise. Thermo-gravimetric analysis (TGA) was employed to explore the chemically bound water (WB) of the binders. The results showed that Australian FA pastes had higher heat of hydration, adiabatic temperature rise, WB and compressive strength compared to Indonesian FA pastes. The new method of calculating chemically bound water can be successfully applied to HVFA binders. Linear correlation could be found between the WB and compressive strength.


Author(s):  
A Aswani and Janardhan G

In construction world concrete plays a vital role, around 60% of structure consists of Concrete. However, the production of Portland cement, an essential constituent of concrete, leads to the release of significant amounts of CO2, depletion of natural resources and environmental degradation. This paper investigates the compressive strength of concrete by replacing cement with GGBS and silica fume effect of glass fibers on performance of concrete is studied. In this present work a humble attempt had been made to evaluate and compare the compressive strengths of GGBS blended concrete cubes with controlled concrete cubes cured under sea water for 28 days. By conducting the tests on the cubes, conclusions were drawn after plotting and analyzing the results. Compressive strength test is conducted on the samples after 28 days. The optimum value is obtained at 15% replacement with GGBS and 5% with Silica fume. In this study again we trailed addition with Glass fibers with the percentage of 0.5%,1.0%,1.5%, compressive strength have been studied. Finally at 1.0% addition we get maximum strength compared to controlled mix.


2015 ◽  
Vol 744-746 ◽  
pp. 628-631
Author(s):  
Yi Xiang Chen ◽  
Kai Xi An ◽  
Ke Xin Zhou ◽  
Chen Hao Xu

In order to reveal the effect of type of admixture and its content on the strength of stabilized soil, this paper uses the sludge as raw soil and cement, fly ash as curing agent, and analyzes the strength characteristics of samples mixed stabilized according to certain content. Using the unconfined compressive strength test, the compressive strength of the samples is tested. The effect of curing agent type and its content on the compressive strength is investigated. From the experimental results, it can be seen that the content of cement and fly ash has much effect on the strength. The conclusions obtained can have some conference values on the foundation treatment and reuse of waste resources utilization.


2018 ◽  
Vol 917 ◽  
pp. 297-302
Author(s):  
Jul Endawati ◽  
R. Utami ◽  
Rochaeti

Fly ash as a pozzolanic waste material can be utilized to substitute part of Portland cement in concrete mixture. The concrete paving industry utilizes the fly ash up to 50% (by weight) of the total binder. This study aims to obtain the characteristics of fly ash applications for pervious concrete. The composition of the binder developed based on the optimal proportion of fly ash from the previous study and the maximum of fly ash percentage used by the local paving industry in general. Other mix variations were made of the same binder composition with the addition of 6% of fine aggregates. The compressive strength of pervious concrete which binder composed of 63% portland cemet composite-25% fly ash-12% silica fume gained at 28 days, was not much different from the compressive strength of the pervious concrete without fine aggregate and with the binder composition of 50% FA-50% PCC and 0% SF. The value of the compressive strength test of the pervious concrete without fine aggregate is still within the range of compressive strength values ​​according to the ACI 522 R-10. The permeability rate of the pervious concrete is in the range of permeability research result of Chopra, 2013 (0.97 ÷ 1.90 cm/sec), but still higher compared to permeability rate gained by Dewoolkar, 2009 (0.83 ÷ 0.98 cm/sec).


2020 ◽  
Vol 2 (2) ◽  
pp. 145-152
Author(s):  
Murat Saydan ◽  
◽  
Nematullah Rahimi ◽  
Esra Yel ◽  
Ulku Sultan Keskin

Sulfate salts which available in seawater with high concentrations cause the formation of ettringite in hydrated structures which formed as a result of the hydration of cement. On the other hand, ettringite causes excessive volume expansions and eventually leads to cracking of the concrete due to the internal stresses in concrete since it is a large volume mineral structure. In this study, ultrafine cement and silica fume as mineral additive were used together for binder design. Besides, microfiber has been added to the binder systems produced in different proportions. The produced specimens were kept separately in water, in solutions containing 2% Na2SO4 and 2% MgSO4 by weight for 90 days. The compressive strength test was performed at 28th and 90th days on cured specimens. In addition to the compressive strength test, the solution samples were taken from the curing solutions every 10 days and the change of sulfate concentrations was followed in the solutions. According to the results, in Na2SO4 solution higher compressive strength values were observed up to 66 MPa while strength loss was observed in the specimens cured in the MgSO4 solution. In parallel to this result, the remaining concentrations of SO42- ions in the MgSO4 solution were lower than those in the Na2SO4 solution. It was inferred that in Na2SO4 solution, the fibers could compensate for the internal stresses. This situation shows that especially the microfiber additive can compensate for the expansion that will occur as a result of ettringite formation, and thus it can help the mechanical stability of the concrete.


2016 ◽  
Vol 1 (02) ◽  
Author(s):  
Krisna Adhitya Wardhana ◽  
Sri Purwati ◽  
Saepulloh , ◽  
Toni Rachmanto

Deinking sludge and coal fly ash are classified as hazardous wastes that have to be treated before disposed in landfill. Solidification is an alternative treatment to prevent hazardous materials release to the environment. The research was conducted to find solidification combination formula of deinking sludge and coal fly ash that pass compressive strength test (>10ton/m2) and paint filter test so it can be disposed to landfill. The concretes were made from cement and aggregate (50% deinking sludge and 50% fly ash) on range combination 1:11 - 1:20. In addition, based on pozzolanic characteristic of fly ash, concretes without cement was made. The results showed that solidification products with combination 1:11 - 1:20 have compressive strength that exceed the regulation and passed paint filter test. Combination of 50% deinking sludge and 50% coal fly ash without portland cement addition had compressive strength that met requirement for landfill disposal.Key words : deinking sludge, fly ash, solidification, landfill ABSTRAKDeinking sludge dan fly ash batubara termasuk kedalam kategori limbah B-3 yang harus diolah terlebih dahulu sebelum ditimbun di landfill. Proses solidifikasi adalah salah satu pengolahan untuk mencegah tersebarnya kandungan limbah B-3 ke lingkungan. Tujuan dari penelitian ini adalah menentukan formulasi solidifikasi kombinasi deinking sludge dengan fly ash batubara yang memenuhi persyaratan kuat tekan (> 10 ton/m2) dan uji paint filter sehingga dapat ditimbun di landfill. Penelitian ini dilakukan dengan variasi perbandingan semen terhadap agregat (50% fly ash dan 50% deinking sludge) mulai dari 1:11 sampai dengan 1:20 dan juga dilakukan perlakuan agregat tanpa semen. Hasil penelitian menunjukkan bahwa komposisi 1:11 s/d 1:20 memiliki nilai kuat tekan yang jauh melebihi persyaratan dan lolos uji paint filter. Sedangkan hasil dari perlakuan tanpa semen menunjukkan bahwa kombinasi 50% deinking sludge dan 50% fly ash batubara telah memiliki nilai kuat tekan yang cukup besar dan memenuhi persyaratan penimbunan di landfill.Kata kunci : deinking sludge, fly ash batubara, solidifikasi, landfill 


2013 ◽  
Vol 826 ◽  
pp. 187-191
Author(s):  
Qiang Li ◽  
Jin Huo ◽  
Zhi Jun Ma ◽  
Yuan Li ◽  
Jun Ce Wang ◽  
...  

The ultrafine powder composite admixture of fly ash and silica fume were researched in this article according to ultrafine powder fly ash and silica fume features.Through the different proportions of admixture strength test to determine the best ratio.The experimental results showed that appropriate admixture with 21.5%,12% of fly ash,8% of silica fume,1.5% of compound activator 28 days of flexural strength could be achieved 10.8Mpa,compressive strength could reach 54Mpa.


2015 ◽  
Vol 754-755 ◽  
pp. 400-405 ◽  
Author(s):  
Ridho Bayuaji ◽  
Muhammad Sigit Darmawan ◽  
Boedi Wibowo ◽  
Nur Ahmad Husin ◽  
Srie Subekti ◽  
...  

This study is conducted to determine the effect of four variables on compressive strength of geopolymer concretes. These four variables are binder/aggregate, Alkalinene/fly ash, effect of superplasticizer (SP) addition and curing system. The compressive strength is important mechanical properties for construction material. Taguchi experimental design method is used to compile the concrete composition of geopolymer to achieve the maximum compressive strength. Specimens concrete used is a cylinder with 100 mm diameter and 200 mm height. Compressive strength test is performed at 28 day using SNI 03-6825-2002, Indonesian National Standard. This study concludes that the chloride environment has a beneficial effect on the compressive strength of the concrete. In addition, the Alkalinene/fly ash ratio and binder/aggregate give a significant effect on the compressive strength of geopolymer concretes.


2020 ◽  
Vol 14 (1) ◽  
pp. 18
Author(s):  
Nahari Rasif ◽  
Indri Silvia Dewi ◽  
Nisya Aviani ◽  
Widya Utama

This study aims to determine how the properties of non-sand concrete with variations in the amount of mixing fly ash. This property was analyzed by compressive strength test. We also do calculations using the MATLAB application with interactive script methods. There are 16 numbers of test objects conducted in this study. The specimen is cylindrical with a size of 7.5 cm and a height of 15 cm. Flying ash variations used ranged from 0%, 25%, 50%, and 75%. In this research, we use 1: 6 between cement and gravel. The results of the average compressive strength obtained in the mixture of 0% fly ash are 1,172 MPa, 25% 0.871 MPa, 50% 2,367 MPa and 1,465 MPa for mixture of 75% fly ash. The best compressive strength results on the 50% fly ash mixture. The density is also affected by the mixing of this fly ash. The greater the mixing of the fly ash, the smaller the density value. Keywords: compressive strength, density, fly ash, MATLAB


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