scholarly journals Chloride Induced Reinforcement Corrosion in Mortars Containing Coal Bottom Ash and Coal Fly Ash

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1933 ◽  
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Steel Corrosion ◽  
Chloride Diffusion ◽  
Chloride Ingress ◽  
Chloride Diffusion Coefficient ◽  
Coal Bottom Ash ◽  
Coal Ashes

Coal bottom ash is normally used as aggregate in mortars and concretes. When it is ground, its characteristics are modified. Therefore, the assessment of its long-term durability must be realized in depth. In this sense, an accelerated chloride ingress test has been performed on reinforced mortars made of Portland cement with different amounts of coal bottom ash (CBA) and/or coal fly ash (CFA). Corrosion potential and corrosion rate were continuously monitored. Cement replacement with bottom and fly ash had beneficial long-term effects regarding chloride penetration resistance. Concerning corrosion performance, by far the most dominant influencing parameter was the ash content. Chloride diffusion coefficient in natural test conditions decreased from 23 × 10−12 m2/s in cements without coal ashes to 4.5 × 10−12 m2/s in cements with 35% by weight of coal ashes. Moreover, the time to steel corrosion initiation went from 102 h to about 500 h, respectively. Therefore, this work presents experimental evidence that confirms the positive effect of both types of coal ashes (CBA and CFA) with regard to the concrete steel corrosion.

scholarly journals Ternary Mixes of Self-Compacting Concrete with Fly Ash and Municipal Solid Waste Incinerator Bottom Ash

2020 ◽  
Vol 11 (1) ◽  
pp. 107
Author(s):  
B. Simões ◽  
P. R. da Silva ◽  
R. V. Silva ◽  
Y. Avila ◽  
J. A. Forero
Keyword(s):  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Bottom Ash ◽  
Chloride Diffusion ◽  
Waste Incinerator ◽  
Chloride Diffusion Coefficient ◽  
Municipal Solid Waste Incinerator ◽  
Self Compacting Concrete ◽  
Solid Waste Incinerator

This study aims to evaluate the potential of incorporating fly ash (FA) and municipal solid waste incinerator bottom ash (MIBA) as a partial substitute of cement in the production of self-compacting concrete mixes through an experimental campaign in which four replacement levels (i.e., 10% FA + 20% MIBA, 20% FA + 10% MIBA, 20% FA + 40% MIBA and 40% FA + 20% MIBA, apart from the reference concrete) were considered. Compressive and tensile strengths, Young’s modulus, ultra-sonic pulse velocity, shrinkage, water absorption by immersion, chloride diffusion coefficient and electrical resistivity were evaluated for all concrete mixes. The results showed a considerable decline in both mechanical and durability-related performances of self-compacting concrete with 60% of substitution by MIBA mainly due to the aluminium corrosion chemical reaction. However, workability properties were not significantly affected, exhibiting values similar to those of the control mix.

scholarly journals Reactivity of Ground Coal Bottom Ash to Be Used in Portland Cement

J ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 223-232
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Blended Cement ◽  
Coal Ash ◽  
Pozzolanic Reaction ◽  
Natural Sand ◽  
Coal Bottom Ash ◽  
Novel Material ◽  
Pozzolanic Properties

Ground coal bottom ash is considered a novel material when used in common cement production as a blended cement. This new application must be evaluated by means of the study of its pozzolanic properties. Coal bottom ash, in some countries, is being used as a replacement for natural sand, but in some others, it is disposed of in a landfill, leading thus to environmental problems. The pozzolanic properties of ground coal bottom ash and coal fly ash cements were investigated in order to assess their pozzolanic performance. Proportions of coal fly ash and ground coal bottom ash in the mixes were 100:0, 90:10, 80:20, 50:50, 0:100. Next, multicomponent cements were formulated using 10%, 25% or 35% of ashes. In general, the pozzolanic performance of the ground coal bottom ash is quite similar to that of the coal fly ash. As expected, the pozzolanic reaction of both of them proceeds slowly at early ages, but the reaction rate increases over time. Ground coal bottom ash is a promising novel material with pozzolanic properties which are comparable to that of coal fly ashes. Then, coal bottom ash subjected to an adequate mechanical grinding is suitable to be used to produce common coal-ash cements.

Adsorption of Iron(II) from Acid Mine Drainage Contaminated Groundwater Using Coal Fly Ash, Coal Bottom Ash, and Bentonite Clay

2016 ◽  
Vol 227 (3) ◽  
Author(s):  
Emelda Obianuju Orakwue ◽  
Varinporn Asokbunyarat ◽  
Eldon R. Rene ◽  
Piet N. L. Lens ◽  
Ajit Annachhatre
Keyword(s):  
Fly Ash ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Bentonite Clay ◽  
Contaminated Groundwater ◽  
Coal Bottom Ash ◽  
Acid Mine

Influence of Fly Ash to Concrete Protecting Steel Corrosion Ability

2015 ◽  
Vol 744-746 ◽  
pp. 169-172 ◽  
Author(s):  
Qiao Yang ◽  
Xiao E Zhu
Keyword(s):  
Diffusion Coefficient ◽  
Fly Ash ◽  
Water Absorption ◽  
Permeability Coefficient ◽  
Corrosion Potential ◽  
Steel Corrosion ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Concrete Permeability ◽  
The Common

The compressive strengths of the concrete cubes added fly ash were increased 53.2%, the density was almost unchanged, but the water absorption was decreased 30%. The concrete permeability coefficient and chloride diffusion coefficient added fly ash were lower than the common concrete at all ages. The concrete specimens corrosion potential added fly ash were higher than-300mV, while common concrete almost were lower than-500mV. Corrosion probability was small and there was no crack and corrosion pot on the surface of the specimens until 82 times cycles in wet-dry chlorides solution. Fly ash in concrete has obvious act for improving concrete behavior in protecting the embedded steel in corrosion.

scholarly journals Coal ash Portland Cement Mortars Sulphate Resistance

2021 ◽  
Vol 7 (1) ◽  
pp. 98-106
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Coal Fly Ash ◽  
Electrical Power ◽  
Bottom Ash ◽  
Coal Ash ◽  
Sodium Sulphate ◽  
Sulphate Attack ◽  
Coal Bottom Ash ◽  
Cement Mortars

Coal fly ash (CFA), coal bottom ash (CBA) are residues produced in thermo-electrical power stations as result of the coal combustion in the same boiler. Therefore, some characteristics of the coal fly ash (CFA) are comparable with those of the coal bottom ash (CBA). Nevertheless, coal bottom ash size is larger than coal fly ash one. Consequently, it was found that it is necessary to grind the coal bottom ash (CBA) to reach a similar size to that one of the CFA. The objective of this paper is to evaluate the performance of Portland cement mortars made with coal fly ash (CFA), coal bottom ash (CBA) or mixes (CFA+CBA), against sulphate attack. The methodology is based on the expansion of slender bars submerged in a sodium sulphate solution (5%) according to the ASTM C-1012/C1012-13 standard. It has been found that mortars elaborated with CEM I 42.5 N (without ashes) presented the largest expansion (0.09%) after a testing period of 330 days. Mortars made with CEM II/A-V exhibited lower expansion (0.03%). Summing up, it can be established that mortar expansion decreases when the coal ash amount increases, independently of the type of coal ash employed. The novelty of this paper relies on the comparison between the performances of Portland cement mortars made with coal fly ash (CFA) or coal bottom ash (CBA) exposed to external sulphate attack. Doi: 10.28991/cej-2021-03091640 Full Text: PDF

A Review on the Effect of Fly Ash, RHA and Slag on the Synthesizing of Coal Bottom Ash (CBA) Based Geopolymer

2021 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Nor Farhana Binti Ab Gulam ◽  
A. B. M. Amrul Kaish ◽  
Abir Mahmood ◽  
Sudharshan N. Raman ◽  
Maslina Jamil ◽  
...  
Keyword(s):  
Fly Ash ◽  
Erosion Resistance ◽  
Rice Husk Ash ◽  
Lightweight Concrete ◽  
Bottom Ash ◽  
Curing Temperature ◽  
Curing Time ◽  
Construction Sector ◽  
Coal Bottom Ash

Geopolymerization is widely used in the construction sector for its characteristics of strong compressive strengths, quick hardening, long-term durability, fire resistance, and erosion resistance. This paper has gone through the geopolymer performances utilizing coal bottom ash (CBA), CBA blended with fly ash (FA), CBA mixed together with slag, and CBA with rice husk ash (RHA). CBA shows a better performance than FA in the compressive strength. This paper has discovered several elements that influence geopolymerization, the curing time, the curing temperature, the silicate and hydroxide ratio, and grinding CBA surfaces. The combination of CBA and RHA is suitable for lightweight concrete, as the range of the volumetric weight is within 1192 kg/m3 to 1655 kg/m3. The slump result decreases, as the ratio of CBA and slag increases. Slag particles are uneven in shape, which increases water consumption and leads to a honeycombed structure, whereas CBA particles are spherical in shape, which enhances workability.

scholarly journals Optimizing and Characterizing Geopolymers from Ternary Blend of Philippine Coal Fly Ash, Coal Bottom Ash and Rice Hull Ash

Materials ◽  
2016 ◽  
Vol 9 (7) ◽  
pp. 580 ◽  
Author(s):  
Martin Kalaw ◽  
Alvin Culaba ◽  
Hirofumi Hinode ◽  
Winarto Kurniawan ◽  
Susan Gallardo ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Bottom Ash ◽  
Rice Hull ◽  
Ternary Blend ◽  
Rice Hull Ash ◽  
Coal Bottom Ash

scholarly journals Durability of Mortar Containing Coal Bottom Ash as a Partial Cementitious Resource

2020 ◽  
Vol 12 (19) ◽  
pp. 8089
Author(s):  
Nafissatou Savadogo ◽  
Adamah Messan ◽  
Kinda Hannawi ◽  
William Prince Agbodjan ◽  
François Tsobnang
Keyword(s):  
Diffusion Coefficient ◽  
Gas Permeability ◽  
Research Work ◽  
Bottom Ash ◽  
Chloride Ions ◽  
Chloride Diffusion ◽  
Partial Substitution ◽  
Capillary Absorption ◽  
Chloride Diffusion Coefficient ◽  
Coal Bottom Ash

This research work focuses on the study of the durability of composite cements based on coal bottom ash powder produced by SONICHAR in Niger. After a physicochemical and environmental characterization of the coal bottom ash powder, mortar test specimens were made. In these specimens, 10%, 15% and 20% of cement were replaced by identical mass percentages of coal bottom ash powder. Durability studies focused on the determination of the chloride ions apparent diffusion coefficient, the measurement of the depth of carbonation and the accelerated ammonium nitrate leaching. The influence of carbonation and leaching were examined using the following parameters: pore distribution, gas permeability, porosity accessible to water, capillary absorption and electrical resistivity. The results show that the incorporation of coal bottom ash powder into CEM I leads to an increase in the depth of carbonation. This increase is more significant when the substitution rate exceeds 10%. In the leaching test, the partial substitution of coal bottom ash powder in CEM I up to 20% does not significantly affect the durability parameters of the composites compared to the control mortar. Diffusion test shows that for mortars containing less than 15% substitution, there is no significant influence on the chloride diffusion coefficient. A slight decrease is observed for mortar containing 20% substitution.

scholarly journals Evaluation of Concrete Durability Performance with Sodium Silicate Impregnants

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Sang-Soon Park ◽  
Yun Yong Kim ◽  
Byung Jae Lee ◽  
Seung-Jun Kwon
Keyword(s):  
Electrical Potential ◽  
Steel Corrosion ◽  
Chloride Diffusion ◽  
Concrete Durability ◽  
Chloride Diffusion Coefficient ◽  
Different Types ◽  
Chloride Attack ◽  
Scale Test ◽  
Durability Performance

This paper presents an enhanced performance in concrete impregnated with silicate compound. Two different types of impregnant materials (inorganic and combined type) are applied to concrete samples with different strength grade (21 MPa and 34 MPa). Through lab-scale test, improved performances in impregnated concrete are evaluated regarding porosity, strength, chloride diffusion coefficient, permeability of air/water, and absorption. Long-term exposure tests including strength, chloride penetration depth and contents, and electrical potential for steel corrosion are performed for different marine conditions. While the surface-impregnated concrete shows marginal increase in strength, significant improvements of porosity, absorption, and permeability are evaluated. The resistance to chloride attack reasonably improved through simply spraying the inorganic silicate in atmospheric-salt spraying condition.

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