scholarly journals Sulfate attack and embedded steel corrosion resistances of volcanic-aggregate concrete with fly ash and silica fume

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Abaho G. Gershome ◽  
Jean de Dieu Mutabaruka ◽  
Leopold Mbereyaho
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Silica Fume ◽  
Construction Material ◽  
Construction Materials ◽  
Steel Corrosion ◽  
Sulfate Attack ◽  
River Sand ◽  
Concrete System ◽  
Supplementary Cementing Materials

Construction materials are increasingly on high demand in the developing world. The construction industry has a challenge of discovering, new  alternative construction materials to conventional materials which are locally available materials in environmentally friendly manner. The  experimental tests are conducted on volcanic concrete system to analyze its properties especially corrosion resistance potential for its applicability in construction. The major aim is to investigate its suitability and corrosion resistance potential especially when used in construction of structures with embedded steel. The test results of the material show that volcanic concrete system with 30% fly ash and 10% silica fume cementing materials is an alternative green construction material. Permeability properties are reduced by 8% and 24% with 30% fly ash and 10% silica fume respectively. Tests also indicate that Compressive strength, Corrosion potential and polarization resistance in volcanic concrete system with supplementing  cement materials has more potential to resist sulfate attack when compared with conventional volcanic concrete systems. The supplementary cementing materials (SCM) reduce the pore system and hence decrease the ingress of corrosive ions an  water in concrete. Corrosive ions, moisture and air would initiate corrosion to the embedded steel in concrete leading to reduced service life such structures. Key word: Supplementary Cementing Materials, Sulfate attack, volcanic concrete system, Granite powder, river sand, Corrosion of embedded steel

Shrinkage of Blended Cement Pastes with Mineral Additions

2013 ◽  
Vol 539 ◽  
pp. 55-59
Author(s):  
Yi Chen ◽  
Wu Yao ◽  
Dan Jin
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Cement Paste ◽  
Mercury Intrusion Porosimetry ◽  
Construction Materials ◽  
Blended Cement ◽  
Cement Pastes ◽  
Mercury Intrusion ◽  
Mineral Additions ◽  
By Products

Mineral additions such as fly ash and silica fume are industrial by products, and play an important role in properties improvement for construction materials. In this work, the shrinkage of cement paste blended with fly ash and silica fume by different substitute ratio was studied. Pore structures of specimens at different ages were determined by mercury intrusion porosimetry (MIP) and shrinkage deformation was measured by standard shrinkage tests. The effects of mineral addtions on shrinkage were discussed. The results show that the fly ash was significantly effective on shrinkage at early ages. Based on the research, several suitable advices were offered to optimize the performances of materials and reduce the shrinkage.

scholarly journals Increased fly ash utilization — value addition through forest road reconstruction

2017 ◽  
Vol 44 (3) ◽  
pp. 223-231 ◽  
Author(s):  
Tomi Kaakkurivaara ◽  
Heikki Korpunen
Keyword(s):  
Fly Ash ◽  
Construction Material ◽  
Construction Materials ◽  
Cost Calculation ◽  
Value Addition ◽  
Construction Costs ◽  
Forest Road ◽  
Uniform Layer ◽  
Cost Calculations ◽  
Fly Ash Utilization

Increasing forest bioenergy utilization is increasing the need to discover more applications for fly ash to avoid dumping charges. Our study concentrates on defining the work phases of reconstruction work and estimation of construction costs for a method using biomass based fly ash. Cost calculations were carried out for two mixed structures of fly ash and aggregate, two uniform structures of fly ash, and a conventional aggregate structure, where construction material volumes were calculated per kilometre for each structure. Our study defined suitable machines and their productivity per hour for different work phases. Cost calculation equations were formed for the used machines and the transportation of construction materials. Our study showed that building a 250 mm thick uniform layer of fly ash was the best alternative for minimizing construction costs. However, building a 500 mm thick uniform layer of fly ash was the best alternative for minimizing dumping charges.

scholarly journals Mud-Based Construction Material: Promising Properties of French Gravel Wash Mud Mixed with Byproducts, Seashells and Fly Ash as a Binder

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6216
Author(s):  
Yassine El Mendili ◽  
Manal Bouasria ◽  
Mohammed-Hichem Benzaama ◽  
Fouzia Khadraoui ◽  
Malo Le Guern ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Material ◽  
Construction Materials ◽  
Pozzolanic Reaction ◽  
Good Opportunity ◽  
The Sustainable Development ◽  
Crepidula Fornicata ◽  
Earth Construction ◽  
Characterization Study ◽  
Development Goals

The French gravel industry produces approximatively 6.5 million tons of gravel wash mud each year. This material offers very promising properties which require an in-depth characterization study before its use as a construction material, otherwise it is removed from value cycles by disposal in landfills. We examined the suitability of gravel wash mud and seashells, with fly ash as a binder, as an unfired earth construction material. Thermal and mechanical characterizations of the smart mixture composed of gravel wash mud, Crepidula fornicata shells and fly ash are performed. The new specimens exhibit high compressive strengths compared to usual earth construction materials, which appears as a good opportunity for a reduction in the thickness of walls. The use of fly ash and Crepidula shells in addition to gravel wash mud provides high silica and calcium contents, which both react with clay, leading to the formation of tobermorite and Al-tobermorite as a result of a pozzolanic reaction. Considering the reduction in porosity and improvements in strength, these new materials are good candidates to contribute significantly to the Sustainable Development Goals (SDGs) and reduce carbon emissions.

A study on industrial-scale waste utilization in construction material production: the use of fly ash in GRP composite pipe

2020 ◽  
Vol 70 (340) ◽  
pp. 234
Author(s):  
A. Beycioğlu ◽  
H. Mis ◽  
E. D. Güner ◽  
H. Güner ◽  
N. Gökçe
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Construction Material ◽  
Construction Materials ◽  
Waste Utilization ◽  
Industrial Wastes ◽  
Glass Fiber Reinforced ◽  
Axial Tensile ◽  
Long Term Performance ◽  
Term Performance

This study presents a new approach to the utilization of industrial by-products in construction materials by using fly ash (FA) in the production of glass fiber-reinforced polyester (GRP) pipe. The FA was substituted by 10% and 20% (by weight of sand) in the mixtures to produce GRP pipes of 350 mm in diameter and 6 m in length for testing. Stiffness modulus (SM), axial tensile strength (ATS), and hoop tensile strength (HTS) tests were conducted on the produced GRP pipes and their elasticity modulus (EM) values were also calculated. To observe the microstructure of the GRP pipes and the interfacial transition zone of the layers, SEM and microscopic analyses were performed. Furthermore, a strain-corrosion test was conducted to obtain information about long term-performance of samples. The results showed that the FA-filled GRP pipes were found to meet the requirements of the related standards, and that the use of FA in the GRP pipe industry may be an important alternative approach to the utilization of industrial wastes via effective recycling mechanisms.

scholarly journals Comparative Study on the Performance of Blended and Nonblended Fly Ash Geopolymer Composites as Durable Construction Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Debabrata Dutta ◽  
Somnath Ghosh
Keyword(s):  
Fly Ash ◽  
Magnesium Sulfate ◽  
Silica Fume ◽  
Construction Materials ◽  
Sodium Silicate Solution ◽  
Sulfate Solution ◽  
Significant Drop ◽  
One Year ◽  
Magnesium Sulfate Solution ◽  
Geopolymer Paste

This article represents that the mechanical and microstructural properties and durability of fly ash-based geopolymers blended with silica fume and borax are better than those of conventional fly ash-based geopolymers. Fly ash itself contains the sources of silica and alumina which are required for geopolymerisation. But a sufficient amount of high-reactive silica is able to rapidly initiate geopolymerisation with activation. Pure potassium hydroxide pellets and sodium silicate solution were used for preparation of alkaline activator solution. Fly ash geopolymer paste exhibited better mechanical properties in the presence of silica fume with slight portion of borax. The effect of silica fume-blended geopolymer paste on temperature fluctuation (heating and cooling cycle at certain temperatures) showed better performance than nonblended fly ash-based specimens. Durability property was evaluated by immersion of geopolymer specimens in 10% magnesium sulfate solution for a period of one year. The change in weight, strength, and microstructure was studied and compared. In the magnesium sulfate solution, a significant drop of strength to around 37.26% occurred after one year for nonblended fly ash-based specimens. It is evident that specimens prepared incorporating silica fume had the best performance in terms of their properties.

scholarly journals Steel Corrosion Behavior in Light Weight Fly-Ash Based Alkali Activated Mortars

2021 ◽  
Vol 11 (4) ◽  
pp. 1908
Author(s):  
Giulia Masi
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Pore Solution ◽  
Tap Water ◽  
Steel Corrosion ◽  
Steel Structures ◽  
Solution Chemistry ◽  
Light Weight ◽  
Steel Corrosion Resistance ◽  
Alkali Activated

Alkali activated materials as possible sustainable alternative to cementitious binders showed competitive performances in terms of mechanical and durability properties and high temperature stability. For this reason, light weight fly-ash based mortars have already been optimized as passive fire protective coating for steel structures. However, a lack of information about the durability of these innovative systems in terms of steel corrosion resistance is still present. Thus, this study aims at investigating the durability of steel coated with a 20-mm thick light weight mortar layer in a neutral environment (tap water) and in presence of chloride-containing solution (0.2 M NaCl). In addition, the influence of pore solution chemistry and pH was discussed through electrochemical testing in leachate pore solution and NaOH aqueous solutions at different concentrations. It was found that almost complete protection ability of light weight mortar was obtained when coated steel is exposed to neutral solution for 60 days, while in presence of chlorides, steel is more susceptible to corrosion already after 40 days of exposure. In addition, the developed open porosity of the light weight mortars, it was found that pH and the chemistry of the pore solution in contact with steel strongly influenced the steel corrosion resistance.

scholarly journals Mechanical Properties of Silica Fume Modified High-Volume Fly Ash Rubberized Self-Compacting Concrete

2021 ◽  
Vol 13 (10) ◽  
pp. 5571
Author(s):  
Wesam Salah Alaloul ◽  
Muhammad Ali Musarat ◽  
Sani Haruna ◽  
Kevin Law ◽  
Bassam A. Tayeh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Mechanical Strength ◽  
Silica Fume ◽  
High Volume ◽  
Crumb Rubber ◽  
Self Compacting Concrete ◽  
River Sand ◽  
High Volume Fly Ash ◽  
Constituent Component

The existing form of self-compacting concrete (SCC) comprises of a large amount of powdered and fine materials. In this study, a part of the cementitious material was replaced with constant high-volume fly ash, and a portion of fine aggregates was substituted by crumb rubber (CR). Besides that, silica fume (SF) was added, with the hope that by implementing a new type of nanomaterial, the loss in mechanical strength due to previous modifications such as rubberization and replacement will be prevented. Two variables were found to influence the constituent/component in the mix design: SF and CR. The proportion of SF varies from 0% to 10%, while that of CR from 0% to 30% by volume of the total river sand, where 55% of cement was replaced by the fly ash. A total of 13 rubberized SCC samples with CR and SF as controlling variables were made, and their design mix was produced by a Design of Experiment (DOE) under the Response Surface Methodology (RSM). The results reveal a slight increase in the mechanical properties with the addition of SF. The theoretical mathematical models and equation for each different mechanical strength were also developed after incorporating the experimental results into the software.

scholarly journals Studies on manufactured sand effect on mechanical properties of geopolymer concrete as replacement of river sand in fine aggregate

2021 ◽  
Vol 309 ◽  
pp. 01114
Author(s):  
K. Veera Babu ◽  
T. Srinivas ◽  
Mahathi Tummala
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Construction Material ◽  
Environmental Concerns ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
River Sand ◽  
Natural Sand ◽  
Manufactured Sand ◽  
Low Calcium

Concrete is the most adaptable, long-lasting, and dependable construction material on the planet. There are numerous environmental concerns associated with the production of OPC, and natural sand is becoming more expensive and scarce as a result of unlawful river sand dredging. The greatest replacement material for traditional concrete is geopolymer concrete with low calcium fly ash. The purpose of this paper is to investigate the mechanical properties of geopolymer concrete of grades G30 and G50, which are equivalent to M30 and M50, when river sand is substituted in various quantities with manufactured sand, such as 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100%. When compared to the equivalent grades of controlled concrete, geopolymer concrete improves mechanical properties such as compressive, tensile, and flexural strengths.

scholarly journals Corrosion Effect of 65% Nitrate Acid on X4CrNi1812 at 333 K

2019 ◽  
Vol 1 (1) ◽  
pp. 425-432
Author(s):  
Tomasz Lipiński ◽  
Dariusz Karpisz
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Construction Material ◽  
Austenitic Stainless Steels ◽  
Steel Corrosion ◽  
Constructional Material ◽  
Design Stage ◽  
Roughness Parameters ◽  
Aggressive Environment

Abstract Austenitic stainless steels are often used for a materials in the construction of machines and equipment for agricultural and for industrial construction. One of the most important factors constructional material is corrosion resistance. Equipment with austenitic stainless steel can be easy join by quickly welding at a not to high construction price, but one with the serious problem in aggressive environment is their corrosion resistance. A few corrosion processes in crevices and awkward corners can be avoided at the design stage (low roughness parameters, round-section and other). But still the construction material is exposed to corrosion. These steels often come into contact with an aggressive environment based on nitric acid. The main aim of this research is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336 hours). For this used weight loss of test samples and its profile roughness. The research was conducted on austenitic stainless steel in grade in Nitrate acid at 333 K. Corrosion tests confirmed that the research this steel in 65% nitrate acid as a corrosive environments is characterized through proportionate to time corrosion process whose measure may be surface roughness. In industrial practice roughness parameters for all the research times can be used for determine the stage and size of steel corrosion.

The removal of As(V) ions by lime-modified fly ash and reuse of the exhausted adsorbent as an additive for construction material

2020 ◽  
Author(s):  
Milica Karanac ◽  
Maja Đolić ◽  
Vladimir Pavićević ◽  
Aleksandar Marinković
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Low Cost ◽  
Construction Material ◽  
Thermal Power ◽  
Construction Materials ◽  
Practical Applications ◽  
The Impact ◽  
By Products ◽  
Modified Fly Ash

<p>Coal thermal power plants (TPP) actively generate numerous solid combustion by-products, including fly ash and bottom ash. These TPP by-products have already found use in a variety of civil engineering applications, such as a substitute for sand and gravel in structures, as well as a binding component in certain types of cement (generally, concrete and masonry). Furthermore, such by-products have become a subject of increasing interest in environmental engineering as a low-cost and effective adsorbent for the removal of organic pollutants and heavy metals from wastewaters.</p><p>In order to minimize the impact of material cost, novel solutions for the development of a high capacity and long-term adsorbent have provided a high performance adsorbent for practical applications. This study is focused on the use of modified fly ash (MFA) activated by lime (Ca(OH)<sub>2</sub>) as an effective and low-cost adsorbent for the removal of As(V) ions. The adsorption capacity of the MFA adsorbent was found to be 35.40 mg g<sup>-1</sup>, while the kinetic and thermodynamic parameters indicated a spontaneous and endothermic process. Due to the low desorption potential of the exhausted adsorbent (MFA/As(V), their effective further material reuse was established to be feasible. The reuse of the exhausted adsorbent was obtained through pozzolanic MFA particles and Ca(OH)<sub>2, </sub>thereby formulating a construction material of a cementitious calcium-silicate hydrate. The toxicity leaching test (TCLP) and mechanical properties of the new construction material containing exhausted MFA (CM-MFA/As(V)) confirm its safe use in the laboratory as well as its semi-industrial application.</p><p>The specific objectives of this study have been: (i) to improve the adsorption performance of the MFA; (ii) to evaluate the material’s equilibrium, as well as the process’ kinetic and thermodynamic aspects, including  estimating its limiting step; and (iii) to investigate the possible reuse of the exhausted adsorbent in the production of construction materials. The kinetic data were successfully fitted by a pseudo-second-order equation and the Weber-Morris model. The metal-desorption experiments performed on the exhausted FA and MFA indicate a low recovery of the selected pollutants.</p><p>The major outcome of this study, indicates that double-valorization of fly ash opens new directions for waste management toward reuse in effective practical applications; i.e., for actual water –purification systems, as well as in the production of construction material.</p>

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