scholarly journals A study on reinforcement corrosion of concrete structures near coastal areas of Oman

2020 ◽  
Author(s):  
Halima Ghulam Al-Balushi ◽  
Himanshu Gaur
Keyword(s):  
Fly Ash ◽  
Electric Current ◽  
Permeability Test ◽  
Chloride Permeability ◽  
Normal Concrete ◽  
Wall Structures ◽  
Electric Current Passing ◽  
Concrete Blocks ◽  
The Aesthetic ◽  
Acceleration Test

A lot of buildings and structures in coastline areas facing many issues such as huge number of cracks shown on the wall structures. Moreover, this issue is affecting the aesthetic and the beauty of the buildings. Research discover that reasons behind this problem is concrete corrosion or especially corrosion of steel that causes enormous damage to the structure. This issue starts when the chloride is containing in concrete and due to formation of the oxide film. Rapid chloride permeability test according to ASTM C1202 is performed to study the behavior of different concrete mixes such as normal concrete, concrete with fly ash and concrete with Ground Granulated Blast-furnace slag(GGBFS). In this experiment when the concrete blocks are dipped into the solution, the electric current passes through it in order to determine the permeability of the material. In addition, corrosion acceleration test is performed to observe the electric current flow through the different mixes with different time intervals and days when it is merged to sodium chloride (NaCl). From the rapped chloride permeability test results, it is found that the permeability of chloride of all mixes is categorized as a moderate. From the corrosion acceleration test, it is found that all specimen of concrete containing fly ash had an attack at the first days of the test. A little rust appears on the normal concrete mix in the second week as the magnitude of electric current passing through it was not stable.

scholarly journals Durability Assessment of Concrete with Class-F Fly Ash by Chloride Ion Permeability

2019 ◽  
Vol 8 (4) ◽  
pp. 8831-8836
Keyword(s):  
Fly Ash ◽  
Chloride Ion ◽  
Pozzolanic Reaction ◽  
Chloride Ions ◽  
Permeability Test ◽  
Reaction Products ◽  
Chloride Permeability ◽  
Cement Pastes ◽  
Rapid Chloride Permeability ◽  
Class F Fly Ash

This paper discusses on Rapid Chloride Permeability Test investigations on penetration of chloride ions included with replacement of cement by flyash material. By weigth of cement, the fly ash content is replaced from 0% to 60%. Concrete mixes with different binder content varies from 350, 400 and 450 kg/m3 were proportioned with different water binder(w/b) ratios = 0.4, 0.45 and 0.50. Specimens were casted and tested for 28 days. For all the combinations, RCPT was carried out and the charge passed through the specimens was noted. Rapid Chloride Permeability Test value of concrete without fly ash was found to be more than the concrete with fly ash. The Rapid Chloride Permeability Test values are found to be decreased if the percentage of flyash increases. The reason could be the pozzolanic reaction products (CSH) fill the pores between the cement pastes and cause a denser concrete matrix, resulting in better durability. Hence, it can be suggested that the fly ash concrete up to 50% replacement can be used for variety of applications.

scholarly journals Strength and Durability Properties by Replacement of Natural Zeolite and Fly ash in Ordinary Portland Cement

2020 ◽  
Vol 9 (3) ◽  
pp. 805-811 ◽  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Natural Zeolite ◽  
Ordinary Portland Cement ◽  
Mineral Admixture ◽  
Permeability Test ◽  
Chloride Permeability ◽  
Pozzolanic Material ◽  
Alumino Silicate ◽  
Strength And Durability

Natural zeolite and Flyashresidue, a sort of hydrated Alumino-Silicate is used amply as ordinary pozzolanic material in particular areas of the world. In this calculation, the suitability of a secretly quarried zeolite and mineral admixture called fly ash is used for getting better mechanical and durability property of bond. The presentation of strong quality was better with a dissimilar degree of zeolite and fly ash was examined. The substitution on zeolite and fly ash with other proportions like 10% zeolite with ordinary Portland cement (OPC), 10% zeolite and 10% fly ash, 10% zeolite and 20% fly ash, 10% zeolite and 30% fly ash for M25 grade of concrete and done valuations with mechanical properties such as compressive strength, split tensile test, water permeability test, rapid chloride permeability test. By differentiating these effects between a run of the mill concrete and dissimilar degrees of Zeolite and Flyash.By comparing these results between normal concrete with different proportions of Zeolite and Flyash.

Effect of ground granulated blast funrnace slag and fly ash on strength, permeability, and under-water abrasion of fine-grained concrete

2020 ◽  
Vol 71 (7) ◽  
pp. 775-788
Author(s):  
Quyet Truong Van ◽  
Sang Nguyen Thanh
Keyword(s):  
Fly Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Chloride Permeability ◽  
Cement Replacement ◽  
Fine Grained ◽  
Granulated Blast Furnace Slag ◽  
Compressive Strength Test ◽  
Economic Ground

The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA

scholarly journals Pengaruh Penambahan Serat Kawat Bendrat Terhadap Kuat Lentur Beton Geopolimer

2022 ◽  
Vol 10 (1) ◽  
pp. 69-76
Author(s):  
Indrayani Indrayani ◽  
Lina Flaviana Tilik ◽  
Djaka Suhirkam ◽  
Suhadi Suhadi ◽  
Muhammad Prawira Wardana ◽  
...  
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Concrete Beams ◽  
Tensile Load ◽  
Strength Test ◽  
Coal Waste ◽  
Geopolymer Concrete ◽  
Normal Concrete ◽  
Additional Material ◽  
Flexible Beams

Currently, innovation continues to be developed to replace cement with other materials so that the use of cement as a building material can be reduced. Utilization of coal waste (fly ash) is an alternative to subtitude cement. From previous studies, fly ash mixed with alkaline materials in the form of NaOH and Na2SiO3 in a ratio of 1:5 can produce geopolymer concrete. This geopolymer concrete research was continued by adding bendrat wire fibers into the geopolymer concrete mixture. The method used in testing the aggregate, testing the compressive strength of normal concrete K225, testing the flexural strength of normal concrete and geopolymer concrete refers to SNI. Another additional material that is mixed is bendrat wire fiber. The research was carried out in the form of making flexible beams of 10 cm x 10 cm x 50 cm with fiber variations of 0%, 0.5%, and 1,0% at the age of 14 and 28 days. The results of the flexural strength test of the BN beam at the age of 28 days can withstand loads than BG. The average flexural strength obtained with variations of BN, BN+SB 0.5% and BN+SB 1.0% respectively were 2.796 MPa, 3.113 MPa, and 3.879 MPa. The results of testing the average flexural strength of geopolymer concrete beams at 28 days, obtained variations of BG, BG+SB 0.5%, and BG+SB 1.0% respectively were 0 MPa, 0.055 MPa and 0.104 MPa. In addition, geopolymer concrete cannot be used as a beam and the addition of bendrat wire fiber to geopolymer concrete cannot withstand the tensile load on the concrete.

scholarly journals Road Construction by using Rolled Compacted Concrete

2019 ◽  
Vol 8 (12) ◽  
pp. 673-678
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Road Construction ◽  
Normal Concrete ◽  
Low Traffic

Rolled compacted concrete (RCC) is important of newly technique in construction of pavement. that can be employed in low traffic or high trafficked roads. Due to its inexpensive, quick creation , durable and low maintenance RCC is becoming more commonly gradually . If the UHPC compared to normal concrete has some privilege such as plenty stability and supreme permanence however the utilization of it is restricted owing to its expensiveness and minimal cods for design.. Its constancy leads to its stay persistent when subjected to vibratory compacter, since it has sufficient wetting so it causes permit enough mixing and repartition of paste without segregation. Fly ash, silica fume and some admixture can be utilized to concrete to decrease the quantity of water cand generate high arid mixture.

scholarly journals Application of High Volume Fly-Ash Concrete Blocks for the Mounds Coastal Fishing Grounds

2000 ◽  
Vol 38 (12) ◽  
pp. 17-22
Author(s):  
K. Fukudome ◽  
T. Suzuki ◽  
E. Saitoh ◽  
S. Nagataki
Keyword(s):  
Fly Ash ◽  
High Volume ◽  
Fly Ash Concrete ◽  
High Volume Fly Ash ◽  
Concrete Blocks

Corrosion Resistance Performance of Ethylamines in Fly Ash Blended Cement Concrete

2014 ◽  
Vol 507 ◽  
pp. 286-290
Author(s):  
V. Rajkumar
Keyword(s):  
Corrosion Resistance ◽  
Fly Ash ◽  
Blended Cement ◽  
Impedance Measurement ◽  
Chloride Ions ◽  
Experimental Investigations ◽  
Optimal Dosage ◽  
Cement Concrete ◽  
Chloride Permeability ◽  
Resistance Performance

The main aim of this investigation is to study the influence of monoethylamine, diethylamine and triethylamine inhibitors on the corrosion resistance performance of 25% fly ash blended cement concrete. These inhibitors were added in dosages of 1%, 2%, 3% and 4% by weight of cement and experimental investigations have been carried out to compare the effectiveness of these three inhibitors with regard to strength and corrosion resistance. The mechanical strength properties studied were compressive, split tensile, flexural and bond strengths. The resistance to corrosion was evaluated based on the performance of the concrete for the penetration of chloride ions by means of impressed voltage technique, Rapid chloride permeability test (RCPT), AC impedance measurement, and weight loss measurement and ultimately the most effective of the three inhibitors and its optimal dosage has been determined.

scholarly journals Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

2020 ◽  
Vol 40 (2) ◽  
Author(s):  
Daniela Eugenia Angulo-Ramírez ◽  
William Gustavo Valencia-Saavedra ◽  
Ruby Mejía de Gutiérrez
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Water Absorption ◽  
Blast Furnace Slag ◽  
Construction Materials ◽  
Chloride Ion ◽  
Chloride Permeability ◽  
Alkaline Activator ◽  
Furnace Slag

Concretes based on alkaliactivated binders have attracted considerable attention as new alternative construction materials, which can substitute Portland Cement (OPC) in several applications. These binders are obtained through the chemical reaction between an alkaline activator and reactive aluminosilicate materials, also named precursors. Commonly used precursors are fly ash (FA), blast furnace slag (GBFS), and metakaolin. The present study evaluated properties such as compressive strength, rate of water absorption (sorptivity), and chloride permeability in two types of alkaliactivated concretes (AAC): FA/GBFS 80/20 and GBFS/OPC 80/20. OPC and GBFS/OPC* concretes without alkaliactivation were used as reference materials. The highest compressive strength was observed in the FA/GBFS concrete, which reported 26,1% greater strength compared to OPC concrete after 28 days of curing. The compressive strength of alkaliactivated FA/GBFS 80/20 and GBFS/OPC 80/20 was 61 MPa and 42 MPa at 360 days of curing, respectively. These AAC showed low permeability to the chloride ion and a reduced water absorption. It is concluded that these materials have suitable properties for various applications in the construction sector.

Magnetic polarity and neutrality

1883 ◽  
Vol 36 (228-231) ◽  
pp. 404-417
Keyword(s):  
Electric Current ◽  
Magnetic Polarity ◽  
Closed Circuit ◽  
Silk Fibre ◽  
Iron And Steel ◽  
Current Passing ◽  
Electric Current Passing ◽  
Electromagnetic Effects ◽  
Magnetic Needle

In recent papers upon the Theory of Magnetism, I gave the opinion drawn from a long series of personal researches, that magnetism in iron and steel is entirely due to the inherent polarity of its molecules, the force of which could neither be destroyed nor augmented; that, when we have evident magnetism, the molecules rotate so as to have all their similar polarities in one direction; and that neutrality is a symmetrical arrangement or a balancing of polar forces, as in a closed circuit of mutual attractions. The series of researches which I now present bear unmistakable testimony to the truth of these views, showing the opposite polarities which exist in an apparently neutral bar of iron; and that it is by this means alone that external neutrality occurs in the iron cores of an electro-magnet upon the cessation of the inducing current. The instrument used for measurements consists of a delicate silk fibre-suspended magnetic needle, always brought to its zero-mark by the influence of a large magnet at a distance, the angle of which gives the degree of force required to balance any magnetised body placed on the opposite side of the needle. It can also employ electromagnetic effects by the use of two opposing coils on each side of the needle, balanced so that an electric current passing through the coils has no influence on the needle, except when a piece of iron or steel is placed inside one of the coils; this again being balanced and measured by the large revolving magnet.

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