Mechanical Properties And Durability Of High Strength Concrete Containing Rice Husk Ash Pdf

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mechanical properties and durability of high strength concrete containing rice husk ash pdf

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This paper studied the fire resistance of rice husk ash concrete. They were cured and tested at 7 days, 28 days, 30 days, 60 days, 90 days, days, days and days.

This paper for the first time investigates the workability, compressive and tensile strength of concrete containing Fly Ash, Rice Husk Ash and Waste Glass Powder. The cubes were tested for axial compression and tensile tests.

Abstract The preliminary and inevitable interest in the use of partial replacements or by — products as complementary pozzolanic materials was mostly induced by enforcement of air pollution control resulted from cement production industry. Rise husk is by- product taken from rice mill process, with approximately the ratio of kg per one ton of rice, even in high temperature it reduces to 40kg. The same results obtained for water absorption ratios likely to be unfavourable.

Fire resistance evaluation of rice husk ash concrete

This study comparably assessed the pozzolanic effect of silica fume SF and ground rice husk ash RHA as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume SF and locally-produced rice husk ash RHA samples with two finenesses one with larger size than cement and the other with smaller size than cement were used in this study.

Hydration and mechanical properties of cement pastes incorporating SF and RHA were determined by thermogravimetric analysis TGA and compressive strength tests, respectively. Properties of concretes regarding workability, mechanical property, durability, and microstructure were evaluated.

Results showed that, although the finely ground RHA used in this study possessed lower SiO 2 content and higher particle size compared to SF, it exhibited comparable pozzolanic reactivity with SF due to the nano-scale pores on its each single particle, leading to a higher specific surface area.

At the same mix, incorporation of finely-ground RHA in cement composites provided comparable mechanical properties, hydration degree, and durability with SF blended cement composites, owing to the porous structure and high specific surface area of RHA particles. Microstructure morphology analysis of concretes explored by scanning electron microscopy SEM further validated the strength and the durability test results. In the manufacture of cement, the clinker production process requires a great amount of energy and emits a large amount of carbon dioxide CO 2 into the atmosphere.

The increase in CO 2 emissions has led to the greenhouse effect and an increase in the temperature of the Earth. To reduce the environmental problems, industrial and agricultural byproducts such as fly ash, metakaolin, granulated blast furnace slag, etc. Moreover, the incorporation of these cement replacement materials in concretes has been reported to improve the mechanical properties and penetration resistance of the concretes [ 8 , 9 , 10 , 11 , 12 , 13 ].

They are highly concentrated sources of amorphous SiO 2 and possess similar chemical reaction mechanism in cement matrix system. The reactivity of SF and RHA contributes to the strength enhancement of cement-basted materials by pozzolanic reactions between amorphous silica and calcium hydroxide liberated during the cement hydration process. SF is very fine non-crystalline silica produced by an electric arc furnace as a byproduct of the smelting process in the production of metallic silicon or ferrosilicon in the alloys industry.

Then, SF is composed of submicron particles of silicon dioxide, which occur as almost-perfect spheres with diameters ranging from 20 to nm [ 17 ]. It is estimated that current global output of SF is, at most, between one and 1. It has been widely reported that higher strength and durability enhancement can be obtained for concretes containing silica fume.

Performance of silica fume concretes in sulfate environment is also better than normal Portland cement concretes [ 19 , 20 , 21 ]. RHA is the combustion residue of the rice husks, which are the shells produced during the dehusking operation of paddy rice. Each tonne of paddy rice produces about kg of husk which, on combustion, yield approximately 40 kg ash.

Rice plants ingest orthosilicic acid from groundwater, whereupon it is polymerized to form amorphous silica in the husks [ 22 ]. After combustion, the organic compounds are devolatilized as carbon dioxide, while the silica is retained in the ash residue. Studies have shown that the main chemical composition of RHA is biomass silicon dioxide SiO 2 , and processing conditions have a significant effect on the characteristics of silica in RHA.

The ash formed during open-field burning or uncontrolled combustion in furnaces generally contains a large proportion of less reactive crystalline silica minerals such as cristobalite and tridymite. Reactivity of RHA is attributed to its high content of amorphous silica and its very large surface area governed by the porous structure of the particles [ 24 ]. Generally, the reactivity is also favored by increasing the fineness of the ash [ 25 ]. RHA with high fineness can improve the compressive strength and produce mortars with low porosity.

For durability, the use of RHA significantly improves resistance to water permeability, chloride ion penetration, and sulfate deterioration of concretes [ 27 , 28 , 29 ]. To date, intensive research efforts have been made in optimal cement replacement level and enhancement of blended concretes for SF dust and RHA. It has been widely accepted that SF and RHA as super pozzolans can significantly improve various properties of concretes.

However, it is not aware of any literature wherein a systematically comparative study on pozzolanic reactivity of SF and ground RHA as reactive silica in cementitious system. Moreover, one of the main dimensions of this investigation was to explore the feasibility of RHA instead of SF which is not economically available even in developed countries in mortars and concretes.

This would also reduce the environmental problems associated with the current open field burning of the rice husk. Therefore, efforts may be made to encourage the use of RHA in construction materials. The hydration properties of cement pastes incorporating SF and RHA after the compressive strength test were determined by thermogravimetric analysis. Properties regarding workability and mechanical properties of concretes were monitored by slump test, compressive strength test, and splitting tensile strength test.

The durabilities of concretes were evaluated by rapid chloride iron penetration testing. The microstructures of concretes were explored through scanning electron microscopy SEM analysis. The cement had a specific gravity of 3. A commonly commercial silica fume used in this study was supplied from Xilong Chemical Co.

Shantou, China. For the grinding process, a laboratory stainless ball mill manufactured by Nanjing University, Nanjing, China, was used to grind the raw ash to smaller particles. The rotational milling speed was set as RPM, and the mass ratio with ball to powder was The grinding duration was set as 5 and 30 min, respectively. After each grinding intermission the ground sample was taken out to keep in a dry sealed container for subsequent tests.

River sand with a fineness modulus of 2. Crushed granites with two size ranges 20 and 40 mm and having specific gravity of 2. A naphthalene-based superplasticizer, Daracem , Grace Construction Products, Hong Kong, produced in liquid form was used. The chemical compositions of constituent materials were monitored by X-ray fluorescence XRF. Specific surface areas were determined by the Blain method for cement and nitrogen adsorption analysis for SF and RHA. The mixtures were thoroughly homogenized and kept in sealed bags.

The blended cement pastes were prepared with a water to binder ratio of 0. As for the compressive strength tests, all the cementitious pastes were tested at 1, 3, 7, 28, and 90 days in accordance with ASTM C standard [ 32 ]. In order to study the hydration reaction of the cementitious pastes, the paste specimens were ground to obtain homogeneity of the grain size below 50 microns and subjected to the quantitative thermogravimetric analysis TGA.

The TGA curves were plotted and the weight losses of the pastes at 1, 3, 7, and 28 days were calculated. As the different chemical compounds in cement correspond to certain decomposition weight losses of TGA curves, the qualitative evaluation of the hydration degree of pastes can be assessed [ 33 ]. Concrete mix proportions were listed in Table 1. The amounts of superplasticizer in all concrete mixtures were adjusted in order to control the slump of fresh control concrete between 60 and 90 mm.

The effects of SF and ground RHA on the workability of concrete were determined by comparing slump values of fresh concretes. After water curing for 7, 14, 28, and 90 days, the specimens were subjected to compressive strength tests using an AIMIL compression testing machine Aimil Ltd. The tests were carried out on triplicate specimens and the average compressive strength values were recorded.

The splitting tensile test was carried out in concrete cylinders of size mm diameter and mm height as per ASTM C [ 34 ]. After water curing for 28 days, the concrete cylinders were subjected to splitting tensile test by using a universal testing machine.

Tests were carried out on triplicate specimens and the average splitting tensile strength values were recorded. Concrete discs with 85 mm diameter and 50 mm thickness were cast and cured for 28 days. Two halves of the specimen was sealed with PVC container of diameter 90 mm. Current is measured every 30 min for up to 6 h.

Chloride contamination and temperature at every 30 min was also monitored. From the results using current and time, chloride permeability was calculated in terms of Coulombs at the end of 6 h. Table 2 shows a significantly high content of amorphous SiO 2 in SF, with small amounts of iron, magnesium, alumina, calcium, and alkali oxides. RHA exhibits a lower SiO 2 amount The specific gravity of RHA increase with the increase of grinding duration. The mean particle size of RHA decreases from 9.

However, FRHA presents a higher specific surface area compared to SF, attributed to its very porous structure of each single particle. This analysis is complemented with the SEM images in Figure 2. As shown in Figure 2 a, spherical particles of silica fume present a smooth, dense surface. The size of these surface pores on FRHA particles is less than 50 nm.

These nano-scale pores greatly contribute to high specific surface area and high pozzolanic reactivity of RHA. The SF blended paste shows the highest strength value This is related to the high content and high surface area of pure glassy silica in SF, which exhibits excellent pozzolanic reactivity and the well packing effect of SF particles in the cement composite.

It can be seen that the paste incorporating CRHA shows the lowest compressive strength at all the testing curing ages, which may be due to the larger particle size and lower surface area of coarse RHA particles.

Strength of paste incorporating RHA increases with increase of grinding duration from 5 to 30 min. The FRHA paste presents a Results show that the addition of finely ground RHA to paste gives rise to an increase of the compressive strength compared to the control concrete, due to the increasing specific surface area and pozzolanic reactivity of RHA.

It is seen that curves of all pastes show three rapid weight losses. The quantitative analysis for the first weight loss and the second weight loss can be used as an indicator of the hydration reaction degree of the cement composite matrix. The weight losses of paste specimens are summarized in Table 4.

These values are calculated from the testing data in Figure 4. It is observed that the weight loss of the control paste is increased from The weight loss of the control paste is The weight loss of SF at the first stage is increased from For the FRHA paste, the weight loss caused by the dehydration reaction at the first stage is increased from Comparing the dehydration weight losses of all the paste samples at the age of 28 days, the SF presents the highest value compared to the control paste and the FRHA paste.

Results also indicate that the rate of hydration of FRHA paste is initially lower than that of SF paste but higher than the control paste. Therefore, SF particles can contribute to the high early age strength and the FRHA increases the long-term strength, although this strength is lower than SF blended paste at all ages, which is consistent with previous reports [ 20 ]. As for the second weight loss stage corresponding to dehydroxylation, the control, the SF paste and the FRHA paste shows The slump testing results of fresh concrete mixtures are listed in Table 5.

It is observed that the slump of the control concrete is 85 mm. The values of the SF mixtures vary between 95 and 25 mm with an increase in the dosage of SF.

The Effect of Rice Husk Ash on Mechanical Properties and Durability of Sustainable Concretes

Kanthe, V. International Journal of Engineering , 31 7 , International Journal of Engineering , 31, 7, , International Journal of Engineering , ; 31 7 : Toggle navigation. These by-products are having high pozzolanic reactivity. In this study, the compressive strength, workability, durability performance, and microstructure of concrete were examined.

The split tensile strength generally increased with increase in RHA content for the mixes. The hydration of cement produces calcium silicate hydrate CSH gels known to give strength and cohesion to concrete. The amorphous silica in RHA reacts with lime liberated as a result of cement hydration to produce additional CSH gels that improves concrete strength and durability properties Yu et al. The reactivity of RHA in concrete is influenced by the ash properties. Previous studies on RHA suggest that incinerating conditions, pre-incinerating treatment of the rice husk, geographical location and specific surface affects the reactivity of RHA in concrete Salas et al. In addition to the pozzolanic reactions of the amorphous silica, the filler effect of the fine RHA particles in the concrete also improves strength at the interfacial transition zone ITZ between aggregate and the cement paste Bui et al. In addition to the amorphous silica content, the specific surface is one significant factor that influences the reactivity of RHA.

Сьюзан на какое-то время забыла про Хейла. Она молила Бога, чтобы Стратмору звонил Дэвид. Скажи мне скорей, что с ним все в порядке, - думала.  - Скажи, что он нашел кольцо. Но коммандер поймал ее взгляд и нахмурился. Значит, это не Дэвид.

The Effect of Rice Husk Ash on Mechanical Properties and Durability of Sustainable Concretes

Если бы Сьюзан не была парализована страхом, она бы расхохоталась ему в лицо. Она раскусила эту тактику разделяй и властвуй, тактику отставного морского пехотинца. Солги и столкни лбами своих врагов. - Это чистая правда! - кричал .

Но еще более страшной ей показалась другая фигура, прятавшаяся в тени, где-то в середине длинной лестницы. Ошибиться было невозможно. Это мощное тело принадлежало Грегу Хейлу. ГЛАВА 58 - Меган - девушка моего друга Эдуардо! - крикнул панк Беккеру. -Держись от нее подальше.

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Хоть бы замолчала эта омерзительная сирена. Почему Стратмор отмел такую возможность. Хейл извивался на полу, стараясь увидеть, чем занята Сьюзан.

 Ключ… - Ее передернуло.  - Коммандер Стратмор отправил кого-то в Испанию с заданием найти ключ. - И что? - воскликнул Джабба.  - Человек Стратмора его нашел. Сьюзан, больше не в силах сдержать слезы, разрыдалась. - Да, - еле слышно сказала.  - Полагаю, что .

Я человек, - подумал. И с ироничной усмешкой вспомнил: - Без воска. Беккер стоял с закрытыми глазами, а человек в очках в металлической оправе приближался к. Где-то неподалеку зазвонил колокол. Беккер молча ждал выстрела, который должен оборвать его жизнь.

4 Comments

  1. Isidre P. 04.05.2021 at 19:22

    PDF | This paper reports an investigation on the strength properties, a time dependent property as well as durability High Strength Grade 60 Concrete Containing Rice Husk Ash. Hilmi Bin rice husk ash (RHA) to enhance the mechanical proper- this method, a control concrete containing superplasti-.

  2. Boleslao M. 08.05.2021 at 07:14

    This study comparably assessed the pozzolanic effect of silica fume SF and ground rice husk ash RHA as supplementary cementing materials on the properties of blended cement pastes and concretes.

  3. Hayjincontleg 09.05.2021 at 20:38

    Authors: H.

  4. Vikki94 11.05.2021 at 10:28

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