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2.2. Barium sulfate dissolutions rates with organic matter shielding experiment. Non-axenic phytoplankton cultures of the diatom Thalassiosira weissflogii were cultured to produce organic matter aggregates in 2 L flasks with f/2 media under a 12:12 h LED light/dark cycle. On day 10, the cell concentration in each culture was measured …
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This study investigates the performance of recycled aggregate concrete incorporating different sizes and concentrations of coarse aggregate under sodium sulphate and normal water curing.
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Paint booth waste as an alternative aggregate for the production of interlocking concrete blocks. Open access 07 February 2024. Containment of sulfate in …
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The mechanical test results show that when the sulfate content is less than 3%, the sulfate is almost completely dissolved and the aggregate is less, which …
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Table 2 shows the limit values of sulphate salt content in natural aggregates recommended in different standards. In this table, sulphate salt content in aggregates is tested by hydrochloric acid dissolution method. Thus, the tested sulphate salt is also called acid-soluble sulphate salt (calculated by SO 3 %). Additionally, since …
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Weigh samples consisting of 100 6 0.1 g out of each of the separated fractions after final sieving and place in separate containers for the test. 7.2 Coarse Aggregate—Thoroughly wash and dry the sample of coarse aggregate to constant weight at 230 6 9°F (110 6 5°C) and separate it into the different sizes shown in 6.3 by sieving to refusal.
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Al-Hubbubi S and Abbas Z [1] patented a device of magnetic water to wash sulfate from aggregate; many samples with different SO 3 contents (0.3, 0.8, and 3) % were treated with magnetized water (12, 8, 4 and 2) liter that needed for each 1 kg of sand with magnetic intensity (9000 and 5000 Gauss).
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The alkali-aggregate reaction and the internal sulfate attack are two chemical reactions that lead to expansions in concrete structures. The former is one of the main causes of expansions in concrete dams and has been extensively reported in the literature, whereas the latter is less common and, thus, less studied. ... The water …
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For the SO3 limit, 0.4% SO3 by weight of concrete may be equivalent to about 3% by weight of cement, doubling the equivalent SO3 in the portland cement and effectively surpassing any ASTM C 150 limit. For U.S. designers, call on your friendly cement chemist for advice. Mine is: It depends on the type of chloride and sulfate in the aggregate, so ...
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Dehieb et al. [8] studied the effect of using recycled concrete aggregate (RCA) polluted in chloride and sulfate solution on the mechanical properties and durability of RCC mixtures. The results ...
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Dec 17, 2012· sulfate sulphate content aggregates washing – Grinding Mill China. sulfate contents in fine aggregate fo concrete Aggregate mining and washing stone; Aggregate mining in vietnam . The report lists chloride and sulfate content . »More detailed. Learn More.
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4.2 Values for the permitted-loss percentage by this test method are usually different for fine and coarse aggregates, and attention is called to the fact that test results by use of the two salts differ considerably and care must be exercised in fixing proper limits in any specifications that include requirements for these tests. The test is usually more …
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The soluble sulphate content is strongly influenced by the gypsum percentage fixed to the masonry particles in the RMA. These high sulphate contents were found in some materials that were not subjected to a selection process that included the removal of a large amount of impurities [13]. ... Current Knowledge and Pending …
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Skip to search form Skip to main content Skip to account menu. Semantic Scholar's Logo. Search 216,921,540 papers from all fields of science ... {Zhang2021ImprovingTS, title={Improving the sulfate resistance of recycled aggregate concrete (RAC) by using surface-treated aggregate with sulfoaluminate cement (SAC)}, …
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Analysis of total chloride content in concrete - ScienceDirect. 01-12-2015· It can be seen in Fig. 1 that the BS 8500 (BS 8500-1, 2006) total chloride limit for reinforced concrete that is non-heat curing and made with sulphate resistance cement (0.2) is nearly violated at mix M4 (w/c = 0.48) even though the chloride content is less than BS 882 (BS 882, 1992) …
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Sodium sulphate solution; Magnesium sulphate solution; Test procedure of soundness test. After the selection of aggregate samples, wash them thoroughly on a 300 micron IS sieve. Then dry them at 105 to 110-degree celsius in drying oven. After that immerse the sample in a solution of sodium sulphate or magnesium sulphate for 16 to 18 hours.
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The mechanical test results show that, when the sulfate content is less than 3%, the sulfate is almost completely dissolved and the aggregate is less, which can make the compressive strength and the cohesion increase; when the sulfate content is more than 3%, too much sulfate cannot be dissolved and precipitated so that the aggregate …
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The evaluation of the damage process of recycled aggregate concrete made with different recycled coarse aggregate (RCA) replacements (30%, 50%, 70% and ) exposed to sodium sulfate solution (50 ...
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In this context, Barbudo et al. [43] also investigated the correlation between sulphate content and leached SO 4 in recycled aggregates with different contents of concrete, bituminous particles ...
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Study on the sulfate freeze thaw resistance of recycled coarse aggregate self-compacting concrete. Author links open ... rate is about 32%, the density is 500–600 g/L, the solid content is 98 ± 1%, the pH is 6–8, the chloride ion content is less than 0.01%, and the sulfate ion content is about 2.6%. ... sulphate attack, acid attack, freeze ...
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As mentioned early, a part of the excavated materials intended to be use as concrete aggregates have a high sulphate content of 3.47% of SO 3 in mass (60% anhydrite and 40% gypsum) and so they are ...
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Aggregates with a particle size of 4.75–9.5 mm were chosen. Deposits were attached to the pores of the aggregate surface (see Fig. 1). The surface structure of coral aggregate was relatively loose, and the interior was porous. The chemical composition and physical properties of the coral aggregate are shown in Table 1 and Table 2, respectively.
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The majority of the coarse aggregate samples (10–20 mm) passed the EN magnesium sulphate heptahydrate test (Fig. 2) and could thus be characterised as durable. In contrast, all the fine aggregates tested (Table 5) failed to provide losses below 35%, which is the maximum permissible category of the EN standard (Table 4).
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However, some sulfate minerals, such as alunite and jarosite, that may affect the performance of concrete are insoluble in water; and, moreover, the significance of the …
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The sulfate ions content migrating into the surrounding matrix was obtained by Equation (1). (1) S I C = − 1.61542 A B S 2 + 15.88956 A B S + 0.17295 where SIC is the sulfate ions amount (mg) and ABS is the absorbance (%). Download : Download high-res image (231KB) Download : Download full-size image; Fig. 3.
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The combined effect of sulphates present in aggregates and high levels of chloride ions in the mixing water on some properties of concrete was studied. Different amounts of sulphates in sand (0.38, 0.50, 0.75 and 1.0% SO3) with chloride contents in water (50, 750, 1000, 3000 and 6000 p.p.m. as Cl−) were used. The compressive strength was lower for …
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Wash by circulating hot tap water (40 to 60°C) in their containers. A continuous flow of fresh hot water shall be maintained throughout the washing period. In the washing operation, the sample shall not be subjected to impact or abrasion that may tend to break up particles. After the magnesium sulphate has been removed, dry the samples to a ...
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The results showed that significant expansion and great loss in compressive strength did not occur in concrete if the content of SO 3 lay below 1.5% and 3% in fine and coarse aggregates, respectively. The concentration of sulfate ions in concrete was not enough to form new a phase of gypsum.
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The aggregate slices were washed at 48°C for 15 min in a washing buffer containing 20 mM Tris-HCl (pH 7.4), 0.01% (wt ... In the sulfidogenic aggregates, sulfate reduction is restricted to the outer 200 to ... Mouritsen K N, Finster K. Diel cycles of sulphate reduction rates in sediments of a Zostera marina bed (Denmark) Aquat Microb ...
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Most regulations prescribe the limiting content of sulfates in aggregates as a total percentage of their weight, with values between 0.2 and 1.0% [9,11]. However, …
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