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| fabwiki:research:canada:delijani:chapter_2 [2023/10/15 13:28] – [Fabric Tests Using Normal Concrete] rpschmitz | fabwiki:research:canada:delijani:chapter_2 [2023/10/15 13:33] (current) – [External Links] rpschmitz |
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| ==== Fabric Tests Using 30% Flyash Concrete ==== | ==== Fabric Tests Using 30% Flyash Concrete ==== |
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| <align justify><fs medium>There are reports on fine additives such as Silica fume having the tendency to clog filter fabrics associated with permeable rigid formworks or drainage formliners [9]. Mixes of normal concrete on the other hand, have not shown any significant blockage in the formwork liner [10]. Generally, particles of a typical silica fume are smaller than 1 micron [11] while the average diameter of a typical cement particle is approximately 10 μm [12]. The size of the spherical particles of the fly ash ranges between 10 and 100 micron [13]. Herein, another experiment was conducted to observe if flyash particles are able to clog the pores of the fabrics used in this research study. Using the two selected fabrics from the first box test, a second box was made and new experiment (Figure 14) was conducted with 30% type C flyash added to the mix design.</fs></align> | ### |
| | <fs medium>There are reports on fine additives such as Silica fume having the tendency to clog filter fabrics associated with permeable rigid formworks or drainage formliners [9]. Mixes of normal concrete on the other hand, have not shown any significant blockage in the formwork liner [10]. Generally, particles of a typical silica fume are smaller than 1 micron [11] while the average diameter of a typical cement particle is approximately 10 μm [12]. The size of the spherical particles of the fly ash ranges between 10 and 100 micron [13]. Herein, another experiment was conducted to observe if flyash particles are able to clog the pores of the fabrics used in this research study. Using the two selected fabrics from the first box test, a second box was made and new experiment (Figure 14) was conducted with 30% type C flyash added to the mix design.</fs> |
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| | <fs medium>Similar to the first box test, bled water and cement paste from the fabrics were collected in containers and weighed in wet and dry form to measure the amount of water and cementitious materials bled through the two fabrics. Since only 6 pieces of fabric were installed in this box (three samples of Geotex 315ST and three samples of Geotex 104F), individual samples had a larger area exposed to the fresh concrete. Therefore, before deriving the results, corrections were applied to the areas to make the results consistent with the first box test results.</fs> |
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| <align justify><fs medium>Similar to the first box test, bled water and cement paste from the fabrics were collected in containers and weighed in wet and dry form to measure the amount of water and cementitious materials bled through the two fabrics. Since only 6 pieces of fabric were installed in this box (three samples of Geotex 315ST and three samples of Geotex 104F), individual samples had a larger area exposed to the fresh concrete. Therefore, before deriving the results, corrections were applied to the areas to make the results consistent with the first box test results.</fs></align> | |
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| {{:fabwiki:research:canada:delijani:delijani_fig_14.jpg?300x300|Figure 14: Box made for Box Test 2}} | {{:fabwiki:research:canada:delijani:delijani_fig_14.jpg?300x300|Figure 14: Box made for Box Test 2}} |
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| ==== Results ==== | ==== Results ==== |
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| <align justify><fs medium>As seen in Figure 15, each fabric bled almost the same amount of cementitious material when exposed to normal concrete and flyash concrete. Both fabrics bled less water when exposed to flyash concrete meaning that some clogging happened when cementitious paste tried to pass through the fabric. It is hypothesized that this is caused by the increase in the amount of very fine particles in the flyash mix.</fs></align> | ### |
| | <fs medium>As seen in Figure 15, each fabric bled almost the same amount of cementitious material when exposed to normal concrete and flyash concrete. Both fabrics bled less water when exposed to flyash concrete meaning that some clogging happened when cementitious paste tried to pass through the fabric. It is hypothesized that this is caused by the increase in the amount of very fine particles in the flyash mix.</fs> |
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| | <fs medium>In order to investigate characteristics of collected dried cementitious material from this experiment, dry bled paste powder was examined under a stereoscopic zoom microscope (Nikon SMZ800) using maximum magnification of 378x to observe if flyash bled through the fabrics. Dried passed cementitious material was set under the microscope and the visual results were compared to both pure flyash and pure cement. Based on observations, Geotex 315ST did not bleed any flyash at all while Geotex 104F which has larger pores let a small amount of flyash bleed out (Figures 16 a,b,c). As seen in Figure 15, Geotex 315ST bled much less cementitious material compared to Geotex 104F which is caused by the size of its openings and their potential clogging by flyash particles.</fs> |
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| <align justify><fs medium>In order to investigate characteristics of collected dried cementitious material from this experiment, dry bled paste powder was examined under a stereoscopic zoom microscope (Nikon SMZ800) using maximum magnification of 378x to observe if flyash bled through the fabrics. Dried passed cementitious material was set under the microscope and the visual results were compared to both pure flyash and pure cement. Based on observations, Geotex 315ST did not bleed any flyash at all while Geotex 104F which has larger pores let a small amount of flyash bleed out (Figures 16 a,b,c). As seen in Figure 15, Geotex 315ST bled much less cementitious material compared to Geotex 104F which is caused by the size of its openings and their potential clogging by flyash particles. | |
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| {{:fabwiki:research:canada:delijani:delijani_fig_15.jpg?420x300|Figure 15: The effect of flyash on the amount of bled water and cementitious material}} | {{:fabwiki:research:canada:delijani:delijani_fig_15.jpg?420x300|Figure 15: The effect of flyash on the amount of bled water and cementitious material}} |
| {{:fabwiki:research:canada:delijani:delijani_fig_16a.jpg?250x300|Figure 16a: Microscopic picture of Pure Flyash with different sizes of flyash beads}}{{:fabwiki:research:canada:delijani:delijani_fig_16b.jpg?250x300|Figure 16b: Microscopic picture of Material bled from Geotex 104F showing some flyash beads along with the fine aggregates (mostly cement)}}{{:fabwiki:research:canada:delijani:delijani_fig_16c.jpg?250x300|Figure 16c: Microscopic picture of Material bled from Geotex 315ST with almost no flyash beads}} | {{:fabwiki:research:canada:delijani:delijani_fig_16a.jpg?250x300|Figure 16a: Microscopic picture of Pure Flyash with different sizes of flyash beads}}{{:fabwiki:research:canada:delijani:delijani_fig_16b.jpg?250x300|Figure 16b: Microscopic picture of Material bled from Geotex 104F showing some flyash beads along with the fine aggregates (mostly cement)}}{{:fabwiki:research:canada:delijani:delijani_fig_16c.jpg?250x300|Figure 16c: Microscopic picture of Material bled from Geotex 315ST with almost no flyash beads}} |
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| <align justify><fs medium>Additionally, when exposed to flyash concrete, Geotex 104F bled much less water comparing to the time when normal concrete was used. Since the amount of passed cementitious material that passed through each fabric in both normal and flyash concrete was constant, the amount of bleeding water became a definitive factor in this comparison test. When flyash concrete was used, Geotex 104F showed about 48% reduction in amount of bled water (from 9.85 gr down to 5.15 gr) compared to water bled from normal concrete. While Geotex 315ST showed only 27% reduction in bled water (from 6.28 gr to 4.56 gr) due to clogging effect. This indicates that Geotex 104F is susceptible to clogging when flyash concrete is used. Compared to its use with normal concrete, Geotex 104F looses less water and air bubbles when exposed to flyash concrete. Consequently, when flyash concrete is the concrete of choice, use of textile with smaller openings is recommended.</fs></align> | ### |
| | <fs medium>Additionally, when exposed to flyash concrete, Geotex 104F bled much less water comparing to the time when normal concrete was used. Since the amount of passed cementitious material that passed through each fabric in both normal and flyash concrete was constant, the amount of bleeding water became a definitive factor in this comparison test. When flyash concrete was used, Geotex 104F showed about 48% reduction in amount of bled water (from 9.85 gr down to 5.15 gr) compared to water bled from normal concrete. While Geotex 315ST showed only 27% reduction in bled water (from 6.28 gr to 4.56 gr) due to clogging effect. This indicates that Geotex 104F is susceptible to clogging when flyash concrete is used. Compared to its use with normal concrete, Geotex 104F looses less water and air bubbles when exposed to flyash concrete. Consequently, when flyash concrete is the concrete of choice, use of textile with smaller openings is recommended.</fs> |
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| ===== See Also ===== | ===== See Also ===== |
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| <align justify><fs medium>[1] Comments by RPS on Discussion page on test box construction, Figures 8 and 14.</fs></align> | <fs medium>[1] Comments by RPS on Discussion page on test box construction, Figures 8 and 14.</fs>\\ |
| <fs medium>[2] //Place text here.//</fs> | <fs medium>[2] //Place text here.//</fs> |
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| ===== References ===== | ===== References ===== |
| [13] FHWA. //Fly Ash Facts for Highway Engineers.// Aurora: U.S. Department of Transportation, 2003.\\ | [13] FHWA. //Fly Ash Facts for Highway Engineers.// Aurora: U.S. Department of Transportation, 2003.\\ |
| </fs> | </fs> |
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| ===== External Links ===== | ===== External Links ===== |
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| <fs medium>//Place text here.//</fs> | <fs medium>//Place text here.//</fs> |
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