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| fabwiki:research:canada:delijani:chapter_1 [2023/10/15 12:33] – [Objectives and Scope] rpschmitz | fabwiki:research:canada:delijani:chapter_1 [2023/10/19 15:03] (current) – [External Links] rpschmitz |
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| ==== Objectives and Scope ==== | ==== Objectives and Scope ==== |
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| <align justify><fs medium>The present research study was designed to reevaluate the change in concrete properties due to fabric formwork and to evaluate the applicability of the ASTM standard for testing fabric formed cylinders.</fs></align> | ### |
| | <fs medium>The present research study was designed to reevaluate the change in concrete properties due to fabric formwork and to evaluate the applicability of the ASTM standard for testing fabric formed cylinders.</fs> |
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| <align justify><fs medium>The need for conducting such research became essential for several reasons: test methods used in former fabric formwork studies were not compatible with any specific standard testing method, all but one previous study used cement grout instead of concrete, and all previous studies used relatively high water cement ratio mix designs except Ghaib et al. [16]. Although Ghaib et al. used woven polypropylene fabric the specific type of fabric they used is unspecified [16].</fs></align> | ### |
| | <fs medium>The need for conducting such research became essential for several reasons: test methods used in former fabric formwork studies were not compatible with any specific standard testing method, all but one previous study used cement grout instead of concrete, and all previous studies used relatively high water cement ratio mix designs except Ghaib et al. [16]. Although Ghaib et al. used woven polypropylene fabric the specific type of fabric they used is unspecified [16].</fs> |
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| <align justify><fs medium>Taking advantage of the work done in C.A.S.T. and years of using different types of available fabrics and geotextiles to form concrete, The Geotex 315ST geotextile (formerly named Propex 2006) was chosen for use in this research study. In full scale construction tests, Geotex 315ST showed good mechanical properties as a formwork fabric. It created a very good texture when exposed to cement mortar or fresh concrete. It is also one of the less expensive fabrics available among Geotex products. This geotextile is a woven “structural” fabric made of ultraviolet (UV) resistant polypropylene fibre with sufficiently high tensile strength in both warp (yarns running the length of the fabric) and weft (yarns running across the width of the fabric) weave directions.</fs></align> | |
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| <align justify><fs medium>Although mechanical properties and practical workability of Geotex 315ST were known to us, the change in overall quality of the concrete was undefined. The knowledge of change in concrete properties due to fabric formwork was limited to a few research studies available, claiming up to hundred percent increase in concrete’s compressive strength when cast in different types of fabrics [7]. The need for conducting such research became essential when the methods used in former fabric formwork studies were not compatible with any specific standard testing method. The scope of this project is limited to two types of Geotex geotextile fabric and two types of concrete; Normal concrete (NC) and flyash concrete (FAC).</fs></align> | ### |
| | <fs medium>Taking advantage of the work done in C.A.S.T. and years of using different types of available fabrics and geotextiles to form concrete, The Geotex 315ST geotextile (formerly named Propex 2006) was chosen for use in this research study. In full scale construction tests, Geotex 315ST showed good mechanical properties as a formwork fabric. It created a very good texture when exposed to cement mortar or fresh concrete. It is also one of the less expensive fabrics available among Geotex products. This geotextile is a woven “structural” fabric made of ultraviolet (UV) resistant polypropylene fibre with sufficiently high tensile strength in both warp (yarns running the length of the fabric) and weft (yarns running across the width of the fabric) weave directions.</fs> |
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| <align justify><fs medium>There are no ASTM or Canadian standards for forming fabric formed laboratory test cylinders, but the type of mold used in this research study provides some basis for testing and comparing the quality of concrete cast in fabric molds. Compared to the “sock” technique [8] or the “mattress” technique [16] used in previous research testing, the test procedure proposed in this thesis is attempting to be close to conventional cylinder casting as recommended in ASTM C39/C39M-04a [17]. The method provides more practical comparisons for structural applications. Compressive strength of all cylindrical concrete specimens was determined on the basis of the standard test method [17].</fs></align> | ### |
| | <fs medium>Although mechanical properties and practical workability of Geotex 315ST were known to us, the change in overall quality of the concrete was undefined. The knowledge of change in concrete properties due to fabric formwork was limited to a few research studies available, claiming up to hundred percent increase in concrete’s compressive strength when cast in different types of fabrics [7]. The need for conducting such research became essential when the methods used in former fabric formwork studies were not compatible with any specific standard testing method. The scope of this project is limited to two types of Geotex geotextile fabric and two types of concrete; Normal concrete (NC) and flyash concrete (FAC).</fs> |
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| | <fs medium>There are no ASTM or Canadian standards for forming fabric formed laboratory test cylinders, but the type of mold used in this research study provides some basis for testing and comparing the quality of concrete cast in fabric molds. Compared to the “sock” technique [8] or the “mattress” technique [16] used in previous research testing, the test procedure proposed in this thesis is attempting to be close to conventional cylinder casting as recommended in ASTM C39/C39M-04a [17]. The method provides more practical comparisons for structural applications. Compressive strength of all cylindrical concrete specimens was determined on the basis of the standard test method [17].</fs> |
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| | <fs medium>The mix design in this study was selected in order to simulate an everyday use general concrete quality. Compressive strength of 30 MPa (at 28 days) was selected as the average strength range to satisfy the above mentioed condition. The mix design used in this research (Table 2) was adopted from Mindess et al. [18]. Expected average 28 days compressive strength was 30 MPa with the slump value between 75 and 100 mm. The properties of the material were as follows:</fs> |
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| <align justify><fs medium>The mix design in this study was selected in order to simulate an everyday use general concrete quality. Compressive strength of 30 MPa (at 28 days) was selected as the average strength range to satisfy the above mentioed condition. The mix design used in this research (Table 2) was adopted from Mindess et al. [18]. Expected average 28 days compressive strength was 30 MPa with the slump value between 75 and 100 mm. The properties of the material were as follows:</fs></align> | |
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| * <fs medium>**Cement:** Type I (produced by Lafarge Canada)</fs>\\ | * <fs medium>**Cement:** Type I (produced by Lafarge Canada)</fs>\\ |
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| <align justify><fs medium>Based on proportions expressed in Table 2, water-cement ratio in this mix design was found to be 0.37 which unlike former studies described in Table 1, is a relatively low. For flyash concrete, 30 percent of the cement in the ordinary concrete mix design was replaced with type C flyash (Table 3).</fs></align> | ### |
| | <fs medium>Based on proportions expressed in Table 2, water-cement ratio in this mix design was found to be 0.37 which unlike former studies described in Table 1, is a relatively low. For flyash concrete, 30 percent of the cement in the ordinary concrete mix design was replaced with type C flyash (Table 3).</fs> |
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| {{:fabwiki:research:canada:delijani:delijani_table_2.jpg?450x300|Table 2: Mix design for normal concrete}}{{:fabwiki:research:canada:delijani:delijani_table_3.jpg?400x300|Table 3: Mix design for flyash concrete used}} | {{:fabwiki:research:canada:delijani:delijani_table_2.jpg?450x300|Table 2: Mix design for normal concrete}}{{:fabwiki:research:canada:delijani:delijani_table_3.jpg?400x300|Table 3: Mix design for flyash concrete used}} |
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| <fs medium>//Place text here.//</fs> | <fs medium>//Place text here.//</fs> |
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| ===== References ===== | ===== References ===== |
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| <fs medium>[[http://www.fab-form.com/|Fab-Form Industries, Ltd.]]</fs>\\ | <fs medium>[[http://www.fab-form.com/|Fab-Form Industries, Ltd.]]</fs>\\ |
| <fs medium>[[http://www.umanitoba.ca/cast_building/|The Centre for Architectural Structures and Technology (C.A.S.T.)]]</fs>\\ | <fs medium>[[http://www.umanitoba.ca/cast_building/|The Centre for Architectural Structures and Technology (C.A.S.T.)]]</fs>\\ |
| <fs medium>[[http://www.fabricforming.org/|The International Society of Fabric Forming (ISOFF)]]</fs>\\ | |
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