iosr-JMCE   Volume-9 ~ Issue-3

Abstract: This study aimed at investigating the effect of subjecting concrete, produced with cement being partially replaced with saw dust ash (SDA) to elevated temperatures. The performance of the test concrete cubes was done by exposing them to elevated temperatures of 200oC, 400oC, 600oC and 800oC, and allowed to cool down to room temperature before testing for their properties. Both the physical and thermal properties of the concrete cubes were determined. The concrete produced by blending cement with 10% SDA with an average percentage loss of 23.04% retained more of its compressive strength when exposed to the different temperatures, than concrete produced using only OPC, which has an average percentage loss of 29.11%. It is also found that, at an elevated temperature of 800oC, concrete fail totally in flexure due to the effect of high heat on binding elements. The flexural strength of both the control concrete (at 0% OPC replacement) and OPC/SDA blended concrete (at 10% OPC replacement) decreased as the temperature is increased. The replacement of OPC by 10% SDA increased the thermal shock resistance of the concrete by 11 cycles than the 0% OPC concrete at the same temperature. The concrete produced with OPC has better thermal conductivity than the concrete produced by blending OPC with SDA, as a result, the dislodgement of the concrete edges is relatively lower in the SDA blended cement concrete than in the OPC concrete. The result shows that, blending OPC with SDA in concrete performed better at elevated temperatures than concrete produced with only OPC. Therefore, the replacement of OPC with 10% SDA can be applied as a fire resisting bonding material in concrete.

Keywords: Blended Concrete, Elevated Temperatures, Ordinary Portland cement (OPC), Performance, Saw Dust Ash (SDA)

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[3] S.A. Sumaila, and O.F. Job, Properties of SDA-OPC Concrete: A Preliminary Assessment, Journal of Environmental Sciences, 3(2), 1999, 155-159

[4] I.I. Dashan, and E.E.I. Kamang, Some Characteristics of AHA/OPC Concretes: A Preliminary Assessment, Nigerian Journal of Construction Technology and Management, 2(1), 1999, 22-28.

[5] M.M. Morsy, S.S. Shebl, and A.M. Rashad, Effect of Fire on Microstructure and Mechanical Properties of Blended Cement Pastes Containing Metakaoline and Silica Fume. Asian Journal of Civil Engineering (Building and Housing), 9(2), 2008, 93-105.

[6] G. Narenda, Effect of Fire on Concrete, Concrete International Magazine, April, 2006, www.highbeam.com/doc/1P3-1106559491.html, Retrieved 22nd June, 2013

[7] M.S. Morsy, and S.S. Shebl, Effect of Silica Fume and MetakaolinePozzolana on the Performance of Blended Cement Pastes Against Fire. Ceramic Silikaty, 51(1), 2007, 40-44.

[8] CCAA, Concrete Basics: A Guide to Concrete Practice, A Publication of Cement Concrete and Aggregate Australia, 2004, 6th edition. www.concrete.net.au, retrieved 15th April 2010.

[9] B. Erlin, and W. Hime, The Fire Resistance of Concrete, Concrete Construction. Dec. 2004. [10] M. Zeiml, and R. Lackner, Experimental Investigation on Spalling Mechanisms in Heated Concrete, In Kukla, K. (2010), Concrete at high temperatures hygrothermo-mechanical degradation of concrete, doctoral thesis, Department of Civil Engineering, University of Glasgow, 2010. http://thesis.gla.ac.uk/1666/, retrieved 3rd July, 2011.

Abstract: The polyurethane processing for panel air filters (flexible foam)for high yield (free of all defects) is very critical and sensitive on account of Polyurethane making chemistry, short reaction times, process conditions, ambient temperature and humidity , equipment dispensing-mixing precision and moulds' surface quality, moulds' temperature and uniformity impacting the defects in filters like pin holes, short filling, over filling or growth, skin damage, loose skin, voids, hardness variations, shrink marks, knit lines etc. Research is conducted to study and establish a correlation between various parameters so that process settings can be altered to ensure minimum variation to output in spite of variation in inputs and noise to the system.

Keywords: Cell, Gel time, ISO Ratio, Nucleation. Cell-A single small cavity surrounded partially or completely by walls Gel Time-For polyurethanes, the interval of time between mixing together the Polyol and the di-isocyanate and the formation of the non flowing, semisolid jelly like system ISO ratio-The selected ratio by weight of Isocyanate with Polyol as 100 Nucleation- Process of forcing in air particles as bubbles in the Polyol molecules.

[1] Shau-Tarang Lee, Chul B. Park, N.S.Ramesh(Book Style) ―Polymeric Foams‖

[2] I.R.Clemitson, Herrington R, Hock K (Book Style) ―Castable Polyurethane Elastomers Flexible Polyurethane Foams,Chemistry and Technology‖
[3] Woods G. (Book Style) ―Flexible Polyurethane Foams, Chemistry and Technology‖ Appl Sci Pub Ltd.

Abstract: Friction Stir Welding (FSW) is a solid state joining process that can be applied to a number of materials including aluminium, magnesium, copper and steels. A number of researches have been conducted in Friction Stir Welding of steels and it is the focus of this paper to make a comprehensive review of the work that has been done. Ultra-low carbon steels, low carbon steels, medium carbon steels, high carbon steels and ultra-high carbon steels have been considered and several aspects of FSW of steels have been outlined. These are tools, mechanical properties and microstructure. It was determined that carbon content, welding speed as well as rotational speed affect both mechanical properties and microstructure of the joint.

Key words: Friction Stir Welding, FSW parameters, FSW tools, Mechanical properties, Microstructure.

[1] Don-Hyun Choi, Chang-Yong Lee, Byung-Wook Ahn, Jung-Hyun Choi, Yun-Mo Yeon, Keun Song, Seung-Gab Hong, Won-Bae Lee, Ki-Bong Kang and Seung-Boo Jung, Hybrid Friction Stir Welding of High-carbon Steel, J. Mater. Sci. Technol., 2011,27(2), 127-130.
[2] R. Rai, A. De, H. K. D. H. Bhadeshia and T. DebRoy, Review: friction stir welding tools, Science and Technology of Welding and Joining, 2011 VOL16 NO4 325.
[3] Hidetoshi Fujii, Ling Cui, Nobuhiro Tsuji, Masakatsu Maeda, Kazuhiro Nakata and Kiyoshi Nogi, Friction stir welding of carbon steels, Materials Science and Engineering, A 429 (2006) 50–57.
[4] Y. K. Yousif, K. M. Daws and B. I. Kazem, Prediction of Friction Stir Welding Characteristic Using Neural Network, Jordan Journal of Mechanical and Industrial Engineering, Vol. 2, No. 3 (2008) 151 – 155.
[5] T. J. Lienert, W. L. Stellwag, Jr., B. B. Grimmett and R. W. Warke, Friction Stir Welding Studies on Mild Steel, Supplement To The Welding Journal, 2003.
[6] Hoon-Hwe Cho, Suk Hoon Kang, Sung-Hwan Kim, Kyu Hwan Oh, Heung Ju Kim, Woong-Seong Chang and Heung Nam Han, Microstructural evolution in friction stir welding of high-strength linepipe steel, Materials and Design 34 (2012) 258–267.
[7] Y.S. Sato, H. Yamanoi, H. Kokawa and T. Furuhara, Microstructural evolution of ultrahigh carbon steel during friction stir welding, Scripta Materialia 57 (2007) 557–560.
[8] M. Jafarzadegan, A. Abdollah-zadeh, A.H. Feng, T. Saeid, J. Shen and H. Assadi, Microstructure and Mechanical Properties of a Dissimilar Friction Stir Weld between Austenitic Stainless Steel and Low Carbon Steel, J. Mater. Sci. Technol., 2013, 29(4), 367-372.
[9] A.P. Reynolds, Wei Tang, T. Gnaupel Herold and H. Prask, Structure, properties, and residual stress of 304L stainless steel friction stir welds, Scripta Materialia 48 (2003) 1289–1294.
[10] Seung Hwan C. Park, Yutaka S. Sato, Hiroyuki Kokawa, Kazutaka Okamoto, Satoshi Hirano and Masahisa Inagaki, Rapid formation of the sigma phase in 304 stainless steel during friction stir welding, Scripta Materialia 49 (2003) 1175–1180.

Abstract:Over the decades, there has been a significant increase in the use of fibres in concrete for improving its properties such as tensile strength and ductility. The fibre concrete is also used in retrofitting existing concrete structures. Among many different types of fibres available today, glass fibre is a recent introduction in the field of concrete technology. Glass fibre has the advantages of having higher tensile strength and fire resistant properties, thus reducing the loss of damage during fire accident of concrete structures. In this investigation glass fibres of 450 mm length are added to the concrete by volume fraction of up to 1% to determine its strength and fire resistant characteristics. Comparison of the strength and fire-resistance performance of conventional concrete and glass fibre concrete was made. The paper presents the details of the experimental investigations and the conclusions drawn there from.

Key words: Concrete, Glass fibre, Volume Fraction, Strength properties, Fire resistant characteristics.

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[2]. Banthia, N, Yan, C.B, Lee W.Y, (1997) "Restrained shrinkage cracking in fiber feinforced concrete with polyolefin fibres", Fifth International Concrete on Structural Failure, Durability Retrofitting, Singapore, November 27-28, pp. 456-463.
[3]. Chandramouli, K, Srinivasa Rao, P, Pannirselvam, N, Seshadri Sekhar,T, and Sravana, Priyadrashini, T .P, (2010), " Strength and durability characteristic of glass fibre concrete", International Journal of Mechanics of Solids,Vol. 5, No.1, pp. 15-26.
[4]. Chawla, K. and Tekwari, B. (2012), "Glass fibre Reinforced concrete",Yahoo Group – Civil Engineering Portal, pp. 1-7.
[5]. Muthuawamy K.R. and Thirugnanam G.S,(2013), "Mechanical properties of hybrid fibre reinforced high performance concrete", Indian Concrete Journal, Vol 87, No. 4, April, pp. 50-55.
[6]. Naaman. A.E (1997) ," High Performance Fibre Reinforced cement composites distinctive attributes for fibre applications", Fifth International Concrete on Structural Failure, Durability Retrofitting Singapore November 27-28. PP 429 - 439.
[7]. Sinha, D.A, Varma, A.K and, Prakash, K.B, (2013), "Properties of ternary blended steel fibre reinforced concrete", The Indian Concrete Journal, Vol- 87, August, pp. 26-30.
[8]. Siddique, R, (1997), "Properties of concrete reinforced with low percentage of synthetic fibres", Fifth International Concrete on Structural Failure, Durability Retrofitting Singapore November 27-28, pp. 448-455.