iosr-JMCE   Volume-4 ~ Issue-2

Abstract: Properties of concrete depend up on properties of ingredients and their relative proportion. Due to addition of mineral as well as chemical admixture in concrete design of concrete mixes has become increasingly complex. BIS has rationalized concrete mix proportioning code in Dec 2009, which is used to design standard concrete mixes using both mineral as well as chemical admixtures. By considering the code, the present work deals with the development of fly ash based concrete mix proportion. This paper presents the results of an investigation dealing with Concrete cubes of 100 mm size, to replace 0%, 5%, 10% and 15% cement with fly ash. To cover a wide range of concrete mixes water cementitious material ratio (W/C) of 0.3, 0.4 and 0.5 were used for water content of 186 kg/m3, 191.58 kg/m3 and 197.16 kg/m3 each. The effect of various parameters such as replacement of cement by fly ash, water to cementitious material ratio and water content is studied on fresh and hardened properties of concrete. The study mainly consisted of establishing relation between these parameters in the form of Graphs to specify proportioning of required fly ash based concrete. Both workability and strength aspects are considered.
Keywords:compressive strength, fly ash, Mix design, water content, W/C ratio

[1]. Indian standard concrete mix proportioning - Guidelines (First revision) IS: 10262-2009, Bureau of India Standard, New Delhi,
India.
[2]. Code of practice for plain and reinforced concrete (fourth edition) IS: 456-2000, Bureau of India Standard, New Delhi.
[3]. M.C. Nataraja and Lelin Das, "Concrete mix proportioning as per IS: 10262-2009 Comparison with IS: 10262-1982 and ACI
211.1-91." THE INDIAN CONCRETE JOURNAL, September 2010.
[4]. S.C. Maiti, Raj K. Agarwal and Rajeeb Kumar, "Concrete mix proportioning" THE INDIAN CONCRETE JOURNAL,
December 2006.
[5]. Durocrete Engineering services pvt. Lit. "Mix Design Manual."
[6]. M.C. Nataraja and Lelin Das, "Some studies on concrete mix proportioning following IS 10262-2009." THE INDIAN
CONCRETE JOURNAL, January 2011.
[7]. Mukund joshi, "performance of fly ash and understanding IS: 3812-2003(part-1)," CE and CR, April 2005, pp. 45-48.
[8]. Abrams, D. A., Design of Concrete Mixtures, Lewis Institute, Structural Materials Research Laboratory, Bulletin No.1, PCA
LS001, Chicago, 1918.
[9]. Shilstone, James M., Sr., "Concrete Mixture Optimization," Concrete International, American Concrete Institute, Farmington
Hills, Michigan, June 1990.
[10]. IS 383, "Specifications for Coarse and Fine Aggregates from Natural Source of Concrete," Bureau of Indian standard New
Delhi, 1982.

Abstract: Tensile behaviour was investigated for reinforcing steel bars used in the Nigerian Construction Industry; this was done to ascertain the level of conformity of the tested parameters with the standards. A total of thirteen (13) companies operating in Nigeria were considered and (19) nineteen samples selected randomly with each sample containing ten specimens which were used in the tests. Out of the nineteen (19) samples, thirteen (13) were locally produced in Nigeria, while six (6) were imported. Thus, a total of 190 specimens were used for the experiment. It was found that eleven (11) samples out of the nineteen (19) samples examined failed to meet the requirements of BS4449:1997 in respect of the characteristic strength. In case of the Ultimate: Yield ratio, while only one (1) out of the nineteen (19) samples did not record the minimum values of 1.25 as prescribed by the code.
Keywords:Yield, Ultimate, And Tensile: Yield Ratio.

[1] Arum, C. (2008): "Verification of Properties of Concrete Reinforcement Bars:- Nigerian Case Study" - Published by : A Journal of Indoor and Built Environment by SAGE Publications. http:ibe.sagepub.com PP.370-376
[2] American Society for Testing of Materials (2003): AASHTO No. M 31 "Standard Specifications for Deformed & Plain Billet Steel Bars for Concrete Reinforcement": American Association of Highway and Transport Officials - A615/A615M- 03a
[3] American Society for Testing of Materials: (2007) "Standard Test Methods and Definitions for Mechanical Testing of Steel Products": ASTM A37-07a
[4] American Society for Testing of Materials: (1988) "Standard Specifications for Structural Steel", ASTM – A38/A38M, 25th edition, pp.105
[5] American Society for Testing of Materials: (1988) "Standard Specifications for Structural Steel", ASTM – A38/A38M, 25th edition, pp.562
[6] British Standards Institutions. BS 4449(1997) -"Carbon Steel Bars for the Reinforcement of concrete" London. pp.1-17
[7] Charles K.K. and Mark A (2002) "Strength & Ductility Characteristics of Reinforcing Steel Bar milled from Scrap Metals"- Materials and Design 23 pp.537-545
[8] Certification Authority for Reinforcement Steels (1984-1995) (UK CARES Vol. 1 – 10).
[9] FIROZE, P.E. Engr. "Attributes of Ductile Reinforcing Steel" – PDF Extracts from internet – m.firoze@bsm.com . pp. 18-20
[10] Jibrin, M.U. (2012): "Characterisation of Reinforcing Bars in the Nigerian Construction Industry" A Ph.D Thesis in Civil Engineering , Ahmadu Bello University, Zaria – Nigeria. PP. 44 - 94

Abstract:Scheduling problem for repetitive construction projects involves three conflicting objectives. These objectives are project duration, project total cost, and project total interruption time. This paper presents a multi-objective fuzzy linear programming model (FLP) for resolving this problem. Literature concerned with scheduling problems for repetitive construction projects was reviewed. Multi-objective fuzzy linear programming was then explained. The proposed model formulation was then presented. A bridge project from pertinent literature was selected for model validation purpose. An optimization of each individual objective was performed with a linear programming (LP) software (Lindo) that gave the upper and lower bounds for the multi-objective analysis. Fuzzy linear programming was then applied to optimize the solution. Two scenarios were adopted in solution. In the first scenario, the three above objectives were considered simultaneously. Analysis of the results revealed that project duration, and project total cost are deviated only by 7.2%, and 1.8%, respectively as compared to their corresponding ideal values in the crisp LP model. On the other hand, the percentage of total interruption time to project duration in FLP is 5.3% against zero in LP. In the second scenario, each two objectives were considered in a single run. The purpose is to explain how can the model's user generate and evaluate the optimal tradeoff solution between any two objectives that suit his demands.
Keywords:Fuzzy Linear Programming; Linear Programming; Repetitive Construction Projects; Multi Objective Analysis.

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[3] Faheem, M.I., Khalique, M.A., and Kalam, M.A..."Project Management Decisions Using Fuzzy Linear Programming." International J. of Multidispl. Research, ISSN 0975-7074, Vol. 2, No. I, April, 2010, 323-339.
[4] Chang, N.B., Wen, C.G., and Chen, Y.L... "A Fuzzy Multi-objective Programming Approach for Optimal Management of the Reservoir Watershed." European j. of Operational Research, 99, 1997, 289-302.
[5] Bragadin, M.A., and Kahkonen, K.,"Heuristic Solution for Resource Scheduling for Repetitive Construction Projects." Proc. of Management and Innovation for a Sustainable Built Environment conf., Amsterdam, Netherlands, June 2011.
[6] Ammar, M. "Integrated LOB and CPM Method for Scheduling Repetitive Projects." J. Constr. Eng. Manage., 134(4),2012.
[7] Selinger, S.."Construction Planning for Linear Projects." J.Constr. Div., ASCE, 106(2), 1980, 195-205.
[8] Russell, A., and Caselton, W." Extensions to Linear Scheduling Optimization.' J. Constr. Eng. Manage., 114(1), 1988, 36-52.
[9] Handa, V.K., and Barcia, R.M..."Linear Scheduling Using Optimal Control Theory." J. Constr. Eng. Manage., 112(3), 1986, 387-393.
[10] El-Rayes, K., and Moselhi, O. "Optimizing Resource Utilization for Repetitive Construction Projects." J. Constr. Eng. Manage., 127(1), 2001, 18-27.