Document Type : Research Paper

Authors

Civil Engineering Department, University of Technology, Baghdad, Iraq.

Abstract

Protection of environmental and conservation of natural resources is a fundamental issue in today’s world. In this research, the shear behavior of reinforced concrete box girders with recycled aggregate (RA), steel fiber, and internal diaphragms were investigated. Eleven reinforced concrete box girders with typical longitudinal and transverse reinforcement were tested under two point loading until failure. The RA was prepared by crushing the collected waste of concrete from the laboratory test cylinders and cubes. The experimental variables considered include; RA percent of 50%, 75%, and 100%(replacing from NA), steel fiber with volumetric ratios (Vf) of 0.5%, 1.0%, and 2%, diaphragm numbers (two and three).The test results revealed that the shear strength of the box girders affected by the RA content, the ultimate load was decreased by (32, 25, and 19) % for the (100, 75, and 50) %RA concrete, respectively in compared with the control specimen. In contrast the steel fiber was more effective in strengthening of the RA concrete specimen, for the (Vf) of 0.5%, 1.0%, and 2.0% with non-fibrous 100% RA concrete, the strengthening were (25, 40, and 77) % respectively. Moreover, when 1.0% steel fibers added to the 100%, 75%, and 50%RA concrete respectively, the strengthening were (40 ,45 ,and48 )% compared  each with its reference specimen.  On the other hand, when two and three diaphragms used, the strengthening for the non-fibrous 100% RA concrete was (6% and 9%) respectively. cracking load, ultimate load, load- deflection, and concrete surface strain has been taken into consideration in this research.

Highlights

  • The recycled aggregate concrete mix shows decrease in the cylindrical compressive strength, splitting tensile strength, flexural strength, and elastic modulus of concrete.
  • The RA has a significant effect on the load capacity of the box- girder without steel fibres.
  • The test results showed that it is recommended to use Vf of 1.0% steel fiber with 100 % RA to retain the NA concrete strength for the shear box-girder.

Keywords

[1] S. C. Kumar,V. K. Varanasi, and P. Saha,“Sustainable development usingsupplementarycementitiousmaterials and recycled aggregate,” International Journal of Modern Engineering Research (IJMER),Vol. 2, Issue.1, pp.165-171, 2015
[2] V. Radonjanin, M. Malešev, S. Marinkovic, and A. E. S. Al Malty, "Green recycled aggregate concrete," Construction and Building Materials, Vol.47, pp. 1503-1511,2013.
[3] A. M. Wagih, H. Z. El-Karmoty, M.Ebid, and S. H. Okba, "Recycled construction and demolition concrete waste as aggregate for structural concrete." HBRC Journal, Vol.9, pp. 193-200, 2013.
[4]  F. Debieb, L. Courard, S. Kenai, and R.Degeimbre "Mechanical and durability properties of concrete using contaminated recycled aggregates," Cement and Concrete Composites, Vol.32, pp.421-426, 2010.
[5] E.K. Sayhood, A.S. Resheq, and F.L. Raoof “Behavior of Recycled Aggregate Fibrous Reinforced Beams Under Flexural and Shear Loading” Engineering and Technology Journal, Vol. 37, Part C, No. 3, 2019
[6] M.A.E. Al Hamdani, M.M. Hamid and N.M. Al Hussiny, “The Influence of Recycled Crushing Strength of RC Beams under Repeated Loading,” Engineering and Technology Journal, Vol. 37, Part C, No. 1, pp. 93-100, 2019.
[7] V.Corinaldesi "Mechanical and elastic behaviour of concretes made of recycled-concrete coarse aggregates," Construction and Building Materials, Vol.24, pp.1616-1620, 2010.
[8] A.M. Knaack, Y. C. Kurama, “Design of normal strength concrete mixtures with recycled concrete aggregates,” ASCE, pp.3068–3079, 2014.
[9] Y. Guo, J. Zhang, G. Chen,andZ. Xie, “Compressive behaviour of concrete structures incorporating recycled concrete aggregates,” structural material J, Vol.60, pp. 78-96, 2014
[10] S. J. K. Al-Obaidy, “The Effects of Using Steel Fibers on Self-Compacting Concrete Properties: A Review,” Engineering and Technology Journal, Vol. 38, Part A, No. 11, pp. 1666-1675, 2020.
[11] A.Upadhyay, and S.Maru “Comparative Study of PSC Box Girder Multi Cell (3- Cell) Bridge of Different Shapes: A Review Paper,” Global Research and Development Journal for Engineering, Volume 2 , 2017.
[12] S. Manzi, C. Mazzotti, and M. C. Bignozzi, “Self-compacting concrete with recycled concrete aggregate: study of the long-term properties,” constructioin and building materials, Vol.157,pp. 582–590, 2017
[13] R. T. Abdulkareem, M. S.Hassan, I. N. Gorgis, “Effect of Steel Fibers, Polypropylene Fibers and/ or Nanosilicaon Mechanical Properties of Self-Consolidating Concrete” Engineering and Technology Journal, Vol. 34, Part A, No. 3, pp. 527-538, 2016.
[14] Iraqi Specification, No. 5, “Portland Cement” Baghdad,1984.
[15] ‎Iraqi Specification, No. 45, “Aggregate from Natural Sources for Concrete and    Construction”Baghdad,1984.
[16] American Society of Testing and Materials,“Standard Specifications for Concrete Aggregates,” ASTM C 33/C 33M-08, West Conshohocken, 2008.
[17] AASHTO LRFD Bridge Design Specifications" American Association of State Highway and Transportation Officials, USA, Fifth Edition, 2012.
[18] ACI committee 318, Building Code Requirements for Structure Concrete, (ACI 318M-14) and Commentary (ACI 318RM-14), American Concrete Institute, Farmington Hills, Michigan 2014.
[19] The European Federation of Specialist Construction Chemicals and Concrete Systems (EFNARC), “The European Guidelines for Self- Compacting Concrete; Specification, Production and Use”.2005.
[20] ASTM C 39/C 39M-05, "Standard Test Method for Compressive Strength of Cylindrical Test Specimens", Vol. 04.02, 2005, 9 pp.
[21] ASTM C496/C 496M-04, "Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens", Vol. 04.02,2004, 5 pp.
[22] ASTM C 78-02, “Standard Test Method for Flexural Strength of Hydraulic– Cement Mortars”, Vol. 04.02,  2002,  6 pp.
[23] ASTM C469-02 "Standard specification for testing method for static modulus of elasticity and poison's ratio of concrete in compression", Annual Book of ASTM Standards, American Society for Testing and Material, Philadelphia, Pennsylvania, Section 4, Vol.(4.02), pp 236-239, 2002.