Flexural Stress-Strain Behavior of RC Beams made with Partial Replacement of Coarse Aggregates with Coarse Aggregates from Old Concrete: Part-2: Rich Mix

M. Oad, A. H. Buller, B. A. Memon, N. A. Memon, S. Sohu


Crowded city centers pose serious problems of infrastructure and associated facilities. Construction industry is obliged to opt for vertical construction in place of short height structures in order to meet with the needs. This leads to the generation of huge quantities of demolishing waste whose management is a serious issue. One of its best uses is its utilization in new concrete. Concrete is widely used in construction industry. Normally 1:2:4 mix is used, but the use of rich mix is also common in columns and elsewhere. Therefore, this research work focuses on evaluating the flexural stress-strain behavior of rich concrete mix beams made with 50% replacement of natural coarse aggregates with coarse aggregates from old concrete. A total of 12 reinforced concrete beams 1:1.5:3 ratio mix and 0.54 w/c ratio are prepared in two batches in 0.9mx0.15mx0.15m beams. In the first batch, natural coarse aggregates are replaced in 50% with coarse aggregates from demolished concrete and the second batch contains beams made with all-natural coarse aggregates. To reinforce the beams, 2#4 deformed bars are used in compression and tension zone along with #3 stirrups at 15cm c/c all along the length of the beam. In each batch, half of the beams are cured for 7 days and half for 28 days. After curing, all beams are tested for load, deflection, and strain in a universal load testing machine. All parameters are recorded at regular intervals and cracking and failure patterns are monitored. From obtained results, it is analyzed that the beams presented 11.68% reduction in flexural capacity. Cracking pattern and failure mode of the beams is similar to those of the control specimen.


flexural stress; green concrete; old concrete; recycled coarse aggregates; strain

Full Text:



B. A. Memon, “Recent Development on Use of Demolished Concrete as Coarse Aggregates”, International Journal of Emerging Technology and Innovative Engineering, Vol. 2, No. 1, pp. 1-11, 2016

S. Tanwani, B. A. Memon, “Relationship Between Weight and Tensile Strength of Concrete Cylinders Made by Partial Replacement of Coarse Aggregates from Old Concrete”, International Journal of Engineering Inventions, Vol. 5, No. 6, pp. 1-9, 2016

M. Oad, B. A. Memon, “Compressive Strength of Concrete Cylinders using Coarse Aggregates from Old Concrete”, 1st National Conference on Civil Engineering (NCCE 2013-14) - (Modern Trends and Advancements), April 28-29, 2014

A. A. Bhatti, B. A. Memon, “Strength, Deflection and Cracking Behavior of Concrete Slab Using Demolished Concrete as Coarse Aggregates”, International Journal of Engineering Sciences & Research Technology, Vol. 3, No. 6, pp. 492-506, 2014

B. A. Memon, G. S. Bhatti, “Lexural Behavior of Beam made by Partial Replacement of Natural Aggregates with Coarse Aggregates from Old Concrete”, International Journal of Engineering Sciences & Research Technology, Vol. 3, No. 5, pp. 52-61, 2014

M. O. A. Mtallib, A. I. Marke, “Comparative Evaluation of the Flexural Strength of Concrete and Colcrete”, Nigerian Journal of Technology, Vo. 29, No. 1, pp. 13-22, 2010

P. A. Bekoe, Concrete Containing Recycled Concrete Aggregate for use in Concrete Pavement”, MSc Thesis, University of Florida, 2009

J. O. Ukpata, M. E. Ephraim, “Flexural and Tensile Strength Properties of Concrete using Lateritic Sand and Quarry Dust as Fine Aggregates”, ARPN Journal of Engineering and Applied Sciences, Vol. 7, No. 3, pp. 324-331, 2012

W. Bai, B. Sun, “Experimental Study on Flexural Behavior of Recycled Coarse Aggregate Concrete Beam”, Applied Mechanics and Materials, Vol. 29-32, pp. 543-548, 2010

G. N. Yang, B. R. Huo, M. X. Zheng, “Flexural Behavior of Reinforced Concrete Beams Strengthened with BFRP Bars”, International Conference on Power Electronics and Energy Engineering (PEEE 2015), Hong Kong, China, April 19-20, 2015

M. Kaarthik, K. Subrmanian, “Flexural Behavior of Concrete Beams using Recycled Fine Aggregates and Steel Fibers”, International Conference on Biological, Civil and Environmental Engineering, Dubai, UAE, March 17-18, 2014

M. Kosior-Kazberuk, M. Grzywa, “Recycled Aggregate Concrete as Material for Reinforced Concrete Structures”, Journal of Sustainable Architecture and Civil Engineering, Vol. 2 No. 7, pp. 60-66, 2014

R. Sato, I. Maruyama, T. Sogabe, M. Sogo, “Flexural Behavior of Reinforced Recycled Concrete Beams”, Journal of Advanced Concrete Technology, Vol. 5, No. 1, pp. 43-61, 2007

ACI 318, Building Code Requirement For Structural Concrete, American Concrete Institute, 2005

eISSN: 1792-8036     pISSN: 2241-4487