24-hour Fire Produced Effect on Reinforced Recycled Aggregates Concrete Beams

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

Abstract


In this article, the effect of prolonged fire (24-hour duration) on reinforced concrete beams made with recycled aggregates from demolished concrete was experimentally investigated. Demolished concrete was used recycled coarse aggregates in equal proportion with natural coarse aggregates. Normal and rich mix concrete with water-cement ratio equal to 0.54 were used. As a control specimen, beams with all-natural aggregates were also cast to compare with the results of the proposed beams. All beams were cured for 28 days and exposed to fire at 1000°C in an oven for 24 hours. After the elapse of this fire period, the beams were allowed to air cool, followed by testing till failure in a universal load testing machine. Comparison of the test results shows that rich mix concrete beams more reduction in flexural strength, more increase in maximum load carrying capacity and deflection than normal mix beams. The maximum reduction in flexural strength was 32.41% for beams cast with 50% RCA and rich mix. Although the fire duration used in this study is rare, yet the outcome provides guidelines for taking proper decisions for retrofitting/strengthening of the fire affected structure before putting it back in service.


Keywords


green concrete; fire effect; flexural behavior; demolished waste; recyclable aggregates

Full Text:

PDF

References


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

B. G. Fonteboa, S. Seara-Paz, J. D. Brito, I. G. Taboada, F. M. Abella, R. V. Silva, “Recycled concrete with coarse recycled aggregates. An overview and analysis”, Materiales de Construccion, Vol. 68, No. 330, 2018

M. Malesev, V. Radonjanin, G. Broceta, “Properties of recycled aggregate concrete”, Contemporary Materials, Vol. 2, pp. 239-249, 2014

M. Oad, B. A. Memon, “Compressive Strength of Concrete Cylinders Using Coarse Aggregates from Old Concrete”, 1st National Conference on Civil Engineering, Modern Trends and Advancements, Pakistan, April 28–29, 2014

M. Oad, A. H. Buller, B. A. Memon, N. A. Memon, “Flexural stress-strain behavior of rc beams made with partial replacement of coarse aggregates with coarse aggregates from old concrete: Part-1: 1:2:4 ratio”, Engineering Technology and Applied Science Research, Vol. 8, No. 3, pp. 3048-3053, 2018

M. Oad, A. H. Buller, B. A. Memon, N. A. Memon, S. Sohu, “Flexural stress-strain behavior of rc beams made with partial replacement of coarse aggregates with recyclable concrete aggregate: Part-2: Rich mix”, Engineering Technology and Applied Science Research, Vol. 8, No. 5, pp. 3338-3343, 2018

A. H. Buller, B. A. Memon, “Effect of Fire on Strength of Concrete Cubes with RCA as Coarse Aggregates”, 1st National Conference on Civil Engineering-Modern Trends and Advancements, Pakistan, April 28–29, 2014

C. J. Zega, A. A. Di Maio, “Recycled concrete exposed to high temperatures”, Magazine of Concrete Research, Vol. 58, No. 10, pp. 675-682, 2006

F. U. A. Shaikh, “Mechanical properties of concrete containing recycled coarse aggregate at and after exposure to elevated temperatures”, Structural Concrete, Vol. 19, No. 2, pp. 400-410, 2018

S. R. Sarhat, E. G. Sherwood, “Residual mechanical response of recycled aggregate concrete after exposure to elevated temperatures”, Journal of Materials in Civil Engineering, Vol. 25, No. 11, 2013

I. Adebakin, T. Ipaye, “Effect of elevated temperature on the compressive strength of recycled aggregate concrete”, Journal of Engineering Sciences, Vol. 5, No. 9, pp. 2278-9472, 2016

G. M. Chen, Y. H. He, H. Yang, J. F. Chen, Y. C. Guo, “Compressive behavior of steel fiber reinforced recycled aggregate concrete after exposure to elevated temperatures”, Construction and Building Materials, Vol. 71, pp. 1-15, 2014

A. Gupta, S. Ghosh, S. Mandal, “Coated recycled aggregate concrete exposed to elevated temperature”, Global Journal of Researches in Engineering – Civil and Structural Engineering, Vol. 12, No. 3, 2012

G. Etse, S. M. Vresh, M. Ripani, “Constitutive theory for recycled aggregate concretes subjected to high temperature”, Construction and Building Materials, Vol. 111, pp. 43-53, 2016

G. Gowda, B. S. Rao, S. M. Naik, “Behavior of recycled aggregate concrete on exposed to elevated temperature”, International Journal of Civil Engineering, Vol. 4, No. 6, pp. 5-13, 2017

ASTM, Active Standard ASTM C131/C131M: Standard Test Method for Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine, ASTM, 2008

ASTM, Active Standard ASTM C293/C293M-16: Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Center-Point Loading), ASTM, 2008

A. H. Buller, M. Oad, B. A. Memon, “Flexural strength of reinforced concrete rac beams exposed to 6-hour rire: Part 2: Rich mix”, Engineering Technology and Applied Science Research, Vol. 9, No. 1, pp. 3813-3816, 2019




eISSN: 1792-8036     pISSN: 2241-4487