Evaluating Concrete Strength by Replacing Coarse Aggregate with Steel Slag and Cement with Bentonite Powder

Abstract

This research investigates the mechanical strength of concrete by partially replacing cement with bentonite powder and coarse aggregate with steel slag. Bentonite is used at replacement levels of 0%, 10%, 20%, and 30%, while steel slag is uniformly incorporated at 60%. To assess the performance, tests such as compressive strength, split tensile strength, and flexural strength are performed. The results demonstrate enhanced strength properties compared to traditional concrete. Prior studies on the use of bentonite and steel slag highlight their promising potential, and this experiment aims to specifically analyze the strength behavior of concrete incorporating these alternative materials.

Introduction

Summary:

Concrete is a widely used construction material composed of cement, sand, coarse aggregates, and water, valued for its strength and versatility but limited by low tensile strength and cracking issues. Due to environmental concerns and increasing costs of natural aggregates, this study investigates sustainable concrete by partially replacing cement with bentonite powder and coarse aggregates with steel slag.

Objectives:

1. Assess strength improvements using bentonite powder and steel slag.

2. Compare properties of modified concrete (with replacements) to conventional M30 concrete.

3. Identify the optimal percentage of bentonite powder for cement replacement without degrading performance.

Methodology:
Concrete specimens (cubes, cylinders, beams) were prepared with varying replacement levels of cement by bentonite (0%, 10%, 20%, 30%) and coarse aggregates by steel slag (60%). Material quantities were calculated accordingly.

Results:

• Workability: Slump tests showed minor variation with replacements, maintaining good workability.

• Compressive Strength: Increased strength observed up to 20% bentonite replacement with steel slag; 30% replacement led to strength reduction.

• Split Tensile Strength: Improved tensile strength with 10-20% bentonite, declining at 30%.

• Flexural Strength: Similar trend to compressive strength, with peak performance at 20% bentonite replacement.

Conclusion

Based on the findings and observations from this experimental study, the following conclusions have been drawn: 1) This research demonstrates an effective method for producing strong and durable concrete while addressing the disposal issues associated with steel slag. 2) Test results indicate that replacing cement with up to 20 percent bentonite enhances compressive strength and split tensile strength. However, using bentonite in equal proportion to conventional cement proves to be inefficient. 3) The study confirms that bentonite can partially replace cement without significantly affecting the concrete\'s strength characteristics. 4) The compressive, split tensile, and flexural strengths of cubes, cylinders, and beams improve when 10 percent and 20 percent of cement is replaced with bentonite and 60 percent of coarse aggregates with steel slag. However, replacing 30 percent of cement with bentonite and 60 percent of coarse aggregates with steel slag results in a decline in strength. 5) A 14.23 and 13.85 percent increase in compressive strength is observed at 20 percent cement replacement with bentonite and 60 percent coarse aggregate replacement with steel slag at 7 and 28 days, respectively, compared to conventional concrete. However, strength decreases by 10.11 and 12.37 percent when 30 percent cement is replaced with bentonite and 60 percent coarse aggregate with steel slag, using an aggregate-to-cement (A/C) ratio of 3.25 and water-to-cement (W/C) ratio of 0.40. 6) An increase of 15.63 and 10.52 percent in split tensile strength and 13.33 and 12.86 percent in flexural strength is recorded at 20 percent cement replacement with bentonite and 60 percent coarse aggregate replacement with steel slag at 7 and 28 days, respectively. However, a reduction of 10.68 and 8.26 percent in split tensile strength and 19.32 and 9.84 percent in flexural strength is noted when 30 percent cement is replaced with bentonite and 60 percent coarse aggregate with steel slag, maintaining an A/C ratio of 3.25 and W/C ratio of 0.40.

References

[1] M. Karthikeyan, P. Raja Ramachandran, A. Nandhini, R. Vinodha (2008), “Study on the partial replacement of fine aggregate using induction furnace slag”, American Journal of Engineering Research, vol-4, pp 01-05. [2] P. Santoshkumar (2014), “Effect of Bentonite on the Rheological of superplasticizerbehavior of cement grout in presence”, International Journal of Civil, Environmental Engineering. [3] Surya M C Arya Krishna, Bincy Paul (2019), “Study on Concrete using Steel Slag as Coarse Structural, Construction and Architectural Engineering, vol:8, no:11. [4] Aggregate replacement and Eco sand as Fine Aggregate replacement” IJREAT International Journal of Research in Engineering & Advanced Technology, volume 1, issue 3, june-july, 2013. [5] Junaid Akbar, Bashir Alam, Muhammad Ashraf, Salman Afzal, Asfandyar Ahmad, Khan Shahzada (2017), “Usability of sand-bentonite-cement mixture in the construction of impermeable layer”, Scientific Research and essays vol. 6(21), pp. 4492-4503, 30. [6] M. Aravindhraj, B. T. Sapna (2014), “Effects of Polymer and Bentonite support fluids on concrete–sand interface shear strength”, C. Geotechnique 64, No.1, 28–39. [7] R. Selvaraj, R. Priyanka, “Experimental investigation of using slag as an alternative to normal aggregates (coarse and fine) in concrete”, International Journal of Civil and Structural Engineering volume 3, No 1. [8] Subathra Devi. V, Gnanavel. B. K, Murthi. P, “Uilization of industrial waste slag as aggregate in concrete applications by adopting taguchi’s, approach for optimization”, India open journal of civil Engineering, 2012, 2, 96-105. [9] R. Padmapriya, V. K. Bupesh Raja, V. Ganesh kumar, and J. Baalamurugan, “Concrete containing Steel Slag Aggregate: Performance After high temperature exposure”, Concrete Repair, Rehabilitation and Retrofitting III. [10] Ravikumar H, Dr. J. K. Dattatreya, Dr. K. P Shivananda, “Study on Strength Properties of Concrete by Partially Replacement of Sand by Steel Slag”, International Journal of Engineering Technology and Sciences, volume 1, Issue-6, oct 2014. [11] P. S. Kothai1, Dr. R. Malathy “Hydraulic Conductivity and Small-Strain stiffness of a Cement-Bentonite sample exposed to sulphates \"Laboratory of Geotechnics, Ghent University, Belgium. [12] IS 10262:2009, “Ordinary concrete mix design guidelines”, Bureau of Indian Standards, New Delhi. [13] IS 456:2000, “Plain and Reinforced Concrete”, Bureau of Indian Standards, New Delhi. [14] IS 10262-2009 Indian Standard Concrete Mix Proportion [15] IS 15658-2006 Indian Standard Precast Concrete Blocks for Specimen. [16] A. Khitab, W. Anwar, I. Mehmood, U.A. Khan, S. Minhaj, S. Kazmi, M.J. Munir, Sustainable Construction with Advanced Biomaterials: An Overview, Sci.Int.(Lahore). 28 (2016) 2351–2356. [17] A. Khitab, W. Anwar, I. Mansouri, M.K. Tariq, I. Mehmood, Future of civil engineering materials: A review from recent developments, Rev. Adv. Mater. Sci. 42 (2015) 20–27. [18] J. Liu, Q. Yu, W. Duan, Q. Qin, Experimental investigation of glass content of blast furnace slag by dry granulation, Environ. Prog. Sustain. Energy. 34 (2015) 485–491. doi:10.1002/ep.12024. [19] Awoyera et al. (2015) Influence of Electric Arc Furnace (EAF) Slag Aggregate Sizes on the Workability and Durability of Concrete, International Journal of Engineering and Technology (IJET), Vol 7 No 3 Jun-Jul 2015. [20] Biradar, K. B., kumar, A. U. And Satyanarayana, P.V.V. (2014) Influence of Steel Slag and Fly Ash on Strength Properties of Clayey Soil: A Comparative Study, International Journal of Engineering Trends and Technology (IJETT) – Volume 14 Number 2 – Aug 2014. [21] Brindha, D., Baskaran,T, and Nagan,S. (2010) Assessment of Corrosion and Durability Characteristics of Copper Slag Admixed Concrete, International Journal Of Civil And Structural Engineering, Vol. 1, no. 2, pp.192-211. [22] Bhagwan, J. and Guru Vittal, U. K. (2014) Use of Marginal Materials for Rural Road Construction - Some Recent Initiatives, Proceedings of Indian Geotechnical Conference IGC-2014 December 18-20, 2014, Kakinada, India.

Copyright

Copyright © 2025 Krishna Sahebrao Rathod, Prof. Vaibhav B. Chavan . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.