Replacement of Fine Aggregate with Crumb Rubber

Abstract

The use of crumb rubber as a replacement for fine aggregates in concrete has gained attention due to the environmental and economic benefits it offers, particularly in reducing waste from used tires. This study investigates the effects of replacing fine aggregates with varying percentages of crumb rubber (5%, 7% and 9%) on the properties of concrete. Concrete mixes were prepared, and their workability, compressive strength, and durability characteristics were tested. The results indicated a decrease in compressive strength as the percentage of crumb rubber increased, due to the lower density and weaker bonding between crumb rubber particles and cement paste. However, the incorporation of crumb rubber improved the concrete\'s flexibility and impact resistance, making it a potential candidate for specific applications such as pavement construction and non-structural elements. The study also highlights the environmental benefits of reusing crumb rubber, contributing to waste management and promoting sustainability in the construction industry. Further research is recommended to optimize the mix designs and explore the long-term performance of crumb rubber concrete in various environmental conditions.

Introduction

Overview:
Partially replacing fine aggregate in concrete with crumb rubber—small granules made from recycled tires—offers cost savings, improves concrete quality, and reduces greenhouse gas emissions. Optimal replacement (around 15% combined with other materials) slightly enhances concrete strength and durability while contributing to environmental benefits by recycling waste tires.

Benefits of Crumb Rubber in Concrete:

• Mechanical improvements:

  • Increases compressive strength by over 5%.

  • Enhances elasticity and energy absorption, reducing brittleness.

• Durability improvements:

  • Lowers permeability, resisting water and chloride ion penetration.

  • Increases resistance to freeze-thaw cycles and chemical attacks.

  • Helps reduce carbonation and prevents shrinkage cracks.

• Environmental impact:

  • Provides a sustainable way to reuse discarded tires, reducing landfill waste.

  • Lowers the carbon footprint associated with concrete production.

Experimental Program:

• Concrete cubes (15 cm each) were made with crumb rubber replacing fine aggregate at 5%, 7%, and 9%.

• Tests conducted: slump cone (workability), compaction factor, and compressive strength at curing intervals of 7, 14, and 28 days.

Results:

• The 7% replacement showed the highest compressive strength across all curing days.

• Increasing crumb rubber beyond 7% led to a noticeable drop in strength.

Conclusion

As expected, the addition of crumb rubber reduces the workability of concrete, especially at higher replacement levels. The incorporation of crumb rubber decreases the compressive strength of concrete. While the reduction is not severe at lower replacement levels (5–10%), it becomes significant at higher levels (15–20%).The durability tests revealed a decrease in water absorption and chloride resistance with the increase in crumb rubber content. This suggests that crumb rubber could compromise the concrete’s long-term durability.

References

[1] Rubber Manufacturer’s Association, NW Suite 900, Washington DC 20005,2000 [2] Tantala, M.W., Lepore, J.A., and Zandi, I., “Quasi-elastic behavior of rubber included concrete”, Proceedings 12th International Conference on Solid Waste Technology and Management, Philadelphia, 1996. [3] Paul, J., Encyclopedia of polymer science and engineering, Vol. 14, 1985, pp. 787-802. [4] Takallou, H.B. and Takallou, m.B., Elastomeric, Vol. 123, 1991, pp.9. [5] O’Keefe, W., Power, Vol. 128, No. 10, October 1984, pp. 115.

Copyright

Copyright © 2025 Dhumal Chandrashekhar Hanmant, Keskar Samadhan Sanjay, Aiwale Kirti Amir, Lawate Prajkta Hari, Gawade Rohini Sunil. 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.