Effects of Recycled Rubber Particles Incorporated as Partial Sand Replacement on Fresh and Hardened Properties of Cement-Based Concrete: Mechanical, Microstructural and Life Cycle Analyses

Abstract

Cement is one of the most valuable materials in today’s society, as it is used in most construction developments known to mankind. However, the energy intensive process and significant environmental impacts related to the production of Ordinary Portland Cement have shown the importance of searching for more sustainable materials. Concrete uses different aggregates added to the cement binder to lower, not only cost, but other factors like environmental burden, while maintaining good mechanical properties. This study analyzes the properties of fresh and hardened concrete incorporating recycled rubber to replace fine aggregate. Locally sourced 2 mm diameter rubber was incorporated in a regular strength concrete matrix into three different replacement levels, i.e., 3%, 5%, and 10%. Compression, tensile, flexural, and modulus of elasticity of hardened concrete were carried out in specimens aged 7, 14, and 28 days. In addition, non-destructive ultrasonic pulse velocity and rebound number tests were only performed on specimens aged 28 days. Once the tests were carried out, the fresh and hardened concrete properties were obtained. Similarly, the compressive and flexural strengths had the exact relationship between the values obtained. On the other hand, the modulus of elasticity tends to decrease due to the presence of the rubber. Consequently, it is recommended not to develop mix designs with more than 5% rubber because it is not meaningfully affected. The fine aggregate can be partially replaced by the rubber, keeping almost the same performance compared with sand-only counterparts. In addition, the life cycle assessment showed a reduction of up to 40% in the global warming potential. In fact, the 15% recycled rubber concrete mix has a climate change indicator of approximately 245 kg of CO2 eq.

Strength and durability assessment of high-strength concrete with weathered crystalline rock waste as a sustainable partial replacement for fine aggregate

“…Results of the compression test conducted on the specimens are shown in Figure 10. The results are similardecreasing with increase in the percentage of WCR replacement -to that of crushed clay brick for sand replacement done by GARCIA-TRONCOSO et al [45], OLOFINNADE et al [46] and ZHU and ZHU [47].…”

Comparative Analysis of Conventional Concrete Mixture and Concrete Incorporating Recycled Rubber and Iron Oxide

“…In [1], it is indicated that while rubber is a material that causes pollution, crushed rubber in recycled products helps reduce its negative impact on the environment. In a study conducted by [2], the viability of replacing fine aggregate with recycled rubber in different proportions in concrete is demonstrated without significantly affecting its compressive and flexural strength. [3] considered the possibility of replacing rubber for half of the total fine aggregate to promote the circular economy.…”