EFFECT OF RECYCLED PLASTIC IN CONCRETE ON ITS COMPRESSIVE AND FLEXURAL STRENGTH
Open Access
- Author:
- Wanjare, Prafful
- Graduate Program:
- Civil Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- November 08, 2023
- Committee Members:
- Dr. Ali Memari, Thesis Advisor/Co-Advisor
Bryan Vogt, Committee Member
Tong Qiu, Professor in Charge/Director of Graduate Studies
Benay Gursoy Toykoc, Committee Member
Aleksandra Radlińska, Committee Member - Keywords:
- Keywords: recycled plastic
concrete
HDPE
PET
LDPE
durability
sustainable construction
mechanical properties - Abstract:
- The integration of recycled plastics into concrete mixtures represents a significant stride towards sustainable construction practices. This research investigates the utilization of four distinct plastic types: High-Density Polyethylene (HDPE), Polyethylene Terephthalate (PET), Low-Density Polyethylene (LDPE), and a mixture of these plastics (Mix), as additives in concrete. The primary objective of the study presented in this thesis is to assess the influence of adding plastic beads to the concrete mixture on mechanical properties. The results presented in this thesis are part of a broader study, wherein an experimental approach is employed, encompassing tests for compressive strength, flexural strength, durability, and microstructural analysis. The results of the study for this thesis reveal that the incorporation of recycled plastics leads to varying effects on concrete properties. For example, characterized by its high strength and toughness, HDPE exhibits the least pronounced reduction in both compressive and flexural strengths. Recognized for its stiffness, PET follows HDPE in its impact on strength. The use of a mixed plastic by preparing a mixture of PET, HDPE, and LDPE, composition generates effects intermediate between HDPE and PET. Valued for its flexibility, LDPE imparts the mildest decrease in concrete strength among the plastics considered. The observed order of the reduction in composite properties not aligning with the pure component modulus of the plastics suggests that factors beyond individual material properties can influence mechanical performance. One hypothesis could be that the interfacial adhesion between the plastic particles and the concrete matrix, as well as the dispersion uniformity of the particles, play significant roles in determining the overall mechanical behavior of the composites. These factors may override the inherent modulus ranking of the plastics, highlighting the importance of interfacial interactions and composite microstructure in controlling performance. While this thesis is focused on strength properties, the broader project has additional objectives that are to be done as a continuation of this part and include the durability aspects of plastic-modified concrete, exploring resistance to environmental factors such as freeze-thaw cycles and chemical exposure. Furthermore, microscopic analysis elucidates the interaction/bond between plastic particles and the cementitious matrix. The findings provide valuable insights into the viability of utilizing recycled plastics in concrete construction, offering a nuanced understanding of the strengths and limitations associated with different plastic types. This research contributes to the ongoing efforts to enhance sustainability in the construction industry by reducing plastic waste while expanding the repertoire of eco-friendly construction materials.