Investigation Using Granular Material Obtained from High-Density Polyethylene and Polypropylene Plastic Waste as...

Area of Science:

• Materials Science
• Environmental Science
• Civil Engineering

Background:

• Plastic waste accumulation poses a global environmental threat.
• Reusing plastic waste in construction offers a sustainable solution.
• Recycled plastics can potentially replace traditional aggregates in building materials.

Purpose of the Study:

• To investigate the feasibility of using recycled high-density polyethylene (HDPE) and polypropylene (PP) as partial aggregate replacements in mortar.
• To evaluate the impact of these plastic aggregates on mortar's physical and mechanical properties.
• To determine the optimal replacement percentage for enhanced performance.

Main Methods:

• Seven mortar mixtures were prepared with 10%, 20%, and 30% volumetric replacement of limestone aggregate with HDPE and PP.
• Properties evaluated included flow value, unit weight, water absorption, porosity, compressive strength, flexural strength, and capillary water absorption.
• Results were compared against a control mixture without plastic aggregates.

Main Results:

• Plastic aggregates significantly improved mortar workability (flow increased by 9%–13%) and reduced unit weight (by 15%–15.3%).
• Compressive and flexural strengths decreased substantially (48%–30% and 46%–54%, respectively) with increasing plastic content.
• Water absorption and porosity values increased with the addition of HDPE and PP aggregates.

Conclusions:

• Incorporating recycled HDPE and PP as partial aggregate replacement in mortar enhances workability and reduces density.
• While beneficial for workability, plastic aggregates negatively impact mechanical strength and increase water absorption.
• A 10% replacement level was identified as the optimum for balancing performance characteristics in sustainable mortar applications.