Paving blocks produced with crushed glass and high-density polyethylene: A case study of glass bottle and plastic waste management on Si Chang Island

Abstract

This study aimed to increase alternate methods of managing waste problems on Si Chang Island, where crushed glass and high-density polyethylene (HDPE) granules were used in the production of paving blocks. This study used these materials as fine aggregates for the production of paving blocks with a mold size of 50 × 50 × 50 mm. We tested six ratios of paving block by replacing sand with 0 %, 5 %, 10 %, 15 %, and 20 % wt. of crushed glass and 0 %, 5 %, 10 %, 15 %, and 20 % wt. of HDPE granules. The initial binder to fine aggregate to coarse aggregate ratio was 1:2:2. The water-to-cement ratio was 0.4, and the superplasticizer-to-cement ratio was 0.005. After curing in water at room temperature for 28 days, the specimens’ compressive strength, water absorption, and carbon emissions were tested. The findings show that replacing sand with 20 % crushed glass resulted in the highest compressive strength (27.00 MPa) and that substituting sand with 20 % HDPE granules resulted in the lowest compressive strength (3.60 MPa). Replacing sand with crushed glass reduced the water absorption value, and substituting sand with HDPE granules increased water absorption. The highest compressive strength specimen had a carbon footprint higher than the control due to the carbon emissions produced by using a glass grinding machine. In terms of usage, while no specimens were compliant with the American Society for Testing and Materials C140 standard, all ratios were compliant with the Thai Industrial Standards Institute 378–2531 standard. Thus, they are suitable for use as concrete tiles and walkways in public areas such as parks. However, the glass and plastic grinding process should be improved to reduce carbon emissions.

Keywords

• Crushed glass
• HDPE granules
• Paving block
• Carbon footprint