The impact of recycled polyethylene terephthalate as aggregate replacement on mechanical and ecotoxicological properties of mortar

Legan, Maša (author), Štukovnik, Petra (author), Zupan, Klementina (author), Žgajnar Gotvajn, Andreja (author)

The purpose of the study was to determine the mechanical and ecotoxicological properties of mortars with differently shaped recycled PET plastics as a partial natural aggregate replacement and assess its environmental impact. Different methods were used for determining mechanical properties, while ecotoxicity tests with two types of plants were performed for the assessment of the ecotoxicological potential of mortars. Results of strength tests revealed that PET in mortars increased 28-day compressive strength by up to 3% and decreased flexural strength by up to 14% compared to conventional mortar. Ultrasonic pulse velocity and dynamic modulus of elasticity were lower in PET mortars, while XRD and SEM-EDS showed fewer hydration products in PET mortars. Duckweed ecotoxicity test results revealed that frond growth inhibition values in PETS and conventional mortar leachate (100 g L$^{−1}$) were around 50%, while root growth inhibition values did not exceed 40%. Mustard seed germination test results revealed root growth inhibition values in both mortar leachates were lower than 20%. Ecotoxicity tests showed that conventional and PET mortar were non-toxic to duckweed in aquatic environments and non-toxic to mustard seeds in terrestrial environments. Characterization of mortar leachates showed a significant increase in chloride, Ca, Si, and Ba content as potential causes for growth inhibition of both plants. Plastic waste reduction due to the potential use of PET in mortars confirmed that plastic waste could be completely eliminated and the global consumption of primary natural resources for concrete production reduced up to 4%. Such an approach could increase mortar sustainability.

• Language: English
• Keywords: cement mortar, ecotoxicological properties, mechanical properties, natural aggregate, recycled PET plastic, plastic waste reduction, sustainability
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology; FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 28 str.
• Numbering: Vol. 10, iss. 1, art. 8
• PID: 20.500.12556/RUL-166779
• UDC: 502/504:666.971.4:678.742.2
• ISSN on article: 2313-4321
• DOI: 10.3390/recycling10010008
• COBISS.SI-ID: 222653699
• Publication date in RUL: 24.01.2025

Record is a part of a journal

• Title: Recycling
• Shortened title: Recycling
• Publisher: MDPI AG
• ISSN: 2313-4321
• COBISS.SI-ID: 526328345

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: cementna malta, ekotoksikološke lastnosti, mehanske lastnosti, naravni agregati, reciklirana PET plastika, zmanjšanje količine plastičnih odpadkov, trajnost