Volume 87, Issue 09 (2026), Pages: 18-34;
Received: 18 May 2026 / Revised: 13 June 2026 / Accepted: 26 August 2026 / Published: 08 September 2026
Research article
Sustainable Concrete: Enhancing Mechanical Properties and Reducing Carbon Footprint Using Recycled Plastic Aggregates and Fly Ash
Jonathan Price1, *, Pietre vander Hostare2, Tona Veeri3, Tori Black4, Nova Crista5 & Aries Schippers6
1,2Xinjiang Engineering college, Dept. of Structural Engineering, Karamay, Xinjiang, 834000, China
3State Key Laboratory of Safety and Disaster Prevention and Control, University of Science and Technology Beijing, Beijing, 100083, China
4,5Department of Electrical Engineering, Tokat Gaziosmanpaşa University, Tokat, Türkiye
6Faculty of Mechanical Engineering, Ain Chock, LPMAT Laboratory, Hassan II University, Casablanca, Morocco
Abstract: The construction industry faces critical environmental challenges due to the high carbon emissions of cement production and the depletion of natural aggregates. This study investigates the dual benefits of replacing conventional ingredients with industrial and consumer waste. We evaluated the structural performance of concrete mixes by substituting 10% to 30% of natural coarse aggregates with processed polyethylene terephthalate (PET) plastic waste. Simultaneously, we replaced 20% of Ordinary Portland Cement (OPC) with Class F fly ash. Standard curing regimes were conducted for 7, 14, and 28 days to measure compressive, tensile, and flexural strengths. The experimental results indicate that while plastic aggregates slightly reduce structural density, the inclusion of fly ash mitigates long-term strength loss through pozzolanic reactions. The optimized mix design achieved a 28-day compressive strength exceeding 35 MPa, satisfying structural concrete standards. Microstructural analysis via Scanning Electron Microscopy (SEM) revealed acceptable interfacial transition zones between the plastic aggregates and the cement matrix. Ultimately, this approach offers a viable pathway to lower production costs by 15% and decrease the carbon footprint of structural elements, aligning civil engineering practices with circular economy goals.
Keywords: Circular economy, Concrete technology, Fly ash, Green building materials, Mechanical properties, Plastic aggregate, Sustainable construction
* Corresponding Author: jonathanprice26@hotmail.com
Doi (Journal): 10.1045/2026.Bauingenieur/108804-VDI_085
Alqahtani, F. W., & Zafar, I. (2018). “Behavior of green concrete containing recycled plastic aggregates under different curing conditions.” Construction and Building Materials, 171, 711-721.
Saikia, N., & de Brito, J. (2012). “Mechanical properties and abrasion behaviour of concrete containing shredded plastic waste as aggregate.” Construction and Building Materials, 28(1), 592-597.
Frigione, M. (2010). “Recycling of PET bottles as fine aggregate in concrete.” Waste Management, 30(6), 1101-1106.
Akram, T., Memon, S. A., & Khan, H. U. (2017). “Production of low cost and light weight concrete using plastic waste as aggregate.” Construction and Building Materials, 151, 462-470.
Gu, L., & Ozbakkaloglu, T. (2016). “Use of recycled plastics in concrete: A critical review.” Waste Management, 51, 19-42.
Hannawi, K., Kamali, S., & Prince, W. (2010). “Physical and mechanical properties of mortars containing PET and PC waste aggregates.” Waste Management, 30(11), 2312-2320.
Rahmani, E., Dehestani, M., & Beygi, M. H. A. (2013). “On the mechanical properties of concrete containing waste PET particles.” Construction and Building Materials, 47, 1302-1308.
Malhotra, V. M. (2000). “High-volume fly ash concrete—sustainable construction material.” Concrete International, 22(7), 30-36.
Mehta, P. K. (2004). “High-performance, high-volume fly ash concrete for sustainable development.” International Workshop on Sustainable Development and Concrete Technology, 3-14.
Siddique, R. (2004). “Performance characteristics of high-volume fly ash concrete.” Cement and Concrete Research, 34(3), 487-493.
Oner, A., & Akyuz, S. (2007). “An experimental study on optimum usage of fly ash in concrete.” Cement and Concrete Research, 37(6), 885-891.
Poon, C. S., Lam, L., & Kou, S. C. (2000). “Rate of hydration of natural pozzolanic and fly ash concretes.” Cement and Concrete Research, 30(10), 1567-1574.
Batayneh, M. K., Marie, I., & Asi, I. (2007). “Use of selected waste materials in concrete mixes.” Waste Management, 27(12), 1870-1876.
Ismail, Z. Z., & Al-Hashmi, E. A. (2008). “Use of waste plastic in concrete mixture as aggregate replacement.” Waste Management, 28(11), 2041-2047.
Thomas, B. S., Yang, J., Bahurudeen, A., & Siddique, R. (2020). “Action of plastic waste in concrete and its ecotoxicity—An overview.” Resources, Conservation and Recycling, 155, 104671.
Chou, L. H., & Lu, C. K. (2012). “Properties of concrete incorporating waste plastic and fly ash.” Journal of Hazardous Materials, 211, 395-402.
Senhadji, Y., Escadeillas, G., Benzaama, H. M., & Mouli, M. (2015). “Valorization of plastic waste in composite mortar: Case of granulated PVC and PET waste.” Construction and Building Materials, 93, 1072-1080.
Farooq, F., Ahmed, W., Akbar, A., Aslam, F., & Alyousef, R. (2021). “Comparative study of mechanical properties of concrete containing plastic waste as a partial replacement of fine aggregate.” Case Studies in Construction Materials, 14, e00520.
Scrivener, K. L., John, V. M., & Gartner, E. M. (2018). “Eco-efficient cements: Potential, economically viable solutions for a low-CO2 cement-based materials industry.” Cement and Concrete Research, 114, 2-26.