RETRACTED: Sustainable Use of Waste Polypropylene Fibers and Palm Oil Fuel Ash in the Production of Novel Prepacked Aggregate Fiber-Reinforced Concrete (Sustainability, (2020), 12, 12, (4871), 10.3390/su12124871)

Our journal, Sustainability, retracts the article “Sustainable Use of Waste Polypropylene Fibers and Palm Oil Fuel Ash in the Production of Novel Prepacked Aggregate Fiber-Reinforced Concrete” [1], cited above. Following publication, concerns were brought to the attention of the Editorial Office regarding the reliability of the figures presented in this article [1]. Adhering to our complaint procedure, an investigation was conducted by the Editorial Office and Editorial Board that confirmed a high level of similarity between Figure 6 in this paper [1] and Figure 14 in a previously published article [2] and between Figure 8 and Figure 11 and Figure 7 in previously published articles [2,3], presenting different experimental conditions. Although the authors cooperated with the Editorial Office during the investigation, they were unable to satisfactorily explain the overlap between the figures nor provide appropriate raw materials for an Editorial Board Evaluation. Consequently, the Editorial Board has lost confidence in the reliability of the findings and decided to retract this publication [1], as per MDPI’s retraction policy (https://www.mdpi.com/ethics#_bookmark30). This retraction was approved by the Editor-in-Chief of Sustainability. The authors did not provide a comment on this decision.