Rahayu Kusumaningrum, Ludfi Djakfar, Femiana Gapsari, Wisnumurti, Jossie Mutiara, Felicia Larasati
Indonesia has abundant Buton asphalt, but its use in roads is limited due to its comparatively lower mechanical performance compared to petroleum-based asphalt. To address this, the present study investigated dosages ranging from 0 to 12 % of ι-carrageenan, a natural polymer derived from Eucheuma denticulatum known for its high sulfate content and strong gelling properties compared to other bio-based additives. The experimental methodology involved synthesizing ι-carrageenan through an alkaline extraction process and incorporating it into Buton asphalt concrete-wearing course (AC-WC Asb) mixtures. Marshall tests and Indirect Tensile Stiffness Modulus (ITSM) tests were conducted to evaluate the mechanical performance. Additionally, ι-carrageenan was characterized using Fourier-transform infrared spectroscopy (FTIR) to identify functional groups and thermogravimetric analysis (TGA) to assess thermal stability. Results showed that an 8.5 % ι-carrageenan significantly enhanced the asphalt mixture's performance: stability rose by 2.68 %, flow by 17.88 %, and void parameters (VMA, VIM, VFB) were optimized within specifications. The improved flow at higher ι-carrageenan content reinforced cracking resistance, contributing to better durability under traffic loads. Furthermore, the incorporation of ι-carrageenan enhances the stiffness modulus of the mixture, thereby augmenting its resistance to permanent deformation, particularly in terms of rutting. TGA revealed multi-stage thermal degradation but confirmed stability up to ∼250 °C, ensuring compatibility with hot mix asphalt processes. However, excessively high ι-carrageenan concentrations diminished stability and Marshall Quotient, indicating that 8.5 % provides an optimal balance. This research highlights ι-carrageenan's potential as a sustainable, bio-based additive to enhance Buton asphalt's durability and mechanical properties, promoting eco-friendly infrastructure by utilizing local seaweed resources. © 2025
Civil Engineering Department, Faculty of Engineering, Brawijaya University, MT Haryono 167 Malang, 65145, Indonesia; Mechanical Engineering Department, Faculty of Engineering, Brawijaya University, MT Haryono 167 Malang, 65145, Indonesia
