Puput Risdanareni, Moch. Fatkhurrahman, Agustina A.M.B Hastuti, Khadija Zai, Rahmi Karolina, Irfan Mustafa, Stefanus Adi Kristiawan, Andri Kusbiantoro
Bacteria-based self-healing mechanisms have become a strategic approach to mitigate microcracks in concrete. Although they offer fast and reliable healing relative to other autonomous healing mechanisms, an effective form of bacteria protection is still required. Hydrogel, a smart polymer that could swell and absorb high amounts of liquid of a certain pH, has become an interesting bacteria carrier candidate for bacteria-based self-healing mortar production. However, the high swelling ability of hydrogel has negative impact on mortar, as it stimulates the formation of pores that leads to a reduction of strength. Although various types of hydrogels have been developed to address the issue of excessive swelling, a gap remains in creating environmentally friendly hydrogels that not only exhibit lower swelling than commercial alternatives but also preserve the mechanical strength of the resulting mortar. Thus, in this research two mixed natural based hydrogel from carboxymethyl-cellulose (CMC) and xanthan gum were developed as those two materials have an ability to swell less in high pH conditions. In this research, endospores of Bacillus Sphaericus R20 were employed as healing agents. To investigate the full performance of B. Sphaericus R20 which was encapsulated into novel hydrogels, the swelling capacity of hydrogels, the viability of spores after encapsulation, the fresh properties, the hardened properties, the healing performance and the capillary water absorption of the resulting mortar was observed. The result shows that xanthan gum hydrogel has become a promising bacteria carrier as it has superior properties among other hydrogels. Introducing xanthan gum-based hydrogel into mortar mixture improved the fresh properties, harden properties and healing capacity of the resulting mortar. The maximum crack width that could be healed in mortar containing bacteria encapsulated into Xanthan gum-based hydrogel was 0.55 mm. The results demonstrate the potential for large-scale production of xanthan gum-based healing agents, highlighting their cost-efficiency, chemical compatibility with cementitious systems, and practical applicability for incorporation into self-healing concrete technologies. © 2025 The Author(s).
Department of Civil Engineering, Faculty of Engineering, Universitas Negeri Malang, Jalan Semarang no 5, East Java, Malang, 65145, Indonesia; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia; Department of Pharmaceutics, Faculty of Pharmacy, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia; Department of Civil Engineering, Faculty of Engineering, Universitas Sumatera Utara, North Sumatra, Medan, 20222, Indonesia; Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Brawijaya, Malang, 65145, Indonesia; Department of Civil Engineering, Faculty of Engineering, Universitas Sebelas Maret, Jalan Ir. Sutami 36 Kentingan, Jebres, Jawa Tengah, Surakarta, 57126, Indonesia; Faculty of Engineering Technology, Universiti Tun Hussein Onn, Johor, Malaysia
