Transforming Sidoarjo Volcanic Mud as Nano Filler to Improve Mechanical Properties of Hydrogel-Based Self-Healing Mortar

Hydrogel-based self-healing mortar often experiences a decrease in strength that may impact the self-healing concrete performance under mechanical loadings. It has been shown that the addition of colloidal nano silica can improve the strength of hydrogel-based self-healing mortar. However, commercial nano silica is relatively expensive. This work examines the development of an alternative and affordable nano filler. Aiming to improve the mechanical strength of hydrogel-based self-healing mortar, this research synthesizes nano filler from abundance Sidoarjo volcanic mud (Lusi) as mineral admixture in the production of hydrogel-based self-healing mortar. The nano filler is generated by milled Lusi powder into nano particle size. Three concentrations of 2%, 4% and 6% nano fillers by mass replacement of cement are used in the mortar mixture. The particle size distribution of nano filler, the setting time, the workability and the compressive strength of resulting mortar was investigated in this research. The results show that the particle size of nano filler was around 37.3 nm. From the setting time result, the addition of nano filler tends to speed up the hydration process. The results are also in accordance with the compressive strength of mortar where the addition of nano filler successfully improves the mortar compressive strength. In conclusion, nano silica filler from Lusi can be considered as an alternative mineral admixture that can improve the mechanical properties of hydrogel based self-healing mortar.