1 A Novel Framework for Biomaterial-Assisted Self-Healing in Lightweight Concrete using Porous Aggregate Micro-Reservoirs Biplab Munshi Email: biplabmunshi@gmail.com Abstract This study introduces a biomaterial-assisted self-healing strategy for lightweight concrete using porous aggregates as micro-reservoirs. By embedding healing agents such as bacterial spores within the aggregate pores, the system enables autonomous crack repair triggered by moisture. The framework balances structural performance with healing efficiency, showing promising results in crack closure, strength recovery, and durability enhancement. This approach offers a scalable solution for sustainable infrastructure, especially in precast and 3D-printed applications. I. I NTRODUCTION Concrete remains the most widely used construction material globally, yet its susceptibility to cracking poses significant challenges to structural durability and long-term performance. Microcracks, often invisible during early stages, can propagate under environmental stressors, leading to reduced service life and increased maintenance costs. Traditional repair methods are reactive, labor-intensive, and often economically unsustainable, especially in large-scale infrastructure. In response, self-healing concrete technologies have emerged as a promising solution to en- hance resilience and reduce lifecycle costs. Among these, biomaterial-assisted healing—particularly using bacterial spores and enzymatic systems—has gained attention for its ability to autonomously seal cracks through biomineralization. However, integrating such healing agents into concrete without compromising its mechanical and rheological properties remains a challenge. Lightweight concrete, valued for its reduced density and thermal insulation properties, presents unique opportunities and constraints for self-healing integration. Its porous structure can be