Evaluasi Mortar ECC serta Bio Fiber-ECC yang Berbasis Fly Ash dan Abu Cangkang Sawit Berdasarkan Kajian Microstructure

Abstract

This study aims to evaluate the microstructural characteristics and mechanical performance of Engineered Cementitious Composite (ECC) mortar modified with waste-based additives such as fly ash and palm shell ash (PSA), along with natural fibers including bamboo and rattan (Bio Fiber-ECC). Sieve analysis revealed that fly ash had the finest particle size (FM = 0.00), allowing for better void filling, which enhanced mortar density and compressive strength. XRF testing identified key pozzolanic compounds (SiO₂, Al₂O₃, Fe₂O₃) in fly ash and PSA that contribute to the formation of hydration products like calcium silicate hydrate (CSH). FTIR analysis detected dominant functional groups (Si-O, Al-O, O-H), indicating active pozzolanic and hydration reactions, with noticeable peak shifts suggesting the formation of new bonds and amorphous silica/aluminosilicate structures. SEM observations revealed diverse particle morphologies: spherical, smooth fly ash particles enhanced workability and packing density, while irregular, porous PSA particles accelerated hydration due to their high surface area. The optimal sample (M33) exhibited a denser and more compact microstructure with smaller pores. In Bio Fiber-ECC, uniform fiber dispersion provided a bridging effect, reducing crack propagation, whereas samples with minimal fiber content showed voids that contributed to decreased compressive strength. Overall, the synergy of fly ash, PSA, and natural fibers significantly improved the mechanical and microstructural properties of the mortar.