Karakteristik dan Durabilitas Mortar Self Healing Geopolymer Berbasis Hydrogel sebagai Material Green Repair dengan Berbagai Variasi Molaritas Pada Lingkungan Air Laut

Abstract

Indonesia, the country with the second-longest coastline in the world, requires construction materials for marine infrastructure resistant to aggressive marine environments. The concept of self-healing in cement-based and other silica-based materials is a novel approach that needs to be developed to enhance the service life of cement-based infrastructure, thereby preventing damage and improving its durability. This study aims to develop a self-healing geopolymer mortar based on fly ash and hydrogel as a green repair material resistant to seawater environments. The geopolymer mortar was designed with variations in NaOH molarity (6 M, 8 M, 10 M, and 12 M) to evaluate its mechanical characteristics and durability, using 150 test specimens. This study used fly ash as a cement substitute, while hydrogel served as a self-healing agent capable of storing water and repairing micro-cracks. The test specimens included 5x5x5 cm mortar cubes for compressive strength testing under normal water curing, seawater, and 3.5% NaCl solution; 4x4x16 cm mortar prisms for water capillary absorption testing under three different immersion conditions; and Ø10 cm x 20 cm mortar cylinders for chloride binding tests. Geopolymer mortar with higher molarity demonstrated better workability. Geopolymer mortar required a longer setting time compared to conventional mortar. The maximum compressive strength reached 37.47 MPa for GFA 10M immersed in seawater, followed by 36.8 MPa for GFAH 10M immersed in 3.5% NaCl solution, and 34.347 MPa for GFAH 12M immersed in normal water. Geopolymer mortar exhibited lower water capillary absorption compared to conventional mortar. GFA 10M and 12M showed better resistance to chloride-induced corrosion.