<![CDATA[The limitation of conventional material resources in coastal areas has driven the utilization of sea sand and seawater as alternative materials for sea dike mortar construction, requiring a comprehensive evaluation of their mechanical properties and durability performance in coastal environments. This study aims to analyze the effect of using sea sand and seawater as mortar constituents on compressive strength development and water absorption rates compared to conventional mortar. This study employed an experimental method conducted at the Structure and Materials Laboratory of Universitas Muhammadiyah Parepare, encompassing aggregate characteristics, compressive strength, and water absorption testing. The research results indicate that all mortar variations exhibited an increase in compressive strength with age. At 28 days, the highest value of 12.67 MPa was obtained for the river sand + seawater variation (seawater-cured) and the river sand + freshwater variation (seawater-cured). The sea sand + seawater variation (seawater-cured) reached 11.33 MPa, while the control variation—river sand + freshwater (freshwater-cured)—reached 10.67 MPa. Water absorption at 28 days ranged from 3.06% to 3.40%; the sea sand + seawater variation (seawater-cured) was 3.22%, whereas the control variation was 3.35%. These differences result from a combination of variables changing simultaneously; therefore, they cannot be used to determine the effect of any single variable in isolation.]]>
