Enteromorpha prolifera polysaccharide as a novel bio-based foaming agent: Preparation, foaming performance, and properties of foam concrete

In this study, Enteromorpha prolifera -derived polysaccharides (EPP) were employed as a bio-based foaming agent for foam concrete, and their effects on fresh properties, pore structure, physical performance, and compressive strength were investigated. Surface tension tests indicated that EPP effectively reduced both static and dynamic surface tension, and the dynamic surface tension exhibited time-dependent interfacial adsorption characteristics. This reduction in surface tension promoted air entrainment, while the accompanying moderate increase in viscosity enhanced foam stability. With increasing EPP content, the fresh density decreased significantly, accompanied by prolonged setting time and noticeable changes in settlement behavior. X-ray computed tomography further revealed a gradual transition from isolated pores to increasingly interconnected pore networks with increasing EPP dosage. As a result, the dry density was reduced from 2115 to 880 kg/m 3 , leading to lower thermal conductivity but higher water absorption. Meanwhile, compressive strength showed a continuous decline with decreasing density. Overall, the findings suggest that EPP is a promising alternative to conventional chemical foaming agents, particularly for the development of lightweight and sustainable cementitious materials.