Eco-friendly modification of earthen construction with carrageenan: Water durability and mechanical assessment

•Carrageenan bioadditives positively modified properties of earthen construction.•Increments in compressive strength of up to 85% were observed in admixture samples.•Tensile strength was increased up to 52% according to three-point bending tests.•Water repellence and erosion resistance were enhanced by using coating treatments.•Admixtures remained water resistant after 95days of environmental exposure.