A marine ecological engineering construction method, an asphalt cement-based coating, and a preparation method thereof are provided. The asphalt cement-based coating can make discarded concrete have the capacity of inducing the settlement of sessile organisms, achieve the purpose of using discarded concrete to construct ecological engineering, and has the characteristics of discarded object recycling and marine ecological restoration.

A method of building marine concrete elements layer-by-layer, the method including extruding a flowable construction material through an outlet of a deposition head in order to form a layer of construction material, the construction material including a hydraulic cement and a superabsorbent polymer, wherein successive layers of construction material are placed on top of each other and allowed to cure and harden, in order to obtain the marine concrete element.

A restoration cap unit for construction of eco-friendly structures in a body of water is provided, which is constructed from materials including a primarily calcium carbonate material; and a cement that is capable of holding the primarily calcium carbonate material, wherein the restoration cap unit has a first side and a second side which are attached at an edge to form a tent shaped structure, such that the restoration cap unit is configured to be placed on top of an existing restoration assembly to extend the height of the restoration assembly.