Lightweight composite panels and compositions and methods for manufacturing and using same

A lightweight composite panel, comprising:

• a polymer foam core having a first surface, a second surface opposite the first surface, a first side edge forming a perimeter of the first surface, a second side edge forming a perimeter of the second surface, and a side surface extending between the first and second side edges;
• a first protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the first surface of the polymer foam core;
• and
• a second protective fiber mesh reinforced cementitious layer formed over and covering at least a portion of the second surface of the polymer foam core,
• wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure,
• wherein each of the first and second protective fiber mesh reinforced cementitious comprises fiberglass mesh embedded within a hardened cementitious composition comprising reaction products of a fresh cementitious composition comprising water, Portland cement, silicon dioxide, calcium oxide, and gypsum hemihydrate.

A lightweight composite panel, comprising:

• a polymer foam core having a first surface, a second surface opposite the first surface, a first side edge forming a perimeter of the first surface, a second side edge forming a perimeter of the second surface, and a side surface extending between the first and second side edges;
• a first protective thermoset polymer layer formed over and covering at least a portion of the first surface of the polymer foam core;
• and
• a second protective thermoset polymer layer formed over and covering at least a portion of the second surface of the polymer foam core,
• wherein the polymer foam core comprises a polymer selected from the group consisting of extruded polystyrene (XPS), expanded polystyrene (EPS), polyisocyanurate, polyurethane (PUR), phenolic polymers (e.g., phenol-formaldehyde), melamine polymers (e.g., melamine-formaldehyde), and other thermoplastic and thermoset polymers that can be formed into a rigid or semi-rigid polymer foam structure,
• wherein the first and second thermoset polymer layers are independently selected from polyurea and polyaspartic and are optionally fiber-reinforced.