Compatibility is uncertain and highly formulation-dependent. Papercrete is porous, water-retentive, and alkaline, which can destabilize some emulsions and create weak, moisture-sensitive interfaces. Anionic or nonionic systems may behave differently than cationic ones, but you must validate with trials for adhesion, water uptake, freeze-thaw, and dimensional stability. Asphalt emulsion can improve water resistance, yet it may reduce vapor permeability and can soften under heat, affecting structural performance. For real projects, treat it as an experimental composite requiring lab testing, not a standard spec solution.