Resole resins are preferred. [0072] Another heat set binder is polymer/cement combinations in which the polymer comprises a phenol-aldehyde polymer, polyamide, polyimide or olefins such as polyethylene or straight or branched chain polypropylene. [0073] Specific thermoplastics include polyethylene, acrylonitrile-butadiene styrene, polystyrene, polyvinyl chloride, fluoroplastics, polysulfide, polyp