Mathematical Model of Coextrusion Molding of Polymer-concrete Building Structures Valery Dyadichev, Andrey Kolesnikov, Aleksandr Dyadichev, Ekaterina Dyadicheva, Sergey Menyuk and Svitlana Chornobay E3S Web Conf., 97 (2019) 02014 Published online: 29 May 2019 DOI: 10.1051/e3sconf/20199702014