Bending performance of a novel geopolymer non-dismantling sandwich insulation formwork: Experimental, theoretical, and numerical simulation

With the acceleration of urbanization, the energy shortage and environmental problems caused by the construction industry have gradually received high attention from the society. Therefore, there is an urgent need for innovative, sustainable construction materials and techniques. This study introduced a novel geopolymer non-dismantling sandwich insulation formwork, aiming to evaluate its bending performance under four-point bending loads. Sandwich insulation formwork comprised of core materials, alkali-activated insulation materials (AAI) and extruded polystyrene (XPS), with surface layer of alkali-activated ultra-high toughness composite materials (AUTC) and fiberglass-reinforced mortar. The study examined the impact of core thickness and connectors on load-deflection behavior, strain characteristics, ductility index, and bending strength. A comprehensive experimental study and theoretical analysis were conducted on the bending capacity of sandwich insulation formwork, supported by numerical simulation to assess bending capacity and failure patterns. The results showed that sandwich insulation formworks with AUTC surface and AAI core significantly improved ductility and bearing capacity, while sandwich insulation formwork with mortar-based surface and XPS core exhibited brittle failure, reduced strength, and ductility. Increasing core thickness and incorporating connectors further improve load capacity and stiffness. The numerical and theoretical results align well with experimental data, demonstrating the predictive accuracy of the model. This study offers valuable insights into optimizing sandwich insulation formwork, contributing to sustainable, efficient, and environmentally friendly building practices.