Study on the influence of thermal insulation material on the flexural performance of precast sandwich panel connected by steel wire mesh

Precast concrete sandwich insulation panel system connected by steel wire mesh connector (SWMC) is a type of green energy-saving wall panel, welded into space truss connectors by oblique steel wire and steel wire mesh, embedded in concrete inner and outer wythes, and filled with insulation materials, such as expandable polystyrene (EPS) or rock wool (RW). The effects of oblique steel wire diameter, spacing, and pitch were analyzed by flexural performance tests and ABAQUS finite element numerical simulations to study the flexural performance of SWMC panel with EPS and RW as thermal insulation materials under uniform load. Based on the combination theory of concrete sandwich wallboard proposed by Benayoune.A, the combination degree calculation index of SWMC panels in elastic stage and limit stage were calculated respectively. The results showed that SWMC panels had been experiencing the uncracked stage, the working stage with cracks, and the failure stage during the stress process. The cracks presented a dense distribution in the middle and sparse distribution on both sides. The failure mode of the SWMC sample was flexural, and the flexural ultimate bearing capacity of the EPS samples was relatively high compared to the RW samples. The increase of the diameter of the oblique steel wire in SWMC panel had relatively little influence on the flexural capacity in elastic stage, while the SWMC panel was showing high combination performance. In limit stage, the combination degree of SWMC has decreased to a certain extent and the increasing of spacing and pitch of oblique steel wires have led to the weakening collaborative working ability during the whole loading process. Therefore, in order to fully develop the performance of SWMC in practical engineering, it is recommended that the oblique steel wire spacing need to be designed at 50 mm (no more than 100 mm) and the pitch at 100 mm within the precast concrete SWMC panel.