The Effect of Different Service Loads on the Behavior of Full-Scale Precast Concrete Sandwich Panels

This research aims to develop low-cost and light-weight precast concrete sandwich panels (PCSPs) suitable for the limited loads they may be applied in the future applications, such as lightweight roofing panels. The mixture of concrete was designed to accomplish light weight and ease of workability. Self-compacting concrete (SCC) was used, containing 850 kg/mm of sand and 500 kg/m3 of cement at a water-to-cement ratio of 0.35, with the addition of a superplasticizer at 1% by weight of cement. A full-scale panel was examined with dimensions of 4.5 m length , 1 m in width and thickness of 0.13m The bottom layer of PCSP reinforced with a 2.15 mm steel mesh with 32 × 32 mm openings, the top layer reinforced with chicken wire, and the insulation layer made of expanded polystyrene (EPS) insulation. The two concrete layers were connected using 1.47 mm diameter steel mesh shear connectors grids distributed in five locations along the specimen to ensure composite bonding between the layers. Five major flexural tests were conducted on the panels under graded loads of 250 kg stimulation to examine the behavior of the panel to withstand dead loads, 100 kg, 200 kg of person's weights and 1000 kg to represent different loading levels. Vertical displacements were measured using LVDTs located at specific positions along the specimen span. The results showed that increasing the load resulted in a significant increase in vertical deflections with near-linear behavior up to certain load limits. Then, flexural failure features (cracks) began to appear. The results also established that the mesh connectors performed effectively in maintaining composite behavior up to intermediate loading levels, while the degree of bonding decreased at higher loads (1000 kg). The study shows that the proposed structural system has acceptable proficiency for limited load bearing, with high light weight, making it suitable for economical precast roof applications in low-cost buildings.