Structural Behavior of Durable Composite Sandwich Panels from buzai232's blog

Structural Behavior of Durable Composite Sandwich Panels

Sandwich panels comprising prefabricated ultra-high performance concrete (UHPC) composites can be used as eco-friendly and multi-functional structural elements. To improve the structural and thermal performance of composite sandwich panels, combinations of UHPC and expanded polystyrene (EPS) beads were investigated. High-performance expanded polystyrene concrete (HPEPC) was tested with various EPS bulk ratios to determine the suitability of the mechanical properties for use as a high-strength lightweight aggregate concrete. As a core material in composite sandwich panels, the mechanical properties of HPEPC were compared with those of EPS mortar. The compressive strength of HPEPC is approximately eight times greater than that of EPS mortar, and the thermal conductivity of approximately a quarter that of EPS mortar. The structural behavior of composite sandwich panels was empirically analyzed using different combinations of cores, face sheets, and adhesive materials. In the flatwise and edgewise compression tests, sandwich panels with HPEPC cores had high peak strengths, irrespective of the type of face sheets, as opposed to the specimens with EPS mortar cores. In the four-point bending tests, the sandwich panels with HPEPC cores, or reinforced UHPC face sheets combined with adhesive mortar, exhibited higher peak strengths than the other specimens, and failed in a stable manner, without delamination.Get more news about Eps Cement Sandwich Panel Supplier,you can vist our website!

Lightweight concrete can be applied in a number of ways, such as a reduction in self-weight of structures with smaller cross sections. The lightweight concrete developed could be a suitable material for high-rise buildings, with a number of advantages: cost saving due to extra insulation not being required, more flexibility for architects and structural engineers when designing buildings, sustainability due to relatively easy maintenance, and easier recycling (Yu et al. 2015).

One of the typical applications is as a core material in a composite sandwich structure. Sandwich structures can comprise various types of cores and skin materials to create an optimal design for a specific performance target. Composite sandwich structures are used widely in weight-sensitive structures where high flexural rigidity is required, because of the high-specific strength, stiffness, light weight, high thermal insulation, and the capability to be formed into complex geometries (El Demerdash 2013). Typical composite sandwich panels comprise a relatively thin, stiff, and strong skin plate with a relatively thick and light core. To improve the structural performance of standard composite sandwich panels, numerous strengthening methods have been proposed and studied. One was the change of core materials or configurations to strengthen the elements. The contribution of core materials with high flexural strength and shear stiffness is significant.

Expanded polystyrene (EPS) was first used as an aggregate for concrete in 1957. It is the most well-known core material because of its low density and high thermal insulation capacity. As opposed to the limited resources of lightweight mineral aggregates, EPS aggregates are commercially available worldwide. Therefore, EPS concrete can be considered as an alternative lightweight aggregate concrete (Short and Kinniburgh 1978; Babu and Babu 2003; Sadrmomtazi et al. 2011). The composite sandwich panels evaluated in this study are constructed with an EPS concrete core, with face sheets on either side of the panel, as shown in Fig. 1. Precast concrete sandwich panels are composed of two concrete wythes separated by a layer of rigid foam plastic insulation, typically (PCI Sandwich Wall Committee 1997). Compared with the typical sandwich panels, EPS concrete core in the EPS concrete sandwich panels can provide the dual function of transferring load and insulating structure in a single element, and enveloped face sheet acts as a strengthening reinforcement of EPS concrete core. However, the compressive strength of EPS concrete is generally less than 10 MPa (Ravindrarajah and Tuck 1994; Miled et al. 2004; Babu et al. 2006), which makes it difficult to use as a structural construction material. Additionally, mixture segregation of EPS beads and mortar during the manufacturing process easily leads to a deterioration in quality, and a degradation in durability.

In this study, high performance expanded polystyrene concrete (HPEPC) is proposed in place of EPS concrete. It was found that the rate of strength development of concrete increased with an increasing percentage of silica fume (Babu and Babu 2003; Sadrmomtazi et al. 2011). Therefore, the combination of EPS beads and ultra-high-performance concrete (UHPC) matrix is expected to be stronger than EPS concrete. An optimized core material and composite sandwich system was proposed to produce an eco-friendly, lightweight system with highly resistant mechanical properties and good thermal insulation. To investigate the mechanical properties of HPEPC, the compressive strength, flexural strength, modulus of elasticity, and Poisson’s ratio were measured, with varying percentages of EPS beads, to evaluate different densities. After determining the optimum mixture composition of HPEPC as a high-strength lightweight concrete, the mechanical and thermal properties of possible components in composite sandwich panels were investigated. Compressive and flexural behavior tests of the various composite sandwich panels, using developed lightweight concrete, were conducted to investigate the potential for applications as walls, slabs, and other components in high-rise buildings.