Construction projects are often challenged by tight budgets and limited time and resources. Contractors are, therefore, looking for ways to become competitive by improving efficiency and using cost-effective materials. Using three-dimensional (3D) printing for shaping materials to produce cost-effective construction elements is becoming a feasible option to make contractors more competitive locally and globally. The process capabilities for 3D printers and related devices have been tightened in recent years with the booming of 3D printing industries and applications. Contractors are attempting to improve production skills to satisfy firm specifications and standards, while attempting to have costs within competitive ranges. The aim of this research is to investigate and test the production process capability (Cp) of 3D printers using fused deposition modeling (FDM) to manufacture 3D printed parts made from plastic waste for use in the construction of buildings with different infill structures and internal designs to reduce cost. This was accomplished by calculating the actual requirement capabilities of the 3D printers under consideration. The production capabilities and requirements of FDM printers are first examined to develop instructions and assumptions to assist in deciphering the characteristics of the 3D printers that will be used. Possible applications in construction are then presented. As an essential outcome of this study, it was noticed that the 3D printed parts made from plastic waste using FDM printers are less expensive than using traditional lightweight non-load bearing concrete hollow masonry blocks, hourdi slab hollow bocks, and concrete face bricks.

In this study, a finite element model was developed, and a detailed analysis was carried out to investigate the impact of inclusions on the mechanical characteristics of a 3D-printed composite sandwich beam that could initiate when printing the layers, especially during the transition period between the dissimilar material that would affect the interfacial strength between the layers that would cause the failure of the 3D-printed beams. Several parameters that could influence the failure mechanism have been investigated. These parameters include the location, size, material properties, and interfacial location of the inclusion along the beam. Linear elastic behavior has been adopted in this finite element analysis using the ‘Ansys’ simulation tool to model and analyze the defective beams compared to the intact ones. The effects of defects related to maximum shear stress (MSS) and maximum principal stress (MAPS) were investigated. The results revealed that the midpoint of the composite is highly stressed (31.373 MPa), and the concentration of stress decreases outward as we move toward the edges of the composite to reach zero at the edges. For the intact case, the deformation was maximum at the center of the composite (4.9298 mm) and zero at both ends of the beam. The MSS was highest at the center (23.284 MPa) and decreased gradually as we approached the ends on both sides to reach 0.19388 MPa at the edges, making the shear stress distribution symmetrical. The MAPS is constant throughout the beam apart from the lower face of the beam and is maximum at the face material. The MSS is high at the endpoints where we have the support reactions, which may weaken the entire material’s mechanical properties. It was also observed that along the load L3 (applied at 2 mm from the top face of the beam), the MSS values decrease as we move away from the center, which may cause failure at the end of the beam. It was also noticed that the presence of inclusions along load L2 (applied at 2 mm from the bottom face of the beam) initially causes a sharp decrease in MAPS while moving away from the center, at 25 mm, while the MAPS increases as it approaches the end of the beam. This increase in the MAPS near the beam support might be due to the reaction of the fixed support, which tends to oppose the applied flexural load and hence increases the principal stress capability of the beam.