## 4 Results
### Process Time Analysis  
The Scenario 1 (S1) process starts with the preparation of the CAD design model and receiving the required approvals for the construction. This step could take up to 90 days. The next step after the design approval is the preparation of the design for additive manufacturing, during which the design is fine-tuned based on the specification of the printer selected for the project, and export of the design to the robot tool path generator. This step could take up to eight hours. The dry mix, which is the raw material for 3 DCP, is then ordered and received by the company before being shipped to the project site. This step has a seven-day lead time. Thereafter, the dry mix, the robotic arm, and the concrete mixer are transported to the project site in approximately two hours. Once the robotic arm is on the site, it should be installed, calibrated at the first house construction location, and connected to a concrete pump attached to a mixer. The preparation of the robotic arm could take up to one hour. In the next step, the construction of the house walls starts, and the robotic arm lays the wet mix of concrete layer by layer according to the pre-determined path. Reinforcement also takes place during the construction phase, which includes adding steel components for structural tension. The construction and reinforcement steps last for 21.5 h. Once the whole house is printed, the robot could be unmounted from the floor and relocated to the next site location, and the process is repeated until all the walls of 100 houses are completed (Figure 3). Printed house walls could take up to 72 h to dry and be ready for the next phase of construction. The estimated total time required for each S1 house construction step (excluding the material ordering, design, and approval steps) is 34.5 h.  
Scenario 2 (S2) starts with the design and approvals, and then the preparation of a design for modular production that could then be transferred to the construction site for assembly is performed. The preparation of the design also includes exporting the design to the robot tool path generator. This step takes approximately eight hours. The dry mix is retrieved from the inventory and is prepared in 10 min. Thereafter, the additive  
Figure 3: The process map for Scenario 1.  
construction of the wall modules at the factory starts using robotic arms. The reinforcement of the modules takes place simultaneously with the 3 DCP process. The additive construction and reinforcement steps take approximately 21.5 h to complete. The wall modules could go through a drying period of 14 days in storage before being shipped to the site. Transportation to the site is assumed to take two hours. On the site, the wall pieces should be assembled by the workers using a crane, which could take approximately five and a half hours. The process of construction, transportation, and assembly is repeated until the walls of all 100 houses are installed on the project site and ready for the remaining construction steps. The estimated total time required for the S2 construction steps (excluding the material ordering, design, and approval steps) is 15 days and 13.16 h (Figure 4). This is considerably longer than the S1 time due to the 14 days required for the walls to dry before they could be transported to the project site. If the delay caused by the concrete drying is excluded from S2, the process for each house only takes 37.16 h.  
For the round houses in Scenario 3 (S3), the proper conventional construction method is cast-in-place concrete. The process map for S3 is presented in Figure 5. In this process, after the CAD design, the first task is to ship the formwork to the construction site. Formwork includes setting up molds for both the external and internal walls. For curved walls, this should typically be carried out using timber. After formwork, exterior walls must be reinforced with steel according to recognized construction codes. Ready-mixed concrete is then transported from the factory to the site and cast from the truck into the molds.