###### Abstract  
Earthwork scheduling (during the planning phase of road construction) is an important task that directly affects the cost and time of a project. However, the current scheduling methods are not performed at a detailed level and carry forward gaps from the actual schedule in the construction stage, causing problems, including time delays and additional costs, during the construction stage and thereby leading to the modification and supplementation of existing plans. Many studies related to scheduling have focused on process optimization or automation; therefore, the gaps between the planning and construction stages have not been studied well. These gaps must be determined in advance to solve the fundamental problem of earthwork scheduling in road construction. Therefore, this study proposes a detailed activity-based scheduling model for earthwork at the planning stage to minimize the gap between the planned schedule and the actual process at the construction stage. The proposed model comprises a detailed activity-based database of earthwork in road construction (DADER), which enables the subdivision of the existing earthwork schedule plan, and a dynamic programming (DP) procedure, which enables the combination of activities. The earthwork schedule at the case site, planned for only three activities, is subdivided using DADER into 36 activities. Additionally, the DP procedure is used to derive a combination of activity alternatives that minimizes the cost among the conditions that satisfied the input target duration. The model is verified through an expert survey using a 7-point Likert scale. Results show that the model has cost efficiency (4.19), onsite applicability (4.70), and task efficiency (4.48). The findings indicate that performing scheduling during the planning stage of earthwork projects can help reduce additional work caused by the gap between the site and the plan. This study will help improve the productivity of road construction projects by providing correct process optimization and automation research data. 15 November 202324 November 202324 November 202326 November 202326 November 20231 December 202326 November 202326  
While comprehensive scheduling is intrinsic to project planning [9], most of the scheduling during the construction planning phase is often subjected to recalibration by managers at successive sites. A substantial proportion of time-related delays stemming from these practices is attributed to limited exhaustive construction plans and timelines [10]. Consequently, one of the salient challenges pertains to the lack of meticulous detail as the construction periods, workforce inputs, and costs (outlined at the project's outset) may diverge from the actual values as the construction progresses. However, despite the importance of considering detailed activities in the construction scheduling process, in actual projects, it is common to perform scheduling without giving sufficient consideration to this aspect during the planning stage. A preliminary survey conducted for this study also confirmed that (on average) road construction projects were scheduled for fewer than five activities during the planning stage for earthworks. There is a considerable gap between the construction site and the plan, thus resulting in additional work, costs, time, and increased time consumption. Hence, this study proposed a detailed activity-based scheduling model to mitigate the issues stemming from low-level earthwork scheduling during the road construction planning stage to solve the problems caused by the inadequate consideration of detailed activities. The research on this model was conducted in several steps. Firstly, the detailed database of earthwork in road construction [referred to as detailed activity-based database of earthwork in road construction (DADER)] was developed based on earthwork data. Secondly, the dynamic programming (DP) algorithm was applied using the standardized DADER as a foundation to perform scheduling by considering various combinations of activities.