APPLICATION STUDY OF THE JUST-IN-TIME (JIT) CONCEPT IN REINFORCED CONCRETE MATERIAL MANAGEMENT IN GREEN CONSTRUCTION CONCEPT BUILDING

• Main Author: ARIEF FADHILLA , NANDA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/53914
• Institution: Institut Teknologi Bandung

Building material is one of the project resources which is quite decisive in the quality of construction results. The use of materials is the most important part which has a large enough percentage of the total project cost. Therefore, material management needs to plan carefully, especially for materials that are on the critical path. For example, reinforced concrete materials such as ready mix concrete and reinforcing steel have the largest proportion of construction materials. Considering the large proportion of the material used, it is common to find waste. Categorized into two types of waste that are interrelated: waste in the concept of lean construction in the form of non value added (NVA) activity and waste in the concept of green construction that causes waste in the use of energy, water and resources and harm the environment by causing CO2 emissions. Reinforced concrete (ready-mix concrete and reinforcing steel) is suspected to be the biggest contributor to CO2 emissions during the material transfer and construction process. One of the Lean Concepts, namely Just-in-Time (JIT), has a focus on eliminating waste and strives to deliver materials in the right quality, quantity and time. By applying the JIT concept which focuses on minimizing waste in the form of NVA activity, it can help overcome the waste problems that arise during the reinforced concrete material management process. This research examines the application of the JIT concept in helping to minimize waste in reinforced concrete material management and its contribution to reducing CO2 emissions so that it can support the material management process based on environmentally friendly green construction. This research begins by identifying the material management process and reinforced concrete construction process using the analysis of the current value stream map and the CYCLONE model to determine the NVA waste that appears and has an effect on increasing CO2 emissions during the process. Then an analysis of the future value stream map is carried out to plan improvements according to the JIT Concept to eliminate these wastes. Then analyzing JIT contribution by conducting a comparative analysis of CO2 emissions before and after the application of the JIT Concept. From the results of the analysis, it can be concluded that the JIT concept has a contribution to reducing CO2 emissions during the material management process. Given the JIT concept developed from the manufacturing sector, its application in the construction industry cannot be fully implemented, due to the higher level of variation and uncertainty in the construction industry. So that it raises trade-offs on efforts to minimize inventory which have consequences on material availability in the field, efforts to plan buffer materials in inventory which have consequences on aspects of shipping costs and efforts to focus on work at night which have consequences on the use of electrical energy and aspects of the cost of using electrical energy. Thus, the effort to implement the JIT Concept must be based on the goals or focus the project wants to achieve to be sustainable with the JIT Concept itself.