ANALYSIS OF STATISTICAL PROCESS CONTROL APPLICATION AS A TOOL FOR READYMIX CONCRETE QUALITY MANAGEMENT IN BATCHING PLANT

• Main Author: DWI PUTRANTO (NIM : 25015301), AFRIZAL
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25088
• Institution: Institut Teknologi Bandung

Construction project and property volumes are projected will increase by 2018. It is estimated that the government will budget Rp 2,204 trillion and the government budgeted Rp. 230.5 trillion or about 10.5% for the infrastructure sector. With the increament of infrastructure projects volume, the quality of the infrastructure should remain as the main focus. Currently, reinforced concrete still the most common material used in Indonesia. In reinforced concrete structures, the quality of concrete is the most important factor affecting the quality of an established infrastructure. The quality of this concrete affected by the quality of readymix concrete which is a quality indicator that is difficult to control because it contains many variability in the production process and it can be relied inconsistency quality of the concrete product. A quality management step is required to minimize the variability of the readymix concrete production process and the results of the product can have a quality as targeted. Statistical Process Control (SPC) is a method which hold the principle of Total Quality Management which have a purpose to minimize variability. This method can be applied by using control charts tool. This method used by 2 steps analysis. The first step of this method performed by check the variability level for existing condition. If the existing condition have a variability that excess the limit, then the production process have a problem. After that, identification of the root cause problem need to be identified. Based on preliminary research conducted on 4 companies, found that SPC method is not commonly used in readymix concrete industry in Indonesia for production in batching plant. <br /> <br /> Based on research conducted on one of the readymix concrete producers in Indonesia that is firm A using Statistical Process Control method, there are 2 things found in existing condition process analysis stage. In this analysis, the control level of variability of the process can be achieved. The control level can be defined as in-control or not in-control. Furthermore, this stage analysis obtained capability of production process that take place. The result of the analysis of the existing condition for firm A shows that the resulting compressive strength product has high variability and indicates the production process is not under control yet. In addition, the existing condition of firm A indicates that the existing condition is not capable yet. It is shows from the compressive strength value of the average concrete characteristic products is still far below the average compressive strength needs to be targeted. With the results of the analysis it is necessary to identify the root of the problem. <br /> <br /> In the root cause analysis stage, there are two impacts that are used as the main focus of the analysis that is the process that has not been in control and the product is not capable because the value of the average compressive strength are down compared to average compressive strength required. This analysis can be done with check sheet and cause-effect diagram tools. The results of this analysis indicate that there is a problem why the production process is not in control, namely methods and procedures aspect, equipment and materials treatment aspect, product quality control aspect, and communication and document management. Meanwhile, the root causes why the average compressive strength of the productis lower than the average compressive strength needs to be among others mix design, mixing process, and test procedure of the concrete product. These problems must be eliminated with remedial solutions to make the production process in control and capable. The results of the analysis also show that the problem aspects of methods and procedures are the most significant problems affecting the variability of the production process is not under control. In addition, the mix design aspect is the most significant problem to give the impact of decreasing the average characteristic compressive strength lower than the average compressive strength required.