Analysis of Quality Control for Ready-Mix Concrete in the BKPSDM Building Construction Project

Abstract

This study aims to evaluate the quality and consistency of ready-mix concrete based on compressive strength test results from the Personnel and Human Resources Development Agency (BKPSDM) Building construction project in Bandung Regency. A quantitative descriptive approach was employed using secondary data obtained from laboratory testing. A total of 28 cylindrical concrete specimens (150 mm × 300 mm) with a design strength of fc’ 25 MPa (K-300) were tested at the ages of 14 and 28 days in accordance with SNI 1974. The results indicate that the average compressive strength at 28 days reached 303.89 kgf/cm², which exceeds the specified design strength. However, a significant variation in compressive strength was observed, ranging from 189.32 kgf/cm² to 424.60 kgf/cm². Statistical analysis shows a standard deviation of 67.52 kgf/cm² and a coefficient of variation (CV) of 22.23%, indicating low consistency in concrete quality. Furthermore, only 64.29% of the test specimens met the design strength requirement, suggesting that a considerable proportion of the concrete did not comply with the specified standard. Control chart analysis reveals that all data points remain within statistical control limits, indicating that the process is stable. Nevertheless, the relatively high variability suggests that the process is not yet capable of producing consistent concrete quality. These findings imply that while the average compressive strength satisfies the design requirement, the overall quality consistency has not been achieved. Therefore, improvements in quality control are necessary, particularly in transportation, casting, and curing processes, to ensure more uniform and reliable concrete performance.