Knowledge-Based Expert System for Concrete Mix Design

In the United States, the American Concrete Institute method (ACI 211) is the most widely used concrete mix design. However, ACI 211 does not consider all factors regarding concrete mix design. The acceptance of a freshly mixed concrete depends on concrete quality control test results. If the results indicate that the concrete does not meet the specification, mix design adjustment must be made. Concrete mix design and adjustment are somewhat complicated and time-consuming tasks that are performed best by experienced persons. In this project, a rule-based expert system was developed to assist the user in concrete mix design, including the necessary adjustments to the design. The expert system can handle mix designs for normal-weight concrete, normal-weight-mass concrete, normal-weight no-slump concrete, heavyweight concrete, and lightweight concrete. Besides workability, consistency, strength, durability, and density, the expert system considers other criteria such as admixtures, transportation, and air temperature that affect the concrete mix design. The system was tested on three projects. The system's selection of concrete proportions compared favorably with the experts' selections.