A knowledge-based system for selecting proportions for normal concrete

摘要

Design of concrete mixtures can be defined as the process of selecting the most economical and practical proportions of all the ingredients to produce a quality concrete that satisfies the requirements of strength, durability, uniformity, workability, permeability, and economy. A sound mix design is often the combined result of following guidelines and applying heuristic knowledge, such as experience and rules of thumb. Most procedures outlined in any specific standards are typical of the empirical and heuristic nature of mix design. Because of the nature of the mix design process and all the heuristic knowledge that is associated with it, concrete mix design lends itself well to a knowledge-based application. This article presents the development and application of a knowledge-based system called EXMIX, for the proportioning of normal concrete mixtures. EXMIX is capable of selecting proportions of mixing water, cement, and aggregates, with consideration being given to the effects of air-entraining admixtures and moisture conditions of aggregates. EXMIX is developed in accordance with CSA A23.1-M90 and ACI211.1-89. EXMIX also conforms to building code ACI 318-89 with respect to concrete quality requirements.