Perspective and Performance based Concrete Mix Design: A Review

Abstract

Concrete mix design is a well-established practice around the world. The mix design methods serve as basis to mix the ingredients of concrete and to achieve the intended performance during the life of the structures. Most of the guidelines developed across the world for mix design are strength based which incorporate trial-and-error process and do not objectively focus on obtaining an optimum mixture to meet performance criteria with least cost. A comprehensive review of concrete mix design guidelines available to obtain optimum design and proportioning concrete ingredients is presented here. The various codal provisions present the effective utilization of concrete constituent materials which results in optimum mix. Generally, the concrete mix design is carried out by perspective or performance-based method. Prescriptive specification is a method that follows the guidelines to select ingredients, design standards and code of practice. Whereas performance-based method imposes no strict guidelines for selecting the ingredients and mixture proportion, in fact it is based on the performance requirement of the end product. The key factors responsible to obtain the optimum mixture design in terms of performance are the workability, mechanical properties, durability, cost and environmental sustainability which in turn these properties depend on the type, size, shape, specific gravity, density and proper proportions of constituent materials like water, cement content, aggregates and admixtures.  Therefore, to design the concrete mix design based on the performance criteria, a thorough understanding of material characteristics of its ingredients is required.  Presently many different methods are developed to achieve the optimum mixture with the application of current technology such as particle packing method, computer algorithm, artificial intelligence, simulation methods, technology of integrated system, machine design. Even though these methods will not provide the comprehensive solution for the concrete mix design. Thus, its required to develop comprehensive model by considering the multiple objectives to statisy the many design criteria of concrete mixtures in terms of performance of mixture.