Title: Microstructural Basis of Selection of Materials and Mix Proportions for High-Strength Concrete

Author(s): P. K. Mehta and P. C. Aitcin

Publication: Symposium Paper

Volume: 121

Issue:

Appears on pages(s): 265-286

Keywords: admixtures; aggregates; C3A; high-strength concretes; microcracking; microstructure; mineral admixtures; mix proportioning; plasticizers; strength; workability; Materials Research

DOI: 10.14359/2500

Date: 11/1/1990

Abstract:
During the 1980s, the use of high-strength concrete gained wide acceptance. The materials and mix proportions for making high-strength concrete are selected empirically by extensive laboratory testing since there are no accepted procedures, such as the ACI method of proportioning normal concrete mixtures. For someone who, for the first time, would like to make high-strength concrete from local materials, the problem is complicated by the fact that a variety of newly developed chemical and mineral admixtures may have to be incorporated simultaneously into the concrete mixture. The published literature has enough information on the new admixtures, but is essentially of little help in selecting the type and optimum dosage of these admixtures. In this paper, the authors have attempted to address the problem of selection of materials and mix proportions for high strength from a microstructural standpoint. Principles underlying the strength of brittle solids are discussed and important features of concrete microstructure, which influence the strength, are described. Microstructural considerations are used as a basis for the selection of materials and for establishing guidelines that are helpful in the development of a simple procedure for concrete mix proportioning.