Title: Needed--Paradigm Shifts in the Technology for Normal Strength Concrete

Author(s): J. M. Shilstone, Sr., and J. M. Shilston, Jr.

Publication: Symposium Paper

Volume: 144

Issue:

Appears on pages(s): 61-84

Keywords: admixtures; cement additives; cements; concrete construction; constructability; durability; high-performance concretes; quality control; specifications; strength; water-cement ratio; workability; General

DOI: 10.14359/4533

Date: 3/1/1994

Abstract:
The authors have been involved in concrete technology in the field over the past half-century. While there have been many beneficial advances, there have also been subtle, but important, regressions. To gain full advantage of concrete's potential, the undesirable effects of those regressive aspects must be corrected through a series of paradigm shifts. Performance requirements are changing, accentuating the need for new and advanced technologies. Concrete qualities other than 28-day strength must be recognized when durability is considered. High strength does not assure high durability. However, the characteristics that improve durability will generally produce higher strength than that required for structural purposes for concrete exposed to an aggressive environment. When this occurs, strength based on durability must be a deciding strength factor. Standard concrete practices are not always in the best interest of quality and constructability. These conditions are traced and solutions are offered. The principal concern is that most engineers are no longer trained to provide broad concrete industry leadership, as in the past. A major technical void has developed between design and construction teams. Just as geotechnical engineers took over foundation design, concrete engineers must be trained to lead concrete design and construction into the 21st century.