The world was once simple. That was when man huddled on cold clods and stood in even colder air until he found some peace in caves and the warm breath of fire, and fought to survive the elements with little knowledge but by sheer strength. The main terrorists were the environment, animals, lack of food, and water—sickness was almost unheard of because most bad bacteria had not yet been birthed—but the weak were constantly gleaned from the environment by the environment. To survive meant strong bodies, a defensive posture, and a will to overcome nature's atrocities. Man had not yet self-taught the anger and anxieties that accompany progress.
Slowly, first with foot speed, then rapidly by horse, locomotive, automobile, jet, and rocket, and finally by wireless, our world changed overnight.
Wars of competition began as families got larger and groups coalesced into tribes. Dependency on each other eventually fostered a semblance of government. First led by the physical strongest, eventually helped by conniving bloodlines, then by politicians, religious zealots, and always by weapons, concealed or otherwise. What brought it about was learning and education—the more we know, the more we suspect, the more we distrust, and eventually, everyone knows so much we think ourselves into obliteration.
Thomas A. Edison, looked at the way portland cement was manufactured and said, “There must be a better way to make that cement.” In the late 1800s, he patented a rotary kiln, a better way to make cement clinker, and also ways to improve its strength-developing properties. He enlarged the existing steel-riveted, boiler-iron-plate, sewer pipe-like kiln from 6 to 9 feet in diameter, and extended its length from 60 to 150 feet. The time from simple bearingless vertical kilns to oiling 10,000 bearings for the long kilns didn't take long. Short kilns produced 200 barrels of clinker per day with new ones producing 400 barrels per day. Kilns eventually reached more than 1100—once an impossibility.
The rise of portland cement-based concrete came just in time: to help satisfy the need for hard-surfaced roadways and sidewalks that replaced the compacted dirt. Edison's plants supplied the cement needed for construction of “The House that Ruth Built”—Yankee Stadium. Eventually, it became the mainstay of building foundations and other building elements.
Invention has always been followed by progress—but not without research—and sometimes by accident. Portland cement came about by inadvertent argillaceous natural impurities (clay) that in limestone calcination formed nodules having portland cement clinker-like properties that kindled the inventiveness of Joe Aspin, who crushed it, added water—and the rest is history. Duff Abrams coined water-cement ratio (w/c) in the late 1920s, more recently accepted as w/cm (note the italicization) upon the advent of supplementary (complementary) cementitious materials. Progress on the move! The nonfearing mix concrete in seconds—green it using industrial wastes—cure it using internal and external methods—place it by pumping—spread and consolidate it using self-leveling admixtures—compact it by rolling—achieve strength using dramatic water-reducing admixtures and by chewing up the weak calcium hydroxide component of cement hydration by pozzolanic reactions using fly ash—and take steps using shrinkage-compensated concrete and 120-foot joint spacing footprints.
We have jumped from sleeping on clods to fire-warmed caves; from individual to family to “communal” living in villages, towns, cities, and now the megalopolis; from the Model T to computerized cars; from simply formulated portland cement-water-aggregate concrete systems to solid and chemical-admixed, and complex, concrete. The age of straight portland cement concrete is waning, replaced by an inventiveness to extend its use by complimentary enhancements that change, modify, and minimize the disadvantage sides of its use in concrete. So where do we go from here? There is only one direction up—however impossible that may seem. So keep abreast of things. don't get left behind, because simple doesn't last long.