What if our cement was as reliable as our software


One of my favorite news sites is CIO.com. I might not be a CIO, but it often covers very insightful articles about high level concepts.

The article I read today was named “Insecure Software’s Real Cost: Software and Cement” and written by David Rice. It was an excerpt from his book “Geekonomics: The Real Cost of Insecure Software”.
(ISBN-10: 0-321-47789-8 / ISBN-13: 978-0-321-47789-7).

Honesty forces me to say that I’m a sucker for morale tales, and I have to say that it was a while ago since I read a story that made such a nice reference to history in regards to modern technology.

Book excerpt:

For the city of London, 1854 was a dreadful year. An outbreak of cholera, the third in 20 years, claimed over ten thousand lives. Six previous city Commissions failed to adequately address London’s growing sewage problem, leaving the entire metropolitan area—more than one million people—subject to the vagaries of overflowing cesspools, ill-constructed sewers, contaminated groundwater, and a dangerously polluted Thames River. Considering London was one of the most populated cities at the time and depended heavily on the Thames River, inaction had unfortunate consequences. Sadly, thousands of deaths could not properly motivate Parliament to overcome numerous bureaucratic and political obstacles required to address the crisis.

It was not until an inordinately hot summer in 1858 that the stench of the Thames so overwhelmed all those in close proximity to the river—particularly members of Parliament, many of whom still believed cholera to be an airborne rather than a waterborne pathogen—that resistance finally subsided. The “Great Stink” served as impetus to the largest civic works project London had ever seen.1

For the next ten years, Joseph Bazalgette, Chief Engineer of the Metropolitan Board of Works, constructed London’s newer and larger sewer network against imposing odds. Despite Parliament’s hard-won support and a remarkable design by Bazalgette himself, building a new sewer network in an active and sprawling city raised significant technical and engineering challenges.

Most obvious among these challenges was excavating sewer lines while minimizing disruption to local businesses and the city’s necessary daily activities. Less obvious, but no less important, was selecting contracting methods and building materials for such an enormous project. Modern public works projects such as the California Aqueduct, the U.S. Interstate highway system, or China’s Three Gorges Dam elicit images of enormous quantities of coordination and concrete. Initially, Bazalgette enjoyed neither.

Selecting suitable building materials was an especially important engineering decision, one that Bazalgette did not take lightly. Building materials needed to bear considerable strain from overhead traffic and buildings as well as survive prolonged exposure to and immersion in water. Traditionally, engineers at the time would have selected Roman cement, a common and inexpensive material used since the fourteenth century, to construct the extensive underground brickworks required for the new sewer system. Roman cement gets its name from its extensive use by the Romans to construct the infrastructure for their republic and empire. The “recipe” for Roman cement was lost during the Dark Ages only to be rediscovered during the Renaissance. This bit of history aside, Bazalgette chose to avoid Roman cement for laying the sewer’s brickwork and instead opted in favor of a newer, stronger, but more expensive type of cement called Portland cement.

Portland cement was invented in the kitchen of a British bricklayer named Joseph Aspdin in 1824. What Aspdin discovered during his experimentation that the Romans did not (or were not aware of) was that by first heating some of the ingredients of cement—finely ground limestone and clay—the silica in the clay bonded with the calcium in the limestone, creating a far more durable concrete, one that chemically interacted with any aggregates such as stone or sand added to the cement mixture. Roman cement, in comparison, does not chemically interact with aggregates and therefore simply holds them in suspension. This makes Roman cement weaker in comparison to Portland cement but only in relative, not absolute terms. Many substantial Roman structures including roadways, buildings, and seaports survived nearly 2,000 years to the present.

It is the chemical reaction discovered by Aspdin that gives Portland cement its amazing durability and strength over Roman cement. This chemical reaction also gives Portland cement the interesting characteristic of gaining in strength with both age and immersion in water.2 If traditional cement sets in one day, Portland cement will be more than four times as hard after a week and over eight times as hard in five years.3 In choosing a material for such a massive and important project as the London sewer, Portland cement might have rightly appeared to Bazalgette as the obvious choice. There was only one problem: Portland cement is unreliable if the production process varies even slightly.

The strength and therefore the reliability of Portland cement is significantly diminished by what would appear to the average observer as minuscule, almost trivial changes in mixture ratios, kiln temperature, or grinding process. In the mid-nineteenth century, quality control processes were largely non-existent, and where they did exist were inconsistently employed—based more on personal opinion rather than objective criteria. The “state of the art” in nineteenth century quality control meant that while Portland cement was promising, it was a risky choice on the part of Bazalgette. To mitigate any inconsistencies in producing Portland cement for the sewer project, Bazalgette created rigorous, objective, and some would say draconian testing procedures to ensure each batch of Portland cement afforded the necessary resiliency and strength. His reputation as an engineer and the success of the project depended on it.

Bazalgette enforced the following regimen: Delivered cement sat at the construction site for at least three weeks to acclimate to local environmental conditions. After the elapsed time, samples were taken from every tenth sack and made into molds that were immediately dropped into water where the concrete would remain for seven days. Afterward, samples were tested for strength. If any sample failed to bear weight of at least five hundred pounds (more than twice that of Roman cement), the entire delivery was rejected.4 By 1865, more than 11,587 tests were conducted on 70,000 tons of cement for the southern section of the sewerage alone.5 Bazalgette’s testing methodology proved so thorough, the Metropolitan Board who oversaw the project eventually agreed to Bazalgette’s request to construct sewers entirely from concrete. This not only decreased the time required to construct the sewerage, but eliminated the considerable associated cost of the brickworks themselves.6

Once completed, Bazalgette’s sewer system saved hundreds of thousands of lives by preventing future cholera and typhoid epidemics.7 The sewer system also made the Thames one of the cleanest metropolitan rivers in the world and changed the face of river-side London forever. By 1872, the Registrar-General’s Annual Report stated that the annual death rate in London was far below any other major European, American, or Indian city, and at 3.3 million people (almost three times the population from the time Bazalgette started his project), London was by far the largest city in the world. This state of affairs was unprecedented for the time. By 1896 cholera was so rare in London, the Registrar-General classified cholera as an “exotic disease.” Bazalgette’s sewer network, as well as the original cement used in its construction, remains in use to this day. Given that Portland cement increases with strength over time, it is likely London’s sewer system will outlive even some of Rome’s longest standing architectural accomplishments such as the aqueducts and the Pantheon.

While Bazalgette’s design of the sewer network was certainly important, in hindsight the selection and qualification of Portland cement was arguably the most critical aspect to the project’s success. Had Bazalgette not enforced strict quality control on production of Portland cement, the outcome of the “Great Stink of London” might have been far different. Due to Bazalgette’s efforts and the resounding success of the London sewer system, Portland cement progressed in a few short years from “promising but risky” to the industry standard used in just about every major construction project from that time onward.

Portland cement’s popularity then, is due not just to its physical properties, but in large part to Bazalgette’s strict and rigorous quality tests, which drastically reduced potential uncertainties associated with Portland cement’s production. At present, more than 20 separate tests are used to ensure the quality of Portland cement, significantly more than Bazalgette himself employed. World production of Portland cement exceeded two billion metric tons in 2005, with China accounting for nearly half of that production followed closely by India and the United States.8 This works out to roughly 2.5 tons of cement for every person on the planet. Without Portland cement, much of modern civilization as we know it, see it, live on it, and drive on it would fail to exist.

Cement is everywhere in modern civilization. Mixed with aggregates such as sand and stone, it forms concrete that comprises roadways, bridges, tunnels, building foundations, walls, floors, airports, docks, dams, aqueducts, pipes, and the list goes on. Cement is—quite literally—the foundation of modern civilization, creating the infrastructure that supports billions of lives around the globe. One cannot live in modern civilization without touching, seeing, or relying on cement in one way or another. Our very lives depend on cement, yet cement has proven so reliable due to strict quality controls that it has to a large extent disappeared from our field of concerns—even though we are surrounded by it. Such is the legacy of Bazalgette’s commitment to quality: We can live our lives without thinking twice about what is beneath our feet, or more importantly, what may be above our head.

Civilization depends on infrastructure, and infrastructure depends, at least in part, on durable, reliable cement. Due to its versatility, cost-effectiveness, and broad availability, cement has provided options in construction that could not otherwise be attained with stone, wood, or steel alone. But since the 1950s, a new material has been slowly and unrelentingly injected into modern infrastructure, one that is far more versatile, cost-effective, and widely available than cement could ever hope to be. It also just so happens to be invisible and unvisualizable. In fact, it is not a material at all. It is software.

Like cement, software is everywhere in modern civilization. Software is in your mobile phone, on your home computer, in cars, airplanes, hospitals, businesses, public utilities, financial systems, and national defense systems. Software is an increasingly critical component in the operation of infrastructures, cutting across almost every aspect of global, national, social, and economic function. One cannot live in modern civilization without touching, being touched by, or depending on software in one way or another.

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