I am a Christian. I believe in the God of the Bible, in God the Father, in His Son Jesus Christ, and in the Holy Spirit. I believe in Genesis 1:1 - "In the beginning God created the heavens and the earth. (NIV)" I am a biochemist and a pharmacist by education. As such I have a desire to understand nature. I am writing this blog as my way to express the facts of true science as I understand them, from the perspective of one who believes that all things were created by God, for God and for His purposes.

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Sunday, March 25, 2012

The Whole Nine Yards! - Concrete Chemistry

Many years ago I was told that this saying came from the capacity of your typical Ready-Mix concrete truck. But as I researched this blog, I discovered that this was just one of the many proposed origins for this colloquialism. So before we move to the chemistry, lets get "the whole nine yards" on "The Whole Nine Yards."

The phrase "The Whole Nine Yards" means everything, the whole lot, completely or the works. It is a reference to the full measure of something. The origin of the phrase has been described as, "the most prominent etymological riddle of our time" as it is not clearly known how or where the expression came into use. Its first known appearance was in 1962 in a "Michigan's Voices: A Literary Quarterly Magazine" story entitled "Man on the Thresh-hold" by Robert E. Wegner. The quoted line goes like this:

...mad, mad, mad, the consequence of
house, home, kids, respectability, status as a
college professor and the whole nine yards, as a
brush salesman who came by the house was fond of

But how did it come to be there? And what did the brush salesman have to do with it? No one seems to know for sure. There are any number of explanations for the origin of the phrase but none seem to be satisfactory. Here are a few of the more popular ones:

"Nine Yards"
  • Amount of cloth needed for a Scottish kilt, a burial shroud, or a three-piece suit
  • Length of some World War II military artillery (US bombers bomb racks or RAF Spitfire's machine gun ammunition belts)
  • Yardage in American football (but ten yards are needed for a first down)
  • Other types of "yards" (number of properties on a city block, naval shipyards or yardarms on a sailing ship)
  • Capacity of a ready-mix concrete truck, coal truck, or garbage truck (in cubic yards)

So getting back to my initial explanation of "the whole nine yards" as a cubic measure and the volume of a cement mixer. Cement mixers were much smaller in the 1960's (4-6 cubic yards) and none of the early references to the saying relate to concrete or even to construction. It seems rather unlikely that a term from such a specialized field would become so well known. Even the capacity of today’s trucks varies a great deal, and only a few of them actually carry nine cubic yards of concrete.

So in spite of the fact that the phrase is not specifically about concrete mixer capacity, lets look past that and see if we can get "the whole nine yards" on the liquid rock that these mixers supply - Concrete.

Concrete is one of the most versatile
Construction Materials in the World

As a construction material, concrete can be cast in almost any shape, and once hardened, can become a structural or load bearing building element. It is one of the most versatile construction materials available in the world. Concrete should not be confused with cement, because the term cement refers to the material used to bind the materials in concrete. Concrete is a mixture of aggregate, cement and water. Aggregate is generally a coarse gravel or crushed rock such as limestone, or granite, along with a fine aggregate such as sand (Silicon Dioxide - SiO2). Cement is a binder, a substance that sets and hardens independently, and can bind other materials together.

The cement used in concrete is a hydraulic cement (Portland cement) and hardens due to hydration, a series of chemical reactions that occur independently of the mixture's water content, and can harden underwater or when constantly exposed to wet weather. The chemical reaction that results when the anhydrous (dry) cement powder is mixed with water produces hydrates that are not water-soluble. Carbon dioxide is absorbed to convert the portlandite (Calcium Hydroxide - Ca(OH)2) into insoluble calcium carbonate (CaCO3). The constituents slowly hydrate and crystallize and the interlocking of the crystals gives cement its strength. Maintaining a high moisture content in cement during curing increases both the speed of curing, and its final strength. The time it takes for cement to cure varies depending on the contents of the mixture, if gypsum (calcium sulfate dihydrate - CaSO4·2H2O) is added to slow the curing, and the environmental conditions. Initial hardening can occur in as little as twenty minutes, while a full cure can take over a month. Cement typically cures sufficiently to be put into service within 24 hours to a week.

Portland Cement is made by heating limestone (calcium carbonate), in a kiln to 1450°C, with small quantities of clay (alumino-silicates or SiO2) or other materials. This process, known as calcination, liberates a molecule of carbon dioxide from the limestone to produce calcium oxide (CaO), or quicklime. The quicklime is then blended with other materials to make a "clinker." Portland cement clinker is a hydraulic material consisting mainly of calcium silicates (3CaO·SiO2 & 2CaO·SiO2). The clinker is ground, with a small amount of gypsum, into a powder to create Portland Cement, the most commonly used type of cement. Beside concrete, Portland cement is a basic ingredient of mortar and most non-specialty grouts.

Concrete is poured into forms to make almost any design. The forms can be made with wood, metal or plastic but need to be strong enough to hold back the pressure created by the hardening material. Steel screen or rebar (short for reinforcing bar) is frequently used to supply additional tensional strength to the finished concrete. Intricate artwork can be added to the surface using specialized forms or by the use of shaping tools or stamps and by scraping the surface as the concrete dries. Concrete can also be poured into simple wooden molds to make concrete block, one of the most widely used construction materials. Concrete blocks can be easily made on site making them an excellent material for building homes and other structures in remote locations in underdeveloped countries.

If not for the strength of this liquid rock, we would not be able to build much of the backbone of this country - the highways, the skyscrapers, the bridges. Concrete is the foundation of our modern urban infrastructure. A simple but versatile chemical from God's Chemistry Set.

Matthew 7:25 (NIV) - The rain came down, the streams rose, and the winds blew and beat against that house; yet it did not fall, because it had its foundation on the rock.

Psalms 89:14 (NIV) - Righteousness and justice are the foundation of Your throne; love and faithfulness go before You.

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