I was recently revising a presentation and that began with a definition of concrete. Here is the definition: A mixture of paste (Cement, Water, Chemical Admixtures, & Other Cementitious Materials) & aggregates (Rock & Sand) that forms a solid mass as the paste hardens. I decided to check the definition using my trusty search engine and came up with a great variety of definitions. Here are a few of the definitions of concrete I found:
An artificial, stone like material used for various structural purposes, made by mixing cement and various aggregates, as sand, pebbles, gravel, or shale, with water and allowing the mixture to harden. (Dictionary.com)
A hard, strong construction material consisting of sand, conglomerate gravel, pebbles, broken stone, or slag in a mortar or cement matrix. (Thefreedictionary.com)
An artificial stone made of a mixture of cement, aggregate (hard material), and water. In addition to its potential for immense compressive strength and its ability, when poured, to adapt to virtually any form, concrete is fire-resistant and has become one of the most common building materials in the world. The binder usually used today is Portland cement. The aggregate is usually sand and gravel. Additives called admixtures may be used to accelerate the curing (hardening) process in low temperature conditions. Other admixtures trap air in the concrete or slow shrinkage and increase strength. (Merriam-Webster)
Early in my career I was told that concrete would be the simplest building material I would ever work with. Then I was told that it would be the most complicated building material, and I would learn something new every day. I think the varied definitions above illustrate the simplicity and complexity of concrete. Concrete is very simple to design. It is basically as ACI CT-13 - ACI Concrete Terminology states; a mixture of hydraulic cement, aggregates, and water, with or without admixtures, fibers, or other cementitious material. Concrete is very simple, but as we work with this product we can find many complex combinations to produce a mixture with properties that meet stringent project requirement. This is the reason I love my job.
Georgia Chapter ACI, President