The Babylonians from 1700 BC used clay as their bonding substance and the Egyptians used gypsum and lime as binders, which more closely resembles modern concrete. Lime, derived from limestone and chalk, continued to be the primary cement-forming agent until the early 1800s. And in 1824, an English inventor named Joseph Aspdin ground together a mixture of clay and limestone. We now know it as Portland cement and is still the dominant cementing agent used in concrete production. It is a structural construction material most commonly known as aggregate (gravel and sand). Cement and water are mixed to make concrete.
Concrete is one of the better achievements of humanity as it embodies our tendency for stability. And like many other of our advancements, concrete is found in nature. We take it in its purest form (rocks) and process it until it meets our standards for creation and security. Concrete is characterized by the type of cement mixture used, by its qualities or by the methods used to manufacture it. The character of concrete used in ordinary structures is established by its water to cement ratio. The less the water content, the more impregnable the concrete. The mixture has to have just enough water to ensure that each particle is surrounded by cement paste, that the spaces between them are filled, and that the concrete is fluid enough to be poured and spread effectively.
In 1867, a Parisian gardener invented ferroconcrete or reinforced concrete. This is when concrete is poured onto steel (rods, bars, or mesh), to harden. Plain concrete is unsuitable for structures since it does not withstand pressures such as wind, vibrations, or earthquakes. On the other hand, reinforced concrete combines the strength of steel and the strength of concrete making it capable of sustaining any heavy stress over considerable periods.
Another method used in construction is the use of pre-stressed concrete achieved by either pre-tensioning or post-tensioning. Pre-tensioning sees lengths of steel wires, ropes or cables stretched and weighed down in an empty mold. The concrete is then spilled and left to set, and the fastens are released. The concrete gets compressed as the steel returns to its original length. In post-tensioning, concrete is poured and only then is the tension applied. The level of compression transmitted to the concrete is carefully regulated.
When you’re dealing with concretes, there is always a big chance that you will damage your nails. You can check out a cheap nail salon to repair your nails if that’s the case. By then you can just go and visit Switzerland for your extra time!