Expansives
Introduction
Cement is a dry powder made of silica, alumina, lime, iron oxide and magnesium oxide, which hardens when mixed with water.
Context: types of cement
There are many types of cement: aluminous, asphalt, bituminous, white, air-entrained, masonry, high temperature, asbestos, sulfur or expansive.
The latter is characterized because it replaces the explosive with a large number of advantages: it does not pollute, it does not produce vibrations, it does not require permits,... It is used in demolition work of all types of rocks and concrete, in quarries, underwater work, construction, civil and public works, etc. The main feature is that it works in large diameters with the same results as in small diameters.
History
The technology used by this cement is the chemical hydration reaction. This chemical reaction has been used since ancient times since it was used in the construction of the Egyptian pyramids for the extraction and production of large blocks of granite.
They used wooden wedges and wet them with water. As a result of the chemical hydration reaction, a great expansive force was produced and the subsequent breakage. Demolition cements, mixed with water, produce the chemical hydration reaction, generating an expansive force of 7,000 to 9,000 T/m².
modern development
In the mid-seventies of the century, an Italian engineer and chemist, Rossano Vannetti, began the study and development of the modern formulation of expansive cement. Based on calcium carbonates, he manages to develop a formulation that allows him to regulate the reaction time of the product at will, and therefore, based on reaction catalysts, control the breakage times.
This differential fact allows him, starting from a small laboratory in Italian Tuscany, in Casteglione de la Pesacia, to found what is today a great industrial, commercial and economic empire around this product. It established factories and commercial headquarters on the five continents and in a relatively short time became the world's largest producer of expansive cement, with industries in Italy, Brazil, Argentina, Egypt and South Africa.