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Walter Casquino writes "Discrecionalidad minera" motivated by the precept "everything that is ignored is scorned" and also by the poem by Antonio Machado (Seville, Generation of 98) that says,

discrecionalidad minera

Caminante, son tus huellas
el camino y nada más;
Caminante, no hay camino,
se hace camino al andar.
Al andar se hace el camino,
y al volver la vista atrás
se ve la senda que nunca
se ha de volver a pisar.

The book "Discrecionalidad minera" is based on notes collected throughout his long career as a mining engineer and the characteristics of his environment. In the presentation of his book, Walter tells us what four objectives motivated him to write "Discrecionalidad minera". That four objectives motivated him to undertake the writing of it. The first, the precious gift of freedom of thought and expression that happily continues to be revered in our culture; the second that the following generations do not stumble over the same stone; the third is honouring that line of teachers who support the culture by making a devotion to the transfer of knowledge, and the fourth, thanking their friends and acquaintances who go around the world caring for the common good.

Conventional concrete results from the combination of aggregates and a binder material or hydraulic glue, for example, portland cement, which is one of the most used. Concrete aggregates play a fundamental role in the final characteristics of concrete. The final result will depend on the chemical nature of the aggregates: silicic, limestone, basaltic, pozzolanic, etc., on their composition and granulometry. This last characteristic determines whether we are talking about concrete or mortars; thus, when the aggregate granulometry exceeds 5 mm, we speak of concrete.

Polymeric concretes in which the cementitious binder or glue is completely changed: portland, lime ..., for an exclusively polymeric binder or glue, and the most common is that curing resins are used as polymer at room temperature.

hormigones

Polymers are organic macromolecules whose origin can be natural or synthetic, consisting of chains of thousands of repeating structural units. The chains of a particular polymer have a specific size and shape, and that is why there is an immense number of polymers that differ between them: by the different lengths and conditions of their chains, by the type of bonds and forces that make them they unite, and according to the conformations or spatial arrangement that they acquire, which gives each polymeric material different characteristics and properties.

Polymeric concretes has the nature of composite materials, also called "composites", which are mixtures of different materials used to take advantage of their combined qualities. Attention, it is not about alloys or chemical compounds, but materials that, when forming each one, maintain their original identity, but in such a way that in the mixture, a synergistic effect or improvement and reinforcement of the properties that each develops is produced separately.

More generally, polymeric concrete is the name given to concretes. Polymeric binders or glues, organic compounds, only partially replace the hydraulic matrix, inorganic compounds, or modifiers to obtain an organic-inorganic hybrid material. For this reason, polymeric concretes can be classified based on the nature of the binder, or glue, into three types:

Polymer Portland Cement Concrete (PPCC)

We speak of "polymeric portland cement concrete" or PPCC when the polymer is incorporated into the concrete mass at its manufacture and distributed equally in it.

Polymer Impregnated Concrete - PIC

We consider that a block of concrete is impregnated with polymer (PIC) when the addition of the polymer is carried out after the setting of the cementitious concrete. The polymer will only partially or superficially cover the mass of the concrete.

Polymeric concrete - PC

"Polymeric concrete" or PC is manufactured when an exclusively polymeric matrix entirely replaces the hydraulic binder.

Typical characteristics of polymeric concrete

Impermeability
Durability
Resistance to chemical attacks
Thermal insulator
Electrical insulator

These are the uses and Typical applications of polymeric concrete

Structural repair
Pave roads
Pipe manufacturing
Decorative panels and flooring
Construction

Sources: Own elaboration by the GLOBAL3CCS team

CONCRETES WITH POLYMERS IN THEIR CONSTRUCTION PROPERTIES AND APPLICATIONS
A. Aguado, Dr. Ing. Caminos. - E.T.S. Ingenieros de Caminos, Canales y Puertos.
J. M. Salla, Dr. Ing. Industrial. - E.T.S. Ingenieros Industriales de Barcelona.
Universitat Politécnica de Catalunya.
© Consejo Superior de Investigaciones Científicas Licencia Creative Commons 3.0 España (by-nc)
http://informesdelaconstruccion.revistas.csic.es

Polyurea is a synthetic polymer product of the reaction of a diamine with an isocyanate; it is a polymerization reaction very similar to that of polyurethane. However, for Polyurea, the resulting bond is of the "urea" type, which is why it is called Polyurea. uretano y urea enlaces

POLYUREA BEHAVIOR

Polyurea is the new generation of polymer product systems for coating and surface protection. The Polyurea application has superior durability and performance compared to epoxy and urethane coatings, as well as greater flexibility in its application. The curing time is fast, resistant to extreme temperatures (-17 ºC and 120 °C to 175 °C) and humidity, which makes it an ideal solution for coatings in large-area projects.

The Polyurea dries to the touch and is passable in less than 30 seconds and fully cured in 1 hour. It also adheres to virtually any substrate (concrete, metal, wood, plastic) in a wide variety of conditions and environments. The most significant advantage over traditional systems is the speed with which it can be applied and comfortably adapted to the most intricate details; The result is a waterproof and seamless seam.

FREQUENT APPLICATIONS

Polyurea has a very low water permeability, which makes it an ideal resin for moisture barrier applications. The most critical applications are industrial spray coatings and elastomers used in harsh environments, including exposure to hydrocarbons, saltwater, bases, and diluted acids, fuels, fuel oils, and hydrogen sulfide. However, long-term exposure to these chemicals can affect performance and durability, so they must first be tested.

WHAT WE MUST DEMAND A POLYUREA

With the urea bond, we achieve that from the molecular structure, a moisture insensitivity is generated, which makes Polyurea (as long as it is pure) one of the best waterproof membranes.

We say "whenever it is pure" because, in the market, there are numerous Polyureas of the so-called "hybrids", which are a mixture between polyurethane and Polyurea. These membranes do not have the same mechanical properties as pure Polyurea (highlighting their excellent elongation and abrasion resistance); the difference shown in the following relationship:

Polyurea (pure) = polyamide + isocyanate

Polyurethane = isocyanate + polyol + catalyst

Polyurea (hybrid) = polyamide + isocyanate + polyol

Elastomeric Polyurea systems formulated only with polyamides and isocyanate are incredibly reactive, resulting in a 100 percent pure polyurea. Now so that the reactions carried out under the most optimal conditions, the isocyanate is added with a catalyst additive, which regulates the response and curing time, being able to achieve concise reaction and curing times, from 3 to 6 seconds. What is genuinely advantageous is that the proportions of the catalyst additive can be adjusted, to obtain the most appropriate reaction and cure times depending on the conditions required for each application and finish requested, the activator or catalyst additive used is DETDA80.

PURE POLYUREA, AROMATIC OR ALPHATIC?

Polyurea, depending on its chemical structure, can be of two types: aliphatic or aromatic. The aromatic is more tenacious than the aliphatic. Still, it does not resist exposure to ultraviolet (UV) rays, which causes discoloration and loss of brightness, which does not make it advisable for “face view” applications.

Aliphatic polyurea, on the contrary, is more resistant to UV radiation, so it is significantly better as a topcoat, but its production cost is higher since the raw materials needed to manufacture it have a higher price.

POLYUREA REQUIREMENTS

IN-SITU MANUFACTURING OF THE POLYUREA

A product system to manufacture the polyurea requires precise temperature and pressure conditions, so two-component hot projection equipment needed that must operate at high pressure to produce the polyurea in a chemical gun-tip reactor. Therefore, hardware capable of supplying strains in the environment of 19 MPascal and high temperatures above 70 ºC is necessary.

Today there is technology available to produce polyurea outside a traditional factory. Advanced technology manages by remote software, which allows the manufacture of polyurea on-site. Supported by advanced control modules that automatically collect data from work registration and manufacturing parameters, allowing to confirm that the work Manufacturing has been carried out according to the specifications, allowing a more precise adjustment of costs and forecasts.

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