The natural compatibility with the reinforcement bars, which determine the greatest part of the mechanical characteristics of flexion and traction, combined with the relative ease of its installation and the ductility with which it’s possible to create works and structures with more articulated shapes, make of concrete the best known and most used material in construction.
Often, however, due to negligence and superficiality of the workers or due to the bad implementation on site, combined with environmental degrading factors, its duration has proved to be limited in time, unlike what was theorized at the dawn of this technology, where concrete was thought “indestructible”.
To avoid these anomalies, the National and European Regulations have prescribed the necessary and mandatory methods for the making of durable concrete.
According to Ministerial Decree 17/01/2018 “Technical standards for construction” durability is defined as the conservation of the physical and mechanical characteristics of materials (such as concrete) and structures, essential properties so that safety levels are maintained throughout life work.
The nominal project life of a work is conventionally defined as the number of years in which the work, provided it is subject to the necessary maintenance, is expected to maintain specific performance levels.
CAN CONCRETE BE DEFINED AS
AN ETERNAL MATERIAL?
Basically, a concrete durable in an aggressive environment must be “mixed, cast and cured” to be impermeable to water and resistant to potentially harmful agents.
The European standard EN 206 establishes the criteria for the prescription, mixing and installation of concrete in the various environments.
The concrete designer must ensure that all the significant requirements for the properties of the concrete, established by EN 206, are included in the specification supplied to the manufacturer, which in turn, in addition to respecting these requirements, must be equipped with a Control System of Production (FPC). From the compositional point of view we can derive, from the experience gained so far, some certain rules: additions of silica fume with pozzolanic activity (MICROSIL 90) and fiber reinforcement with anti-cracking and/or structural filaments (READYMESH technology) are able to make an essential contribution to durability of concrete, even in the most severe exposure environments mentioned in the EN 206 standard.
In addition to this, the company that will take care of the installation will have to pay particular attention, in addition to the implementation with due care, also of the correct curing of the concrete, to increase the degree of hydration, protecting it from rapid drying with curing, anti-evaporating agents (CURING AID) or simply by constantly humidifying the surface by sprayed water or damp sheets.