Analysis and characterization of building materials

A construction project, whether new or repairing old, necessarily calls for the use of materials, the definition of which is included in the specifications. At this level, the question arises as to how to specify the order, on the understanding that the designer is primarily interested in the constructive function of the material he has chosen, its mechanical, protective and even aesthetic properties, and is based on the assumption that the material in place will correctly fulfill the role assigned to it.

Reality reminds us that we can't ask everything of a material at once, and that a minimum knowledge of its physico-chemical structure is essential. Specialized books can be consulted for this, but there may also be unresolved questions for a given application. Good chemical or physico-chemical analysis methods are needed to supplement suitability tests in certain difficult cases.

But where analysis really comes into its own, and proves to be a powerful ally, is in verifying that the material delivered is indeed the one expected, i.e. that it can be considered identical to the one defined in the project: recourse to chemical analysis is based on the principle that, if two samples are of identical composition, they are likely to have the same properties in use.

A second important contribution of analysis is its ability to provide elements for understanding or anticipating, in certain cases, the behavior of a material by analogy with similar cases encountered in the past. This involves the study of material pathologies, on the one hand, and functional characterization (ability to perform a function), on the other. The first application is standard practice. The second requires a great deal of care on the part of the user.

In all cases, material characterization methods should be considered as a whole, in which each element has its place, chemical methods as well as mechanical or rheological tests. It is generally not useful to analyze a product completely in order to characterize it in the context in which it is used, and in some cases it is even preferable to abandon analysis in favor of a global test based on a relevant and significant physical quantity.

The methods described below attempt to respond to these premises, family by material family. If the paragraphs are of unequal length, it's because the methods described are more or less commonly used, or even replaced by another procedure in the quality plan in question. The principle of complementarity described above applies here.