Overview

Organic binders have been known to humanity since the highest antiquity. With liana and interlaced ropes, they discovered the basic jointing technique, both for housing and for household furniture and objects of common use, even jewels. But whereas ropes functioned essentially by virtue of their mechanical properties and the entanglements that they formed, glue, excrements, pap, bitumen brought into play physico-chemical processes completely unknown to their users, though relatively well mastered in practice. Today s materials are certainly better known but adhesive bonding mechanisms have not yet revealed all their secrets. We will see further below (Chapter 4) how far we must go to give this mode of jointing the place that could be its in civil engineering.

In general, we call binder any substance used to bring together and maintain together particles that are generally solid. In civil engineering, we can distinguish:

• hydraulic binders, such as cement, so-called because they require water for setting;

• organic binders, such as bitumens or synthetic resins (polymers) so-called because they are made up of organic molecules.

We may note in passing that in road engineering, we refer to the former as white binders in contrast to black binders or more commonly hydrocarbon binders for the latter category.

The role of binder is particularly suitable for organic molecules. We will see about gluing (Chapter 4) that contact jointing, carried out by means of natural organic binders, is as old as the man. To limit ourselves to the field of...