Treatment of materials

Soil treatment has been used in France since the 1960s.

Up until the 1970s, the main focus was on the reuse of water-sensitive and/or wet soils as fill, notably during the construction of major freeway link programs in northern, eastern and western France, and the construction of runways and aprons at Roissy-Charles de Gaulle airport (figure 1 ).

Subsequently, the technique was extended to the creation of subgrades, starting with the reuse of fine soils, more particularly silts, then progressively a wider and wider range of materials such as clayey gravels, or even mixtures of fine soils with blocky elements or natural gravels.

In 1972, the LCPC and Setra drew up their first guide: "Recommandation pour le traitement des sols fins à la chaux" ("Recommendations for treating fine soils with lime").

The GTS technical guide "Traitement des sols à la chaux et/ou aux liants hydrauliques (Application à la réalisation des remblais et des couches de forme)", the most comprehensive existing guide on the subject (published in 2000), is a coherent complement to the GTR guide, both drawn up by LCPC and Setra. Like the GTR, it was developed with the participation of various industry players (CETE engineers, project owners, prime contractors, earthworks contractors).

Other guides and specifications are also worth mentioning:

• "catalog des structures types de chaussées neuves" 1998 (LCPC and Setra);

• LGV civil engineering standards currently being revised by SNCF ;

• technical specification no. 590.B published in 1999 (SNCF) ;

• Manuel de conception des chaussées d'autoroutes" technical guide, reissued in 2005 (Scetauroute);

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