STABILIZATION OF GRANITIC SHALE IN THE AUVERGNE WITH LIME AND LIME-CEMENT MIXTURES. LABORATORY STUDY

Results are given of the laboratory study of the stabilization of two types of shale with a view to finding A means of using this material with a high moisture content. Tests on stabilization with quick lime show that the addition of the latter brings an immediate marked increase in the CBR index. However, most of this increase can be caused by the reduction in moisture content due to the addition of lime as the immediate CBR index in shale is very sensitive to water. If stabilization with lime is used in earthworks, the technique appears to be worthwhile for wet shale or temporary stabilization, but if used in improved subgrades it seems that the action of the lime cannot be guaranteed over a long period. The second part of the article investigates the use of shale in improved subgrade in a general way. CBR punching tests after 4 days immersion and the study of simple compressive strength give good results.