WATER BEHAVIOR IN LIMESTONES AS A FUNCTION OF PORES STRUCTURE - APPLICATION TO FROST-RESISTANCE OF SOME LORRAINE LIMESTONES

The frost resistance of limestones is determined by their ability to w ithstand damage caused by water freezing in microscopic pores. The fac tors which limit frost action are connected with the saturation state of the material and the distribution of water in the porous media. The behaviour of fluid in some limestones from the Lorraine area of north east France was studied in laboratory experiments. Carbonate grainston es with bimodal porous networks have high values of air-trapped porosi ties and permeabilities, and their degree of saturation, resulting fro m capillary absorption or total immersion, is restricted to 60%. For t hese materials, the predictive frost resistance is high. The result of frost action on limestones with unimodal porous networks depends on t he rock texture (mudstone to packstone, more or less well-cemented), t he influence of parameters such as pore radius, pore shape, permeabili ty, and the strains developed during freezing. These relations are con firmed by in situ observations and by experiments with frost in a clim atic cabinet.