IMMEDIATE IMPROVEMENT WITH LIME. THE STABILIZATION OF WET COHESIVE SOIL WITH LIME. V 1

THE GEOTECHNICAL CHARACTERISTICS OF WET COHESIVE SOIL ARE QUICKLY IMPROVED BY ADDITION OF LIME. A QUANTITY OF LIME OF THE ORDER OF 1% IS GENERALLY SUFFICIENT TO MODIFY THE SOIL STRUCTURE WITHIN A FEW MINUTES BY FORMATION OF STABLE GRANULES. THIS IS THE MOST IMPORTANT IMMEDIATE EFFECT WHICH RESULTS IN IMPROVEMENTS IN THE GEOTECHNICAL PROPERTIES: INCREASE IN PLASTIC LIMIT, MODIFICATION OF THE PROCTOR CURVE, INCREASE IN THE CBR INDEX. HIGHER PROPORTIONS OF LIME HAVE VERY LITTLE INFLUENCE ON THESE IMMEDIATE EFFECTS. THE LATTER ARE ACCENTUATED BY DRYING OF THE SOIL WHEN QUICK LIME IS USED AND BY EVAPORATION OF THE WATER DUE TO EXTERNAL FACTORS (MIXING, ATMOSPHERIC CONDITIONS). THE REDUCTION IN MOISTURE CONTENT DUE TO THE TYPE OF EVAPORATION IS, UNDER FAVOURABLE CONDITIONS, FAR MORE IMPORTANT THAN THAT DUE TO THE ADDITION OF A SMALL PROPORTION OF QUICK LIME. DIFFERENT TESTS CARRIED OUT WITH A VIEW TO EXPLAINING THE PHYSICO-CHEMICAL MECHANISM OF THE IMMEDIATE EFFECT OF LIME ON CLAYEY MINERALS SHOW THAT THE MAIN CAUSE OF THIS ACTION IS THE BRIDGING OF THESE MINERALS BY LIME HYDRATES.