LAB VERSUS FIELD SLAKING BEHAVIOR OF CLAY-BEARING ROCKS
The experimental set up for investigating the field disintegration behavior consisted of exposing 240 samples, containing 12 replicates of each of the 20 clay-bearing rocks, to natural climatic conditions. Each sample consisted of 10 pieces and weighed from 450 to 550 g. The samples were placed on the roof of McGilvrey Hall at Kent State University for a period of 1 year. Each month, one of the replicate samples from each of twenty rock types was taken down to the laboratory for grain size analysis and determination of disintegration ratios.
The preliminary results show a moderate degree of correlation between disintegration ratios of the samples determined after 2nd cycle durability test in the laboratory and the samples slaked for twelve months under atmospheric conditions. Samples slaked in the laboratory have average DR values of 0.705 for shales, 0.324 for claystones, 0.462 for mudstones, and 0.847 for siltstones whereas field-slaked samples have DR values of 0.494 for shales, 0.223 for claystones, 0.302 for mudstones, and 0.698 for siltstones after 3 months of slaking. The best correlation between DR values is exhibited by samples subjected to two cycles of durability testing in the lab and samples exposed to atmospheric conditions for two months.