Compacted clay-industrial wastes blends: Long term performance under extreme freeze-thaw and wet-dry conditions

The use of industrial wastes (coal fly ash and carbide lime) is appropriate procedure to enhance the long-term performance of clays under extreme freeze-thaw and wet-dry conditions. This investigation assesses the impact of lime content (L) and dry unit weight (γd) on the durability and long-term performance of compacted clay-fly ash-carbide lime mixes. It defines the accumulated loss of mass (ALM) after freeze-thaw and wet-dry cycles as a function of the porosity/lime index. Results have shown that compacted clay-fly ash-carbide lime blends under wet-dry cycles presented better performance that when submitted to freeze-thaw cycles. Specimens were statically compacted in 3 stratums to reach required dry unit weights in the interior of cylindrical moulds, stipulating in each case the dry weight of solids to the volume of the specimen moulded. Moulding moisture content (w) of all specimens was 29%. In addition, the existence of mathematical equations connecting accumulated loss of mass divided by the number of freeze-thaw (and wet-dry) cycles and porosity/lime index, as well as with unconfined compressive strength is revealed empirically. This broadens the applicability of such index by demonstrating it controls not only mechanical but also long term performance of compacted clay-industrial wastes mixes.