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16 Photo 2. Core Compaction. Note compacting in paths parallel to dam axis and the hand tamper in photo that will be used to compact zone immediately next to wall. Almost invariably, there will be areas within the core section, such as at contacts with outlet conduits or other structures and at the contact areas with rock foundations and abutments, where the equipment used for compacting the mass fill areas is not suitable. These areas are referred to as special compaction areas, and should be addressed with their own specification. Compacted density requirements should not be compromised in these areas, but it may be desirable to maintain soil moisture contents on the wet side of optimum to ensure the plasticity of the fill, so that it readily deforms to the shape of the surface contacted. Rubber-tired compaction equipment, such as heavy front-end loaders, should be used where possible in these areas, rather than sheepsfoot rollers, to avoid damaging foundation and abutment surfaces and to permit compaction of soils directly against structures. Smaller, hand-operated compaction equipment may be necessary in more confined areas, but their use should be minimized as much as possible, and lift thicknesses should be reduced accordingly to allow for full effectiveness and uniformity of the compactive effort. The specifications should also provide for protecting the placed core material from excessive drying, overwetting, and freezing. Any areas that are allowed to dry excessively should be scarified, watered and recompacted to ensure that subsequent lifts can bond adequately. Similarly, if the core zone is exposed to excessive rainfall or ponding of water on the surface, it may be necessary to scarify the wet material and allow it to air dry to an acceptable moisture content prior to recompaction, or, in some cases, completely strip the overwet material prior to proceeding with subsequent fill placement. The specifications should also address preventing the incorporation of frozen materials within the embankment, and the protection of placed fills from freezing. Method Specifications versus End-Result Specifications For earthwork projects, specifications may be written to require either a specific methodology to achieve a desired result (“method specification”) or to require a certain specific outcome which is verified by testing (“end-result specification”). A method specification may be appropriate if limited material is being placed, or if testing of materials is difficult or too time-consuming for real-time test results. A typical usage of a method specification would be to control the placement and compaction of granular materials, such as would be used for filters and drains within dams. Since these types of materials do not exhibit the type of moisture/density compaction behavior typical of fine-grained soils, test procedures developed for fine-grained soils are not generally applicable, and the types of tests which have been developed to determine placed densities can be somewhat problematic. Method specifications are, therefore, often more appropriate for controlling the placement of these materials. A method specification would typically specify a required type and amount of effort to be expended to achieve the desired result, without necessarily testing for the result. Method specifications are usually verified by requiring the contractor to perform a scaled test pad using proposed source materials and equipment. The test pad places the material in accordance with the proposed method specification. Testing of the in-place compacted materials including gradation (for particle