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File No. 20-1008-49.1 K L E I N F E L D E R December 8, 1992 test pad being constructed. Changes in the process of clay deposition and spreading will be at the discretion of the Engineer or representatives of Kleinfelder, Inc. to allow optimum efficiency in the construction process. If a 12-inch lift is used, then the amount of deposited soil and clay will be doubled. Once the Engineer has determined that the clay has been satisfactorily deposited, then the process of premixing may begin. Because the borrow soil and clay may not be sufficiently moisturized to be at a moisture content of at least 3% over optimum after mixing, the addition of water during the mixing process may be necessary. Water may be added in one of several manners as directed by the Engineer or representatives of Kleinfelder, Inc. Water may be added through the use of a spray bar attachment to the mixing apparatus or sprayed by a water truck at some point during the mixing operation. Premixing will involve mixing the Ione clay and upper 1-2 inches of loose soil for the sole purpose of breaking down the Ione clay into smaller particles. Premixing should continue until a maximum 10 percent is retained on a 3/a inch sieve. Once premixing is complete, the entire layer thickness, whether 6 or 12 inches, shall then be mixed. Mixing of the soil and clay will be by a large rototiller or self-propelled soil mixer. The mixing apparatus will be capable of completely and uniformly mixing the two soils together throughout the entire depth of the lift, whether 6 inches or 12 inches. This will require that the mixing of the upper lift penetrate the lower lift by 1 to 2 inches to ensure that no untreated soil is left inplace. Mixing will continue until compliance with Section 24 of Caltrans Standard Specifications regarding particle size are met. A minimum of 60 percent of the mixed material will pass the number 4 sieve before mixing will be considered completed. In addition to the above provisions for construction procedure, the following specifications shall be followed during construction: • If the barrier layer is constructed in multiple lifts and is allowed to dry between lifts, the surface of each successive lift shall be scarified to a depth of two inches before the placement of the next loose lift. The purpose of the scarification is to improve bonding between successive lifts. • Equipment or truck traffic on the scarified surface shall not be permitted during the period between scarifying and the placement of the following lift. • Each lift shall be thoroughly compacted and satisfy moisture/density controls before a subsequent lift is placed. Copyright 1992 Kleinfelder, Inc Page 4 of 6