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Robert Anderson <br /> February 4, 1993 <br /> Page 2 <br /> Comment 3: <br /> "The specifications state that a minimum of 60% of mixed material <br /> will pass a number 4 sieve. Furthermore, Caltrans Standard <br /> Specification Number 24 does not have a clear correlation with the <br /> Sone Clay/Borrow Source admixture except for the test pad <br /> specification statement regarding soil particle size. The maximum <br /> particle size for the admixture of not more than 2 .5 inches should <br /> also be considered, unless you wish to have the maximum particle <br /> size smaller (one inch?) . The workplan should explicitly state the <br /> value of the test pad specification or criteria for pass/fail . If <br /> the in-place mixing of the soil admixtures fails to satisfy the <br /> minimum prescriptive and performance standards for the final cover <br /> under Titles 14 and 23 of the California Code of Regulations, then <br /> the test admixtures are to be mixed on a mixing table. " <br /> Response: <br /> The pass/fail criterion for particle size is 1 .5 inches. The <br /> workplan has been amended to specify 1 .5 inches as the maximum soil <br /> particle size for the admixture. A revised copy of page 4 of the <br /> plan is attached for your records. <br /> Comment 4: <br /> "The Board and the Regional Water Board prefer that the soil <br /> admixture barrier layer be built in two, six-inch thick lifts <br /> instead of one, twelve-inch thick lift; however, if the operator <br /> intends to construct the soil admixture barrier layer in one, <br /> twelve-inch thick lift, then the following information must be <br /> provided. " <br /> A. "The specifications indicate that the Engineer of Record <br /> (Engineer) can decide to construct the clay layer in a <br /> single, twelve-inch thick lift. The specifications do <br /> not state what criteria or judgement/justification that <br /> the Engineer would use to allow construction of the clay <br /> layer in a single lift. The Engineer must discuss, in <br /> writing how he/she intends to demonstrate that the lower <br /> portion of a twelve-inch lift meets the construction <br /> criteria for compaction and permeability. ,, <br /> Response: <br /> San Joaquin County will only construct the clay layer in a single, <br /> twelve-inch lift if heavy large equipment is obtained and employed <br /> in construction. Equipment such as Bros or Raygo cross shaft mixers <br />