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29-03 <br /> <br />29-04 <br /> <br />Ce <br /> <br />Filter Blanket: Material for filter blanket shall consist of <br />crushed rock or pit run gravel and shall conform to the'f~llowing <br />grading requirements: <br /> <br />Sieve Size <br /> <br />Percentage Passing Sieves <br /> <br />2-1/2" 100 <br />1-1/2" 80 - 100 <br />3/4" 60 - 95 <br />No. 4 45 - 65 <br />No. 8 22 - 50 <br />No. 30 5 - 25 <br />No. 200 0 - 5 <br /> <br />The materials shall be composed of tough, hard, durable particles <br />and shall be reasonably free of thin, flat or elongated pieces ~nd <br />shall contain no organic matter of soft friable particles. <br /> <br />The Contractor, at least ten (10)' days in advance of importing <br />filter material to the jobsite, shall advise the Engineer of the <br />source from which the material will be obtained and no material <br />shall be used until approved by the Engineer. <br /> <br />Placing Filter Blanket: The excavated subgrade shall be kept free of <br />water. Mudholes, ruts, or soft spots due to the Contractor's operations <br />shall be repaired prior to placement of filer material. <br /> <br />The materials for the blanket shall be spread to such a depth as is <br />necessary to obtain the specified thickness after compaction. Compac- <br />tion shall be accomplished by not less than two passes of a tandem <br />roller lapping one foot each pass. the weight of the roller shall be <br />not less than 7 tons, except as otherwise approved by the Engineer. <br />Areas inaccessible to the roller shall be compacted by the use of <br />manually operated pneumatic tampers or by other means as approved by the <br />Engineer. <br /> <br />Water from surface drainage or other sources, mud, muck, or debris shall <br />be prevented from running or entering into the blanket material both <br />during and after its placement. -- <br /> <br />Placing Slope Protection: Slope protection composed of rock conforming <br />to the requirements of these specifications, shall be placed by equip- <br />ment at the toe and sides normal to the slope, with barring and hand <br />placing where necessary. The allowable tolerance from planned lines and <br />grades shall be determined by the Engineer as follows: <br /> <br />Smooth Finish Surface: A tolerance of plus 3 inches or minus 3 <br />inches fro~ finished lines and grades shown on the plans will be <br />allowed. <br /> <br />Rough Finished Surface: A tolerance of plus 12 inches or minus 6 <br />inches from finished lines and grades shown on the plans will be <br />allowed. <br /> <br />CDS.1.18 29-2 <br /> <br /> <br />