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HomeMy WebLinkAbout262.60UNDERDRAIN AGGREGATE, BIORETENTION SOIL MIX, AND MULCH SPECIFICATIONS STD. PLAN - 262.60 UNDERDRAIN AGGREGATE PUBLIC WORKS DEPARTMENT APPROVED: DATEGregg Zimmerman Public Works Administrator UNLESS OTHERWISE NOTED, DRAWING IS NOT TO SCALE (NTS) TABLE: UNDERDRAIN AGGREGATE GRADATION SIEVE SIZE PERCENT PASSING 3/4-INCH 100 PERCENT 1/4-INCH 30 TO 60 PERCENT U.S. NO. 8 20 TO 50 PERCENT U.S. NO. 50 3 TO 12 PERCENT U.S. NO. 200 0 TO 1 PERCENT BIORETENTION SOIL MIX BIORETENTION SOIL MIX (BSM) SHALL BE A WELL-BLENDED HOMOGENEOUS MIXTURE OF 60 TO 65 PERCENT BY VOLUME MINERAL AGGREGATE FOR BIORETENTION SOIL AND 35 TO 40 PERCENT BY VOLUME COMPOST AS DETAILED IN THE TABLES BELOW. TABLE: MINERAL AGGREGATE GRADATION SIEVE SIZE PERCENT PASSING 3/8-INCH 100 PERCENT U.S. NO. 4 95 TO 100 PERCENT U.S. NO. 10 75 TO 90 PERCENT U.S. NO. 40 25 TO 40 PERCENT U.S. NO. 100 4 TO 10 PERCENT U.S. NO. 200 2 TO 4 PERCENT COMPOST COMPOST MUST ORIGINATE A MINIMUM 65 PERCENT BY VOLUME FROM RECYCLED PLANT WASTE COMPRISED OF YARD DEBRIS, CROP RESIDUES, AND BULKING AGENTS, AND MEET THE DEFINITION OF "COMPOSTED MATERIAL" IN WAC 173-350-100. COMPOST SHALL HAVE A MOISTURE CONTENT THAT HAS NO VISIBLE FREE WATER OR DUST PRODUCED WHEN HANDLING THE MATERIAL. COMPOST SHALL HAVE AN ORGANIC MATTER CONTENT OF 40 PERCENT TO 65 PERCENT BY DRY WEIGHT, A CARBON TO NITROGEN RATIO BELOW 25:1, AND A pH BETWEEN 6.0 AND 8.0 TABLE: COMPOST GRADATION SIEVE SIZE MIN. PERCENT PASSING 2-INCH 100 PERCENT 1-INCH 99 PERCENT 5/8-INCH 90 PERCENT 1/4-INCH 75 PERCENT ABORIST WOOD CHIP MULCH ARBORIST WOOD CHIP MULCH SHALL BE COARSE GROUND WOOD CHIPS (APPROXIMATELY 1/2" TO 6" ALONG THE LONGEST DIMENSION) DERIVED FROM THE MECHANICAL GRINDING OR SHREDDING OF THE ABOVE-GROUND PORTIONS OF TREES. IT MAY CONTAIN WOOD, WOOD FIBER, BARK, BRANCHES, AND LEAVES, BUT MAY NOT CONTAIN WEEDS, WEED SEEDS, OR VISIBLE AMOUNTS OF SOIL. TABLE: ARBORIST WOOD CHIP MULCH GRADATION SIEVE SIZE PERCENT PASSING 6-INCH 100 PERCENT 2-INCH 95 TO 100 PERCENT 1-INCH 70 TO 100 PERCENT 5/8-INCH 0 TO 50 PERCENT U.S. NO. 4 0 TO 30 PERCENT UNDERDRAIN AGGREGATE MUST CONSIST OF SCREENED SAND, GRAVEL OR OTHER INERT MATERIALS, OR COMBINATIONS THEREOF, FROM SOURCES APPROVED BY THE ENGINEER, HAVING HARD, DURABLE PARTICLES FREE FROM ADHERENT COATINGS. THE MATERIALS MUST BE WASHED THOROUGHLY TO REMOVE CLAY, LOAM, ALKALI, ORGANIC MATTER, OR OTHER DELETERIOUS SUBSTANCES. PARTICLES HAVING A SPECIFIC GRAVITY LESS THAN 1.95 MUST NOT EXCEED 1.0 PERCENT OF THE TOTAL WEIGHT. ORGANIC MATTER, BY CALORIMETRIC TEST, MUST NOT BE DARKER THAN THE REFERENCE STANDARD COLOR (ORGANIC PLATE NO. 3) AASHTO T21 UNLESS OTHER TESTS PROVE A DARKER COLOR TO BE HARMLESS. MINERAL AGGREGATE FOR BIORETENTION SOIL MINERAL AGGREGATE FOR BIORETENTION SOIL MUST BE FREE OF WOOD, WASTE, COATING, OR ANY OTHER DELETERIOUS MATERIAL, AND ALL AGGREGATE PASSING THE NO. 200 SIEVE SIZE MUST BE NON-PLASTIC. MINERAL AGGREGATE MUST BE ANALYZED BY AN ACCREDITED LAB USING THE SIEVE SIZES NOTED IN THE TABLE TO THE LEFT, AND MUST MEET THE REQUIRED GRADATIONS. DocuSign Envelope ID: 6EECF5B6-602A-4E4A-B436-A317AA638878 9/28/2018 | 9:45 AM PDT