ASTM_D_7207_-_05.pdf

Designation:D 7207 05Standard Test Method forDetermination of Unvegetated Rolled Erosion ControlProduct(RECP)Ability to Protect Sand from Hydraulically-Induced Shear Stresses under Bench-Scale Conditions1This standard is issued under the fixed designation D 7207;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This index test method establishes the guidelines,re-quirements and procedures for evaluating the ability of unveg-etated Rolled Erosion Control Products(RECPs)to protect soil(sand)from hydraulically induced shear stress in a bench-scaleapparatus.1.2 This index test method utilizes bench-scale testingprocedures and shall not be interpreted as indicative of fieldperformance.1.3 This index test is not intended to replace full-scalesimulation or field testing in acquisition of performance valuesthat are required in the design of erosion control measuresutilizing unvegetated RECPs.1.4 The values stated in SI units are to be regarded asstandard.The inch-pound values given in parentheses areprovided for information purposes only.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil,Rock,and ContainedFluidsD 698 Test Method for Laboratory Compaction Character-istics of Soil Using Standard EffortD 4354 Practice for Sampling of Geosynthetics for TestingD 6460 Test Method for Determination of Erosion ControlBlanket(ECB)Performance in Protecting Earthen Chan-nels from Stormwater-Induced Erosion3.Terminology3.1 For definitions of terms used in this method,seeTerminology D 653.4.Summary of Test Method4.1 Soil cores consisting of containers with bare soil and/orRECP-protected soil are immersed in water and subjected toshear stresses caused by the rotation of an impeller with threeblades.At a minimum,testing of containers with bare soilshould be performed when a new or renewed soil stockpile isused.4.2 The amount of soil that erodes at each of three shearstress levels is measured.5.Significance and Use5.1 This index test method indicates an unvegetated RECPsability to reduce soil erosion caused by shear stress induced bymoving water under bench-scale conditions.Only tangentialshear is measured in this method.Radial and uplift forcesgenerated by the circular motion of the water are not measured.5.2 This test method is bench-scale and therefore,appropri-ate as an index test for general soil/product composite behaviorunder hydraulic shear conditions,and for product qualityassurance/conformance testing.The results of this test shall notbe interpreted as indicative of field performance.6.Apparatus6.1 The shear stress test apparatus includes a shear tank,false floor with test wells,transition cover plate,and motor-driven impeller.(See Fig.1.)6.1.1 Shear TankA cylindrical tank of sufficient diameterand depth to develop the desired shear levels.(See Fig.1 for anexample.)6.1.2 False FloorA false floor shall be positioned in thetank with at least three test wells cut into the false floor to holdsoil cores.When soil cores are placed in the wells,the soilsurfaces must be flush with the false floor surface.(See Fig.1.)6.1.3 Motor-driven Impeller AssemblyThe impeller motorshall be capable of driving the impeller assembly at sufficientrevolutions per minute(RPMs)to develop the necessary shearstresses.The blades of the three-blade impeller must be1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.25 on Erosion andSediment Control Technology.Current edition approved Nov.1,2005.Published December 2005.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.sufficiently long enough to extend to within 25 mm(1 in.)ofthe side of the tank.The impeller is mounted in the tank so thatthe lower edge of the blades is 115 mm 6 1 cm(4.5 6 0.4 in.)above the false floor of the tank in which the test cores areFIG.1 Example of a Low-Shear Bench-Scale Laboratory Test ApparatusD 7207 052seated during testing.(See Fig.1.)The apparatus should becapable of producing shear stresses in 24 Pascal(pa)(0.5pounds/square foot(psf)increments below,near,and aboveexpected target shear stress levels.NOTE1The shear stress apparatus shown in Fig.1 has