1993-06-04_GENERAL DOCUMENTS - M1977378

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5upat Supac offers major soil stabilization bents. The traditional method of soil stabilization for Supac is cost effective for the following weak load bearing soils has usually been the reasons: periodic addition of costly aggregate to maintain a .Approximately33%reduction in the aggregate passable access road, construction site yard or log required in the initial design of unpaved sorting yard. This stabilization method has become structural sections. cost prohibitive. The use of other stabilization techniques such 'Amount of subgrade preparation required is as lime or cement has proven restrictive and often reduced. both costly and unpredictable.A more efficient and • Structural section life is prolonged and main- economical soil stabilization method is to use Supac tenance costs reduced because soil intermix- engineered geotextiles. ing between layers is restricted. Supac Installation Guidelines. • It is easily placed so installation costs are low. (1) Clear subgrade of sharp objects, stumps, (3) Place and compact aggregate fill.Aggregate and debris. Grade the surface as much as possible depth is determined by subgrade strength and to provide surface drainage and cross slope anticipated wheel loading (usually between 9 and shaping. 24 inches). Usually it will be necessary to backdump (2) Unroll Supac on the subgrade. Overlap is the aggregate onto the Supac and spread with a dependent upon the load bearing capacity of the dozer or grader. The aggregate must be spread in subgrade, and will vary from 1'k to 3 feet. Sewing the same direction as the geotextile overlap to may be required if the geotextile is to provide avoid separation.Compact the aggregate by conven- reinforcement. tional methods. Supac being placed. Aggregate being placed. Aggregate being spread. Recommended geotextile physical properties for soil stabilization. Category A.Soil has a CBR>3 and the geotextile is to perform primarily as Category C:Soft soil and unprepared subgrade(CBR<1.5). a separator. Category B:Soft soil and prepared subgrade(1.5<CBR<3). TYPICAL TEST RESULTS GEOTE)MLE CATEGORY PHYSICAL PROPERTY TEST PROCEDURE A B C Tensile Strength,wet,lbs. ASTM D-1682 120 170 270 Elongation,wet,% ASTM D-1682 40 >15 >15 Coefficient of Water Pemieability,crn/sec. Constant Head(5omm) 0.10 0.01 0.01 Puncture Strength,lbs. ASTM D-751* 65 90 130 eMullen Burst Strength,psi ASTM D-3786 210 300 410 *Tension testing machine with ring clamp;steel ball replaced with a 5/16"diameter solid steel cylinder with hemispherical tip centered within the ring clamp. 5