Document jB4p9Mq6wDxM67x1a8BpKm2YR

September 24, 1968 R. M. Spec. No. 13 Supersedes R.M. Spec. No. 13 Dated 5/3/66 GROUND LIMESTONE PLAINTIFF'S EXHIBIT DESCRIPTION USE White colored pulverized limestone. Ingredient in Joint System products. GP-168 SOURCES Thompson & Weinman Co. Gantts Junction, Alabama OW 3910 Ground Limestone (Acme plant) Purestone Limestone Co. Marble Falls, Texas (Acme plant) Thompson & Weinman Co. New York, New York (Akron plant) Calcium Carbonate Co. Quincy, Illinois (Chicago plant) SPECIFICATIONS - Color White - Equal to standard #9 - #11 Fineness Maximum Thru 50 mesh 100% " 100 " 100% " 200 " 100% " 325 " 95% Minimum 100% 100% 95% 85% Average 100% 100% 98.5% 90% Method of Testing - 50 gram sample washed thru 325 mesh screen until wash water is clear. Residue on screen dried and when dry, screened on Ro-tap for 15 minutes using 50, 100, 200, and 325 mesh screens. Water Carrying - Maximum Minimum Average Water to T.C 35 cc 28 cc 32 cc Alkalinity - Weigh out 20 grams of pigment in a clean 600 ml beaker. Add 400 mis of freshly distilled water to the beaker and rapidly stir with a small power stiner for 10 minutes. Allow the slurry to stand for 20 minutes and determine the pH of the supernatant liquid using the pH meter. pH Specs. 9.0 Min. 9.5 Max. Sampling - Each plant shall take a representative sample of each shipment and test it for color, fineness, water carrying, and alkalinity. If the shipment does not meet the speci fications, a laboratory batch of Joint System Cement shall be made and tested. If this cement is off-standard and complaints may be anticipated, the limestone shall not be used. A sample of the limestone shall then be sent to the General Laboratory with full particulars. RRB:kkt -/ Denotes change in this re-issue SGP 0015929