SAMPLING AND TESTING HIGHWAY MATERIALS. 



67 



In making the slump test in the laboratory or in the field it is recommended that 

 the form be filled immediately after mixing and withdrawn three minutes after 

 mixing has been completed. 



When central mixing plants are used slump tests shall be made at the plant and 

 at the end of the haul . At the plant the sample of concrete shall be taken after the 



h 4" 



PLAN 



Fig. 35. — Cone for concrete slump test. 



entire batch has been discharged from the mixer. At the end of the haul the slump 

 sample shall be taken from the batch after it has been dumped on the subgrade. 

 The slump at the points of deposition shall be suitable for the particular type of 

 finish employed. 



