While performing a CBR test, certain amount of weight (annular or slotted surcharge) are usually placed during penetration of needle. Why this weight is being placed? What is its purpose?
CBR Surcharge Masses are used in CBR testing for simulation of pavement confining loads. Additional masses simulate pavement loads above the tested material. According to AASHTO T 193-13 (2017) "Place the swell plate with adjustable stem on the soil sample in the mold and apply sufficient annular weights to produce an intensity of loading equal to the mass of the subbase and base courses and surfacing above the tested material.