1. Dear sir,
As per contractor's request for gradation of pipe bedding material and Selected Back fill,
I suggest the following gradation of aforesaid items.
1. Gradation of Pipe Beding Crushed Aggregate Material
As per IS 383
Graded Aggregate of Nominal size 16 mm
Sieve % Passing
20 100
16 90-100
10 30-70
4.75 0-10
2 0
2. The Selected Bakcfill should be the suitable back fill material. According to the
Nepal Standard (DOR 2073), the suitable backfill material is 75 mm down
gravel material with gradation
Sieve % Passing
75 100
0.425 0-60
0.075 <15
with PI <=6
Thanking you
with all the best wishes
Ugrasen chaudhary
Material Engineer
