Cau 3: Mot mau vat lieu de trong khong khi co khoi luong the tich la 1400kg/m3 va do am 3%. Sauk hi hut nuoc bao hoa thi khoi luong the tich cua no tang len 1700kg/m3. Cho biet he so bao hoa la 0,95. Xac dinh do rong cua loai vat lieu nay

Bai giai

Trong truong hop bai ra ta lay

Hbhp= W= (mw-mk)/mk. 100%

               = (ρwv- ρkv).V0/ (ρkv.V0) .100%

               = (ρwv- ρkv)/ρkv .100%

               = (1,7-1,4)/1,4 .100% =21,4%

Do hut nuoc bao hao theo the tich:

Hbhv= 1,4.21,4/1 =29,96%

Do rong cua vat lieu