Fluxural Strength
fcr = 0.7 √fck N/mm2
Penetration Test for Bitumen IS 1203 1978
Hot the Bitumen in oven 90oc + Softening point and pour in in bowl, approx 10 mm more than expacted penetration. Use bowl depth 35 mm, dia 55 mm size for penetrations below 225 Then keep it in room temp for 1 – 11/2 hours (75 min) Then in water bath at temp 25oc for 1 – 11/2 hours (75 min) Use bowl depth 45 mm, dia 75 mm size for penetrations from 225 to 350 Then keep it in air for 11/2 -2 hours (105 min) Then in water bath at temp 25oc for 11/2 -2 hours (105 min) Then place it under the apparatus Wt of assembly should be 100 g (if 50 gm wt + needle + assembly) Wt of assembly should be 200 g (if 150 g wt + needle + assembly) For CRMB 60 penetration will be <50 Penetration ratio = Penetration at 4oc 200 gm for 60 sec ---------------------------------------------- x 100 Penetration at 25oc 100 gm for 5 sec
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