Lifting a Precast beam 12 m length

[XinLok]

Base on ACI code, If I did a precast one beam 60 cm x 60 cm x 1200 cm.

the compressive strength used during design is design be 50 mpa. if I use hardener during precast, and I got 30 mpa compressive strength after 24 hours.
Can I lift the beam up if the strength of concrete reach 30 mpa after 24 hours or 48 hours?, or should reach full strength which is 50 mpa

 

[HTURKAK]

Can I lift the beam up if the strength of concrete reach 30 mpa after 24 hours

Yes.. but lift with overhangs at both sides say 2.5 m. Check tension stresses at span and lifting points. A preliminary calculation for allowable tension stress ( using 4 *SQRT* fc ) is 1.8 mPa . Check lateral stability also.