He and double centurion Rahmat Shah put on 364 for the third wicket before the latter was out having made a career-best 234 at the Queens Sports Club.
Zimbabwe won the toss and posted a record 586 in their first innings. Afghanistan were 515-3 in reply when rain intervened, preventing any play after 1300 local time (1100 GMT).
The umpires waited nearly four hours before calling play off, and strengthening the likelihood of a draw in a match dominated by batters in the southern city.
More rain is predicted for the final day on Monday as both teams chase a first Test victory since beating each other three years ago in a series in Abu Dhabi.
Shah, 231 overnight, added three runs to his personal best before getting an outside edge to a delivery from Test debutant Newman Nyamhuri and Ben Curran caught the ball in the gully.
The departure of Shah, who struck three sixes and 23 fours in a 424-ball stand, brought no respite for the six-man Zimbabwe attack.
Cautious Shahidi continued to bat effectively while hitting 18 fours. He is 22 runs short of a career-best Test total after making an unbeaten 200 against Zimbabwe three years ago.
The skipper received good support from Afsar Zazai, who was unbeaten on 46. The wicketkeeper faced 87 deliveries and scored a six and three fours.
Medium-pacer Trevor Gwandu took the wicket of opener Sediqullah Atal for three. But was the most expensive of the home bowlers, conceding 107 runs.
Afghanistan won Twenty20 and one-day international series in Zimbabwe ahead of the Test -- the first of two with the second set to start on January 2.
Brief scores
Zimbabwe 586 in 135.2 overs (Sean Williams 154, Brian Bennett 113 not out, Craig Ervine 101, Ben Curran 68; Allah Ghazanfar 3-127) v Afghanistan 515-3 in 156 overs (Rahmat Shah 234, Hashmatullah Shahidi 179 not out, Afsar Zazai 46 not out). Rain stopped play
Toss: Zimbabwe
