Assuming the infection is passed by the transfer of bodily fluids such as blood and saliva then your cloth armour is going to act as a sponge.
Chainmail is only really effective against slashing wounds, it's pretty bad at stopping puncture wounds and does very little against bludgeoning attacks.
Full field plate, the type of armour used by knights of yore, would be my choice unless there were other uninfected to deal with. A good set of platemail will provide about the best protection from a zombie you can get while having the advantage of a wipe-clean surface. The helmet does limit visibility somewhat which is why mercenary knights often worked with one or two lightly armoured companions to alert them to attacks from the side or rear.