What I learned about drilling concrete
I frequently drill 1/2 inch holes for anchor bolts I use to winch cars into a given shop bay.
I've had no trouble using an 18v Porter Cable battery drill or a cheap Ryobi corded drill I bought used for $15, and I only use the one bit.
Must be a lot of additional load on 3/4 vs 1/2 or you got some dense concrete.