Which is higher 20000 or 28000? The trailer isn't really relevant since spreading the weight over additional axels makes it significantly less likely to damage roads.
Speaking of which, Texas roads have a single axel weight limit of 20000 lbs and a tandem axel limit of 32000 lbs. Under normal operation, a semi should be fine. A Maxpro can potentially reach the the tandem axel limit on its own and could put it's full weight on a single axle if it his a speed bump going too fast.
Also, many rural roads and smaller bridges won't accommodate a full size semi with or without a trailer. They certainly couldn't handle the even heavier Maxpro.