For walking on concrete, you need work boots that absorb the maximum amount of shock. Concrete is a uniformly hard surface, with little to no "give" in it whatsoever.
The best work boots for farm work let you stay on your feet all day without discomfort, but can stand up to the muck and grime of typical farm life. In other words, a tough work boot that stands up to the elements.
Work boots should fit just tightly enough to support your foot, but loosely enough to let your foot flex and move as it's supposed to. They should neither be too tight or too loose.
Partially, it has to do with the way that sizes are measured. Partially it has to do with the lasts that shoemakers use to make shoes. Boot construction can also make a difference here too.
Chromexcel leather is an excellent bootmaking leather IF it's the look and feel that you want. Chromexcel has a natural shine, but doesn't have the best finish for polish.
Obviously, no one wants to be tying and re-tying their laces when they're supposed to be working, or when stopping to lace them up is dangerous. On a lot of job sites, it would be.