The brick should be very strong with a good quality but as always make sure you test the substrate to make sure it can handle whatever chemicals you're going to use. It looks like several things are going on. One would be lime run from the tops of those caps, some more of it looks like Effluorescence and you also have rust.

Between the two chemicals of F9 Efflo and F9 BARC you should be able to make a significant impact on the surfaces. I would use F9 Efflo first, straight on all of the efflorescence and lime run. Spray on with the pump sprayer, let dwell for a minute or two, respray if needed, scrub with a stick deck brush, neutralize and pressure wash. Repeat process if needed. The efflorescence remover might take off the rust as well see you might not even need the BARC.

Call me with any questions
Craig.