No, no no. Washing detergents are highly toxic to birds who like to peck gaps in block paving for insects, ants and grubs etc. It can cause anything from digestive distress to severe respiratory failure. Salt is no better. It causes kidney failure in birds and mammals, burns paws and feet and the wash off contaminates freshwater habitats Terrible thing to do at this time of year when parent garden birds will be hunting for food for their chicks.
This why I loathe block paving, the purpose of which seems to be to create labour, sell pressure washers and waste our precious water resources as well as being fatal for wildlife.
Every year I dread what can feel like the constant whine of these damn things as neighbours wash the blocks … which in urban environments ments look dirty again a fortnight later.
Employ someone to manually weed the drive, clean it with sand and a stiff broom, resand the gaps and then have it resealed. Sealant is toxic too as it’s likely to contain VOCs but less so once it is dried and cured.