Q. We're pouring a new concrete slab in a ready-mix truck wash bay where we sometimes will be using muriatic acid to wash down the trucks. What coating or sealer would provide good acid resistance?

A. Using about 10% microsilica in the slab will give the concrete some acid resistance by reducing its permeability. Otherwise, a good quality epoxy topping will help reduce deterioration of the slab. One source for such products is Kryton International (www.kryton.com). Another alternative is Stablecrete by Conselcor (www.stablecrete.com) which penetrates into the concrete matrix rather than forming a surface barrier.