Deterioration of deck slabs on Belgian bridges: Study of a complex dysfunction survey

An analysis of the deck's concrete of one of Southern Belgium's bridges (in Bastogne) made it obvious that delamination involves slab deterioration. A number of products issued from secondary reactions have been observed: alkali-silica gel, secondary ettringite and calcium chloroaluminate. Probable causes of this deterioration include failures of the waterproofing, the addition of deicing salts, the presence of reactive aggregates and a sulphating process. The phyllodial sandstones of the Bastogne region have been acknowledged for the first time in an alkali-silicate reaction process. The in situ formation of calcium chloroaluminate crystals has also been clearly observed.