Engineering

Masonry veneer

Geotechnical engineering

Metallurgy

Materials science

Brick

Bridge (graph theory)

Gypsum

Civil engineering

Geology

Mortar

Oceanography

Paleontology

Portland cement

Cement

Lime

Internal medicine

Ettringite

Medicine

Forensic engineering

Masonry

Lime mortar

A case study is presented of severe deterioration of historic late 19th century brick masonry due to combined gypsum, ettringite and thaumasite. The case is remarkable, because these minerals developed in the original mortar made up by a mixture of Rhenish trass and lime, in which in particular for ettringite, no specific precursor (such as C3A in ordinary Portland cement), could be identified. The case study demonstrates that, regardless the sulphate resistant reputation of trass cements, trass - lime mortars may suffer from sulphate attack. Historic brick masonry may be damaged severely. Proper restoration requires prior assessment of any damage. The nature and amount of damage has a huge influence on both restoration techniques to be used and associated costs. In the present paper, a case of severely deteriorated historic brick masonry is described. The investigated structure, Moerputten Bridge, is a discarded railway bridge near the city of 's Hertogenbosch in the south of the Netherlands (Fig. 1). The bridge was built late 19 th century and discarded in 1972. The bridge is made up by a steel construction based on 35 piles and 2 abutments of brick masonry. The piles have dimensions of 10.5 (L) x 2 (W) x 5 (H) metres. Brick masonry is covered by Belgian limestone ('petit granite'). Part of the masonry has been restored in the past. Planned re-opening of the bridge for the general public and its conservation as a state monument, required restoration of the masonry. The masonry displays a damage pattern similar to that of masonry cracking due to high compressive forces and frost damage. Petrographic investigation, however,

DETERIORATION OF HISTORIC BRICK MASONRY DUE TO COMBINED GYPSUM, ETTRINGITE AND THAUMASITE: A CASE STUDY