Influence of top-casting-induced defects on the corrosion of the compressive reinforcement of naturally corroded beams under sustained loading

Wulong Zhang (1) , Linwen Yu (2, 3) , Raoul François (1)

1 LMDC - Laboratoire Matériaux et Durabilité des constructions
2 College of Materials Science and Engineering, Donghua University
3 State Key Laboratory of Green Building Materials

This paper discusses the effect of top-casting-induced defects on the corrosion development of compressive bars in reinforced concrete beams exposed to a chloride environment, under sustained loading. Four reinforced concrete beams, exposed to artificial climate of accelerated natural corrosion for 38 months and 48 months, respectively, were tested. The cracking maps, chloride profiles, cross-sectional loss, and corrosion distribution around the perimeter and along the re-bars of four beams were studied and compared with each other. Experimental results show that top-casting-induced defects encouraged corrosion to develop first at the bottom surface of compressive bars and their presence strongly accelerated the corrosion process. Without top-casting-induced defects, the corrosion was more prominent on the outside part of re-bars facing the concrete surface exposed to chloride ingress. After the appearance of corrosion-induced cracks, corrosion gradually developed all around the perimeter of re-bars, with the result that top-casting-induced defects no longer affected the corrosion process.

Mots clés: Corrosion; Chloride; Top-casting defects; Steel-concrete interface; Reinforced concrete

Domaines: Sciences de l'ingénieur [physics]; Génie civil

Wulong Zhang, Linwen Yu, Raoul François. Influence of top-casting-induced defects on the corrosion of the compressive reinforcement of naturally corroded beams under sustained loading. Construction and Building Materials, 2019, 229, pp.116912. ⟨10.1016/j.conbuildmat.2019.116912⟩. ⟨hal-02417655⟩