EXPERIMENTAL INVESTIGATIONS OF COMBINED SULPHATE AND ACID ATTACK ON CONCRETE BY OXIDATION OF IRON DI- SULPHIDE
In the past uncertainties were raised in practice by several damages in concrete structures,which are in direct contact with soils containing iron disulphides. During oxidation processesof iron disulphides initiated e. g. by excavation during construction measures products likesulphate and sulphuric acid are released that are very aggressive to cementitious materials.The single attacks of sulphate or acid on concrete with their mechanisms have been exten-sively investigated and are separately well understood. However, there is still a lack ofknowledge about the mechanisms that damage concrete by a combined attack. This questionis investigated currently at the Institute for Building Materials at the Ruhr-Universitat Bo-chum. The experimental tests focus on the transport process of both sulphate and acid into theconcrete and on the subsequent evolution of the corresponding damage process in the micro-structure. For that purpose concrete specimens varying in different parameters e. g. type ofcement, curing etc. are embedded in adequate sulphate and acidic solutions as well as in irondisulphidic soils at 8℃. By means of appropriate test methods like SEM-analysis on thinsections in combination with EDX-analysis the degradation process of concrete is investigatedafter different periods within two years. The results after one year of storage in the test solutions show a characteristic formation ofcorrosion zones in the cross-section of the concrete specimens. The appearance including thechemical composition and thickness of the respective zones depend in the first instance on thethe pH-value and secondarily on the sulphate concentration.
B.Siebert R.Breitenbuecher
Institute for Building Materials,Ruhr-Universitat Bochum,Germany
国际会议
南京
英文
393-402
2008-10-13（万方平台首次上网日期，不代表论文的发表时间）