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Comparative study on the resistance of concrete against chloride ingress (AGB1998/097)

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Complete with results
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Infrastructure (INF)
Transport mode
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Background & Policy context

The chloride induced corrosion is one of main causes of damages of the road infrastructure. The tightness of the cover concrete and the thickness of the cover of the rebars have an extraordinary importance.

Because of the premature failure of concrete structures one tries to increase the durability of new structures by using higher (denser) concrete qualities and thicker concrete covers. High performance concrete may be used to increase the tightness of concrete. Standardised and accepted methods for the assessment of the resistance of concrete against the chloride ingress (chloride resistance) are still missing.


The goal of this project is to test different techniques for determination of the chloride resistance of various concrete qualities (normal and high performance concrete) and to compare the results of the different techniques as well as to compare them with the gas permeability and with the results of the measurement of the water conduction, a widely used method in Switzerland (SIA 162/1, test No. 5).

Based on the results of this study the requirements for concrete for durable concrete structures exposed to chloride containing environments should be formulated, the appropriate tests evaluated and the corresponding criteria deduced. Based on this information a SIA-guide for "Concrete for durable concrete structures exposed to chloride" should be elaborated.

Within this research project the chloride resistance of concrete mixes with and without mineral admixtures (fly ash, silica fume, ground granulated blast furnace slag) and of concrete from older Swiss concrete structures has been evaluated. For this work different test methods have been used to characterize the chloride resistance and their validity has been compared.


Following tests were conducted:

  • ASTM-test according AASTHO T259-80 (electric charge)
  • IBAC or CTH-test (chloride migration coefficient or shortly migration coefficient)
  • Streicher test (electrical conductivity)
  • gas permeability (permeability)
  • water conductivity test according to SIA 162/1, test nr. 5 with modification VPL (water conductivity)
  • water suction (chloride content or chloride enrichment)


Parent Programmes
Institution Type
Public institution
Institution Name
Swiss Government: State Secretariat for Education and Research
Type of funding
Public (national/regional/local)


Influence of material parameters
• The investigation has shown that the composition of the concrete, especially the water to cement ration (w/c) and the water to binder ratio (w/B), respectively, as well as the type and content of the mineral admixture mainly determine the chloride resistance.
• The influence of the binder content, the maximum grain size of the aggregate and the chemical admixtures (superplastisizer) has not been systematically studied. It is rather small as it could be concluded from the comparison of the few data of the laboratory concrete mixes and from the concrete mixes of other projects. But, the number of results is too small and does not allow a sound finding.

• Between the chloride resistance and the other material parameters (e.g. w/c or w/B-ratio, porosity, compressive strength) no general relation which is valid for all types of concrete could be found. The materials parameters may give some guidance.
• Generally, the chloride resistance increases with the age of the concrete. According to their age the samples from existing concrete structures showed a moderate to high chloride resistance.
But, the 28-days-values of the chloride resistance, calculated back from the actual values, are significant lower than those of the laboratory concrete mixes.

• The ibac-test reveals well reproducible results as the comparison of the results of this study with those of the literature showed. The results of concrete from existing structures go well together with those results. Additionally, this is the only one of the methods studied which provides a characteristic value for the simulation and the forecast of the development of the state conditions of structures as well as for the life cycle assessment. There is, further, a good chance that this test will be standardised as an EN standard.
• The main advantage of the water conductivity test is that this method is well known as SIA standard (SIA 162/1, test no. 5) and the important elements of the test procedure are regulated.
It is unclear, however, how far the influence of the mineral admixtures is correctly determined and questions to the test procedure remained open (covering the side surfaces of the specimens or not?). This test has practically no chance to be published as an EN standard.
Therefore, the water conductivity is limited or not suitable as a characteristic value of the chloride resistance of concrete. Further investigations would have to be carried out


Lead Organisation
EU Contribution
Partner Organisations
EU Contribution


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