Concrete diagnosis
Assessment of shortcomings and investigation of causes of decay The regulations governing con- crete repair require a thorough investigation of the causes of decay and other shortcomings prior to starting any repair work. A technically appropriate repair plan guaranteeing a lasting repair can- not be devised until this preliminary investigation has been carried out. Important investigation criteria for selecting the ideal protective surface treatment include measurement of carbonation depth, measurement of depth of concrete cover and testing for structurally harmful salts. The results of the investigations make it possible to distinguish bet- ween very different conditions of the concrete, which each require spec i f i c pro t ec t i ve su r f ace treatments.
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Good concrete quality, good depth of cover
Moderate concrete quality, possibly shallow depth of cover Carbonation has nearly reached the reinforcement layer. Carbonation protection is necessary in order to stop further progress. If carbonation penetrates deeper and reaches the reinforcement, the protection of the passivation layer will be eliminated. If carbonation is stopped, the protection of the passivation layer will be retained.
Carbonation depth amounts to only a few millimetres and cannot extend as far as the reinforcement. Carbonation protection (CO 2 -proofing) is not necessary even in the long term. Where concrete quality is good, carbonation is slight and comes to a complete standstill over the course of time, with the depth reached being known as the »maximum carbonation depth«. The reinforcement has lasting protection.
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