PSI - Issue 26

Petr Konečný et al. / Procedia Structural Integrity 26 (2020) 430 –438 Author name / Structural Integrity Procedia 00 (2019) 000–000

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by c(Cl - )/c(OH - ) give a different point of view. The threshold value of 0.6 is higher in both cases. The coefficient of variation in Table 2 indicates a high variability of chloride concentration and corrosion risk. In the previous article by Konečný et al. (2020), it was already recommended to split the data based on the location into the following groups: girder supports such as abutments, bridge deck supporting construction such as girders, concrete patches and injection grouting related to the prestressing tendons and intermediate support and support column (Table 3). 3.1. Carbonation effect It can be seen in Table 3 that the mean values of pH are in every case lower than the depassivation threshold value of 11.8. The mean values of pH are also shown in Fig. 1. In the case of groups Abutments&Bearing Seats and Injecting Grouts of motorway bridges, the mean value of pH is even lower than 10. In general, one can notice that the values of pH are lower for the groups of motorway bridges, except for the Girders, Cross Bars&Longitudinal Joints group, where the pH is lower in case of the main road bridges.

10,00 12,00 14,00

0,00 2,00 4,00 6,00 8,00

pH [-]

Main road bridges

Motorway bridges

Abutments & Bearing Seats

Girders, Cross Bars & Longitudinal Joints

Concrete Patches

Injecting Grouts Mean value of pH

Support Columns, Intermediate support

Figure 1. Mean values of carbonation effect described by mean values of pH [-] of the main road and motorway bridges and respective construction components bridges (Groups are represented by columns with patterns. All samples from the group are represented by outlining frame like column). 3.2. Chloride concentration The chloride concentrations sorted to specific groups are given in Table 3. Concentration higher than the chloride concentration threshold of 0.1 [wt.-%/concrete] is observed on almost every group of the motorway bridges, except for the Girders, Cross Bars & Longitudinal Joints, where the value is 0.07 [wt.-%/concrete] and Support Columns& Intermediate support with the value of 0.08[wt.-%/concrete]. On the main road bridges, the mean values of concentration are in every case lower than the threshold. The respective graph is presented in Fig. 2. 3.3. Corrosion risk via c(Cl - )/c(OH - ) The c(Cl - )/c(OH - ) ratio sorted per group has shown that the worst situation concerning corrosion is in the case of the Abutments&Bearing seats and Injecting grouts of motorway bridges, and in the case of the Abutments&Bearing seats of main road bridges (see Table 3 or Fig. 3). The c(Cl - )/c(OH - ) ratios are almost in every case higher than the critical value of 0.6. The lowest values were measured on the Concrete Patches and Support Columns& Intermediate support of the main road bridges. One should notice that the ratio is higher in the case of the motorway bridges, except