PSI - Issue 33

Fabrizio Pittau et al. / Procedia Structural Integrity 33 (2021) 630–645 Author name / Structural Integrity Procedia 00 (2019) 000–000

643

14

(a)

(b) Fig. 19. Details of the Leakage tests, (a) joint (b) wall.

5. Discussion The experimental campaign shows that most of the leakages are concentrated in the cracks and in singular points. The permeability of a continuous concrete wall is quite reduced, but it is impossible to eliminate the cracking. So, in case of large-scale wall it is essential to provide an impermeabilization strategy on external (or internal) lining. This strategy can be addressed as an overall protection of the surface of the wall or as a local treatment of the cracks. So, it is crucial to identify an effective and easy procedure to apply tan external coating to protect the external surfaces. The best performances have been obtained by specimen A and C. Polyurea and epoxy primer reveals to be very effective in terms of tightness but with different application efforts. If the polyurea requires hot pumps and a proper preparing procedure the epoxy primer can be cold applied with roller, brush, or spray. This makes the second cover technology of particular interest in case of civil construction sites, particularly considering the large extension of civil works. The singularities, as the holes for the threaded bars and for pressure gauge, required a liquid o semi-liquid product to have a best penetration and sealing. These critical points are effectively sealed in case of Specimens A and C. A comparison of the results obtained for the tested specimens in terms of overpressure, tightness and preparing are summarized in Table 1.

Table 1. Comparison of the results of the experimental campaign.

Polyurea

Mineral coating

Epoxy-primer

Epoxy cementitious

Overpressure

Light sealing No signs of leak

No sealing

Light sealing Punctual leaks

No sealing

Tightness

Decrease of leaks

Decrease of leaks

Preparing procedure Application time (days)

Complex

Average

Average

Average

4

15

8

9

Joints

No Leaks

Leaks

Reduced Leaks

Reduced Leaks