PSI - Issue 79

Agnieszka Chowaniec-Michalak et al. / Procedia Structural Integrity 79 (2026) 198–205

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3. Results and Discussion 3.1. Classification and characterization of coating damage

During the tests, two characteristic types of damage to epoxy coatings were observed (Fig. 3a–b). According to the EN ISO 6272-1:2011 standard, impact resistance is defined as the minimum drop height at which the coating continuity is broken. To extend the analysis, an additional, original classification of damage was introduced: type I - corresponding to localized cracking of the coating at the impact point (Fig. 3a); and type II - involving extensive damage with visible radial cracks or detachment of the coating from the substrate (Fig. 3b). This distinction enables a better understanding of the behavior of floor coatings under service conditions, especially in industrial floors, where small, localized defects usually do not pose a functional problem, while more extensive damage may significantly affect performance. a b

Fig. 3. Types of damage observed in epoxy coatings: (a) type I - localized damage; (b) type II - extensive cracking and coating detachment.

3.2. Results - type I damage For the 1 kg load, the damage to epoxy coatings containing granite powders was limited to type I failures, i.e., localized, point-like cracks at the impact site (Fig. 3a). Only the reference sample (REF) behaved differently, at a drop height of 40 cm, it exhibited type II damage, involving extensive cracking and coating detachment. This indicates that in the coating without granite powder, no localized damage occurred instead, failure manifested immediately as a more extensive damage pattern.

Type I damage

0 10 20 30 40 50 60 70 80 90

80

75

72.5

72.5

62.5

60

Minimum drop height [cm]

REF G1-12 G1-36 G1-60 G2-12 G2-36 G2-60

Fig. 4. Minimum drop height causing type I damage for epoxy coatings containing different amounts of granite powders (no type I damage observed for REF).