Issue 75

M. Ramos et alii, Fracture and structural integrity, 75 (2026) 399-434 ; DOI: 10.3221/IGF-ESIS.75.29

there was no reduction in crack length and width. Therefore, a technical analysis of the data will be performed to corroborate the statistical results and determine an exact percentage reduction, thus complementing the statistical tests for a better understanding of crack reduction in concrete slabs. Technical analysis Based on the statistical analysis of data collected during the construction phase, the aim is to determine the optimal dosage of polypropylene synthetic fiber in concrete slabs. To this end, a technical analysis of the information obtained at each curing stage will be performed to understand the cracking process. However, since the Mann-Whitney U test showed a significant difference between the Standard Sample (SS) and the Sample Designs (DM-01, DM-02, and DM 03) at 28 and 35 days, it was decided to identify the optimal dosage using the data corresponding to 28 days. This is because, at this stage, the concrete completes its curing process and reaches its maximum strength, which is more beneficial for the research.

C RACK DEVELOPMENT

C

racks develop during the concrete curing phase, allowing them to be identified through visual observation of their growth. Their appearance is related to the expansion and contraction processes of the material, manifesting primarily in areas where the concrete is thinner. Data collection at the five curing stages allowed for a progressive analysis of crack formation and propagation, as detailed in the following three graphs (Time vs. Width, Length, and Cracks), considering the maximum value for width and length, and the total frequency for the number of cracks.

Figure 28: Graph of width versus curing time.

Figure 29: Graph of length versus curing time.

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