Issue 75

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

The tables show the data collected during the first four hours of curing, a period in which fresh concrete is most susceptible to surface cracking due to rapid water loss through evaporation. This stage is critical because the concrete has not yet developed sufficient internal strength, which favors the appearance and propagation of shrinkage cracks. The information obtained allowed for the creation of comparative graphs that represent the evolution of the concrete's behavior during this interval, facilitating the identification of trends in crack formation and growth over time. Thus, the results not only demonstrate the magnitude of the problem under normal conditions but also highlight the beneficial effect of incorporating polypropylene synthetic fibers as a strategy to control and reduce early cracking.

CUMULATIVE WATER LOST (kg)

WATER EVAPORATION RATE (kg/m 2 .h)

SAMPLE WEIGHT (kg)

WATER LOST (kg)

TIME

30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min 30 min

22.235 22.165 22.158 22.156 22.153 22.144 22.138 22.136 22.131 22.117 22.098 22.093 22.078 22.068 22.064 22.060 22.316 22.283 22.282 22.281 22.278 22.277 22.269 22.267 22.162 22.143 22.133 22.132 22.129 22.128 22.126 22.120

0.05 0.12 0.13 0.13 0.13 0.14 0.15 0.15 0.08 0.09 0.11 0.12 0.13 0.14 0.15 0.15 0.07 0.10 0.10 0.10 0.11 0.11 0.11 0.12 0.07 0.09 0.10 0.10 0.10 0.10 0.11 0.11

0.05 0.17 0.30 0.43 0.56 0.70 0.85 1.00 0.08 0.18 0.29 0.41 0.54 0.69 0.83 0.99 0.07 0.17 0.27 0.37 0.47 0.58 0.69 0.81 0.07 0.16 0.26 0.36 0.46 0.56 0.67 0.78

0.32 1.08 1.89 2.72 3.56 4.46 5.40 6.35 0.52 1.12 1.84 2.60 3.45 4.37 5.31 6.28 0.42 1.05 1.69 2.34 3.00 3.67 4.39 5.12 0.45 1.01 1.64 2.28 2.93 3.60 4.27 4.98

CONTROL SAMPLE (MP)- 01

CONTROL SAMPLE (MP)- 02

SAMPLE DESIGN 02 (DM-02)-01

SAMPLE DESIGN 02 (DM-02)-02

Table 17: Results of the water evaporation rate test according to ASTM C1579.

AVERAGE WATER EVAPORATION RATE (kg/m 2 .h)

SAMPLES

TIME 1 hour 2 hours 3 hours 4 hours 1 hour 2 hours 3 hours 4 hours

1.10 2.66 4.42 6.32 1.03 2.31 3.64 5.05

SAMPLE PATTERN (MP)

SAMPLE DESIGN 02 (DM-02)

Table 18: Results of the water evaporation rate at the evaluated times.

427