Análisis de fisuración con corriente de aire inducido en placas de hormigón reforzado con fibras de palma africana 0.5% y 075% con y sin tratamiento químico: hormigón reforzado con fibras naturales 0.75% sin tratamiento químico.

Abstract

This research examines how plastic shrinkage caused by accelerated drying of concrete plates affects their cracking. Plates with different levels of African palm rachis fiber (0% and 0.75%) in their natural state are used to assess their impact. The inclusion of this fiber is a potential strategy to improve the mechanical properties of concrete, but its effect on cracking under accelerated drying conditions needs to be evaluated. The acquisition of the fibers was made from a palm oil extraction company, it was necessary to clean them superficially and cut them according to the ACI 544.4R18 (2018) standard, which specifies that the ideal length of fibers of natural origin is approximately 4 cm. The whole process was carried out in the concrete laboratory of the FICA, in order to evaluate the cracking, a sample of 2 types of plates was tested, for each of these dosages 3 beams and 3 cylinders were elaborated that were tested after 28 days of curing to determine the bending and compression behavior of each of the mixtures. In order to create a simulated environment that favors the early formation of cracks and collect temperature data, wind speed and photographic record, the plate was tested in a wind chamber that accelerates hot air to a certain speed with the help of a heater and a fan. Using ultrasound equipment, the depth of the cracks was calculated, as well as the total length of the cracks, which was determined by measuring the cracking process using the photographic record. The addition of 0.75% African palm rachis fibers has been shown to have a limited effect on improving mechanical properties but been effective in reducing cracking on the concrete surface. In the tests carried out, a significant decrease in the cracks in the plates was observed, going from a total of 5.57 m in the plates without fibers to 1.71 m with the addition of 0.75% of fibers.