Análisis de fisuración con corriente de aire inducido en placas de hormigón reforzado con fibras de estopa de coco.

Abstract

The present research analyzes cracking due to plastic shrinkage resulting from accelerated drying on the surface of concrete plates. These plates were made with different percentages of coconut fiber addition (0%, 0.5%, 0.75% and 1%) in natural state and with chemical treatment, in addition to imposed environmental conditions. For fiber treatment, it was decided to use mercerization (NaOH). The fibers required surface cleaning and cutting in accordance with ACI 544.4R-18. A sampling of 7 typologies was processed on plates for cracking, each accompanied by 3 cylinders and 3 beams tested at 28 days of curing. For the plate test, a hot air chamber was built in wood, where a heater and fan were used to simulate environmental conditions that facilitated the early formation of cracks, as well as the collection of data on temperature, wind speed, moisture loss and a photographic record for the determination of the total length of the cracks, in addition to the use of ultrasound equipment for the calculation of the depth of these cracks. Both for the improvement of mechanical properties and the reduction of cracks in the concrete surface, the best percentage composition to be used is 0.75% of coconut fiber with the mercerization treatment, since from having a total of 4.57 m in cracks in the plates at 0%, it is reduced to 1.77 m with the addition of 0.75% fibers.