Enhanced Bond Performance of Guadua-Reinforced Concrete Synergistic Effects of Epoxy Resin and Grooved Surface Treatments

This study investigates the bond behavior between concrete and Guadua angustifolia Kunth bamboo using a pull-out test adapted from ASTM C234. A multifactorial experimental design was employed to evaluate two key treatment parameters: surface texture (smooth [S] or grooved [G]) and the application of epoxy resin (with [R] or without [WR]). This resulted in four distinct treatment configurations (SR, GR, SWR, GWR). A total of 36 tests were conducted on concrete specimens at curing ages of 7, 14, and 28 days. The results revealed a significant influence of both treatment and curing time on bond performance. Epoxy resin application emerged as the most critical factor, with the grooved and resin-treated specimens (GR) achieving the highest bond strength at 28 days- 3.92 times greater than that of smooth, untreated specimens (SWR)-alongside a 7% higher friction coefficient. A finite element model was developed and calibrated with experimental data, accurately predicting bond stress (within a 2% margin of error) and providing insights into failure mechanisms. Failure was typically characterized by adhesive failure and pull-out, with the GR treatment exhibiting a larger critical displacement. These findings demonstrate that the synergistic combination of mechanical grooving and epoxy resin treatment drastically enhances the Guadua-concrete interface, highlighting its potential for use in sustainable structural reinforcement systems.