Integration of FDM and self-healing technology: evaluation of crack sealing by durability and mechanical strength

The tensile zone of concrete is prone to cracking due to its limited ability to withstand tension. To address this issue, steel reinforcement is used in these specific regions. The occurrence of little cracks might potentially facilitate the ingress of liquids and gases into the reinforcing material, hence inducing corrosion. Self-healing concrete can repair and seal minuscule cracks, thus impeding the formation of corrosion. This study investigates the potential application of fused deposition modeling (FDM) for generating novel vascular networks and tubes using polylactic acid (PLA) as the material. Poly (lactic acid) (PLA) was fabricated using three-dimensional (3D) printing techniques, and its properties were compared to those of one-dimensional (1D) and two-dimensional (2D) networks. The external diameter measured 5.6 mm, while the internal diameter measured 4 mm. utilized a 10 ml volume to apply healing agents, specifically organic polyethylene glycol liquid and nano-powder (fly ash) derived from recycled materials, to all vascular structures (1D, 2D, and 3D). This application was carried out using a planetary ball mill. Following this, the prepared tubes were incorporated into a concrete beam to introduce self-healing capabilities. The water-to-cement ratio (W/C) utilized for all concrete mixtures was 0.6%, while the definite mixture proportions were 1:2.16:2.98. The quantification of the self-healing phenomenon was conducted by evaluating the restoration of load-carrying capacity following the application of a repaired specimen to a four-point bending test. Furthermore, these enhancements resulted in improved durability, increased compressive strength, and enhanced other physical characteristics. The pipes that are manufactured can be utilized to produce innovative concrete that possesses the ability to undergo self-healing processes by combining low-viscosity healing solutions (PEG) with powders (nano fly ash) that are appropriate for this application by injection into the vascular network , making it well-suited for various self-healing applications.