This work evaluated the photocatalytic activity of 3D-printed cementitious mortar specimens functionalized with TiO₂ nanoparticles to obtain a multifunctional and smart concrete. This research aims to assess the influence of different parameters related to the functionalization process such as adsorption, coating time gaps, and coating rates on the degradation efficiency of the functionalized cementitious specimens. Each specimen was evaluated under the degradation of Rhodamine B (RhB) in an aqueous solution using a sun-light simulation. The obtained results showed a decrease in adsorption (under dark condition) with increasing the sample curing age. The highest photocatalytic efficiency was observed for coated samples aged 7 days. By increasing the coating rates, the photocatalytic efficiency is enhanced. Nonetheless, regardless of the coating rates, all the specimens showed an increase in photocatalytic efficiency for longer time periods of light exposition, i.e., after 8 h of irradiation.

The sustainable development of our societies demands strong efforts on scientific and technological research while informing and educating students and the general population. Air pollution and road safety hazards constitute two main public health problems that are insufficiently addressed pedagogically. With this work, we aim to contribute to tackeling the problem by presenting the results of scientific research on the development of photocatalytic, superhydrophobic, and self-cleaning recycled asphalt mixtures to achieve an eco-social friendly and smart material able to mitigate socioenvironmental impacts. The functionalization of asphalt is implemented by spraying particles’ solutions over a conventional AC 10, then evaluated by dye degradation and wettability. Firstly, different particles’ solutions (with nano-TiO₂ and/or micro-PTFE under water, ethyl alcohol, and dimethyl ketone) were sprayed to select the best solution (BS), which was composed of TiO₂-PTFE (4 g/L each) in ethyl alcohol. Two successive spraying coatings (diluted epoxy resin and BS) were performed over conventional and recycled AC 10 (with reclaimed asphalt pavement and steel slags). Their efficiency decreases with the highest resin amounts. The best results were obtained with 0.25 g resin and BS. For the lowest resin amount, all mixtures achieved superhydrophobicity and performed similarly regarding wettability.

Self-cleaning cementitious materials, particularly with TiO₂-based photocatalytic coatings, offer significant benefits by reducing surface deterioration and maintenance requirements, even in harsh urban environments. Despite the growing interest in self-cleaning cementitious materials, an international standard test method to calculate their efficiency has not yet been established for this specific type of substrate. The objective of this study was to evaluate and compare three different techniques for assessing the photocatalytic efficiency (PE) of cementitious materials coated with TiO₂: (i) spectrophotometric colorimetry (SPC); (ii) digital image processing-based colorimetry (DIP); and (iii) UV-Vis spectrophotometry (UV-Vis). Rhodamine B (RhB) was used as a model pollutant, and the photocatalytic efficiency was monitored under UV-Vis light. The results showed that each method has distinct advantages and specific challenges. SPC proved to be a practical and efficient approach, similarly to DIP, which was also accessible, providing reliable and accurate measurements. UV-Vis stood out for its precision but required careful application on cement-based substrates due to their unique porosity and adsorption characteristics. These results underscore the complementary potential of these techniques and highlight the importance of developing standardized protocols that integrate their strengths to facilitate the wider adoption of self-cleaning materials.

This research aims to develop asphalt mixtures with new capabilities, namely photocatalytic, superhydrophobic, and self-cleaning capabilities. Different solutions were prepared combining nano-TiO2 and micro-PTFE on water, ethyl alcohol, and dimethyl ketone with different concentrations. The solutions were sprayed over the asphalt mixtures, and the photocatalytic and superhydrophobic capabilities were evaluated via decolourization of Rhodamine B dye aqueous solution under simulated solar irradiation and Water Contact Angle (WCA) measurements, respectively. Among the combinations analysed, the best solution was TiO2-PTFE with ethyl alcohol (8 g/L), which provided a decolourization of about 60% after having spent 8 h in light exposure conditions and a superhydrophobic surface with WCA equal to 153º. Thus, this research work aims to contribute to advances in the field of clean technologies, assisting in the transition to the “Green Recovery”, which is environmentally friendly, inclusive, and sustainable.