A dual role on cleaning and healing of foreign agents for sustainable smart buildings using nano?TiO_2

摘要

Cracks incessantly act as a precursor on the surface of the structure, which facilitates the ingress of water and other foreignagents. Such activities would deteriorate the functionality and reduce the lifetime of the building. In this regard, an attemptwas made to clean (self-cleaning) and heal the cracks by itself (self-healing). The mechanism involved in the proposedstudy was autogenous healing. Nano-titanium dioxide was used as a healing agent, and the properties were compared withthe conventional admixture at a recovery period of 14, 28, and 56 days, respectively. Nano-TiO_2 was partially replaced withcement by various dosages viz., 0.5, 1, 1.5, 2, and 2.5 wt.%, respectively. Self-cleaning was analyzed through photocatalyticactivity, phase composition and BET analysis. Similarly, the properties of the healed samples were tested against physiomechanicalproperties including air content, bulk density, compressive strength, and durability aspects of water absorption–immersion, sorptivity, permeability, and seepage flow. Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD)are the microstructural studies. Performance of the healed samples was examined through crack width, and healing degree.Nano-TiO_2 particles accelerate the self-healing ability with a reduction in crack width by 13–36%. The ingress of water bysorptivity was reduced from 25 to 6.5%. The efficiency of permeability reduction was achieved by 19–37%. The potential ofthe research will elevate the life span of the structure as well saves the time and manpower owing for maintenance and repair.