In recent years, nano calcium hydroxide (NCH) finds its potential applications in conservation and restoration of heritage structures due to its improved surface treatment. In the present study hexagonal NCH powders were synthesized for surface treatment of heritage mortar. Lime is usually adopted for the conservation of surface treatment due to quick transformation of lime into calcium carbonate. However the incomplete lime carbonation process and reduced penetration depth are the undesired limits for the surface treatment. Present work will report the chemical stability and mechanical behavior before and after surface treatment using this synthesized NCH powder in heritage mortar. For this purpose, morphologically tuned Calcium hydroxide nono powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy and energy dispersive X-ray analysis (EDAX). For the restoration purpose mortar samples of the heritage building were collected and treated with synthesized NCH powder. The untreated and treated mortar samples were again characterized by XRD, FESEM, EDAX, nano indentation techniques, mercury intrusion porosimetry and thermal expansion coefficient (TEC). The results showed regular hexagonal shaped layered nanoparticles with dimensions about 100-200 nm. These nano particles have pure crystalline features and a high reactivity in terms of the carbonation process. FESEM and EDAX line mapping were performed on the treated mortar sample to evaluate penetration depth and grain adhesion of the nanopowders with treated sample. It was also observed that TEC was decreasing after treatment of synthesized NCH powder which revealed that the mortar under goes shrinkage due to volume decrease of the nano Ca(OH) 2 phase.
The conventional crystallographic structure solution by X-ray Diffraction technique using Rietveld method prove its great potential for determination of the average structure of the materials for long range periodicity. Experimentally, the structural information of long range periodic atomic ordering of material is reflected in the Bragg's peaks while local or short range structure is reflected in the diffuse peaks. In order to obtain structural information about both average and local atomic structures, need a technique that will consider both Braggs peaks as well as diffuse peaks. Therefore, Total Scattering Atomic Pair Distribution Function (PDF) technique based on Debye Scattering function will be the only possible solution. At present synchrotron and neutron sources are the choice for PDF analysis for short range structure study. But there is a need for routine analysis of such type of samples in a conventional laboratory XRD system to get the quick feedback about the short range structure. PDF analysis can be performed in a Laboratory X-ray diffractometer using Ag radiation (λ = 0.5608 Å) to obtain maximum Q value i.e. 22 Å-1. The present work will report PDF based methodology in a laboratory XRD system to extract structural information about nanostructured and disordered materials over short and long range for structural characterization of crystalline and amorphous materials. Present work will report how this PDF technique used to unravel the structure of disordered materials and nanomaterials like amorphous silica, Ni, nano Ba-based Perovskite, etc for better understanding the materials at nano level. Structural information as obtained by the PDF analysis will help to control the performance of the disordered materials for tailoring the materials at nano scale. This method may be applicable to the characterization of the nanoscale crystalline and amorphous materials based on PDF analysis in Laboratory XRD system using Ag Radiation. This proposed experimental technique will help to quick feedback about local or disordered structure based on PDF using Ag radiation in a laboratory XRD system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.