Effects of exfoliation temperature for vermiculate aggregates modified by sodium ions on thermal and comfort properties of a new generation cementitious mortar
Open Access
- 30 December 2022
- journal article
- Published by Yildiz Technical University in Journal of Sustainable Construction Materials and Technologies
- Vol. 7 (4), 266-281
- https://doi.org/10.47481/jscmt.1196292
Abstract
Vermiculite exfoliation is based on the principle when water between the layers evaporate, and the crystal layers spread out pressured by the steam. As a result, elongated, curved particles are formed. The thermal properties of the final product formed are directly related to this exfoliation amount. In this experimental work, exfoliation characteristic of natural vermiculate is studied. A series of experimental analyzes were carried out to examine the expandability of natural vermiculite at different heating temperatures by the Na+ modification method. In addition, the expansion ratios of Na+-modified and unmodified vermiculite samples were analyzed comparatively. Each of the raw and Na+ modified vermiculite material groups prepared for the thermal expansion process was experimentally performed by recording the exfoliation states and times at six different heating temperature values of 350 oC, 450 oC, 530 oC, 620 oC, 710 oC and 840 oC, respectively, in a laboratory environment. In the second phase of the study, thermal properties of new generation composite mortars produced with exfoliated vermiculite aggregate were experimentally analyzed. Parameters such as thermal conductivity, heat storage capacity, specific heat and heat dissipation coefficient of mortar test samples prepared with exfoliated vermiculite aggregates are analyzed and discussed here. Test results showed that Na+-modified vermiculite samples expanded better than unmodified vermiculite samples for all expansion temperatures. When Na+-modified expanded vermiculite is evaluated in composite mortars, it also reduces the unit weight of the mortar as it expands more and the unit weight of itself decreases. Accordingly, the compressive strength of the mortar decreases relatively. However, it has been determined that the thermal comfort properties of mortars using Na-modified exfoliated vermiculite are better than the thermal comfort properties of composite mortars produced using unmodified exfoliated vermiculite.Keywords
This publication has 20 references indexed in Scilit:
- Preparation of energy efficient paraffinic PCMs/expanded vermiculite and perlite composites for energy saving in buildingsSolar Energy Materials and Solar Cells, 2015
- Impact of perlite, vermiculite and cement on the thermal conductivity of a plaster composite material: Experimental and numerical approachesComposites Part B: Engineering, 2015
- Effects of the addition of glass fibers, mica and vermiculite on the mechanical properties of a gypsum-based composite at room temperature and during a fire testComposites Part B: Engineering, 2014
- Properties of gypsum composites containing vermiculite and polypropylene fibers: Numerical and experimental resultsEnergy and Buildings, 2013
- On the mechanism of exfoliation of ‘Vermiculite’Clay Minerals, 2013
- The effect of heating temperature on the properties of vermiculites from Tanzania with respect to potential agronomic applicationsApplied Clay Science, 2009
- Coating protection of loaded RC columns to resist elevated temperatureFire Safety Journal, 2009
- Synthesis of nano-layered vermiculite of low density by thermal treatmentPowder Technology, 2009
- Formation and characterization of polyurethane—vermiculite clay nanocomposite foamsPolymer Engineering & Science, 2008
- Expansibility of some vermiculitesApplied Clay Science, 1989