PSI - Issue 70

Sreegovind M. et al. / Procedia Structural Integrity 70 (2025) 556–563

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In this context, concrete and mortar, which are the most widely used construction materials, are not much being explored for their thermal insulation capabilities (Sakulich, (2012); Shahedan, et al. (2017)). The inherent thermal properties are very limited for conventional cement-based materials, even though it possesses relatively high thermal mass (Papadopoulos, (2005)). Sustainable construction research has put its focus on enhancing these properties by the incorporation of lightweight and porous aggregates. Expanded vermiculite, is a lightweight material, which has shown its potential as a partial replacement for fine aggregates in mortar by its lower thermal conductivity and strong fire resistance (Assis Neto et al. (2023). According to studies, the incorporation of vermiculite in mortar improves the thermal properties (Balbuena et al. (2024); dos Santos et al., (2023)). For instance, A notable reduction in heat transfer when expanded vermiculite is used in coating mortar is reported (Deize D.P. Guilherme et al., (2024)). Ahmet Benli et al. (2020) highlighted enhanced high temperature resistance in vermiculite incorporated self-compacting mortar. The application of EV with and without PCM in cement mortar and foam concrete for thermal regulation purpose is reported (Dora et al., (2023); Dora et al., (2023); Dora et al., (2025)). By using industrial and recycled waste materials as aggregates or fillers, concrete’s role in building insulation can also be improvised. Researchers stressed the potential of implementing the foam concrete system with the addition of waste materials to improve the thermal insulation properties in construction, providing an effective path to the solution of sustainability in construction (Krishnan & Anand, (2018); Chandni & Anand, (2018)). Based on the literature review, expanded vermiculite (EV) as a partial replacement for the fine aggregate in cement mortar, leveraging its thermal insulation qualities, has received limited explicit investigation. The thermal behavior of EV incorporated cement mortar and its mechanical properties are not much explored. Thermal and mechanical properties assessment and the simulation of thermal behavior for various percentages of EV offers a novelty in strength-insulation balance at these substitution rates.

Nomenclature EV Expanded vermiculite CM Controlled mix (0% EV)

CM5 5% EV as replacement to fine aggregate CM10 10% EV as replacement to fine aggregate CM15 15% EV as replacement to fine aggregate

2. Materials and methods 2.1 Materials Portland Pozzolana cement (PPC) is adopted for preparing the mortar mix. The properties of cement used are detailed in Table 1. Manufactured sand (M-sand) with a size less than 4.75mm is used as the fine aggregate. The particle size distribution of the fine aggregate is given in fig. 1. The tests conducted include specific gravity and fineness are conducted based on the IS codes IS 2386 (Part 3): 1963 (Reaffirmed 2021) and IS 383: 2016 and the properties are listed in Table 1. Expanded vermiculite is a naturally occurring mineral, which expand when heated to high temperatures (between 900°C to 1100°C). The result is a low-density material that has excellent thermal insulation, fire resistance, and sound absorption properties (fig.2). Moreover, its eco-friendliness and thermal stability make it a magnificent sustainable building material component. The expanded vermiculite passing through 4.75mm is chosen for the mortar preparation. The particle size distribution curve is shown in fig.1. The properties of expanded vermiculite are given in table 2.