Adhesion, Thermal Conductivity, and Impact on Indoor Air Quality of Plasters Incorporating Rice Husks

The global population growth and the demand for agricultural food products have generated a significant volume of agro-industrial by-products which, inadequately managed, affect the quality of the environment. The construction industry, a large consumer of raw materials and energy, constitutes an important source of waste and greenhouse gas emissions. In this context, the circular economy provides the right framework for the valorization of such natural materials, allowing us to obtain innovative sustainable building materials. The paper presents experimental research that led to the development of twelve plasters incorporating rice husks that were characterized by means of thickness (2.71-6.26 mm, when applied on concrete, and 4.20-10.29 mm, when applied on plasterboards), adhesion to the concrete surface (0.18-0.65 N/mm²), thermal conductivity (0.072-0.083 W/m·K), and impact on indoor air quality, in terms of total volatile organic compounds (TVOCs) emissions (3272-9470 µg/m³). The determined levels of the emissions suggest the possibility that by extending the monitoring for at least seven days after application, the information is more relevant. The findings confirmed that using the rice husks for the obtaining of such plasters represents a possible direction of valorization in construction; additional research is necessary for a more precise delineation of the characteristics of these products.