Performance Characterization of Broad Band Sustainable Sound Absorbers Made of Almond Skins

Thermal and Sound Characterization of a New Biocomposite Material

Bio-based composites are increasingly used. One of the most frequently used materials is hemp shives, which is agricultural waste. However, as the quantities of this material are lacking, there is a tendency towards finding new and more available materials. Corncob and sawdust are bio by-products that have great potential as insulation materials. In order to use these aggregates, it is necessary to examine their characteristics. New composite materials based on sawdust, corncobs, styrofoam granules, and the mixture of lime and gypsum as the binder were tested in this research. This paper presents the properties of these composites obtained by determining the porosity of samples, volume mass, water absorption, airflow resistance and heat flux, which was followed by the calculation of the thermal conductivity coefficient. Three of the new biocomposite materials, whose samples were 1-5 cm thick for each type of mixture, were investigated. The aim of this research was to analyze the results of different mixtures and sample thicknesses in order to determine the optimum composite material of the proper thickness so that the best possible thermal and sound insulation could be obtained. Based on the conducted analyses, the biocomposite with a thickness of 5 cm, composed of ground corncobs, styrofoam, lime, and gypsum, proved to be the best in terms of thermal and sound insulation. New composite materials can be used as an alternative to conventional materials.

The Agro-Waste Production in Selected EUSAIR Regions and Its Potential Use for Building Applications: A Review

The purpose of this study is to provide a snapshot of the agro-waste production in Puglia, Molise, Albania and Montenegro, some of the regions belonging to EUSAIR (ADRIATIC-IONIAN REGIONS) correlating this aspect to the possible use of agro-waste in the building sector. EUSAIR is a functional area, facing the Adriatic sea, treating the marine, coastal and terrestrial areas as interconnected systems. In the first part of the paper, the state of the art about the current consumption of agricultural biomass is carried out referring to the ongoing research lines. It was shown that a great number of international studies have demonstrated that the agro-waste plays an important role in several fields. Moreover, several researchers conducted studies on hygrothermal, physical and acoustical properties of building materials made with biomass proving the potentiality to use this kind of by-product. Then, the state of the art regarding the production and current way of disposal of the agro-waste in the regions of the EUSAIR above mentioned was performed in order to outline the possible by-products which are suitable to be re-used in the building sector. The correlation existing between the agro-waste and the possible use in the building sector is finally presented, focusing on the legislative framework currently existing in each of the regions.

Influence of Flame Retardant Impregnation on Acoustic and Thermophysical Properties of Recycled Technical Textiles with the Potential for Use in Wooden Buildings

This article presents the results of an investigation of acoustic and thermophysical properties of insulation panels made from recycled technical textiles originating from the automotive industry. Measurements were performed on the samples of insulation panels (Senizol AT XX2 TL60), which were modified with liquid flame retardants (ISONEM^® ANTI-FIRE SOLUTION, ECOGARD^® B45, HR Prof). Another method of treatment was carried out by surface application of non-flammable facing (woven carbon fibre, nonwoven carbon fibre). Retardants were applied to the samples by surface spraying and soaking. The results showed a high ability of material to absorb sound in the frequency range 350 Hz–2 kHz. The sound absorption coefficient ranged from 0.82 to 0.9 in the frequency range 500 Hz–2 kHz. The noise reduction coefficient is 0.75. After material modification with the flame retardants, there was no significant change of sound absorption. The thermal conductivity coefficient of material before modification was 0.038 W⋅m⁻¹⋅K⁻¹. After application of the flame retardants, the thermal conductivity coefficient increased depending on type and method of retardant application in the range of 2.6–105.3%. The smallest change was detected after modification of material with ECOGARD^® B45.

Acoustic Properties of Larch Bark Panels

The potential of tree bark, a by-product of the woodworking industry, has been studied for more than seven decades. Bark, as a sustainable raw material, can replace wood or other resources in numerous applications in construction. In this study, the acoustic properties of bark-based panels were analyzed. The roles of the particle size (4–11 mm and 10–30 mm), particle orientation (parallel and perpendicular) and density (350–700 kg/m3) of samples with 30 mm and 60 mm thicknesses were studied at frequencies ranging from 50 to 6400 Hz. Bark-based boards with fine-grained particles have been shown to be better in terms of sound absorption coefficient values compared with coarse-grained particles. Bark composites mixed with popcorn bonded with UF did not return the expected results, and it is not possible to recommend this solution. The best density of bark boards to obtain the best sound absorption coefficients is about 350 kg/m3. These lightweight panels achieved better sound-absorbing properties (especially at lower frequencies) at higher thicknesses. The noise reduction coefficient of 0.5 obtained a sample with fine particles with a parallel orientation and a density of around 360 kg/m3.

Innovative Composite Materials for Sound Absorption and Insulation: Where We Are and Where We Are Going

Materials with sound-absorbing or sound-insulating properties have been rapidly evolving in recent years due to several reasons [...].

Nonwoven Textile Waste Added with PCM for Building Applications

Due to the overall improvement of living standards and considering the priority to reduce the energy consumption, the adoption of efficient strategies, mainly in the building area is mandatory. In fact, the construction sector can be considered as one of the key field essential for the sustainability, due to the diversity of components and their life cycles. Reuse strategies may play an essential role in reducing the environmental impact of building processes. Within this framework, the reuse of textile waste to produce insulating materials represents one of the biggest opportunities for the promotion of a circular economy. It contributes significantly to improve the environmental sustainability reusing a waste as new raw matter involved to achieve high energy efficient buildings. This paper provides the results of an experimental campaign performed using wool waste derived from the industrial disposal of fabrics matched with phase change materials (PCMs) used in order to enhance the thermal mass of the final products. Physical and thermal parameters were measured in order to demonstrate the good performances of the textile materials and the essential role played by PCMs in shifting heat waves and reduce surface temperatures. Furthermore, DesignBuilder software was used to assess the energy consumption of a mobile shelter type structure under three different climatic scenarios. A comparison between the experimented materials and other solutions, currently available in the market, highlighted a significant reduction in energy consumption when adopting the materials under test.