Bio-Wastes as Aggregates for Eco-Efficient Boards and Panels: Screening Tests of Physical Properties and Bio-Susceptibility

Abstract

Screening tests were developed or adapted from RILEM recommendations, standards and past studies, and carried out to characterize some agro-industrial wastes and to assess their feasibility as aggregates for eco-efficient building composites. Spent coffee grounds, grape and olive press waste and hazelnut shells were used, as well as maritime pine chips as control material. Particle size distribution, loose bulk density, thermal conductivity and hygroscopicity properties were analysed. The selected bio-wastes did not show good thermal insulation properties if compared with some bio-wastes already studied and used for thermal insulation composites. Values of loose bulk density and thermal conductivity were between 325.6–550.5 kg/m3 and 0.078–0.107 W/(m·K); moisture buffering values higher than 2.0 g/(m2·%RH). Biological susceptibility to mould and termites were also tested, using not yet standardized methods. The low resistance to biological attack confirms one of the greatest drawbacks of using bio-wastes for building products. However, final products properties may be changed by adding other materials, pre-treatments of the wastes and the production process.

Hygroscopicity and Morphology of Bio-Based Boards—The Influence of the Formulation

“…Giant reed (Arundo donax L.) and hazelnut shells were selected as bio-aggregates, characterized, and prepared as described in past studies [29][30][31]. A. donax was harvested from the cultivation of the Department of Agricultural and Food Sciences, the University of Bologna, in Ozzano dell'Emilia, Bologna, Italy.…”

“…The selected adhesive could also moderate some of the main drawbacks, such as low resistance to water, fire, and biological attack [24][25][26], improving the final composite's performance. Thus, knowing the properties of both the aggregates and the adhesive, individually and in composites, is crucial in building composites' production [27,28].…”

“…Hazelnut shells are a widely produced bio-waste [29], available throughout the year due to hazelnut treatment before their use [31]. Some past studies have already considered the possibility of using hazelnut shells for building practices [32,33].…”

Thermal renders for traditional and historic masonry walls: Comparative study and recommendations for hygric compatibility

“…Among the several retrofit solutions that can be adopted, the thermal retrofit of external walls is often considered. Thermal retrofit can lead to improved indoor comfort while reducing operational energy demands [2,3], which is advantageous in both financial and environmental terms [4]. What is more, in the context of historic and traditional urban environments, thermal retrofits are particularly relevant to help maintaining existing buildings in use, thus contributing to conserve these areas as living entities, which is a social and cultural requirement [5].…”

Re-thinking Indoor Humidity Control Strategies: The potential of additive manufacturing with low-carbon, super hygroscopic materials.

“…Conversely, high humidity can intensify the sensation of discomfort from overheating [8], [9], it can trigger joint problems [10] and even inflammatory rheumatic diseases [11]. Avoiding excessive relative humidity levels helps to minimize the survival of bacteria, limit the growth of mould and fungi, as well as reduce the presence of mites, which are all allergens that can trigger human health [12]- [14].…”