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The present research investigated bio-based construction material based on hemp shives and gypsum. Low-density material was developed with densities of 200, 300, and 400 kg/m3. Simple yet robust production technology was used. For the first time, a binder for biocomposites obtained from phosphogypsum was used and properties were compared to commercial gypsum. CO2 negative building material was developed with up to 92 kg CO2 ekv./m3 entrapped. Both physical and mechanical properties were studied. Thermal conductivity was in the range from 0.058 to 0.101 W/(m·K) and compressive strength from 0.10 to 0.57 MPa. Biodeterioration test results showed that the pH of 5.60–6.55 for biocomposites promoted a rapid mold growth. Mold growth was slightly lower for composites with higher gypsum content, while phosphogypsum induced more rapid mold growth. Cladosporium, Rhizopus, Chaetomium, and other molds were observed on samples even at an early stage of testing giving a serious concern about only limited application in dry conditions for such gypsum-based biocomposite. [ABSTRACT FROM AUTHOR]

Abstract: The study was focused mainly on the biodeterioration of the external wood of the Latvian Ethnographic Open-Air Museum, Riga (1924), and the sacral wooden buildings in Eastern Latvia (Latgale). The inspected wooden structures included windows, stairs, walls, roofs, fences, benches etc. Roofs, walls and fences were the most commonly decayed outdoor structures, while roof constructions and ceilings were the most often deteriorated indoor structures. Fungi from the phyla Basidiomycota, Ascomycota and Protozoa (Myxomycota) were identified. Common fungal genera were Antrodia, Gloeophyllum, Athelia, Hyphoderma, Hyphodontia, Pharenochaete, Postia and Botryobasidium. Mainly corticoid and poroid species were recorded in the wooden structures. The protection measures against the fungal attack should include a proper maintenance of roofs as well as the decrease/elimination of the vegetation around the buildings. The historical value of biodeteriorated structures should be taken into consideration before applying the protection/renovation measures. [Copyright &y& Elsevier]