Temperature and moisture content effects on compressive strength parallel to the grain of paricá

Abstract

The aim of this study is to evaluate the effect of the temperature and moisture content on the compressive strength parallel to the grain of paricá (Schizolobium amazonicum Huber ex. Ducke) from cultivated forests. The experiments were carried out on 3 timber samples under different conditions: heated (HT), thermal treatment (TT) and water saturated (WS). The HT sample consisted of 105 clear specimens assembled in 15 groups, the TT consisted of 90 clear specimens assembled in 15 groups and the WS consisted of 90 clear specimens assembled in 9 groups. The specimens from HT and WS samples were tested at a temperature range from 20 to 230 ºC and 20 to 100 ºC, respectively. The HT specimens were tested at ambient temperature, but after being submitted to thermal treatment. The HT, TT and WS samples present a decrease in the compressive strength, reaching 65%, 76% and 59% of the compressive strength at room temperature, respectively. The decrease in the compressive strength of the HT and WS samples can be associated to the thermal degradation of wood polymers and the moisture content. For the TT sample, the strength increased for a pre-heating temperature of up to 170 °C due to the reduction in the moisture content of the specimens.

Temperature reduction factor for compressive strength parallel to the grain

“…At 100°C, the results of this study are similar to those found by Young and Clancy [14], using 12% moisture content samples of Pinus radiata, by Manríquez et al [26] using water saturated samples of Schizolobium amazonicum.…”

“…Gerhards [8] presented results obtained from dried samples, with 5 mm  5 mm of cross section, while Young and Clancy [14] used dried and 12% moisture content specimens of 90 mm  90 mm  300 mm of Pinus radiata and different heating periods. Manríquez et al [26] used air dried and saturated samples with specimens of 5 cm  5 cm  15 cm, heated in the electric oven for 180 min. The study of the influence of temperature on mechanical properties of wood with normal moisture content is a difficult task, since the specimen heating tends to dry it.…”

The Product Features, Functions, and Benefits of Seafood Products for Competitive Repositioning

“…Furthermore, consumers were concerned about chem-contaminated products because of other consumers' observation, objective information from the media, social networks, and past contamination (Frank & Schvaneveldt, 2016). Changes in moisture content can affect a product's internal structures (Figueroa, Moraes, & Maestri, 2015), as in the surface becomes rougher, getting more turgid, less crisp, and stiff (Hawaree, Chiewchan, & Devahastin, 2009;Onwulata et al, 2013).…”

Avaliação de fragmentos de lenhos carbonizados de Araucariaceae por meio de análise por termogravimetria e infravermelho associado à análise multivariada

“…43 Além de que o lenho, por ser um polímero natural, quando submetido ao fogo, sofre despolimerização e carbonização, alterando suas propriedades mecânicas conforme o nível de temperatura e tempo de exposição ao calor ao qual foi submetida. 44 Ainda, alguns autores citam que as variações de massa entre as espécies e dentre a mesma espécie podem ocorrer em função da diferença de idade entre os indivíduos, 45,46 fato este observado no detalhe apresentado na Figura 1.…”