This study investigates the physical–mechanical behaviour of three tropical wood species Monopetalanthus heitzii (Andoung), Dacryodes buettneri (Ozigo), and Pterocarpus soyauxii (Padouk) commonly used for constructing footbridges, houses and exposed to weather conditions. The principal aim is to optimise their durability in structures by controlling, for example, their dimensional stability during changes in humidity. To rich this goal, species were prepared and analysed along with their transversal and longitudinal directions. Scanning electron microscopy revealed the internal cell arrangement of each species based on radial–tangential (R, T) and tangential–longitudinal (T, L) axis planes. Differential scanning calorimetry tests were conducted to assess thermal stability and degradation. Physical tests, focussing on swelling–shrinkage, were performed in a controlled chamber with constant temperature (T) and pressure (P). Parameters analysed included dimensions of the transversal plane (R, T) × (b, h) and the weight of each specimen. Additionally, compressive static tests were conducted to evaluate the mechanical behaviour of the specimens. The results indicate a correlation between intrinsic microscopic structures and macroscopic physico-mechanical behaviour. Furthermore, variations in water content were found to significantly impact the geometrical parameters of the specimens, particularly notable effects of drying and moistening on dimensional variations before the fibre saturation point (FSP).
GuggemosAAHorvathA. Comparison of environmental effects of steel- and concrete-framed buildings. J Infrast Syst2005; 11: 93–101.
2.
GerillaGPTeknomoKHokaoK. An environmental assessment of wood and steel reinforced concrete housing construction. Build Environ2007; 42: 2778–2784.
3.
AnejoJA. Impact of concrete, steel and timber on the environment: a review. Int J Technol Enhan Emerg Eng Res2014; 2: 58–63.
4.
Nkene MezuiEPambou NzienguiCFMoutou PittiR, et al.Strain and cracks investigations on tropical green wood slices under natural drying: experimental and numerical approaches. Eur J Wood Wood Prod2023; 81: 187–207.
5.
Pambou NzienguiCFMoutou PittiRFournelyE, et al.Notched, beam creep of douglas fir and white fir in outdoor conditions: experimental study. Constr Build Mater2019; 196: 659–671.
6.
NiyigenaCAmzianeSChateauneufA, et al.Variability of the mechanical properties of hemp concrete. Mater Today Commun2016; 7: 122–133.
7.
YadavMAgarwalM. Biobased building materials for sustainable future: an overview. Mater Today Proc2021; 43: 2895–2902.
8.
Pambou NzienguiCFIkogouSMoutou PittiR. Impact of cyclic compressive loading and moisture content on the mechanical behavior of Aucoumea Klaineana Pierre. Wood Mater Sci Eng2018; 13: 190–196.
9.
Manfoumbi BoussougouNPambou NzienguiCFMotou PittiR. Creep behaviour of timber structures in variable tropical climates: application to Dacryodes buettneri and baillonella toxisperma species. Constr Build Mater2022; 344: 128284–128284.
10.
OdoungaBRostandMPToussaintE, et al.Mixed mode fracture of some tropical species with the grid method. Eng Fract Mech2019; 214: 578–589.
11.
Ndong BidzoCHPambou NzienguiCFIkogouS, et al.Mechanical properties of glued-laminated timber made up of mixed tropical wood species. Wood Mater Sci Eng2022; 17: 809–822.
12.
LissouckROPommierRTaillandierF, et al.A decision support tool approach based on the electre TRI-B method for the valorisation of tropical timbers from the Congo basin: an application for glulam products. Southern Forests2018; 80: 361–371.
13.
Atangana AB, Lissouck RO, Ohandja LMA. Assessing the supply and demand of social housing in developing countries: the case of Cameroon. Int J Emerg Technol Adv Eng 10: 106–128.
14.
BobdaFDamfeuJCMvondoRRN, et al.Thermal properties measurement of two tropical wood species as a function of their water content using the parallel hot wire method. Constr Build Mater2022; 320: 125974.
15.
EllisJLBallA. Comparison of two wood filler types with respect to relative shrinkage across variations in temperature, in humidity and within wood species. Int Wood Products J2011; 2: 115–119.
16.
SegoviaFBlanchetPLaghdirA, et al.Mechanical behaviour of sugar maple in cantilever bending under constant and variable relative humidity conditions.Int Wood Products J2013; 4: 225–231.
17.
ZhaoJFengSKouZ, et al.Characterization of hygrothermal properties of two wood species-the impact of anisotropy on their thermal and moisture behaviors. Constr Build Mater2023; 398: 132375.
18.
KanaSKBiwoléABMejouyo HuiskenPW, et al.Physical and mechanical properties of two tropical wood (Detarium macrocarpumandPiptadeniastrum africanum)and their potential as substitutes to traditionally used wood in Cameroon. Int Wood Products J2024; 15: 5–19.
19.
HamdiSEMoutou PittiRDuboisF. Temperature variation effect on crack growth in orthotropic medium: finite element formulation for the viscoelastic behavior in thermal cracked wood-based materials. Int J Solids Struct2017; 115–116: 1–13.
20.
Asseko EllaMGoliGIkogouS, et al.Impact of mechano-sorptive loading on crack propagation of notched beams of White fir and Okume. Proc Struct Integr2022; 37: 477–484.
21.
Nouemsi SoubguiETene FongangRTKamseuE, et al.Microstructure and physico-chemical transformation of some common woods from Cameroon during drying. J Therm Anal Calorim2021; 145: 3003–3018.
22.
NyobeCJNyobeNSNkibeuJB, et al.Effect of slope of grain on mechanical properties of some tropical wood species. Wood Mater Sci Eng2024; 20: 1–7.
GÉRARDJ. Descriptif technique du bois d’essence tropicale–ozigo–Dacryodes buettneri HJ lam (syn. Pachylobus buettneri). Bois Forets Des Tropiques2023; 355: 101–106.
27.
TsujiyamaSIMiyamoriA. Assignment of DSC thermograms of wood and its components. Thermochim Acta2000; 351: 177–181.
28.
ShapchenkovaOLoskutovSAniskinaA, et al.Thermal characterization of wood of nine European tree species: thermogravimetry and differential scanning calorimetry in an air atmosphere. Eur J Wood Wood Products2022; 80: 409–417.
29.
CEN, EN 1995–1–1: Eurocode 5, Association Francaise de Normalisation. Design of timber structures – Part 1–1: General common rules for buildings”. Brussel, Belgium: ComitéEuropeen de Normalisation, 2004.
30.
NyobeCJLissouckROAyina OhandjaLM, et al.Variability of the mechanical strength of Congo Basin timbers. Wood Mater Sci Eng2022; 17: 210–220.
31.
BardetSBeauchêneJThibautB. Influence of basic density and temperature on mechanical properties perpendicular to grain of ten wood tropical species. Ann For Sci2003; 60: 49–59.
32.
MiyoshiYKojiroKFurutaY. Effects of density and anatomical feature on mechanical properties of various wood species in lateral tension. J Wood Sci2018; 64: 509–514.
33.
BigorgneLBrunetMMaigreH, et al.Investigation of softwood fracture criteria at the mesoscopic scale. Int J Fract2011; 172: 65–76.
34.
HuXYLiuZLZhuangZ. XFEM study of crack propagation in logs after growth stress relaxation and drying stress accumulation. Wood Sci Technol2017; 51: 1447–1468.
35.
MedzegueMJGrelierSBertrandM, et al.Radial growth and characterization of juvenile and adult wood in plantation grown okoumé (Aucoumea klaineana Pierre) from Gabon. Ann For Sci2007; 64: 815–824.
36.
Zue OndoJLRuelleJDlouháJ, et al.Caractérisation et variabilité des propriétés physiques et structurelles du bois du kevazingo, guibourtiatessmannii, et de l’okoumé, Aucoumea klaineana, provenant des forêts naturelles du Gabon. Bois Forets Des Tropiques2021; 347: 43–59.
37.
Zink-SharpA. The mechanical properties of wood. In: Wood quality and its biological basis. Boca Raton, FL: Blackwell Publishing-CRC Press. Biological Sciences Series, pp.187–210. 2003.
38.
TeodorescuIȚăpușiDErbașuR, et al.Influence of the climatic changes on wood structures behaviour. Energy Procedia2017; 112: 450–459.
39.
CaiCHeräjärviHHaapalaA. Effects of environmental conditions on physical and mechanical properties of thermally modified wood. Can J For Res2019; 49: 1434–1440.
40.
McCombWCNobleRE. Microclimates of nest boxes and natural cavities in bottomland hardwoods. J Wildl Manage1981; 45: 284–289.
41.
PereiraSAnandSCRajendranS, et al.A study of the structure and properties of novel fabrics for knee braces. J Ind Text2007; 36: 279–300.
42.
BrodaMCurlingSFSpearMJ, et al.Effect of methyltrimethoxysilane impregnation on the cell wall porosity and water vapour sorption of archaeological waterlogged oak. Wood Sci Technol2019; 53: 703–726.
43.
MaryandyshevPChernovALyubovV, et al.Investigation of thermal degradation of different wood-based biofuels of the northwest region of the Russian Federation. J Therm Anal Calorim2015; 122: 963–973.
