The effect of natural aging on the combustion and mechanical properties of ancient architectural Pinus massoniana
The Pinus massoniana inside and outside the Qing Dy-nasty wooden building from approximately 170 years ago was taken as the research object to systematically analyzes the effects and regulations of natural aging on the microstructure,combus-tion behavior and mechanical properties of the Pinus massoniana.The results show that natural aging can significantly damage the cellular structure of the pine,where indoor pine is susceptible to significant surface wormholes due to insect infestation and fungal parasitism during service,while outdoor pine is susceptible to more significant degradation of internal organic constituents due to UV light.Compared to the degradation of internal organic com-ponents,the surface wormholes can deteriorate the mechanical properties of the pine to a greater extent.The tensile and bending strengths of outdoor Qing Dynasty pine are lower than those of modern pine by 34.1%and 34.7%,respectively,while those of indoor Qing Dynasty pine are reduced by 48.2%and 31.6%,re-spectively.Combustion performance analysis reveals that the natu-ral aging effect weakens the combustion strength and thermal sta-bility of the wood,with the peak heat release rate(PHRR)being reduced by 8.4%and 15.4%,and the initial decomposition tem-perature(T5%)being reduced by 19.2 and 10.1℃,for the indoor Qing Dynasty pine and outdoor Qing Dynasty pine,respectively,compared to the modern pine.In addition,compared with outdoor Qing Dynasty pine,the indoor Qing Dynasty pine has lower T5%and higher CO2 and CO production rate,which is mainly related to the greater destruction of cellular structure of indoor Qing Dy-nasty pine,thereby indicating that the indoor Qing Dynasty pine has lower thermal stability and stronger fire smoke toxicity.
NETL
NSTL
万方数据
维普
