STUDY ON PERMEABILITY OF CUNNINGHAMIA LANCEOLATA BASED ON STEAM TREATMENT AND FREEZE TREATMENT

Abstract

In order to improve the permeability of Cunninghamia lanceolata,the weight gain rate of C. lanceolatawas taken as index. The effect of time, temperature and water content on the weight gain rate of impregnated wood was analyzed by frozen and steaming treatment. By comparing the weight gain rate under different modification methods, the optimal modification process was determined.The results indicate that the optimum parameters of C. lanceolatawere saturated water content (-25°C and 8 h) at this time, the three-day gain rate of silica sol impregnated at normal temperature and pressure was 15.058%. AfterC. lanceolatais pre-treated by superheated steam, the weight gain rate of C. lanceolata, which in oven-dried specimen (120°C and 3h) contents was the highest, at this time, the three-day gain rate of silica sol impregnated at normal temperature and pressure was 15.291%.By comparing the results of pre-freezing withthe results of superheated steam treatmentof C. lanceolata,the latter will increase thepermeability of C. lanceolatabetter. Thereforesuperheated steam treatment should be chosen as an effective method for the pretreatment.