冻融循环处理对重组竹抗压弹性模量与抗压强度的影响OA

Bamboo scrimber(BS),due to its excellent mechanical properties,has been increasingly utilized in the construction industry.However,as a structural material,the degradation mechanism of BS under cyclic freeze-thaw treatment is not yet clear.This study investigated the failure modes,elastic modulus,and compressive strength of BS specimens subjected to 0,20,40,and 60 freeze-thaw(F-T)cycles(each cycle comprising freezing at-20℃for 8 hours followed by thawing in water at 20℃for 8 hours)under three loading directions,i.e.,parallel-to-grain loading,perpendicular to grain I loading(perpendicular to the glue layer),and perpendicular to grain II loading(parallel to the glue layer).The results indicated that while F-T cycling did not change the failure modes type of the specimens,it significantly altered the proportions of different failure modes.Notably,the proportion of glue layer cracking increased remarkably with increasing F-T cycles from 0 to 60(from 30%to 64%).Both elastic modulus and compressive strength decreased with an increasing number of F-T cycles across all loading directions,with a decrease of 38.3%and 35.2%in the perpendicular to grain II direction,respectively.Finally,the design characteristic value(0.05 quantile)of the compressive strength of BS was determined based on the statistical analysis of experimental data,and an attenuation model(R2＞0.95)of compressive performance with varying numbers of freeze-thaw cycles was established to provide data support for the reliability design of BS structures in cold regions.