弯曲荷载作用下混凝土碳化和力学性能研究  

Research on carbonation and mechanical properties of concrete under bending load

作　　者：赵燕茹[1] 蔚文豪 王晓勇 王磊[1] ZHAO Yanru;YU Wenhao;WANG Xiaoyong;WANG Lei(School of Civil Engineering,Inner Mongolia University of Technology,Hohhot 010051,China)

机构地区：[1]内蒙古工业大学土木工程学院,内蒙古呼和浩特010051

出　　处：《混凝土》2023年第5期27-31,共5页Concrete

基　　金：国家自然科学基金(11762015,11362013)。

摘　　要：通过混凝土四点弯曲持荷碳化试验,研究了不同持荷水平对混凝土碳化深度的影响规律,建立了考虑持荷作用的混凝土碳化深度预测模型。同时分析了荷载与碳化共同作用下混凝土抗折强度的变化规律,并基于混凝土内部孔结构特征来探讨抗折强度变化的内在机理。试验结果表明:混凝土受拉区的碳化深度随持荷水平的增加而增加,受压区的碳化深度随持荷水平的增加而减小。在持荷水平相同时,碳化时间为7 d时,碳化深度的增长速率相对较快,之后碳化深度增长的速率逐渐变缓。荷载与碳化共同作用下,混凝土抗折强度随碳化时间的增长,首先会有一定程度的下降,然后又逐渐增加。持续荷载会使混凝土内部孔隙粗化,降低混凝土的抗折强度。碳化会使混凝土内部孔结构细化,从而提高混凝土的抗折强度。Based on the carbonation test of concrete under sustained four-point bending load,the influence of different load levels on the carbonation depth of concrete is studied,and the prediction model of carbonation depth considering the effect of load is established.Furtherly,the change rule of flexural strength of concrete under the combined action of load and carbonation is analyzed.The mechanism of flexural strength change is discussed based on the characteristics of internal pore structure of concrete.The test results show that the carbonation depth of concrete in tension zone increases with the increase of sustained load level,and the carbonation depth in compression zone decreases with the increase of sustained load level.When the sustained load level is the same,the growth rate of carbonation depth is relatively fast after 7 days of carbonization,and then the growth rate of carbonation depth slows down gradually.Under the combined action of load and carbonation,the flexural strength of concrete will first decrease to a certain extent,and then gradually increase with the increase of carbonation time.Sustained load will coarsen the internal pore structure of concrete and reduce the flexural strength of concrete.While carbonation can refine the internal pore structure and improve the flexural strength.

关 键 词：混凝土 持续荷载 碳化 抗折强度 孔结构 

分 类 号：TU528.01[建筑科学—建筑技术科学]