摘要
为了研究机械荷载对高性能混凝土耐久性的影响,对经受轴拉静载和循环荷载作用后混凝土的孔隙率进行了测试。结果表明:(1)短期静拉荷载和有限次循环荷载作用均对混凝土产生永久性的损伤。最大荷载水平越高、循环次数越多,微裂缝连通和扩展越明显,总孔隙率越大。(2)荷载水平越高,作用次数越多,微裂缝的连通和开展越明显,混凝土的总孔隙率也越高。特别是随荷载循环次数的增加,混凝土孔隙率变化表现出明显的阶段性特征,对应疲劳应变发展的第2阶段,总孔隙率与加载次数呈线性关系。(3)经受动、静荷载损伤的试块在饱和Ca(OH)2中再养护一定时间后,损伤度有明显的降低,反映出较好的自愈合效果。再养护时间越长,荷载水平越高,损伤自愈合效果越明显。(4)由于经受循环荷载的试块内部损伤裂缝更为均匀、细小,其自愈合的效果比经受静载的试块更明显。
In order to study the effect of mechanical load on the durability of high performance concrete, the total porosity of concrete under uniaxial tensile static load and cyclic load was measured. The results show that （1） Short-term static and finite-time cyclic axial tensile load both caused permanent damage to concrete. The higher the applied maximum load level or the more the cycle number, the more obvious the connection and development of micro cracks, and the higher the total porosity. （2） Especially, with the increase of cyclic load number, the total porosity of concrete showed obvious stage characteristics. There is a linear relationship between total porosity and cyclic loading times in the second developing stage of fatigue strain. （3） After cured in saturated aqueous Ca （OH）2 solution for a certain period, self-healing took place efficiently in specimens damaged by static and cyclic loading from the obvious decreasing of damage index D. The longer the curing period and the higher the load level, the better the effect of self-healing. （4） for there are more smaller micro cracks evenly dispersed in concrete damaged by cyclic load, its self-healing effect is better than that of specimen damaged by static load.
出处
《公路交通科技》
CAS
CSCD
北大核心
2012年第1期64-69,共6页
Journal of Highway and Transportation Research and Development
基金
国家重点基础研究发展计划(九七三计划)项目(2009CB623203)
国家自然科学基金重点课题(50739001)
山东省自然科学基金项目(2009ZRB019HD)
关键词
桥梁工程
轴拉荷载
孔隙率
高性能混凝土
微观损伤
自愈合
bridge engineering
load
porosity
high performance concrete
microscopic damage
self healing
