模型尺寸和骨料级配对混凝土细观非均质影响
Influence of Model Sizes and Aggregates Gradation on Microstructure Heterogeneity of Concrete
杜敏 1金浏 2李冬 2卫爱霞3
作者信息
- 1. 防灾科技学院,河北三河065201;北京工业大学城市与工程安全减灾教育部重点实验室,北京100124
- 2. 北京工业大学城市与工程安全减灾教育部重点实验室,北京100124
- 3. 防灾科技学院,河北三河065201
- 折叠
摘要
针对现有细观力学模型无法反映模型尺寸和骨料级配对混凝土材料细观非均质影响的局限性,假定混凝土由骨料颗粒、砂浆基质及界面过渡区组成,基于Voigt并联模型对细观单元材料力学性能进行等效,建立反映混凝土细观非均质的等效模型.以Weibull分布为假设分布,探讨四种骨料级配边长150～750mm细观等效模型的网格单元尺寸,以单元弹性模量的非均质分布表征材料的细观非均质性,探讨混凝土材料细观非均质性与模型尺寸和骨料级配的相关关系,研究材料细观非均质对混凝土强度及破坏模式的影响机理.研究结果表明:相同骨料级配下,随着模型尺寸的增加,网格单元尺寸增大,混凝土材料非均质性减弱;相同模型尺寸下,随着骨料级配的增大,网格单元尺寸略有增加,混凝土材料的细观非均质性增强;材料细观非均质性增强时,混凝土强度略有降低,损伤破坏区域分布广泛.
Abstract
Current meso-mechanics models cannot reflect the influence of model sizes and aggregates gradation on microstructure heterogeneity of concrete appropriately,therefor the meso-element equivalent models were established,composed of aggregates,mortar matrix and interfacial transition zones.The mechanical properties of each element were processed equivalently based on the Voigt parallel model.The distribution type of element elastic modulus was supposed as the Weibull distribution,and the mesh scale of meso element for different aggregates gradation and model sizes was analyzed.The heterogeneous distribution of element elastic modulus was used to represent the microstructure heterogeneity of concrete.The influence of model sizes and aggregates gradation on microstructure heterogeneity of concrete was studied,and the effect of microstructure heterogeneity on the strength and fracture modes of concrete was analyzed.The analytical results indicated that the element-mesh scale increases with the increase of the model sizes and the raise of aggregates graduation.The microstructure heterogeneity of concrete weakens gradually with the increase of the model sizes;however strengthens with the raise of aggregates graduation.The strength of concrete decreases and fracture bands extend more extensively with the raise of microstructure heterogeneity.
关键词
混凝土/细观非均质/单元弹性模量/网格单元尺寸/模型尺寸/骨料级配Key words
concrete/microstructure heterogeneity/element elastic modulus/element-mesh scale/model size/aggregates graduation引用本文复制引用
基金项目
中国地震局教师科研基金(20120104)
国家自然科学基金(51408127)
出版年
2017
NETL
NSTL
维普
万方数据