摘要
以不同质量分数风积砂代替河砂配制风积砂混凝土,研究其基本力学性能和影响机理.用核磁共振(NMR)技术、CT切片法和扫描电子显微镜(SEM)分析混凝土内部孔隙演变特征、受荷面的初始损伤、界面过度区(ITZ)结构形态及水化产物微观形貌.基于美国ACI经验模型,构建了考虑砂子细度模数或者比表面积变化的抗压强度预测模型.结果表明:当风积砂掺量为20%时,混凝土力学性能最优;适量风积砂改善混凝土抗压强度的机理在于其优化了颗粒级配,改善了混凝土内部孔径分布范围及ITZ结构,减小了受荷面的初始损伤;建立的抗压强度预测模型与试验结果吻合度较高.
River sand was replaced by aeolian sand partly in concrete to study the influence mechanism of aeolian sand on the strength of concrete.The internal pore structure of aeolian sand concrete was tested by nuclear magnetic resonance(NMR),the initial damage of bearing surface was detected by the slicing of CT and the structural form of interface transition zone(ITZ)and the hydration product microstructure were characterized by scanning electron microscopy(SEM).A concrete strength prediction model considering the fineness modulus or specific surface area of sand changing was built based on the American ACI model.The results show that the concrete has the highest strength with an aeolian sand content of 20%.The influence mechanism why a proper amount of aeolian sand increases the strength of concrete is that it optimizes the particle gradation of aggregate,improves the internal pore size distribution and the ITZ structure of concrete,as well as reduces the initial damage of the bearing surface.The theoretical prediction model agrees well with the experimental results.
作者
李玉根
张慧梅
刘光秀
胡大伟
马向荣
LI Yugen;ZHANG Huimei;LIU Guangxiu;HU Dawei;MA Xiangrong(College of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710054, China;School of Architecture Engineering, Yulin University, Yulin 719000, China;School of Chemistry and Chemical Engineering, Yulin University, Yulin 719000, China)
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2020年第5期1212-1221,共10页
Journal of Building Materials
基金
国家自然科学基金资助项目(51868075)
陕西省科技资源开放共享平台项目(2019PT-18)。
关键词
风积砂混凝土
强度预测模型
力学性能
影响机理
aeolian sand concrete
strength prediction model
mechanical property
influence mechanism
