Effects of submicron-MgO and nano-MgO on the expansion and microscopic properties of high-performance concrete  

亚微米氧化镁和纳米氧化镁对高性能混凝土膨胀及微观性能的影响

作　　者：TIAN Chang-jin WANG You-zhi QIU Kai YANG Qi-lin 田长进;王有志;邱凯;杨琪琳(School of Civil Engineering,Shandong University,Jinan 250061,China;School of Transportation Science and Engineering,Harbin Institute of Technology,Harbin 150090,China)

机构地区：[1]School of Civil Engineering,Shandong University,Jinan 250061,China [2]School of Transportation Science and Engineering,Harbin Institute of Technology,Harbin 150090,China

出　　处：《Journal of Central South University》2022年第9期3186-3200,共15页中南大学学报（英文版）

基　　金：Project(51578325) supported by the National Natural Science Foundation of China。

摘　　要：MgO-series expansive agents can effectively compensate for the shrinkage and deformation of concrete structures.However,few experimental studies have been conducted on MgO expansive agents,particularly concerning the difference between and effects of submicron-MgO and nano-MgO in high-performance concrete(HPC)with a low water-cement ratio,thereby limiting their application in practical engineering.To clarify the expansion effect and expansion mechanism of MgO expansive agents in HPC,the effects of submicron-MgO and nano-MgO on the strength,toughness,and expansion characteristics of HPC were examined.The test results showed that submicron-MgO and nano-MgO continued to hydrate in the cement environment to produce Mg(OH)_(2),thus improving the structural compactness and structural strength of HPC.Nano-MgO concrete was found to have more stable mechanical properties and better structural deformability than submicron-MgO concrete.This study provides effective data support and theoretical reference concerning the hydration expansion mechanisms and engineering applications of nano-expanded materials.氧化镁系膨胀剂能有效补偿混凝土结构的收缩变形。然而,当前对氧化镁系膨胀剂的研究相对较少,尤其针对低水灰比高性能混凝土中亚微米和纳米氧化镁的不同作用机制的研究较少,限制了其在实际工程中的应用。为了揭示氧化镁系膨胀剂在高性能混凝土中的膨胀效应及膨胀机理,本文研究了亚微米氧化镁和纳米氧化镁对高性能混凝土强度、韧性和膨胀特性的影响规律和机理。结果表明,亚微米氧化镁和纳米氧化镁在水泥环境中不断水化生成氢氧化镁,提高了高性能混凝土的结构密实度和结构强度。纳米氧化镁混凝土比亚微米氧化镁混凝土具有更稳定的力学性能和更优异的结构变形性能。本研究为纳米膨胀材料的水化膨胀机理及工程应用提供了有效的数据支持和理论参考。

关 键 词：submicron-MgO nano-MgO high-performance concrete STRENGTH TOUGHNESS expansion characteristics microstructure 

分 类 号：TU528[建筑科学—建筑技术科学]