中南大学学报（自然科学版）2012，Vol.43Issue(7)：2534-2541,8.
不同约束条件下掺轻烧MgO混凝土的力学性能
Mechanical properties of concrete with light burnt MgO-based expansive additive under different restrained conditions
摘要
Abstract
Compressive strength, split tensile strength, ultimate tensile strain and axial tensile strength of concrete with 0%, 5%, 8% and 12% light burnt MgO-based expansive agent were tested. By means of scanning electron microscope and optical microscope, the microstnicture of concretes was examined. The results indicate that restraint may improve mechanical properties of concrete to some extent, and three-dimensionaliy restrained concrete shows best mechanical properties when concrete contains the same amount of MgO. Compressive strength of three-dimensionally restrained specimens with 5%, 8% and 12% MgO increases by 16.9%, 22.0% and 16.0% respectively at 360 d, and splitting tensile strength increases by 32.93%, 31.03% and 33.33% respectively at 180 d compared with unrestrained specimens. Ultimate tensile strain of three-dimensionally restrained specimens with 5% and 8% MgO increases by 9.5% and 3.1% respectively, and tensile strength increases by 5.7% and 6.9% respectively compared with unrestrained specimens. Under the free-curing condition, microstnicture of expansive cement paste and concrete is loose, with cracks in the paste and matrix-aggregate interface. Restraint could improve the microstnicture of expansive concrete with light burnt MgO, especially by densifying and intensifying the matrix-aggregate interface. As a result, the mechanical properties of concrete are improved.关键词
约束条件/MgO混凝土/力学性能/微观结构Key words
restrained conditions/concrete with MgO-based expansive additive/mechanical properties/microstnicture分类
建筑与水利引用本文复制引用
李延波,邓敏,莫立武,唐明述..不同约束条件下掺轻烧MgO混凝土的力学性能[J].中南大学学报（自然科学版）,2012,43(7):2534-2541,8.基金项目
国家重点基础研究发展计划(“973”计划)项目(2009CB623105) （“973”计划）
江苏省新型环保重点实验室开放基金资助项目(AE201046) （AE201046）
