利用冲击球压法评价混凝土表面的硬化特征

Evaluation of Harding Characteristic of Concrete Surface by Sphere Impact at Harding Stage

为了研究硬化阶段混凝土表面性能受环境影响而变化的特性,利用冲击球压技术研究了非常规养护制度下(室外、水中及5%Na2SO4溶液)混凝土的冲击荷载与压痕尺寸的关系、动态硬度及恢复系数,对混凝土材料的冲击压痕形貌进行了分析。结果表明:(1)水中养护的混凝土动态硬度和恢复系数较大,随着养护时间的延续增长最快;自然环境中放置的混凝土动态硬度和恢复系数最小,硬化初期这两项性能有一定的增长,但是在硬化中后期发生下降;(2)5%Na2SO4溶液中养护的混凝土硬化初期动态硬度和恢复系数较大,随养护时间的延续动态硬度缓慢增长,而恢复系数明显下降;整个试验证明,利用冲击球压技术评价混凝土的硬化程度是可行的。

Some physical characteristics of concrete at the harding stage, such as the relation between impact load and size of indentation, dynamic hardness, coefficient of restitution and indentation morphology, were investigated by sphere impact. This method aimed to explore the surface characteristic of concrete, which was exposed to different environment such as outdoor, in water and in Na2SO4 solution. The results can be listed as follows ： （ 1 ） The dynamic hardness and coefficient of restitution of concrete in water were highest than other curing systems in value and growth rate. However, this law was opposited to the concrete outdoor. （2）The value and growth ratio of dynamic hardness and coefficient of restitution of concrete in Na2 SO4 solution were presented complicated along with the curing time. Finally, the sensitiveness and convenience of sphere impact method applied to the harding degree of concrete was validated.