不同饱和度下混凝土轴心与立方体抗压换算系数试验研究

Experimental study on conversion coefficient between concrete axial and cubic compressive strength with different saturation

湿度对混凝土抗压强度存在显著影响,混凝土轴心抗压与立方体抗压转换系数亦受湿度影响。研究不同饱和度下混凝土轴心抗压与立方体抗压强度转换关系,为细化混凝土结构设计规程中二者转换系数提供基础。完全干燥状态的C15、C20、C30混凝土在水中浸泡3、10、24、72、240 h的不同时间,形成6种不同饱和度状态的混凝土,分别测定其抗压强度与轴心抗压强度。研究表明:轴心抗压与立方体抗压强度均随饱和度的增大,呈降低趋势;当饱和度条件相同时,强度等级越低,两种抗压强度的降幅越大,即低强度等级混凝土抗压强度对饱和度具有更强的敏感性。混凝土的换算系数随饱和度的增大而线性增加。当饱和度条件相同时,混凝土强度等级越高,轴心抗压与立方体抗压换算系数越大。

Humidity has a significant influence on concrete compressive strength,and the conversion coefficient between concrete axial compressive strength and cubic compressive strength is also affected by humidity.The conversion relationship between the axial compression of concrete and the compressive strength of cube at different saturations was studied to provide a basis for the conversion coefficient of the two in the design specification of refined concrete structure.The completely dry C15,C20,and C30 concretes were immersed in water at different times of 3,10,24,72,and 240 h to form 6 different saturation state concretes,and their compressive strength and axial compressive strength were measured respectively.The research shows that the axial compressive strength and the cubic compressive strength both decreased with increasing saturation.When the saturation conditions were the same,the lower the strength level,the greater the decrease in the two compressive strengths,that is,the concrete compressive strength of low strength grade was more sensitive to saturation.The conversion coefficient of concrete increased linearly with increasing saturation.When the saturation conditions were the same,the higher the concrete strength level,the greater the conversion coefficient between the axial compression and the cubic compression.