卤水腐蚀对改性磷酸镁混凝土轴心受压性能的影响

Effect of brine corrosion on axial compressive properties of modified magnesium phosphate concrete

为考察卤水腐蚀对改性磷酸镁混凝土(单掺聚丙烯纤维、单掺二氧化硅、双掺聚丙烯纤维+二氧化硅)轴心受压性能的影响,通过模拟青海盐湖地区卤水腐蚀环境,对45块改性磷酸镁混凝土试样进行不同次数的卤水腐蚀,并对其进行单轴轴心受压试验.结果表明,改性磷酸镁混凝土的破坏形态主要是承压式破坏;轴心受压应力-应变曲线由上升段和下降段组成,整个完整过程由弹性阶段、强化阶段、弱化阶段和残余阶段组成;在卤水腐蚀环境下,随着腐蚀次数的增加,改性磷酸镁混凝土发生了显著的退化,退化顺序为双掺聚丙烯纤维+二氧化硅<单掺二氧化硅<单掺聚丙烯纤维<无添加.提出改性磷酸镁混凝土在卤水腐蚀环境下的单轴轴心受压性能及曲线,建立本构关系模型.模型曲线与试验值吻合良好,可为实际工程提供依据.

In order to investigate the effect of bittern corrosion on the axial compressive properties of modified magnesium phosphate concrete,including polypropylene fiber,silicon dioxide fiber,polypropylene fiber and silicon dioxide fiber,the corrosion environment of bittern in salt lake region of Qinghai Province was simulated,45 samples of modified magnesium phosphate concrete were corroded in brine in different times and subjected to an axial compression test.The experimental results showed that the failure mode of the modified magnesium phosphate concrete was the mainly confined failure,and the stress-strain curve under the axial compression was composed of two parts,the rising part and the falling part;the whole process was composed of the elastic stage,strengthening stage,weakening stage and residual stage.Under the environment of bittern corrosion,the modified magnesium phosphate concrete degenerated significantly with the increase of the corrosion times;the degradation order from high to low was:double-doped polypropylene fiber and silicon dioxide,single-doped silicon dioxide,single-doped polypropylene fiber and addition free.The axial compressive properties and curves of modified magnesium phosphate concrete under the bittern corrosion environment were presented,and the constitutive relation-ship model established.