冲击球压法研究混凝土表面的腐蚀损伤

EROSIVE DAMAGE CHARACTERISTICS OF CONCRETE SURFACE BY SPHERE IMPACT METHOD

pH=2.54,5mass%的硫酸铵溶液作为腐蚀介质,以干湿循环为条件,利用冲击球压法研究了混凝土冲击荷载-压痕尺寸、冲击应力-应变关系;对与冲击球压试验相关的其他物理量如抗压强度比、损伤区扩展、试件质量变化及溶液pH值变化等也进行了研究。研究发现冲击球压试验得到的混凝土冲击荷载-压痕尺寸关系曲线在低荷载范围呈双线性关系,且随着腐蚀作用的进行曲线斜率逐渐降低;冲击应力随着应变的增加而降低,且随着腐蚀作用的进行冲击应力-应变关系斜率整体降低。随着冲击荷载的增加,球头对混凝土表面造成的磨损、损伤以及局部变形程度远远高于荷载增加速率。在一定时间范围内,酸性硫酸铵溶液不会对混凝土的宏观力学性能产生较大的影响,但是发生的腐蚀反应却足以改变混凝土表面的性质。

Some characteristics of concrete （such as impact load-indentation relation, impact indentation stress-strain relation and abrasion）, eroded by ammonium sulfate solution with pH value of 2.54, were studied by means of sphere impact method. Other physical quantities, such as compressive strength, expansion of damage zone, change of mass and the variety of pH value for solution, were also investigated. The test results indicate that （1） the velocity of abrasion, damage and local deformation for sphere was quicker than that of load; （2） compressive strength of concrete soaked in ammonium sulfate with pH value of 2.54 did not decrease in a certain period of time, whereas the alkaline environment was destroyed by these erosive medium. The conclusion is that ammonium sulfate solution with H＋ did not destroy the macro-mechanical property but surface mechanical property was achieved.