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通过减水剂将少量石墨加入水泥基材料中制成石墨水泥基材料试样,采用交流分压电路测量其电阻率,研究其在一次性加载破坏试验中的压敏特性.试验结果表明,低掺量石墨粉作为导电组份加入水泥基材料后会导致其强度降低,但可以使水泥基材料具有一定程度的压敏特性.随着石墨掺量的增加,各组试样电阻率的离散性变小,材料的压敏特性提高,在加载过程电阻率的波动变小.在本试验的测量方法下得到的石墨水泥基材料的压敏特性曲线与混凝土材料的应力应变曲线有相关性,试样的电阻率随着应力的增大而产生变化的过程大体可分为3个阶段,即波动阶段、稳定下降阶段和急剧下降阶段,分别对应混凝土材料应力应变关系的弹性变化、非弹性变化和应变迅速增大阶段.
A small amount of graphite was added to the cement-based material through a water-reducing agent to make a graphite cement-based material sample, and the resistivity of the graphite-based material was measured by an AC voltage divider circuit to study its pressure-sensitive property in a one-time loading failure test. The addition of graphite powder as a conductive component to cement-based materials will lead to the decrease of strength, but cement-based materials may have some degree of pressure-sensitive properties.With the increase of graphite content, the discreteness of resistivity Smaller, the pressure-sensitive properties of the material increased, the volatility of the resistivity during the loading process becomes smaller.The pressure-sensitive properties of the graphitic cement-based materials obtained under the measurement method of the present test are correlated with the stress-strain curves of the concrete materials. The change of resistivity with the increase of stress can be roughly divided into three stages: the fluctuation stage, the steady decline stage and the sharp decline stage, respectively corresponding to the elastic and inelastic changes of the stress-strain relationship of concrete Strain rapidly increased phase.