Research On Pressure-sensitivity Of Compound Material Of Carbon Black Filled Cement

Concrete is one of popular engineering structural materials. With the quickly development of economy and society, the security of critical civil systems has been getting more and more attention. In the field of civil engineering, the health monitoring and control technique of critical civil structure and infrastructure have been a significant problem.This dissertation was supported by the Key Project of National Science Foundation under grants No. 50238040. Nano-sized carbon black was selected and filled into traditional concrete to fabricate intrinsic dexterity material with intelligent properties. Both the electricity and pressure sensitive behaviors of the newly formulated composite are studied through experimental research. The following conclusions can be obtained:1,Cement-based composites filled with nano-sized carbon black was proposed, then the fabrication method and proportion of materials were studied and defined.2,The polarization effect with different adding amount of carbon black was disclosure. Found that the more distinctness phenomenon of the polarization effect with the more adding amount of carbon black. Confirm the vadose zone of the material.3,This paper mainly studied the pressure-sensitive effect. Analyse the influence of the pressure-sensitive effect between different adding amounts of carbon black. Found that the pressure-sensitive effect is better when the adding amounts near the vadose zone.4,The influence of the pressure-sensitive effect from different loading rate and under cyclic loading with various stress amplitudes were studied. Found that: (1) With the same strain, the sensitivity kept constant from different loading rate. (2) In the area of elastic strain, the sensitivity kept constant under cyclic loading with various stress amplitudes. (3) Based on tunneling effect theory, a mathematic model of the pressure-sensitive effect was proposed.