Carbon fiber cement paste piezoresistive sensors and their properties

Preparation method,measuring method and design method of data acquisition system of carbon fiber cement paste piezoresistive sensors(CFCPS)were studied,and properties of a kind of standardized CFCPS were measured.The results show that CFCPS with steady performance can be made by adjusting water cement ratio and fractions of water reducing agent and dispersing agent,using mixed addition of carbon fiber and black car- bon and adopting suitable mix technology.Embedded net electrode is suitable for CFCPS and measuring method of resistance should use the four-electrode measuring method.The designed data acquisition system based on voltage signal has many advantages such as simple circuit,high precision of data and good practicability,and can realize real-time,on-line and multichannel acquisition.The relationship between input and output of the standardized CFCPS isΔ_ρ=-0.912σ(orΔ_ρ=-0.016e),their input range is 0～10MPa(or 0～578μe),output range is 0～8%,sensitivity is 0.912%/MPa(or-0.016%/μe),linearity is about 13%,repeatability is about 4. 49%,hysteresis is about 5.28%,zero-output is about 2.52% and time zero-drift is about 8.46%.