Strain-Detecting properties of hybrid PE and steel fibers reinforced cement composite (Hy-FRCC) with Multi-Walled carbon nanotube (MWCNT) under repeated compression

Abstract

This experimental research investigates the feasibility of using hybrid polyethylene (PE) and steel fibers reinforced cement composite (Hy-FRCC) with multi-walled carbon nanotube (MWCNT) as strain sensors. Smart construction material presented in the study is a new type of multifunctional cement composite with both structural material and self-sensing functionalities. The effect of MWCNT dosage (1 and 2% by weight of cement) and the magnitude of repeated compressive stress on the strain-detecting function and elastic modulus was studied. The history of applied compressive loading consists of five successive levels (30, 50, 60, 70 and 80% of compressive strength) of stress amplitude to evaluate the repeated strain-sensing ability of Hy-FRCC. Test results revealed that the incorporation of MWCNT within 2% has little effect on the compressive strength of Hy-FRCC at curing ages of 28-day while under repeated compression, MWCNT is effective to decrease the reduction of the elastic modulus in the Hy-FRCC. Piezoresistivity experiments indicated that the change in resistivity of Hy-FRCC-2 (with 2% MWCNT) specimen can simulate the changes in the measured strain during repeated compressive loading at increasing stress amplitudes up to 80% of compressive strength. It is found that the Hy-FRCC-2 mixture proposed in the present study is likely to be used as strain-sensors for structural health monitoring (SHM) of civil infrastructures.