Behaviour of reinforced concrete beams with multiwall carbon nanotubes under monotonic loading: Fid-Bau Portal

Behaviour of reinforced concrete beams with multiwall carbon nanotubes under monotonic loading

Qissab, Musab Aied / Abbas, Shaymaa Tareq

The main goal of this paper is to study the effect of multiwall carbon nanotubes (MWCNTs) on the behaviour of reinforced concrete beams under monotonic loading. In this study seven beams were loaded up to failure under the effect of two concentrated load using a hydraulic testing machine where the failure mode observed and the load–deflection relationships have been reported. Reference beam was reinforced with steel bars only. While the other six beams were reinforced with short and long MWCNTs at different concentrations (0.03, 0.045 and 0.06%) by weight of dry cement in addition to steel bars. The mechanical properties of concrete (compressive strength, splitting tensile strength, flexural strength and static modulus of elasticity) with MWCNTs were also studied. Ultrasonic pulse velocity test was used to evaluate the porosity of concrete nanocomposite. Dispersion of MWCNTs was achieved using Ultrasonic Liquid Processors with surfactant. Scanning electron microscopy images for micro-crack bridging was conducted to examine the bonding between MWCNTs and the cement paste. Test results showed that addition of very low concentrations of MWCNTs led to the reduction of porosity of concrete composite. Reinforcing concrete with MWCNTs led to an improvement in the load-carrying capacity and deflections of the composite beams, compared to the reference beam. The seven beams have also been analysed by the non-linear three-dimensional finite element analysis employing ANSYS package (14.5 release) to determine the load–deflection relations.