This paper presents a finite-element model of pullout test specimens using a nonlinear spring element. The model simulates the bond-slip behavior between three-dimensional crescent ribbed bars and concrete. A total of 180 spring elements were created between the ribbed bar and concrete. This model simulates the gradational deformation from the loading end to the free end of the ribbed bar as closely as possible to the real situation. The displacements and stresses of the ribbed bars obtained were compared to experimental results. Good agreement was achieved from the comparison of the numerical and experimental results. The results indicate the feasibility of simulating the bond-slip behavior between three-dimensional ribbed bars and concrete by using a nonlinear spring.

For designing conductive polymer composites (CPCs), understanding how the fiber curvature affects the percolation behavior of curved conductive fibers is essential for determining the effective electrical conductivity σ_eff of the CPCs.

The anticorrosion properties of polymer emulsion modified cement-based coating with healing effect on carbon steel were investigated. The change of linear polarization resistance (Rp) and electrochemical impedance spectroscopy (EIS) have been used to measure the inhibitive and curative effect of electrodes painted with the coating in 3.5% NaCl solution. The results indicated the high alkalinity of filler (cement) in coating can obviously improve the anticorrosion performance of coated steel electrodes. And the inhibitive ability of cement-based coating with fluoride acrylic emulsion is superior to that of the coating with epoxy emulsion. Moreover, by adding antirust pigments and rust converters in the fluoride acrylic emulsion modified cement-based coating, the inhibitive property was improved and the curative effect can be observed.

Four kinds of alcohol amines were tested to improve the anticorrosion performance of the phosphoric and tannic acid (PTA)-based rust converter. The alcohol amine modified PTA rust converters with the optimum mechanical and functional performances were used to prepare the homogeneous single-component waterborne rust conversion-based paint. The mechanical properties and the long-term corrosion resistance of the synthesized rust converter-based paint were investigated. The results show that alcohol amine modified PTA rust converter can convert the rust layer into a thick passivation film with iron tannate and iron phosphate as the main components, significantly improving the corrosion resistance of the carbon steel. The alcohol amine D modified PTA rust converter (RC-D) showed the best anticorrosion and rust conversion performances. The waterborne rust conversion-based paint can convert the rust layer of steel into a blue-black and relatively flat passivation film layer. The waterborne polymer-based paint containing 10 wt.% RC-D significantly improves the long-term corrosion resistance of the rusty steel and the mechanical property of paint.