Study on Bond Performance between Corroded Deformed Steel Bar and DS-ECC

Abstract

In order to study the bond performance between desert sands engineered cementitious composites (DS-ECC) and corrosion steel bars, seven groups of specimens were designed and manufactured. Through the center pull-out test, the effects of different types of desert sands, the rate of corrosion (0, 5, 10 and 15%), and the anchorage length of steel bars (5d and 8d) on the bonding properties of DS-ECC and corrosion steel bars were studied. Moreover, a de-rusting agent was used to remove the corrosion, and three groups of specimens were pulled out from the center of the de-rusted steel bars. The results showed that both Tengger DS-ECC and Mu Us DS-ECC have good bond properties with corrosion steel bars. The bond stress slip curves between DS-ECC and corrosion steel bars can be divided into four stages: the micro-slip, slip stage, failure stage and residual stage. The bond stress slip curves between DS-ECC and de-rusted steel bars can be divided into the micro-slip stage, failure stage and residual stage, and splitting and pulling-out failure occurs in DS-ECC specimens. The ultimate bond strength is the highest when the corrosion rate is 5%. The bond toughness index is positively correlated with the anchorage length of steel bars, and negatively correlated with the corrosion rate of steel bars. According to the test results, the bond–slip mathematical relationship is established.

Effect of Ambient Temperature on the Mechanical Properties of High Ductility Concrete

“…The low-temperature treatment of HDC causes water to freeze, which slows down the hydration rate of the cementitious material on the one hand and increases the porosity of large internal pores on the other hand, resulting in a loose structure of HDC material and a decrease in its cubic compressive strength, axial compressive strength, and elastic modulus [ 12 ]. Although free water evaporates from HDC during high-temperature treatment, high temperatures accelerate the hydration process of un-hydrated cement or fly ash [ 24 , 25 ], resulting in an increase in the strength and elastic modulus of HDC specimens.…”

Study on Lifetime Performance Evaluation of a Precast Prestressed Concrete Frame in Chloride Environments

“…At the corrosion failure stage, the probability of structural failure varies due to different requirements for structural performance levels. In this phase, a time-dependent probability model for the ultimate limit state of bearing capacity will be established based on Equation (7). IM represents the seismic motion parameters, EDP represents the structural engineering demand parameters, and C represents the structural seismic capacity parameters.…”

“…The results indicate a significant deterioration in the mechanical properties of steel with increasing degrees of corrosion. Numerous scholars have systematically investigated the influence of corrosion on the bond-slip behavior between the reinforcement and concrete, and have proposed corresponding degradation models based on characteristic parameters [4][5][6][7].…”