Yingang Du

Bio: Yingang Du is an academic researcher from Anglia Ruskin University. The author has contributed to research in topics: Corrosion & Beam (structure). The author has an hindex of 13, co-authored 23 publications receiving 1284 citations. Previous affiliations of Yingang Du include University of Birmingham & Glasgow Caledonian University.

Residual capacity of corroded reinforcing bars

Abstract: This paper presents an experimental investigation into the residual capacity of corroded reinforcing bars. By performing both accelerated and simulated corrosion tests on bare bars and on bars embedded in concrete, the mechanism of the reduction of the capacity of corroded reinforcement was investigated. The influence of type and diameter of reinforcement on its residual capacity is discussed. The experimental results show that, due to local attack penetration, the residual cross-section of a corroded bar is no longer round and varies considerably along its circumference and its length. Although the force–extension curves of corroded bars are similar to those of non-corroded bars for up to 16% corrosion, their residual yield and ultimate forces decrease more rapidly than their average cross-sectional area and, therefore, their residual strength decreases significantly. Even though the residual capacity of corroded small diameter and/or plain bars reduces more than that of large diameter or ribbed ones, di...

Mechanical Properties of Corrosion-Damaged Reinforcement

Abstract: Corrosion of embedded reinforcement is the most prevalent form of degradation of reinforced concrete structures, and may impair structural capacity through loss of bar section, loss of bond between reinforcement and concrete as a result of longitudinal cracking, or loss of concrete cross section. The effect of corrosion attack on mechanical properties of reinforcement is investigated through physical tests on bars with simulated and real corrosion damage and through a simple numerical model. Bars subjected to local or pitting attack may suffer a relatively modest loss of strength but a significant loss of ductility, and this is related principally to the variability of attack along the length of the bar. The numerical model supplements experimental work through a parametric study on the influence of steel characteristics. Finally, guidelines on assessment are suggested that are derived from results reported in the paper and from elsewhere in the published literature.

Effect of corrosion on ductility of reinforcing bars

Abstract: An experimental investigation into the effect of corrosion on the ductility of steel reinforcement is reported. Both accelerated and simulated corrosion tests were conducted on bare bars and on bars embedded in concrete. The mechanism and degree of the reduction of ductility of reinforcement due to corrosion were examined. The influence of bar type and diameter on ductility of corroded reinforcement is discussed. The experimental results indicate that, since local attack penetration results in a significant variation of residual cross-section along its length, corrosion significantly reduces ductility of reinforcement. Although the strength ratio, elastic modulus and hardening strain only vary with bar type rather than corrosion level, the elongation, ultimate strain and ductile area of corroded reinforcement reduce much more significantly than do those of their yield and ultimate strengths. There is concern regarding bar ductility since about 10% corrosion may possibly decrease the ultimate strain of reinforcement below the minimum requirement specified in CEB Model Code 90 for class S reinforcement. Even though the elongation, ultimate strength and ductile area parameter of corroded small diameter and/or plain bars reduce more than those of large diameter and/or ribbed ones, such differences are not significant and can be neglected. Finally, a set of simple empirical equations is proposed to assess the ductility of corroded reinforcement in practice.

Impact of Reinforcement Corrosion on Ductile Behavior of Reinforced Concrete Beams

Abstract: This paper reports an experimental study of concrete beams with corroded reinforcement to investigate their failure modes and ductility behavior. Before the beams were simply supported and monotonically loaded to failure, they were subjected to a process of electrochemically accelerated corrosion. The experimental results show that, in addition to reducing beam flexural strength, corrosion alters its failure modes and affects its ductile behavior substantially. When the response of a beam is dominated by cracking of its compression concrete and/or the reduction of its tension bar area, corrosion improves beam ductility. When the behavior of a beam is controlled by deterioration of its bond strength and/or the reduction of its steel ductility, however, corrosion decreases beam ductility. This raises a concern regarding the ductility of commonly used under-reinforced beams if the amount of corrosion exceeds approximately 10% because the beam could fail suddenly by the rupture of its corroded tension reinforcement due to the ultimate strain of the latter being reduced considerably.

Corrosion of steel by concrete

Abstract: The author details the reactions of various concretes on steel reinforcement. Although portland cements, slag cements and high alumina cements are all hydraulic binders, each possess special properties which are examined. The discussion of causes and methods of preventing the corrosion of steel reinforcement covers such aspects as galvanised steel reinforcement, effects of concrete composition, corrosion of steel reinforcments in concrete and prestressed reinforcement. It is concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride; the presence of nitrates; the composition of the concrete; the degree of carbonation of the concrete; concrete compaction and, chlorides and sulphates should be used as far as possible when steel is embedded. (TRRL)

A critical review on research progress of graphene/cement based composites

Abstract: Cement based composite materials (CBCM) with superior mechanical strength and excellent durability are always desirable in practical applications. Although considerable research has been reported in the past decades about the use of Nano materials (NMs) for strength and durability enhancement of cement matrix, there is little information available on the use of graphene nano-sheets and their derivatives (GND) in cement-based materials. Particularly the role of GND in hydration processes and their mechanisms of strengthening in cement matrix are unclear. In this paper, a critical review on recent research findings about GND modified cement-based materials was conducted. The review mainly discussed the influence of GND on properties of cement matrix including microstructure, hydration, mechanical properties, etc. The information revealed in this paper would not only provide a comprehensive understanding of the effect of GND on cement composites, but also provide valuable ideas and guidance for similar studies in the future.