Engineering Commons^™

Micro-Mechanical Analysis Of Corrosion Products Formed During Long-Term Carbonation Induced Corrosion Of Steel, Marijana Serdar, Dubravka Bjegovic, Valérie L’Hostis, Stéphane Poyet, Damien Féron

International Conference on Durability of Concrete Structures

During corrosion distinct types of corrosion products form, composed of different ratios of ferrous ions and oxide, hydroxides. Corrosion products have different physical and mechanical properties, mainly density, resistivity, volume and modulus of elasticity compared to iron. Knowing properties of corrosion products is indispensable for service life modelling of structures and can give valuable insight into the long-term corrosion propagation process. In this study micro-indentation method was used to evaluate mechanical properties of different layers formed during long-term carbonation induced corrosion of steel in concrete. Investigation was performed on three sets of reinforced concrete samples, that underwent corrosion during 50, …

Fem Analysis Of Structural Behaviour Of Reinforced Concrete Beam Under The Effect Of Frost Damage, Zhao Wang, Tamon Ueda, Hiroshi Hayashida, Dawei Zhang

International Conference on Durability of Concrete Structures

Minimizing frost damage is one of the important durability issues for concrete structures in cold and wet areas. This paper performed a Finite Element Model (FEM) analysis on the structural behavior of reinforced concrete beam under the effect of frost damage. The frost damage was considered as degradations in two constituents: concrete material and bond between concrete and reinforcement. The constitutive models of deteriorated concrete material were proposed using a mesoscale simulation approach (Rigid Body Spring Model). DIANA FEA program was adopted for the structural analysis and experiments were also conducted for the verification. It was clarified that the structural …

Strength Of Reinforced Concrete Beams With High-Strength Steel, Brian C. Rogers, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

Structures are commonly made of reinforced concrete, which is a composite material made of concrete and steel reinforcement. Using high-strength steel, with yield stress larger than 100 ksi, could help reduce the quantity of steel required in structural members, thus reducing costs and improving constructability. The hypothesis being tested is that smaller quantities of high-strength steel reinforcement (HSSR) can be used in place of conventional steel in reinforced concrete beams while maintaining similar strength and deformation at failure. Two reinforced concrete beams with two different types of longitudinal steel reinforcement were constructed. The beams were 18 in. wide, 30 in. …

High Strength Steel In The Reinforced Concrete Structures: Serviceability, Alan Kanybek, Aishwarya Puranam, Santiago Pujol

The Summer Undergraduate Research Fellowship (SURF) Symposium

The use of high-strength steel (yield stress larger than 100 ksi) in reinforced concrete structures can provide an effective alternative to using conventional steel (yield stress up to 80 ksi). The goal of this study is to investigate if slabs with reduced quantities of high-strength steel reinforcement meet the serviceability criteria. Instantaneous and long-term deflections in slab specimens with conventional steel and reduced amounts of high-strength steel (as compared with conventional steel) were studied. Two sets of two reinforced concrete slabs, each 14 ft. long, 30 in. wide, were built. The depth, quantity, and type of longitudinal reinforcement were varied …

Response Of High-Strength Steel Reinforced Concrete Structures To Simulated Earthquakes, Lucas Laughery

Open Access Dissertations

In reinforced concrete (RC) structures expected to resist earthquake demands, substituting smaller amounts of high-strength steel for conventional steel reinforcement can help reduce reinforcement congestion and placement costs while keeping strength unchanged.

Provided cross-sectional dimensions remain unchanged, reducing the amount of longitudinal steel in a member will result in a member with similar initial stiffness but lower post-cracking stiffness. Nominal strength can be kept nearly the same if this reduction in the amount of steel is accompanied by a corresponding increase in the strength of the steel. The topic of this investigation is whether two frames with the same initial …

Investigation Of A Novel 3d Non-Destructive Evaluation For Corrosion Process In Reinforced Concrete, Guohao Fang, Biqin Dong, Ningxu Han, Feng Xing

International Conference on Durability of Concrete Structures

X-ray computed microtomography (X-ray μCT) method is proposed to trace the corrosion features of steel bar in cementitious materials. Three-dimensional corrosion morphology (including morphology of steel corrosion, corrosion products and cracks formation) are characterized and reconstructed. Experimental results demonstrate that X-ray μCT can track time-dependent development of corrosion products and the subsequent initiation and propagation of corrosion-induced cracks. In addition, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) are used to morphologically and chemically analyze the corrosion result. The microscopic analysis result is found to be in a very good agreement with the image analysis measured by X-ray μCT. …

An Experimental Study On Effect Of Steel Corrosion On The Bond–Slip Performance Of Reinforced Concrete, Xiaolin Zhang, Xuebing Liang, Hancheng Huang, Haijun Zhou

International Conference on Durability of Concrete Structures

This paper studied the effects of reinforcement corrosion on bond performance between rebar and concrete. Tests were carried out to evaluate the degradation of bond between reinforcing steel and concrete for different corrosion levels of reinforcing steel. A series of 20 specimens of different concrete strength with various reinforcing steel corrosion levels were designed and manufactured. Each specimen was casted as a 200-mm concrete cube, and a steel rebar was centrally embedded with two stirrups around it. The steel rebar were corroded using an electrochemical accelerated corrosion technique. The corrosion crack opening width and length were recorded after the corrosion …

Durability-Based Optimal Design Methodology For Rc Members In Corrosive Environment, Saeid A. Alghamdi, Shamsad Ahmad, Adamu Lawan

International Conference on Durability of Concrete Structures

No abstract provided.

Research On Concrete Durability Improving For Existing Island-Building And Its Application, Mao Jianghong, Zhu Yaofeng, Xu Fangyuan, Jin Weiliang, Xu Yidong, Chen Xu

International Conference on Durability of Concrete Structures

China’s coastal cities contain a large number of islands with abundant human activities, in which buildings are in a typical marine corrosion environment and the corrosion of reinforced concrete structures is very prominent. This paper makes research work on two aspects: (1) the durability assessment and durability improvement after a thorough investigation of the architecture of Xiangtan County, Ningbo city, on an island and (2) the application research of the bidirectional electromigration rehabilitation (BIEM) technology to enhance the durability of existing island building life. This paper designs a set of BIEM equipment based on solar power supply and develops a …

Seismic In-Plane Response Of Reinforced Concrete Frames With Masonry Infill Walls, Rabab Abdel Karim Al Louzi

Open Access Dissertations

Field data gathered after destructive earthquakes indicate that infill walls interact with reinforced concrete (RC) frames in buildings during an earthquake and could cause failure mechanism different than what the frames are originally designed for. A new method to identify the failure modes of RC frames with infill walls is developed. The method requires only the simple geometric and material properties of the elements involved in the frame- wall assembly. The approach checks various possible failure mechanisms, including those that may evolve depending on how the infill wall may fail during strong shaking, for example, the dynamically evolved captive column …

Evaluation Of Collapse Indicators For Seismically Vulnerable Reinforced Concrete Buildings, Nicholas R. Skok

Open Access Theses

Older reinforced concrete buildings can be prone to column shear and compression failures during earthquakes because of inadequate transverse reinforcement. Cities in seismic areas still have large inventories of older and potentially deficient buildings. To analyze every building and estimate its vulnerability in detail is costly. A simple method to rank quickly older buildings according to their seismic vulnerability is needed to help engineers prioritize the use of resources for rehabilitating the most vulnerable buildings.

Four indicators of building damage or collapse were evaluated using numerical analysis and prior data from building surveys: column index (Hassan & Sozen, 1997), R …

Snap-Tite Composite Column Reinforcement, Purdue Ect Team

ECT Fact Sheets

Recent earthquakes throughout the world have demonstrated the vulnerabilities of older reinforced concrete columns to seismic deformation demands. The Snap Tite Composite Column Reinforcement strengthens a concrete column by confining it in an external composite jacket, which prevents the concrete from expanding during seismic activity or prolonged freeze-thaw cycles. The pre-manufactured fiberglass jacket is comprised of glass fibers and corrosion resistant isopolyester resins.

Corrosion Inhibitors For Reinforced Concrete, Purdue Ect Team

ECT Fact Sheets

Steel corrosion in reinforced concrete structures has been a major problem across the U.S. Steel-reinforced concrete structures are continually subject to attack by corrosion brought on by naturally occurring environmental conditions. FerroGard, a corrosion inhibitor, developed by Sika Corporation, penetrates hardened concrete to dramatically reduce corrosion by 65% and extend the structure's service life.

Shear Reinforcement Requirements For High-Strength Concrete Bridge Girders, J. A. Ramirez, Gerardo Aguilar

JTRP Technical Reports

A research program was conducted on the shear strength of high-strength concrete members. The objective was to evaluate the shear behavior and strength of concrete bridge members with compressive strengths in the range of 10 000 to 15 000 psi. The goal was to determine if the current minimum amount of shear reinforcement together with maximum spacing limits in the 2004 AASHTO LRFD Specifications, and the upper limit on the nominal shear strength were applicable to concrete compressive strengths up to 15 000 psi.

A total of twenty I-shaped specimens were tested monotonically to failure. Sixteen specimens were reinforced concrete …

Simplified Shear Design Of Prestressed Concrete Members, Robert J. Frosch, Tyler S. Wolf

JTRP Technical Reports

Design methods for the shear resistance of reinforced and prestressed concrete beams are based on empirical evidence. Due to different approaches in their development different equations are used to calculate the shear strength of reinforced and prestressed concrete. Recent research conducted by Tureyen has proposed a simplified shear model for reinforced concrete which is primarily based upon mechanics and corresponds well with a wide range of test results. The objective of this research was to determine the applicability of the shear model to prestressed concrete. The applicability of the shear model was evaluated by a comparison of its results with …