Author: H. G. RussellPublisher: Transportation Research Board
ISBN: 0309070112
Category : Bridges
Languages : en
Pages : 188
Book Description
At head of title: National Cooperative Highway Research Program.
Concrete Bridge Deck Performance
Author: H. G. RussellPublisher: Transportation Research Board
ISBN: 0309070112
Category : Bridges
Languages : en
Pages : 188
Book Description
At head of title: National Cooperative Highway Research Program.
Corrosion Protection Performance Evaluation of Low Permeable Concretes in Exposure Specimens
Author: Jerzy ZemajtisPublisher:
ISBN:
Category : Concrete bridges
Languages : en
Pages : 152
Book Description
The application of a mineral admixture or a combination of a mineral admixture with corrosion inhibitor are the methods used for the corrosion protection for reinforced concrete bridges. The results of a 1.5-year study on evaluation of three concretes with fly ash, slag cement (SC), and silica fume (SF) and one concrete with silica fume and a corrosion inhibitor (SFD) are presented. The specimens were built to simulate four exposure conditions typical for concrete bridges located in the coastal region or inland where deicing salts are used. The exposure conditions were horizontal, vertical, tidal, and immersed zones. The specimens were kept inside the laboratory and were exposed to weekly ponding cycles of 6% sodium chloride solution by weight. In addition, cover depth measurements from 21 bridge decks and chloride data from 3 bridge decks were used, together with laboratory data, in modeling the service lives of investigated corrosion protection methods. The methods used to assess the condition of the specimens included chloride concentration measurements, corrosion potentials, and corrosion rates (3LP). Additionally, visual observations were performed for identification of rust stains and cracking on concrete surfaces. The results of chloride testing indicate that the amount of chlorides present at the bar level is more than sufficient to initiate corrosion. Chloride and rapid permeability data demonstrate that for low permeable (LP) concretes there appears to be significant difference both in a rate of chloride ingress and in the diffusion coefficients in comparison to the controls. Corrosion potentials agree with corrosion rates and suggest the possibility of an active corrosion process development on control specimens during indoor exposure. The structural cracks that were observed in some specimens appeared to have no influence on the corrosion development on the bars in the vicinity of the these cracks. It was concluded that the silicone and duct tape protection was adequate. The cracking, other than structural, appeared to be related to the reinforcing steel corrosion, except the cracks in the horizontal zone of the specimen with slag cement which were probably caused by the subsidence cracking. The least number of cracks was observed on the SF and SFD specimens. Modeling the time as a function of probability of the end of functional service life (EFSL) was presented. It has been shown that the distributions of surface concentrations of chloride ions (CO) and diffusion constants (DC) are key elements in the model. Model predictions show that the LP concretes provide much better level of protection against moisture and chlorides than the A4 concrete alone. Application of a corrosion inhibitor causes an elevation of the chloride threshold resulting in an additional increase in time to EFSL. Recommendations are to continue monitoring until cracking has occurred in all specimens to a greater extent to better estimate the service lives of LP concretes than is presently known in the construction of concrete bridge components in Virginia. The specimens with LP concretes and one control (continuous reinforcement in the legs) should be taken to the Hampton Road North Tunnel Island and placed in the brackish water to a depth of the immersed zone at low tide for further exposure to chloride. The other control (non-continuous reinforcement in the legs) should remain in an outdoor exposure in Southwest Virginia like the Civil Engineering Materials Research Laboratory in Blacksburg, Virginia. Also more field studies are needed to better estimate distributions of surface chloride concentration and diffusion coefficient of Virginia bridge decks, and to confirm predicted times to EFSL for LP concretes.
PRO 37: 5th International RILEM Conference on Cracking in Pavements – Mitigation, Risk Assessment and Prevention
Author: C. PetitPublisher: RILEM Publications
ISBN: 9782912143471
Category : Pavements
Languages : en
Pages : 748
Book Description
National Experimental Projects Tabulation
Author: Performance Evaluation of Various Corrosion Protection Systems of Bridges in Colorado
Author: Yunping XiPublisher:
ISBN:
Category : Concrete bridges
Languages : en
Pages : 166
Book Description
Corrosion of reinforced concrete structures has been a significant problem for many state and transportation agencies since the application of deicing salts was introduced. Much research has been conducted to develop corrosion protection systems that can prolong the life span of reinforced concrete structures. The Colorado Department of Transportation (CDOT) has several routine and experimental measures to prevent corrosion of the rebar including epoxy-coated rebar, calcium nitrite admixture, organic corrosion inhibitors, a thick cover of quality concrete, and a waterproofing membrane covered by an asphalt overlay. An extensive literature review was performed to collect information on various corrosion protection systems that have been used in the U.S. and around the world. Current CDOT practices in terms of corrosion protection measures were reviewed. A draft inspection plan for Colorado's bridge structures was proposed.
High-performance/high-strength Lightweight Concrete for Bridge Girders and Decks
Author: Thomas E. CousinsPublisher: Transportation Research Board
ISBN: 030925888X
Category : Architecture
Languages : en
Pages : 91
Book Description
"TRB's National Cooperative Highway Research Program (NCHRP) Report 733: High-Performance/High-Strength Lightweight Concrete for Bridge Girders and Decks presents proposed changes to the American Association of State Highway and Transportation Officials' Load and Resistance Factor Design (LRFD) bridge design and construction specifications to address the use of lightweight concrete in bridge girders and decks. The proposed specifications are designed to help highway agencies evaluate between comparable designs of lightweight and normal weight concrete bridge elements so that an agency's ultimate selection will yield the greatest economic benefit. The attachments contained in the research agency's final report provide elaborations and detail on several aspects of the research. Attachments A and B provide proposed changes to AASHTO LRFD bridge design and bridge construction specifications, respectively; these are included in the print and PDF version of the report. Attachments C through R are available for download below. Attachments C, D, and E contain a detailed literature review, survey results, and a literature summary and the approved work plan, respectively. Attachment C; Attachment D ; Attachment E; Attachments F through M provide details of the experimental program that were not able to be included in the body of this report. Attachment F; Attachment G; Attachment H; Attachment I; Attachment J; Attachment K; Attachment L; Attachment M. Attachments N through Q present design examples of bridges containing lightweight concrete and details of the parametric study. Attachment N; Attachment O; Attachment P; Attachment Q. Attachment R is a detailed reference list."--Publication information.
Waterproofing Membranes for Concrete Bridge Decks
Author: H. G. RussellPublisher: Transportation Research Board
ISBN: 0309223466
Category : House & Home
Languages : en
Pages : 67
Book Description
TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 425: Waterproofing Membranes for Concrete Bridge Decks documents information on materials, specification requirements, design details, application methods, system performance, and costs of waterproofing membranes used on new and existing bridge decks since 1995.
Long-term Performance of Polymer Concrete for Bridge Decks
Author: David W. FowlerPublisher: Transportation Research Board
ISBN: 0309143543
Category : Technology & Engineering
Languages : en
Pages : 75
Book Description
TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 423: Long-Term Performance of Polymer Concrete for Bridge Decks addresses a number of topics related to thin polymer overlays (TPOs). Those topics include previous research, specifications, and procedures on TPOs; performance of TPOs based on field applications; the primary factors that influence TPO performance; current construction guidelines for TPOs related to surface preparation, mixing and placement, consolidation, finishing, and curing; repair procedures; factors that influence the performance of overlays, including life-cycle cost, benefits and costs, bridge deck condition, service life extension, and performance; and successes and failures of TPOs, including reasons for both.
Pavement, Roadway, and Bridge Life Cycle Assessment 2020
Author: John HarveyPublisher: CRC Press
ISBN: 1000201724
Category : Technology & Engineering
Languages : en
Pages : 557
Book Description
An increasing number of agencies, academic institutes, and governmental and industrial bodies are embracing the principles of sustainability in managing their activities. Life Cycle Assessment (LCA) is an approach developed to provide decision support regarding the environmental impact of industrial processes and products. LCA is a field with ongoing research, development and improvement and is being implemented world-wide, particularly in the areas of pavement, roadways and bridges. Pavement, Roadway, and Bridge Life Cycle Assessment 2020 contains the contributions to the International Symposium on Pavement, Roadway, and Bridge Life Cycle Assessment 2020 (Davis, CA, USA, June 3-6, 2020) covering research and practical issues related to pavement, roadway and bridge LCA, including data and tools, asset management, environmental product declarations, procurement, planning, vehicle interaction, and impact of materials, structure, and construction. Pavement, Roadway, and Bridge Life Cycle Assessment 2020 will be of interest to researchers, professionals, and policymakers in academia, industry, and government who are interested in the sustainability of pavements, roadways and bridges.
Author: