International Concrete Abstracts Portal

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  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-5 of 463 Abstracts search results

Document:

CI4007Riding

Author(s):

Kyle A. Riding, Michael D.A. Thomas, R. Doug Hooton, Karthik H. Obla, and W. Jason Weiss

Publication:

Concrete International

Volume:

40

Issue:

7

Abstract:

Inclusion of a performance-based alternative for concrete exposed to chlorides in the ACI Code could foster innovation and better in-place concrete. Currently available electrical tests for concrete can be adopted as part of a performance-based approach in the ACI 318 Code until a more practical method to measure the concrete’s resistance to chloride ingress is developed.

Date:

July 1, 2018

DOI:

  


Document:

CI4007Q&A

Author(s):

Scott Tarr

Publication:

Concrete International

Volume:

40

Issue:

7

Abstract:

My company installed a bonded topping on an existing slab. The project specifications required a compressive strength of 4000 psi (27.6 MPa) for the topping concrete. Although our concrete met that requirement, we were directed to remove and replace the topping. The owner’s explanation: The concrete topping was inadequate because pull-off tests failed to achieve 400 psi (2.8 MPa), which is 10% of the compressive strength. Does ACI provide any recommendation on acceptable bond strength for toppings/overlays?

Date:

July 1, 2018

DOI:

  


Document:

SP-323_05

Author(s):

Carlos V. Aguilar, David V. Jáuregui, Brad D. Weldon and Craig M. Newtson

Publication:

Special Publication

Volume:

323

Issue:

  

Abstract:

Off-system concrete bridges with no design plans are currently a concern in New Mexico as many exist throughout the State. Load rating these bridges is problematic since the design documentation is limited or missing, thus creating uncertainties regarding the safe load limits. Two prestressed concrete bridges, a double T-beam and box beam bridge, were evaluated using advanced analyses and experimental methods (including load testing and rebar scanning). Both bridges have damaged and/or missing shear keys between the adjacent beams and thus, the load distribution path was uncertain. The bridges were evaluated based on the following procedures: estimating the material properties from past specifications and amount of prestressing steel via Magnel diagrams; verifying the steel estimate with a rebar scanner; load testing based on strain measurements; and rating the bridges using the load test results. Rating factors were determined for legal loads based on serviceability (i.e., concrete cracking) and strength (i.e., shear or flexural capacity). The serviceability ratings from load testing and strength ratings from analytical software were compared to determine the final load ratings and need for posting the bridges.

Date:

May 1, 2018

  


Document:

SP-323_03

Author(s):

Anna Halicka, Dick A. Hordijk, Eva O.L. Lantsoght

Publication:

Special Publication

Volume:

323

Issue:

  

Abstract:

Nowadays, finite element analyses provide information about the performance of a structure, but they are more or less simplified. Therefore, load tests are the only way to find the “real” behavior of an existing bridge subjected to the rating process. In this paper, the state-of-the-art concerning load tests of concrete road bridges is presented, and the problems of the execution of such tests are specified. It is pointed out that only load tests accompanied with current finite element analyses may result in a proper assessment of the level of safety of the bridge. The authors’ procedure of complex assessment of such bridges combines in-situ examination of the structure, load testing, and finite element modeling. The paper discusses the following topics: aims and fundamentals of static diagnostic and proof load tests; the load application method according to different codes and specifications; the basis for proper assessment of the target load: reliability index, partial factors approach, global rating factor approach; establishing the load allowable on the bridge, based on the applied proof load; and the proposed procedure of assessment of existing concrete road bridges by load testing.

Date:

May 1, 2018

  


Document:

CI4005Obla

Author(s):

Karthik H. Obla, Daniel J. Gancarz, William R. (Rusty) Owings III, Fouad H. Yazbeck, and David G. Tepke

Publication:

Concrete International

Volume:

40

Issue:

5

Abstract:

Performance-based specifications that define explicit durability goals can be successfully used on diverse project types. This article summarizes four examples of such projects (pavement, bridge, development, and column repair) that were presented at a session, Case Studies of Performance-Based Specifications, at The ACI Concrete Convention and Exposition – Spring 2017 in Detroit, MI.

Date:

May 1, 2018

DOI:

  


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