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International Concrete Abstracts Portal

Showing 1-5 of 276 Abstracts search results

Document: 

20-253

Date: 

March 1, 2021

Author(s):

Goran Adil, Ceki Halmen, George Seegebrecht, and John T. Kevern

Publication:

Materials Journal

Volume:

118

Issue:

2

Abstract:

Corrosion performance of reinforced pervious concrete was evaluated through field and laboratory evaluations. Two reinforced pervious cemetery walls in Chicago, IL, were visually evaluated, and samples were investigated through petrographic examination. Corrosion performance of two-layered concrete samples, with an outer layer of conventional concrete and an inner layer of pervious concrete, was evaluated in the laboratory. Results indicated that pervious concrete around the reinforcement can significantly delay the cracking and spalling of samples compared to conventional concrete. Chloride profiles of samples and instantaneous corrosion rate measurements showed that corrosion of reinforcement embedded in two-layered samples was similar to conventional concrete although two-layered samples provided a longer time to cracking. Laboratory results are in agreement with long service life performance observed in the field and with prior pervious concrete corrosion studies.

DOI:

10.14359/51730514


Document: 

18-315

Date: 

March 1, 2021

Author(s):

John S. Lawler, Jonah C. Kurth, Stephen M. Garrett, and Paul D. Krauss

Publication:

Materials Journal

Volume:

118

Issue:

2

Abstract:

Reliability-based durability design of reinforced concrete structures requires a probabilistic service life modeling approach. Probabilistic service life modeling of chloride-induced corrosion should consider the statistical distributions of key parameters that influence corrosion initiation and subsequent damage. For typical reinforced concrete structures (such as bridge decks), these are chloride exposure, chloride penetration resistance of the concrete, chloride-induced corrosion threshold, depth of concrete cover, and corrosion propagation time. Assessing the impact of the use of corrosion-resistant reinforcement, such as epoxy-coated reinforcing bars (ECR), is typically performed through a selection of the chloride threshold and/or propagation time. This paper provides recommendations for statistical distributions for the chloride threshold to be used in service life modeling for structures containing carbon steel and ECR based on both experimental work reported in the literature and field investigations of existing structures conducted by the authors.

DOI:

10.14359/51730411


Document: 

20-080

Date: 

January 1, 2021

Author(s):

Ângela Costa Piccinini, Luiz Carlos Pinto da Silva Filho, and Américo Campos Filho

Publication:

Materials Journal

Volume:

118

Issue:

1

Abstract:

This research evaluated the bond behavior of reinforcement and the mechanical characteristics in a reactive powder concrete (RPC) replacing 35% cement with blast-furnace slag. Pullout tests were performed at the ages of 3, 7, 28, 56, 63, and 91 days on cylindrical samples. The embedded length used was double the diameter of the bar. At 3 days it presented compressive strength of 41% of the maximum obtained, which was 123.06 MPa at 91 days. There was an increase in strength until the age of 56 days and after stabilization of the curves. In pullout tests, it was noticed the considerable influence of the rib, because in tests with plain bars, the bond force was below 20% of the results with ribbed bar, which reached 54.38 MPa of strength. The compression curve was similar to the bond curve. Underestimated values were observed when the researchers’ equations were applied to calculate the maximum bond strength.

DOI:

10.14359/51725995


Document: 

20-040

Date: 

January 1, 2021

Author(s):

R. Kampmann, S. Telikapalli, A. Ruiz Emparanza, A. Schmidt, and M. A. Dulebenets

Publication:

Materials Journal

Volume:

118

Issue:

1

Abstract:

Concrete infrastructure is deteriorating at a fast pace because of corrosion issues inherent to traditional black steel reinforcing bars. Alternative non-corrosive reinforcement materials for concrete structures have been developed and reinforcing bars made from fiber-reinforced polymers (FRP) are one of the most predominantly used non-corrosive materials for internal reinforcement. This research focused on basalt FRP reinforcing bars as this technology is still in development for the U.S. market and no standard specifications are available yet. In an effort to develop basalt specific acceptance criteria, two commonly available BFRP reinforcing bar sizes from five different sources and two different production lots were tested to quantify the tensile strength and stress-strain behavior of this emerging reinforcing bar technology. The obtained results were used to evaluate the performance of each reinforcing bar type in a relativistic comparison to existing benchmark values for glass FRP reinforcing bars given in AC454. The tensile strengths were consistent for all reinforcing bar types and the recorded values surpassed the strength measurements generally reported for comparable GFRP reinforcing bars. It was found that No. 3 reinforcing bars measured guaranteed tensile strengths between 760 and 1266 MPa (110 and 184 ksi), while No. 5 reinforcing bars ranged between 836 Pa and 1074 MPa (129 and 131 ksi). Though the fiber-to-resin ratio of all tested reinforcing bar types was similar, the tensile strength of these reinforcing bars varied due to differences in the raw materials and production. The elastic moduli were calculated according to AC454 and it was noted that this property varied significantly between the different reinforcing bar types because of irregular cross-sectional dimensions and the various proprietary (not standardized) manufacturing processes. It was determined that acceptance criteria for BFRP reinforcing bars can be conservatively defined according to the currently available GFRP values, but more specific criteria can be developed through further research to take advantage of the additional load capacity and potential improved stiffness of BFRP reinforcing bars.

DOI:

10.14359/51729288


Document: 

19-354

Date: 

September 1, 2020

Author(s):

Edward G. Moffatt, Michael D. A. Thomas, Andrew Fahim, and Robert D. Moser

Publication:

Materials Journal

Volume:

117

Issue:

5

Abstract:

This paper presents the durability performance of ultra-high-performance concrete (UHPC) exposed to a marine environment for up to 21 years. Concrete specimens (152 x 152 x 533 mm [6 x 6 x 21 in.]) were cast using a water-cementitious materials ratio (w/cm) in the range of 0.09 to 0.19, various types and lengths of steel fibers, and the presence of conventional steel reinforcement bars in select mixtures. Laboratory testing included taking cores from each block and determining the existing chloride profile, compressive strength, electrochemical corrosion monitoring, and microstructural evaluation. Regardless of curing treatment and w/cm, the results revealed that UHPC exhibits significantly enhanced durability performance compared with typical high-performance concrete (HPC) and normal concretes. UHPC prisms exhibited minimal surface damage after being exposed to a harsh marine environment for up to 21 years. Chloride profiles revealed penetration to a depth of approximately 10 mm (0.39 in.) regardless of exposure duration. Electrochemical corrosion monitoring also showed passivity for reinforcement at a cover depth of 25 mm (1 in.) following 20 years.

DOI:

10.14359/51727022


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