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Home > Publications > International Concrete Abstracts Portal
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.
Showing 1-5 of 289 Abstracts search results
Document:
CI4506Brierley
Date:
June 1, 2023
Author(s):
Gary Brierley, Joseph Klein, and Randall W. Poston
Publication:
Concrete International
Volume:
45
Issue:
6
Abstract:
Tunnel linings are typically curved structures placed in direct contact with and restrained by the surrounding ground. The main objective of this two-part article is to explain how tunnel linings can be designed and analyzed in a reasonable and rational manner that is consistent with tunnel lining behavior. Part 1 focuses on design considerations and a brief history of tunnel linings.
CI4311Bonakdar
November 1, 2021
Amir Bonakdar and Michael A. Mahoney
43
11
Over the last four decades, fibers have been used as a full or partial replacement for conventional reinforcement in slabs-on-ground, pavements, overlays and topping courses, shotcrete, precast concrete, and structural elements. The article summarizes documents related to fiber reinforcement, benefits of using fibers during construction and service, and design with fiber reinforcement.
CI4306ASAAwards
June 1, 2021
The American Shotcrete Association (ASA) annually recognizes notable shotcrete projects with its Outstanding Shotcrete Project Awards.
SP-349_08
April 22, 2021
David I. Stackelberg, Boris I. Wilge, Shimon V. Boiko and Felix A. Goldman
Symposium Papers
349
Hardening and strengthening of cement-concrete compositions (CCC) is a result of forming a moist capillary porous body. Physical water contained in pores and capillaries of the resulting structure is its most informative component. First, it is only the pore solution that is electrically conductive component, and, second, the liquid phase stays perpetually in a thermodynamic equilibrium with the solid surfaces by which it is adsorbed. Thus the physical-moisture state immediately responds to any change in the material’s solid skeleton of hardening CCC. These effects serve as a physical basis for the CCC hardening and strengthening monitoring using the results ofcontinuous measurement of electric resistivity. Such monitoring is aimed at controlling various properties of the material: from the initial viscous fluid or viscous plastic state of fresh mixtures to the final elastic state of artificial stone. The results of measuring the electric resistivity are compared to those of standard tests. Thus established relationships “Electric resistivity ( ρ ) – Parameters ( i P )” (Parameters: W/C, Slump, Setting Time, Plastic strength, Compressive Strength) allow to carry out technological monitoring over the entire range of CCC hardening. All correlations Pi = f (ρ ) are described by linear relations with high correlation coefficients. The linearity of the correlations “Strength – Electric Resistivity” is characteristic of various CCC: regular dense concrete, dry concrete mixtures (W/C ≈ 0.35), shotcrete, rising and plastic strengthening of aerated concrete at the stage of preautoclave hardening, etc.
Hardening and strengthening of cement-concrete compositions (CCC) is a result of forming a moist capillary porous body. Physical water contained in pores and capillaries of the resulting structure is its most informative component. First, it is only the pore solution that is electrically conductive component, and, second, the liquid phase stays perpetually in a thermodynamic equilibrium with the solid surfaces by which it is adsorbed. Thus the physical-moisture state immediately responds to any change in the material’s solid skeleton of hardening CCC.
These effects serve as a physical basis for the CCC hardening and strengthening monitoring using the results ofcontinuous measurement of electric resistivity. Such monitoring is aimed at controlling various properties of the material: from the initial viscous fluid or viscous plastic state of fresh mixtures to the final elastic state of artificial stone. The results of measuring the electric resistivity are compared to those of standard tests. Thus established relationships “Electric resistivity ( ρ ) – Parameters ( i P )” (Parameters: W/C, Slump, Setting Time, Plastic strength, Compressive Strength) allow to carry out technological monitoring over the entire range of CCC hardening. All correlations Pi = f (ρ ) are described by linear relations with high correlation coefficients.
The linearity of the correlations “Strength – Electric Resistivity” is characteristic of various CCC: regular dense concrete, dry concrete mixtures (W/C ≈ 0.35), shotcrete, rising and plastic strengthening of aerated concrete at the stage of preautoclave hardening, etc.
DOI:
10.14359/51732741
SP-345_19
February 1, 2021
Egbert Müller, Sarah Bergmann, Manfred Curbach, Josef Hegger
345
Carbon Reinforced Concrete (CRC) can be used for new structures and to strengthen existing components. Carbon fibre rods and fabrics are used as reinforcement for new components. Besides CFRP-lamellas, grid-like carbon reinforcements and shotcrete are very suitable for strengthening. Due to the low concrete cover, thin strengthening layers can be realised, which minimise the additional dead load. Depending on the chosen fibre material and impregnation, different failure mechanisms can be observed. The fibre strand should preferably be able to reach the maximum stress under load, but at this stage, the bond behaviour has to be thoroughly considered to prevent failure due to pull-out or delamination. Two carbon reinforcement fabrics are currently being investigated in the research programme C³ - Carbon Concrete Composite.This paper presents the results of large-scale tests on reinforced concrete slabs strengthened with CRC. In addition to the strengthening procedure and the large-scale component tests that have been carried out, this paper deals mainly with the recalculation of the test results and the positional accuracy of the carbon reinforcement and its influence on the flexural strength.
10.14359/51731585
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