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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 40 Abstracts search results
Document:
SP82-25
Date:
September 1, 1984
Author(s):
D. Whiting
Publication:
Symposium Papers
Volume:
82
Abstract:
An electronic device and test procedure which can be used to rapidly assess the permeability of various types of concrete to chloride ions is described. The method consists of monitoring the amount of electrical current passed through a test area on a concrete slab when a potential difference of 80 Vdc is maintained across the specimen for a period of six hours. Chloride ions are forced to migrate out of a sodium chloride solution subjected to a negative charge through the concrete towards reinforcing steel maintained at a positive potential. Development of a prototype device and testing on small scale laboratory slabs of ordinary portland cement concrete, latex modified concrete, internally sealed concrete, dense (‘@Iowa) concrete, polymer impregnated, and polymer concrete are des-In addition, field trials carried out on a conventional concrete deck and a deck overlaid with dense Iowa) concrete are discussed. The method has been found to give a good correlation with long-~ term ponding data on companion concrete slabs. It can be used as a quality control tool for new construction or as a means of 6 monitoring permeability of structures currently in-service.
DOI:
10.14359/6570
SP82-26
Yoshio Kasai, lsamu Matsui, and Motoshi Nagano
This paper deals with a rapid air permeability test for site concrete. First, the development of test method is discussed, and the effect of various variables such as capacity of manometer, length of hose, recovery height of mercury head and, depth of test hose, are examined. Secondly, the test is applied to full size specimens, and the relationships between the height of concrete and the strength of cores, carbonation depth and air permeability are discussed. Finally, the developed test method for air permeability of concrete on site is described. Briefly the test method consists of boring a hole of 5 mm in diameter and 40 mm in depth plugging it with a rubber stopper, into which a big injection needle is introduced and connecting it to a manometer. Vacuum is then applied to the system and the recovery speed of mercury head is measured which then represents the air permeability of concrete.
10.14359/6571
SP82-27
Anker Jon Hansen, Niels Saabye Ottosen, and Claus Germann Petersen
able and First, the main test susqested appplies low air pressure to ease over time for a siven depth as a measure of the air-permeability. And hre .40, compressive strength respectively 10 MPa (1450 psi) , 26 MPa (3770 psi), and 86 MPa (12500 psi) all types of concretes having 90% The paper describes methods, theory, and port apparatus for estimating gas-permeability of concrete in situ, the users’ preliminary field experiences.the surface of the concrete, and monitors the pressure incr We present a theory of induced transient air flow in concrete substantiate the theory by laboratory measurements in qualities of concrete ( w/c-ratios 1.00, 0.55 and 0 relative humidity). We also outline field experience with The relative humidity must be monitored and, if nee corrected for. Second, other types of in-situ test applications of reveal other properties, including microcracks and porositie the outer surface layer, resistance to carbonation of concreting for a depth of down to 50 mm. The ded,gas s in the reinforcement cover, and bleeding below aggregates during
10.14359/6572
SP82-28
Nicholas J. Carino
study was performed to eva Iuate the applicability of Synopsis: using the echoes from mechanica I I y produced impact to Iocate hidden defects within concrete. The expected interactions of sphericaI waves with concrete-air interfaces are reviewed, and the results of experiments using artificial flaws in a large concrete s I ab are summarized. The foi lowing aspects were studied: type of impact source; distance from impact point to receiver; type of receiving transducer; depth of reflecting inter faces; and diffraction effects by sharp edges. The contact time of the impact is shown to be an important parameter for the success of the technique. The influence of the concrete thickness from impact point to the reflecting interface is an area of needed research.
10.14359/6573
SP82-29
T.R. Cantor
Practical experiences in the use of downward looking penetrating radar (radar) as applied to non-destructive evaluation (NDE) of masonry structures such as bridge decks, roadways and tunnels are described. Various configurations of radar and data presentation are considered along with theoretical operational concepts. Specific operational examples are cited including automatic signal analysis and processing. Discussion of void and other defect detection is included. The ability of radar to rapidly gather data while moving in traffic at speeds in the neighborhood of ten miles per hour is reviewed and its implications for pavement management systens are commented on. Case histories are presented.
10.14359/6574
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