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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 12 Abstracts search results
Document:
SP108-05
Date:
August 1, 1988
Author(s):
G. Vondran and T. Webster
Publication:
Symposium Papers
Volume:
108
Abstract:
Concretes with and without polypropylene fibers were tested to determine their relationship to permeability. This paper focuses on one type of fiber--bundles of fibrillated polypropylene. The bundles open during concrete mixing and separate into millions of multistrand filament fibers. Tests on permeability, cracking, and steel corrosion show reductions in all three when fibrous concretes are compared with conventional concrete at equal water-cement ratios. A new term, "Perm Point," explains the influence of the fibers on permeability. Subsidence cracking over steel reinforcement increases permeability and accelerates corrosion, whereas polypropylene fiber reinforced concrete reduces this phenomenon. Results suggest an interrelationship exists among permeability, cracking, and steel corrosion.
DOI:
10.14359/2175
SP108-08
D. J. Janssen
Equipment and procedures for measuring actual permeability of portland cement concrete are presented. The equipment is built from readily available parts and materials and requires only standard laboratory air pressure and vacuum sources. The sample size used is 3 in. (7.5 cm) diameter x 3-1/8 in. (8 cm) long, but other sample sizes could be used. Typical measurements are presented to show repeatability and time required for permeability testing. The equipment has been used for permeabilities as low as 1 x 10-11 cm/sec. Concrete with lower permeability would require equipment modifications and/or longer measurement times.
10.14359/3633
SP108-09
B. R. Sullivan
A testing system which can accommodate up to seven samples simultaneously with computer-controlled data acquisition, analysis, and reporting is described. The system consists of seven core holders of the Hassler type which can handle cylindrical samples ranging from 1-1/2 to 4 in. in diameter and from 4 to 11 in. in length. Confining and driving pressures can be independently varied up to 4000 psi. The test medium can be either liquid or gas including brine, since all tubing and containers are stainless steel. Flow is determined by pressure increase in a collector tank for gas and change in liquid level in a pipette column for liquid. Four pressure transducers per core holder are used to monitor all pressure levels during a test. A computer-based data acquisition system is used to scan up to seven tests simultaneously and record all data on a disc. Upon termination of a test, flow and permeability are computed and plotted against time and a report is printed for the test. The data are saved permanently on the disk and a backup copy is transferred to a floppy disk for safe storage. Sample preparation, sealing, and testing procedures are explained. Data analysis and typical results are presented on salt cores and concrete samples.
10.14359/3660
SP108-11
D. Whiting
Study of permeability was made using six concrete mixtures ranging in water-to-cementitious material (w-c) ratio from 0.26 to 0.75. Concrete specimens were tested for permeability to water and air, permeability to chloride ions (rapid and long-term), volume of permeable voids, and porosity. Results confirm that permeability is a direct function of w-c ratio. The addition of silica fume results in even greater decreases in permeability than would be anticipated based solely on w-c ratio. A period of initial moist curing of at least seven days is essential for achieving low permeability. Results also indicate that rapid test procedures offer a reasonable alternative to more lengthy and complex conventional permeability tests.
10.14359/2186
SP108-10
A. Bisaillon and V. M. Malhotra
Paper describes the modifications made to a previously developed CANMET test method to measure the permeability of concrete and discusses test results to determine the reproducibility of the test method. Briefly, the test method consists of measuring the uniaxial water flow through cylinders (125 mm high with a diameter of 150 mm) under a pressure of 3.5 MPa. A large number of concrete specimens with water-cement ratios of 0.65 and 0.80 were tested. A limited number of test specimens having w/c of 0.22 and 0.27 were also tested. Test results show that the within-batch variation for the test method is high, and this is probably due to the heterogenous nature of the concrete. For concrete with w/c of 0.22 and 0.27, there was no outflow of water, and this technique in the present form may not be suitable for measuring the permeability of very high strength concrete.
10.14359/3671
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