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International Concrete Abstracts Portal

Showing 1-5 of 12 Abstracts search results

Document: 

SP108-10

Date: 

August 1, 1988

Author(s):

A. Bisaillon and V. M. Malhotra

Publication:

Symposium Papers

Volume:

108

Abstract:

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.

DOI:

10.14359/3671


Document: 

SP108

Date: 

August 1, 1988

Author(s):

Editors: David Whiting and Arthur Walitt

Publication:

Symposium Papers

Volume:

108

Abstract:

SP108 Designing and building long-lasting concrete structures requires the utilization of state-of-the-art technology. Concrete technologists throughout the world are becoming increasingly aware of the importance of permeability with regard to the ultimate longevity of concrete structures. New materials for reducing permeability and techniques for its measurement are rapidly being developed. Permeability of Concrete, a collection of eleven papers, will give you the knowledge you need to build durable concrete structures.

DOI:

10.14359/14141


Document: 

SP108-02

Date: 

August 1, 1988

Author(s):

S. L. Marusin

Publication:

Symposium Papers

Volume:

108

Abstract:

This paper summarizes the results of permeability studies that have been undertaken since 1979. The research used a test procedure developed during the NCHRP Project 12-19A, "Concrete Sealers for Protection of Bridge Structures", which was reprinted in 1981 as NCHRP Report No. 244. This test method utilizes 10 cm concrete cubes, and chloride ion penetration is determined at 4 depths after 21 days exposure to 15 percent NaCl solution. The test results show that lowering of water-cement ratio in portland cement concrete or presence of superplasticizers, polymer admixtures, and silica fumes are able to significantly reduce concrete permeability.

DOI:

10.14359/2147


Document: 

SP108-09

Date: 

August 1, 1988

Author(s):

B. R. Sullivan

Publication:

Symposium Papers

Volume:

108

Abstract:

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.

DOI:

10.14359/3660


Document: 

SP108-03

Date: 

August 1, 1988

Author(s):

C. Ozyildirim and W. Halstead

Publication:

Symposium Papers

Volume:

108

Abstract:

The effects of two pozzolanic admixtures, fly ash and silica fume, and a ground-granulated blast furnace slag on the chloride ion intrusion of concretes prepared with low water-to-cementitious material ratios (0.35 to 0.45) were investigated. Results of the rapid permeability test (AASHTO T 277) showed that the resistance of concrete to the penetration of chloride ions increases significantly as the water-to-cementitious material ratio is decreased for the same proportions of solid ingredients. Most concretes with pozzolans or slag exhibited higher resistance to chloride ion penetration than the control concretes containing portland cement as the cementitious material. Results of the 90-day ponding test (similar to AASHTO T 259), which was conducted with 0.40 w/c concretes only, indicated minimal chloride content at depths below 3/4 in. (19 mm) for all the test concretes. Strength values for all concretes made with the pozzolans and slag at 90 days were in excess of 5000 psi (34.5 MPa), which is satisfactory.

DOI:

10.14359/2158


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