International Concrete Abstracts Portal

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 17 Abstracts search results

Document: 

SP168-07

Date: 

April 1, 1997

Author(s):

Mary Sansalone, Jiunn-Ming Lin, and William B. Streett

Publication:

Symposium Papers

Volume:

168

Abstract:

This paper describes the use of a P-wave-speed measurement technique in conjunction with the impact-echo method to nondestructively and accurately determine the thickness of new concrete pavements and other plate-like structures. Portable instrumentation (computer, data-acquisition hardware, transducers, and impactors) that can be used to perform both wave speed and impact-echo measurements accurately and reliably is described. Results of preliminary field studies carried out on a Strategic Highway Research Program (SHRP) Test Section in Arizona are reported, including results obtained from pavements having different thicknesses, different strengths, and placed on different types of subgrades. The goal of this work 8 to lay the basis for an ASTM Standard Test Method for determining the thickness of concrete pavements and other plate-like structures.

DOI:

10.14359/5954


Document: 

SP168-08

Date: 

April 1, 1997

Author(s):

N. A. Cumming and 0. S. Ooi

Publication:

Symposium Papers

Volume:

168

Abstract:

A major structural repair and strengthening program was undertaken at a large grain shipping terminal on Canada’s northwest coast. The work was required to correct problems of excessive cracking and internal delamination in the silo walls. During the repair work, it was necessary to survey 42 silos to locate zones of delaminated or deteriorated concrete. This was done successfully using the impact-echo procedure. This paper describes the impact-echo survey and its findings. It further discusses correlation of test results to actual conditions encountered in the field.

DOI:

10.14359/5955


Document: 

SP168-09

Date: 

April 1, 1997

Author(s):

Randall Poston and Mary Sansalone

Publication:

Symposium Papers

Volume:

168

Abstract:

This paper presents both a brief explanation of the impact response of bar-like structures and an application involving the use of the impact-echo method for detecting cracks in the beams and columns of a post-tensioned parking garage structure. The information gained from the impact-echo tests was used to aid in specifying repair measures for the structure. In the process of implementing repair measures, selected impact-echo results were verified. This field study was performed in 1991. This paper was presented at the AC1 Fall Convention in 1992.

DOI:

10.14359/5956


Document: 

SP168

Date: 

April 1, 1997

Author(s):

Editors: Stephen Pessiki and Larry Olson / Sponsored by: ACI Committee 228

Publication:

Symposium Papers

Volume:

168

Abstract:

ACI Committee 228 has been active in the field experiences in the area of nondestructive testing of concrete. This volume contains 16 papers of which many were presented at the two most recent technical sessions organized by the committee. The first session was held during the ACI Spring Convention in 1993 in Vancouver, BC, Canada. The second session was held during the American Concrete Institute Fall Convention in 1995 in Montreal, Quebec, Canada. Note: The individual papers are also available as .pdf downloads.. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP168

DOI:

10.14359/14208


Document: 

SP168-01

Date: 

April 1, 1997

Author(s):

Stephen G. Millard, John H. Bungey, Marcus R. Shaw, Cledwyn Thomas, and Brian A. Austin

Publication:

Symposium Papers

Volume:

168

Abstract:

Experimental work has been undertaken in the laboratory and on site to assist understanding and interpretation of the results of radar testing of structural concrete. This has included the development and use of a large-scale emulsion simulation tank in which a very large range of reinforcing steel and void configurations have been examined with field testing apparatus for a range of simulated concrete properties. A library of characteristic responses as well as limits of size and spacing upon successful resolution have been obtained. A large diameter co-axial transmission line has also been designed, fabricated and used to determine the fundamental electrical properties of a range of concretes and moisture conditions at frequencies from 1 MHz up to 1 GHz. Results have been compared with those for tests on larger concrete specimens with field testing apparatus and confirm the dominant influence of moisture compared with other aspects of the concrete composition. Frequency effects are quantified and related to characteristics of field antennas, and potential errors of using ‘typical’ values of concrete properties in interpretation and numerical modelling are identified. The test results from transmission line studies are compared with experimental and theoretical results from other research workers.

DOI:

10.14359/5940


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