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International Concrete Abstracts Portal

Showing 1-5 of 40 Abstracts search results

Document: 

SP82-13

Date: 

September 1, 1984

Author(s):

R.N. Swamy and A.H. Al-Hamed

Publication:

Symposium Papers

Volume:

82

Abstract:

The paste efficiency concept based on the pulse velocity difference between a control specimen and the concrete in the structure can be used to estimate the air-dried cube strength and hence in-situ concrete strength. This paper presents extensive test evidence to substantiate the validity of the paste efficiency principle. It is shown that the use of air-dried cubes (represent-ing in-situ concrete) produces consistent results; this has the further advantage that the method can be used to estimate the probable strength distribution in a structure prior to construction. The results show that in reality the k values relating control specimen strength to structure strength depend on concrete mix proportions, cement content, size and type of dense coarse aggregate and the type of concrete ie normal or lightweight. Based on this project, a set of k values is recommended, which should enable in-situ strength to be estimated to within + 10%; and these values should apply to site conditions with reasonably good quality control. The paper shows that pulse velocity measurements based on the paste efficiency concept can offer a reliable and consistent method of estimating air-dried cube strength which is shown to have some correlation to core strength.

DOI:

10.14359/6558


Document: 

SP82-06

Date: 

September 1, 1984

Author(s):

J.A. Bickley

Publication:

Symposium Papers

Volume:

82

Abstract:

The standard method of determining the quality of hardened concrete is the cylinder test. Unliess test results fail to meet specified values, and other test procedures are called into play, the standard cylinder test is usually the only quantitative measure of the quality of concrete in a structure. Analysis of test results to ACI 214 enables assessments of this quality to be made. On two large projects in Toronto, horizontal elements were extensively test4d by in-place testing for form removal, termination of shring, and confirmation of specified 28-day strength. Permission to waive standard cylinder testing for these elemnets was obtained from trhe City Building Department. Out of interest the cylinders were made and tested. It is therefore possible to evaluate the quality of the concrete on these projects by both the standard procedure, and by in-place testing. This is addressed in this paper together with a discussion of statistical evaluation of in-place test data.

DOI:

10.14359/6551


Document: 

SP82-26

Date: 

September 1, 1984

Author(s):

Yoshio Kasai, lsamu Matsui, and Motoshi Nagano

Publication:

Symposium Papers

Volume:

82

Abstract:

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.

DOI:

10.14359/6571


Document: 

SP82

Date: 

September 1, 1984

Author(s):

Editor: V.M. Malhotra

Publication:

Symposium Papers

Volume:

82

Abstract:

SP82 Contains 38 papers covering the following in situ/nondestructive testing methods: surface hardness and penetration resistance tests; pullout; ultrasonic pulse velocity; break-off; combined methods; maturity techniques. For tests of concrete other than strength: magnetic; electrical; radioactive; pulse echo; radar; microwave absorption; acoustic emission; nuclear; infrared thermography; and permeability methods. A global review of in situ/nondestructive testing is also included.

DOI:

10.14359/14039


Document: 

SP82-03

Date: 

September 1, 1984

Author(s):

loan Facaoaru

Publication:

Symposium Papers

Volume:

82

Abstract:

This paper summarizes Romanian experience concerning in-situ concrete strength estimation by non-destructive methods. The methods presented include "classical" non-destructive methods such as ultrasonic pulse method and rebound method. The philosophy of transforming the measured property into concrete strength, taking into account concrete composition and maturity, is given. Details about original developments of non-destructive methods for concrete strength estimation are also presented. Such developments are: a) combined SONREB method based on pulse velocity and rebound index measurements, b) sonic coring method, an immersion method using radial transducers, adapted for the inspection of deep foundations, c) acoustic method by shock, a method based on the measurement of the natural period for the quality

DOI:

10.14359/6548


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