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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 34 Abstracts search results
Document:
SP171-28
Date:
August 1, 1997
Author(s):
M. Shoya, Y. Tsukinaga and S. Sugita
Publication:
Symposium Papers
Volume:
171
Abstract:
Three specific in-situ tests to assess the air tightness and water tightness of the surface layer of concrete were examined. Test methods for the tightness are the rapid air permeability, the water absorption applying Figg’s method and the rapid water permeability by author’s method. In the experiments, specific parameters obtained in three different in-situ tests corresponded well to air permeability coefficient and coefficient of water diffusion in the firms indoor tests, and those parameters satisfactorily reflect the change in the tightness of the surface layer caused by the water to cement ratio, age of test and cement type. Those parameters changed when measured at a relatively high temperature. In conclusion, three test methods are promising for providing air tightness or water tightness of the surface layer of concrete . from the view points of the use of simple testing devices and convenient procedures.
DOI:
10.14359/6117
SP171-29
F. Omata, M. Kawakami, H. Tokushige and A. Moriyoshi
This paper describes changes of stress and strain during the setting of prismatic specimens incorporating polymer mortar. A new apparatus measures setting shrinkage stress and strains developed at both ends of polymer mortar specimens while at constant temperature. This apparatus is simple in structure, consisting of a noncontact type displacement device and a load measuring device. The relationships of setting shrinkage stresses and strains, and elastic modulus of three kinds of polymer mortar are reported. Furthermore, the mechanical properties of three kinds of polymer mortar were investigated. Finally, the deflection and strain that occur when polymer mortar is overlaid on ALC (Autoclaved light weight concrete) beams includes both analysis and experimental data on the two layered structure.
10.14359/6118
SP171-30
Jan Skalny, Vagn Johansen and F. M. Miller
It has been reported that the chemical/mineralogical composition of modern Portland-cement clinkers has changed in recent years to such a degree that cements made from them may lead to concrete durability problems even if such cement passed the applicable specifications. The effect of sulfur compounds in clinker on concrete deterioration due to delayed ettringite formation is cited as an example. In this paper, the relevant issues are briefly evaluated in light of available laboratory data and field experience.
10.14359/6119
SP171-31
J. Stark and N. Chelouah
Deicing salt scaling resistance of high-strength concrete with a water-cement ratio < 0.40 remains clearly under the CDF (Capillary Suction of Deicing Chemicals and Freeze-Thaw Test) acceptance criterion of 1,500 g/m* after 28 freezing and thawing cycles even if no air-entrainment is used. It was confirmed by our investigations that a high-strength concrete without air-entrainment and with a low water-cement ratio and consequently almost no capillary pores may have a very high freeze-deicing salt resistance. The effect of phase transformations in hydrated cement under freeze-deicing salt attack which is practically harmless in air-entrained concretes should, however, be taken into consideration when dealing with high-strength concretes without air-entrainment.
10.14359/6120
SP171-32
A. E. Long, P. A. M. Basheer and F. R. Montgomery
The premature deterioration of concrete structures is a major problem in many countries across the world and this has prompted the search for a method of predicting their service life. Whilst prediction methods are in their infancy it is evident that in order to improve their effectiveness it will be necessary to develop more reliable and convenient ways of measuring the relevant in-situ properties. In this context it is widely recognised that results obtained from permeation testing give useful information on the likely durability of concrete. In this paper, based on an holistic model relating permeability to durability the experience gained from the use of the “AUTOCLAM” permeability test, which is convenient and easy to use on site as well as in the laboratory, is presented. Details are included of a laboratory study correlating the “AUTOCLAM” permeation properties with the results of carbonation and freezing and thawing tests. In addition, the results of a field study on a motorway bridge are given. It is concluded that in-situ permeability and strength testing can be used to develop durability based design criteria for concrete, and to assess the remaining life of existing structures.
10.14359/6121
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