Investigation Into Freezing-thawing Durability of Low Permeability Concrete with and Without Air Entraining Agent PDF Download
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Author: Kejin Wang
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 52
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Book Description
The aim of the present study is to investigate the effect of low-permeability concrete, made with reduced water-to-binder ratios (w/b) and/or supplementary cementitious materials (SCMs), on the need for air entrainment to achieve freezing-thawing (F-T) durability. In the present study, concrete mixes were made with different types of cement (Type I and IP), with or without fly ash replacement (15%), with different water-to-binder ratios (w/b=0.25, 0.35, 0.45 and 0.55), and with or without air entraining agent (AEA). All concrete mixtures were controlled to have a similar slump by using different dosages of superplasticizer. The rapid chloride permeability and F-T durability of the concrete samples were determined according to ASTM C1202 and ASTM C666A, respectively. The air void structure of the concrete was studied using the Air Void Analyzer, Rapid Air, and porosity tests (ASTM C642). In addition, the general concrete properties, such as slump, air content, unit weight, and 28-day compressive strength, were evaluated. The results indicate that all concrete mixes with proper air entrainment (ASTM C23 air content greater than or equal to 6%) showed good F-T resistance (durability factor greater than or equal to 86%). All concrete mixes without AEA showed poor F-T resistance (durability factor less than 40%), except for one mix that had very low permeability and high strength. This was the concrete made with Type IP cement and with a w/b of 0.25, which had a permeability of 520 coulombs and a compressive strength of 12,760 psi (88 MPa). There were clear relationships between the F-T durability and hardened concrete properties of non-air entrained concrete. However, such relationships did not exist in concrete with AEA. For concrete with AEA, good F-T durability was associated with an air void spacing factor less than or equal to 0.28 mm (by AVA) or less than or equal to 0.22 mm (by RapidAir).
Author: Kejin Wang
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 52
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Book Description
The aim of the present study is to investigate the effect of low-permeability concrete, made with reduced water-to-binder ratios (w/b) and/or supplementary cementitious materials (SCMs), on the need for air entrainment to achieve freezing-thawing (F-T) durability. In the present study, concrete mixes were made with different types of cement (Type I and IP), with or without fly ash replacement (15%), with different water-to-binder ratios (w/b=0.25, 0.35, 0.45 and 0.55), and with or without air entraining agent (AEA). All concrete mixtures were controlled to have a similar slump by using different dosages of superplasticizer. The rapid chloride permeability and F-T durability of the concrete samples were determined according to ASTM C1202 and ASTM C666A, respectively. The air void structure of the concrete was studied using the Air Void Analyzer, Rapid Air, and porosity tests (ASTM C642). In addition, the general concrete properties, such as slump, air content, unit weight, and 28-day compressive strength, were evaluated. The results indicate that all concrete mixes with proper air entrainment (ASTM C23 air content greater than or equal to 6%) showed good F-T resistance (durability factor greater than or equal to 86%). All concrete mixes without AEA showed poor F-T resistance (durability factor less than 40%), except for one mix that had very low permeability and high strength. This was the concrete made with Type IP cement and with a w/b of 0.25, which had a permeability of 520 coulombs and a compressive strength of 12,760 psi (88 MPa). There were clear relationships between the F-T durability and hardened concrete properties of non-air entrained concrete. However, such relationships did not exist in concrete with AEA. For concrete with AEA, good F-T durability was associated with an air void spacing factor less than or equal to 0.28 mm (by AVA) or less than or equal to 0.22 mm (by RapidAir).
Author: Gilson Lomboy
Publisher:
ISBN:
Category : Air void
Languages : en
Pages : 20
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Book Description
The present research is aimed at investigating effects of concrete properties, particularly concrete rapid chloride permeability, strength, and air void parameters, on freezing-thawing (FT) resistance. In this study, concrete mixtures are made with different types of cement (Types I with 15 % class C fly ash and Type IP cements), different water-to-binder ratios (w/b=0.25, 0.35, 0.45, and 0.55), and with or without air entraining agent. The 28-day compressive strength, rapid chloride permeability, and FT durability of the concrete are determined according to ASTM C873, C1202, and C666A, respectively. The air void parameters of the concrete are measured with air void analyzer, Rapid Air, and porosity (ASTM C642) tests. The results indicate that although concrete made with a low w/b (≤0.35) has low rapid chloride permeability (≤1320 C), it generally still requires proper air entrainment for a desirable FT resistance (with a durability factor of ≥85 %), except for the concrete having very low rapid chloride permeability (520 C) and very high 28-day compressive strength (88 MPa or 12 760 psi). For the non-air-entrained concrete studied, there are clear relationships between FT durability and porosity, w/b, and permeability. However, such relationships do not exist for air-entrained concrete. The FT resistance of air-entrained concrete is largely dependent on the concrete air void characteristics.
Author: J. Marchand
Publisher: CRC Press
ISBN: 0203627091
Category : Architecture
Languages : en
Pages : 323
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Book Description
Concrete durability in climates where freezing and thawing occurs is a continuing problem. It is particularly acute for highway and bridge structures, where de-icing salts are used to combat the effects of frost, snow and ice. These salts can cause damage to concrete and accelerate corrosion of reinforcements. This book presents the latest international research on this area, with contributions from North America and Europe which were presented at an international RILEM workshop.
Author: E. C. Roshore
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 66
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Book Description
Author: M. Pigeon
Publisher: CRC Press
ISBN: 1482271443
Category : Technology & Engineering
Languages : en
Pages : 259
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Book Description
This book provides a comprehensive and authoritative review of durability of the frost resistance of concrete. It will enable both concrete materials specialists and practising engineers to better understand the deterioration processes which take place during freezing and thawing, and the effects of de-icing salts on concrete. It shows how test pro
Author: National Research Council (U.S.). Highway Research Board
Publisher:
ISBN:
Category : Aggregates (Building materials).
Languages : en
Pages : 48
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Book Description
Paper 1 presents laboratory freeze-thaw results as well as field observations on the major Michigan aggregate sources and is considered a first step in formulation of a policy regarding acceptance of future aggregates of unknown service behavior.
Author: Robert E. Philleo
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 44
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Book Description
Recent developments have made a new generation of high-strength concrete a viable material for routine construction. The two principal developments are high-range water-reducing admixtures, which permit the placement of concrete of very low water-cement ratio, and silica fume, a pozzolan of extremely high fineness. The advent of this high- strength concrete has put requirements for strength and durability in conflict. Because entrained air reduces the strength of concrete, builders seek to eliminate or limit the use of entrained air. There are those who argue that high-strength concrete is of such a quality that entrained air is unnecessary. Much of the high-strength concrete currently being used is in buildings, where the question of durability is minor. The question, however, cannot be avoided in exposed highway structures. Service records of non-air-entrained high-strength concrete exposed to freezing are not conclusive. Hence, this report synthesizes the available knowledge on the subject. Its aim is to provide guidance to those who wish to use high-strength concrete in typical highway applications and to indicate where further information is needed.
Author: William O. Tynes
Publisher:
ISBN:
Category : Frost resistant concrete
Languages : en
Pages : 44
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Book Description
Author: William A. Cordon
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 120
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Book Description
Discussion of the behaviour of various concrete structures exposed to freezing and thawing is followed by theories regarding mechanisms which cause this behaviour, and methods of preventing concrete deterioration.
Author: Lawrence J. Kaetzel
Publisher:
ISBN:
Category : Expert systems (Computer science)
Languages : en
Pages : 274
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Book Description
