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Influence Of Air Void System On Freeze Thaw Durability Of Concrete
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Book Synopsis INFLUENCE OF AIR-VOID SYSTEM ON FREEZE-THAW DURABILITY OF CONCRETE. by : ZAFAR AHMED MALIK
Download or read book INFLUENCE OF AIR-VOID SYSTEM ON FREEZE-THAW DURABILITY OF CONCRETE. written by ZAFAR AHMED MALIK and published by . This book was released on 1991 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-way analysis of variance showed that type of air entraining agent, quality of aggregate, and content of condensed silica fume have a major effect on freeze-thaw durability of concrete.
Book Synopsis Freeze-Thaw Durability of Concrete by : J. Marchand
Download or read book Freeze-Thaw Durability of Concrete written by J. Marchand and published by CRC Press. This book was released on 2004-03-01 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Effect of Vibration on the Air-void System and Freeze-thaw Durability of Concrete by : David C. Stark
Download or read book Effect of Vibration on the Air-void System and Freeze-thaw Durability of Concrete written by David C. Stark and published by . This book was released on 1986 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Influence of Pumping Parameters on the Freeze-thaw and Scaling Resistance of Highly Workable Concrete by : Alexandra Nicole Wehar
Download or read book Influence of Pumping Parameters on the Freeze-thaw and Scaling Resistance of Highly Workable Concrete written by Alexandra Nicole Wehar and published by . This book was released on 2019 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Over the past 60 years, pumping concrete has gained popularity due to the economic and technical benefits that typically accompanies it. However, boom configuration and flow rate can adversely affect freeze-thaw and scaling resistance of concrete due to the effects of pressure on the air-void system. Therefore, the objective of this research is to assess the influence of different pumping parameters on the durability of hardened self-consolidating concrete. Self-consolidating, flowable, and conventional concrete mixtures were tested during large scale pumping experiments positioning the pump boom in an 'A' and a flat shape as well as using different pumping speeds. In addition, the effect of adding a reducer and submerging the discharge hose into concrete to minimize the impact on the concrete air-void system was also explored. While pumping, the concrete fresh properties, including the air content were measured. The freeze-thaw durability and scaling resistance were tested for both pumped and non-pumped samples. Furthermore, the air-void size distribution in the hardened state was measured. During pumping, considerable changes in fresh air content were observed from sample to sample. Hardened results indicated that different pumping parameters induced different changes in the air-void system, most importantly the spacing factor. The most notable increases in spacing factor were observed when increasing the flow rate in the A configuration for self-consolidating and flowable mixtures and adding a reducer in the A configuration with self-consolidating concrete. The changes in air-void system corresponded to changes in the severity of scaling. A poor air-void system led to lower scaling resistance. Mixtures with higher air content showed fewer signs that pumping affects the freeze-thaw or scaling resistance"--Abstract, page iii.
Book Synopsis Durability of Concrete in Cold Climates by : M. Pigeon
Download or read book Durability of Concrete in Cold Climates written by M. Pigeon and published by CRC Press. This book was released on 2014-04-21 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Book Synopsis Freeze-thaw Durability of Concretes with and Without Class C Fly Ash by : Chengsheng Ouyang
Download or read book Freeze-thaw Durability of Concretes with and Without Class C Fly Ash written by Chengsheng Ouyang and published by . This book was released on 1997 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The freeze-thaw resistance of concretes was studied. Nine concrete mixes, made with five cements and cement-Class C fly ash combinations, were exposed to freeze-thaw cycling following 110 to 222 days of moist curing. Prior to the freeze-thaw cycling, the specimens were examined by a low-vacuum scanning electron microscope (SEN) for their microstructure. The influcence of a wet/dry treatment was also studied. Infilling of ettringite in entrained air voids was observed in the concretes tested. The extent of the infilling depends on the period of moist curing as well as the wet/dry treatment. The concretes with 15% Class C fly ash replacement show more infilling in their air voids. It was found that the influence of the infilling on the freeze-thaw durability relates to the air spacing factor. The greater the spacing factor, the more expansion under the freeze-thaw cycling. The infilling seems to decrease effective air content and to increase effective spacing factor. The infilling also implies that the filled air voids are water-accessible. These might lead to concrete more vulnerable to the freeze-thaw attack. By combining the above results with field observations, one may conclude that the freeze-thaw damage is a factor related to premature deterioration of PCC pavements in Iowa.
Book Synopsis A Study of Concrete Freeze-thaw Durability and Air Void Parameters by : Frederick Williamson
Download or read book A Study of Concrete Freeze-thaw Durability and Air Void Parameters written by Frederick Williamson and published by . This book was released on 1964 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a result of the knowledge that concrete freeze-thaw durability depends on the number, size, and spacing of air voids throughout the mass, rather than on the total volume of entrained air voids, study of the air void system of hardened concrete has become concentrated on the determination of significant air void parameters. This thesis presents the results of an investigation to determine relationships between freeze-thaw durability and air void parameters of hardened concrete. Specifically, the objective of this study was to establish the pattern of the relationships between concrete durability and both the void spacing factor and the specific surface of the voids. Eighteen concrete mixes, representing six air contents up to approximately nine per cent by volume, and three common cement contents, were prepared and tested during this program. Air void parameters of the hardened concrete, as determined by the lineal traverse method of microscopic examination (A.S.T.M. C 457 - 60T), were measured and related to freeze-thaw durability data obtained from tests performed in accordance with A.S.T.M. procedure C 290 - 57T. Compressive strength data were also obtained for all concrete mixes prepared. Compressive strength test results verified the well-known relationships involving strength, age, cement content, air content, and water-cement ratio. The most significant test results available from this investigation are those relating concrete freeze-thaw durability and air void parameters. It was found that air entrainment up to approximately six per cent air by volume improved the concrete freeze-thaw durability, by decreasing the air void size and spacing, and increasing the specific surface of the voids. At air contents greater than approximately six per cent, further air entrainment did not significantly improve the freeze-thaw durability. Freeze-thaw durability was found to be practically independent of both cement content and water-cement ratio, for air contents above approximately two per cent. Protection of concrete from freeze-thaw deterioration is thus more effectively realized by air entrainment, than by variations in cement content and/or water-cement ratio. Observed data showed that relationships between concrete durability and both specific surface and spacing factor are non-linear. A rapid increase in durability with decreasing void spacing indicates a critical void spacing factor of approximately 0.005 inch, for conditions of these tests.
Book Synopsis Frost Resistance of Concrete by : R Auberg
Download or read book Frost Resistance of Concrete written by R Auberg and published by CRC Press. This book was released on 2004-03-01 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book forms the proceedings of the international workshop to be held in Essen, Germany. This workshop summarises the conclusion of the technical committee's investigations into the resistance of concrete to freeze-thaw attack, specific in this to resistance with or without de-icing chemicals. It presents the RILEM recommendations on testing the freeze-thaw and de-icing salt resistance of concrete.
Book Synopsis Evaluation of the Critical Air-Void System Parameters for Freeze-Thaw Resistant Ternary Concrete Using the Manual Point-Count and the Flatbed Scanner Methods by : Mateusz Radlinski
Download or read book Evaluation of the Critical Air-Void System Parameters for Freeze-Thaw Resistant Ternary Concrete Using the Manual Point-Count and the Flatbed Scanner Methods written by Mateusz Radlinski and published by . This book was released on 2010 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research was conducted to verify whether the semi-automatic method of air-void system characterization (using a flatbed scanner) could be used in lieu of the manual (ASTM C457) method. This research objective was accompanied by evaluating the critical air-void system parameters required to ensure freeze-thaw resistance of ternary concrete containing ordinary portland cement (OPC), 20 % of fly ash (FA), and 5 % of silica fume (SF). It was observed that, due to adverse effect of high superplasticizer dosage on air-void system quality (particularly on specific surface), the majority of high slump ternary mixtures exhibited poor freeze-thaw resistance, even if spacing factor was below the 0.20 mm recommended value. However, when the ternary mixtures were prepared with slump below the limit commonly specified for bridge deck applications (190 mm), the critical air-void system parameters of the OPC/FA/SF concrete were comparable to those typically associated with adequate quality air-void system in conventional concrete. Furthermore, since the critical value of specific surface was independent of slump (i.e., superplasticizer dosage), specific surface appeared to be more objective and reliable predictor of freeze-thaw resistance than spacing factor. When comparing the semi-automatic and manual methods of air-void system characterization, a reasonably strong agreement was obtained for such parameters as air content, void frequency, and spacing factor. Although the results of these methods did not match perfectly, the data suggested that the flatbed scanner technique could be efficiently used for discerning between freeze-thaw durable and non-durable concretes.
Book Synopsis Expert/knowledge-based Systems for Cement and Concrete by : Lawrence J. Kaetzel
Download or read book Expert/knowledge-based Systems for Cement and Concrete written by Lawrence J. Kaetzel and published by . This book was released on 1991 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effects of Air Void Parameters and Water/cementitious Ratio on the Durability Performance of Portland Cement Concrete by : Richard A. Walls
Download or read book Effects of Air Void Parameters and Water/cementitious Ratio on the Durability Performance of Portland Cement Concrete written by Richard A. Walls and published by . This book was released on 2000 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Influence of Design Characteristics on Concrete Durability by :
Download or read book Influence of Design Characteristics on Concrete Durability written by and published by . This book was released on 1990 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Freeze-thaw Resistance of Concrete with Marginal Air Content by : Jussara Tanesi
Download or read book Freeze-thaw Resistance of Concrete with Marginal Air Content written by Jussara Tanesi and published by . This book was released on 2006 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Freeze-thaw resistance is a key durability factor for concrete pavements. Recommendations for the air void system parameters are normally: 6 ± 1 percent total air, and spacing factor less than 0.20 millimeters. However, it was observed that some concretes that did not possess these commonly accepted thresholds presented good freeze-thaw resistance in laboratory studies. This study evaluated the freeze-thaw resistance of several "marginal" air void mixes, with two different types of air-entraining admixtures (AEA)-a Vinsol resin and a synthetic admixture. This study used rapid cycles of freezing and thawing in plain water, in the absence of deicing salts. For the specific materials and concrete mixture proportions used in this project, the marginal air mixes (concretes with fresh air contents of 3.5 percent or higher) presented an adequate freeze-thaw performance when Vinsol resin based air-entraining admixture was used. The synthetic admixture used in this study did not show the same good performance as the Vinsol resin admixture
Book Synopsis Effect of Vibration on Freeze-thaw Resistance of Concrete by : Ahmad A. Ghadban
Download or read book Effect of Vibration on Freeze-thaw Resistance of Concrete written by Ahmad A. Ghadban and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-stressed concrete is used for manufacturing railroad ties. Air entrainment is used in concrete railroad ties to provide durability in freeze-thaw conditions commonly present in track. Vibration practices in pre-stressed concrete railroad tie plants could contribute to excessive air loss during manufacture and thus poor freeze-thaw resistance. Rheological properties of fresh concrete significantly influence the determination of how much air is lost during vibration. This research attempted to increase understanding of the effect of vibration on air bubble distribution and freeze-thaw resistance of concrete given certain compositions and rheological properties of concrete. The objective was achieved by examining the effect of different admixtures combinations, vibration parameters, and rheological properties on the air void system and freeze-thaw resistance of concrete. This research also proposed a method to measure rheological properties of concrete when vibrated and for concrete mixtures too stiff to measure using conventional rheology measurements. Results showed that delaying the initiation of vibration can cause significant air loss but does not necessarily decrease freeze-thaw performance of concrete. Results also showed that a majority of air loss occurs in the first 30 seconds of vibration. The types of admixtures used in the concrete mixture can significantly affect the air system and freeze-thaw durability of concrete; this effect was shown to be more pronounced in mixtures with low yield stress and plastic viscosity. While the peak vibration acceleration had a mild effect, the frequency and peak velocity of vibration did not seem to have a noticeable effect on the air system and freeze-thaw performance of concrete. Results also showed that rheological properties of stiff mixtures can be estimated by running the rheology test during vibration.
Book Synopsis Correlation of Hardened Concrete Air-Void Parameters Obtained by Linear Traverse with Freeze-Thaw Durability as Found by ASTM C 666 by : HN. Walker
Download or read book Correlation of Hardened Concrete Air-Void Parameters Obtained by Linear Traverse with Freeze-Thaw Durability as Found by ASTM C 666 written by HN. Walker and published by . This book was released on 1984 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spacing factor for the proportional number of small air voids ̄Lps as proposed by Walker in 1980 and the air-void parameters normally obtained by ASTM Practice for Microscopical Determination of Air-Void Content and Parameters of the Air-Void System in Hardened Concrete (C 457) were each correlated with the durability factor and weight loss found by ASTM Test for Resistance of Concrete to Rapid Freezing and Thawing (C 666) Procedure A for 151 concretes. The correlation coefficients were examined, and it was found that for the durability factor the classical spacing factor from ASTM C 457 gave a slightly but not significantly better correlation than did ̄Lps. The 151 concretes were divided into three groups according to their source. In no case did the correlation obtained from ̄Lps significantly exceed the spacing factor calculated from ASTM C 457.
Book Synopsis Enhanced Entrained Air Void System Characterization for Durable Highway Concrete by : Anthony Torres
Download or read book Enhanced Entrained Air Void System Characterization for Durable Highway Concrete written by Anthony Torres and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The air void system in concrete provides a strong influence on the behavior of cementitious materials in both the fresh and hardened state, especially as it relates to freeze-thaw resistance and deicer scaling. The most common test procedure to characterize the air void system is ASTM C457 – Standard Test method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete, which involves microscopic determination of the air content, paste content, air-void size distribution, and spatial dispersion of a sawn concrete sample. This procedure is reliant on the user to make hundreds of critical decisions per sample, which requires significant time, and is potentially subject to human error. Additionally, ASTM C457 provides minimal guidance regarding the exact steps and equipment necessary to prepare a sample for evaluation. The outcome of this research not only provides specific information regarding sample preparation for hardened concrete air void analysis, it also develops an alternative characterization technique that drastically minimizes evaluation time, human error, and increases reliability of key hardened air void characterization parameters. Specific results show on average air void difference of 0.5% and 0.7% between the alternative method versus ASTM C457 Procedure A and B, respectively. The results also show a significant reduction of analysis time from approximately 2 – 4 hours per sample to 15 minutes per sample when using the alternative method.
Book Synopsis Significance of Tests and Properties of Concrete and Concrete-making Materials by : Joseph F. Lamond
Download or read book Significance of Tests and Properties of Concrete and Concrete-making Materials written by Joseph F. Lamond and published by ASTM International. This book was released on 2006 with total page 661 pages. Available in PDF, EPUB and Kindle. Book excerpt:
