bluuebunny/crossref_metadata_2025_split huggingface dataset:
Freeze-Thaw Durability of Concrete With and Without Silica Fume in ASTM C 666 (Procedure A) Test Method: Internal Cracking Versus Scaling
Authors: Pigeon M , Pleau R , Aitcin P-C 
Published: January 2010

Abstract
The freeze-thaw durability of concrete with and without silica fume was investigated in accordance with the requirements of ASTM Test Method for Resistance of Concrete to Rapid Freezing and Thawing (C 666 Procedure A). The water-cement ratio of all mixes was 0.5, and the silica-cement ratio of the silica fume mixes 0.1. The test results show that the critical value of the air-void spacing factor in these ASTM C 666 tests is significantly lower for the silica fume concretes. These concretes are therefore more susceptible to internal cracking caused by rapid freeze-thaw cycles in water, even though the use of silica fume decreased the surface scaling of the test specimens. This confirms that scaling and internal cracking are two different forms of frost damage caused by rapid freeze-thaw cycles in water. The use of silica fume also decreased the internal cracking of the nonair-entrained mixes damaged during the tests.
Chloride Concentrations in Concrete Pore Solutions Resulting from Calcium and Sodium Chloride Admixtures
Authors: Diamond S 
Published: January 2010

Abstract
Cement pastes prepared from a “typical” ASTM Type I portland cement at a water/cement ratio of 0.50 were mixed with various calcium chloride (CaCl2) admixture treatment levels, hydrated for various periods, and then subjected to pore solution expression. The expressed pore solutions were then analyzed for chloride and hydroxide ion concentrations. It was found that the concentration of chloride ions drops rapidly but reaches an equilibrium level by about ten days. The equilibrium concentrations attained varied between 20 and 50% of the original concentration in the mix water, the latter value being for the highest CaCl2 treatment level, 2% by weight of the cement. Substituting sodium chloride (NaCl) for CaCl2 as the admixture produced only minor differences in equilibrium concentration. The equilibrium Cl−/OH− ratios for treatments of 0.5% CaCl2 and above were found to be beyond that considered to be the boundary for depassivation, slightly above 0.3. X-ray diffraction results were ambiguous but differential thermal analysis (DTA) trials provided some evidence for the formation of Friedel's salt in these pastes. However, it was considered likely that at least some of the chloride not retained in solution is associated with calcium-silicate-hydrate (C-S-H) gel.
The Application of Neutron Radiography to the Study of Microcracking in Concrete
Authors: Najjar WS , Aderhold HC , Hover KC 
Published: January 2010

Abstract
Radiography of concrete specimens using a neutron flux as the penetrating radiation has been used to identify and study microcracking. The key to the technique is the partial impregnation of the microcracks with a medium with a high neutron attenuation capacity, so as to result in a sharp contrast between the cracks and the surrounding solid mass. Gadolinium has been used as the neutron-attenuating contrast agent, which is applied in the form of an aqueous solution of gadolinium nitrate.
The resulting radiographs are compared with more conventional X-ray studies of the same specimens. Neutron radiography appears to be more effective than X-radiography for the identification of cracking.
Mechanical Properties and Freezing and Thawing Resistance of High-Strength Concrete Incorporating Silica Fume
Authors: Malhotra VM , Painter KA , Bilodeau A 
Published: January 2010

Abstract
This report presents results of an investigation dealing with the mechanical properties and freezing and thawing resistance of high-strength, silica fume concrete using ASTM Test Method for Resistance of Concrete to Rapid Freezing and Thawing (C 666-84, Procedure A). Eighteen nonair-entrained and six air-entrained concrete mixtures, 0.06 m3 in size, were made. The water-to-(cement + silica fume) ratio (W/C + S) of the mixtures ranged from 0.25 to 0.36, and the percentages of cement replacement by silica fume were 0, 10, and 20% on a weight basis. Any loss in slump due to the use of silica fume was compensated for by the use of a superplasticizer.
A number of test cylinders were made for testing in compression at various ages, and test prisms were cast for determining their resistance to repeated cycles of freezing and thawing in accordance with ASTM C 666, Procedure A. Sawn sections of some of the prisms were used for determining the air void parameters of the hardened concrete.
Nonair-entrained, high-strength concrete with a compressive strength of up to 87 MPa at 28 days, regardless of the W/C + S and irrespective of the silica fume content used, had durability factors less than 12 when tested in accordance with ASTM C 666, Procedure A.
Also, air-entrained concrete prisms incorporating 10 and 20% silica fume as replacement for cement failed to complete 300 cycles of freezing and thawing.
High-Strength Semi-Lightweight Concrete with Up to 50% Fly Ash by Weight of Cement
Authors: Johnston CD , Malhotra VM 
Published: January 2010

Abstract
This paper discusses the effects of including a Western Canadian subbituminous fly ash in superplasticized, air-entrained, semi-lightweight concrete. Mixtures were proportioned with 100 ± 20mm slump and 5 ± 1% air content. Cement contents ranged from 250 to 500 kg/m3 with additions of fly ash up to 50% by weight of cement.
In the freshly mixed state, the effects of the fly ash are to reduce the initial water demand, increase the dosage of air-entraining admixture required for the specified air content, and reduce the rate of slump loss after addition of superplasticizer. The dosage of superplasticizer required remains essentially constant when expressed as a percentage of the total weight of binder (cement + fly ash).
In the hardened state, the emphasis is on establishing how the proportion of fly ash to cement affects strength, unit weight, and cost. Each mixture is evaluated in terms of strength-weight ratio and cost in terms of cement equivalent in kg/m3, using the relationship between the costs of cement and fly ash locally to convert the cost of the fly ash into an equivalent cement cost. The bar chart used for this purpose readily facilitates the identification of optimal mixture proportions from the point of view of strength-weight ratio and cost. In addition, the development of strength is examined at various ages to show how the fly ash progressively asserts its effect on relationships between strength and effective W-C ratio. Finally, resistance to freezing and thawing is reported in terms of Procedure A of ASTM Test Method for Resistance of Concrete to Rapid Freezing and Thawing (C 666-84), and performance is shown to be unsatisfactory when using presaturated lightweight aggregate with the specified 14-day moist curing regime. Performance improves substantially after drying followed by further soaking simulative of the curing of lightweight concrete in structures following construction.
Creep of Lightweight Aggregate Concrete Under Variable Stresses
Authors: Tasdemir MA , Akyüz S , Uzunhasanolu N 
Published: January 2010

Abstract
In this work, the creep of lightweight aggregate concrete under constant stress is described by a logarithmic function of time, and the variations of the coefficients with age are experimentally determined. Using the relation thus obtained, an attempt is made to predict the creep of lightweight concrete specimens with the same composition under stepwise varying stresses, assuming a linear viscoelastic behavior. It was established that there is good agreement between the predicted and experimental values.
Production and Evaluation of a New Source of Granulated Blast Furnace Slag
Authors: Douglas E , Wilson H , Malhotra VM 
Published: January 2010

Abstract
A granulation pilot plant was installed at Algoma Steel Corp., Sault Ste. Marie, Ontario, for the production of about 40 metric tons of granulated blast furnace slag to be tested for concrete and mine backfill applications. The granulated slag was obtained by quenching the molten slag by jets of high-pressure water. Heat loss was maintained at the level expected when the full-size plant is in operation so as to generate a representative slag sample. The granulated slag was allowed to drain in the slag pit before being transported to the grinding facilities, where it was dried in a converted kiln, reducing the moisture content from 8 to 0.3%. The unit power consumption for grinding the granulated slag was similar to typical figures for grinding portland cement clinker in the lower Blaine range.
Quantitative X-ray diffraction analysis showed that the granulated slag was about 90% glass. The magnesium oxide content was about 18% and was likely in the form of a calcium magnesium alumino silicate glass.
Mortar tests performed according to ASTM Specification for Ground Iron Blast-Furnace Slag for Use in Concrete and Mortars (C 989) showed that the slag ground to 4600 and 6080 cm2/g met the requirements for Grades 100 and 120, respectively.
The slag investigated has considerable potential for partial replacement of portland cement in concrete. At comparable fineness, the strength characteristics of the concrete incorporating the Canadian granulated slag are comparable with those of the concrete made with the other Canadian slag (pelletized) used in the investigation.
Freeze-Thaw Durability of Wet-Mix and Dry-Mix Shotcretes with Silica Fume and Steel Fibres
Authors: Morgan DR , Kirkness AJ , McAskill N , Duke N 
Published: January 2010

Abstract
This investigation was undertaken to study the freeze-thaw durability of wet-mix and dry-mix shotcretes when tested according to ASTM Test Method for Resistance of Concrete to Rapid Freezing and Thawing (C 666) Procedure A. Parameters of the air voids system were determined using ASTM Recommended Practice for Microscopical Determination of Air-Void Content and Parameters of the Air-Void System in Hardened Concrete (C 457-82).
The effect of substitution of condensed silica fume for part of the cement was studied for plain shotcrete mixes as well as for mixes containing steel fibres. It was concluded that excellent durability was achieved in nonfibre and steel fibre shotcrete mixes manufactured by both the wet-mix and dry-mix shotcrete processes when approximately 13% of the cement was replaced with silica fume. After 300 cycles of freeze-thaw, excellent durability factors exceeding 95% were achieved in both wet-mix and dry-mix shotcretes having total air contents in the range of 4.5 to 6.5% and spacing factors in the range of 0.27 to 0.31 mm. Substantial increases in compressive strength were also realized during the period of freeze-thaw testing. Flexural strength and toughness of the samples were also not significantly affected by the freeze-thaw cycling.
New Approach for a Concrete Scaling Test Based on Field Conditions
Authors: Moukwa M , Adkins D 
Published: January 2010

Abstract
The microenvironment existing at the surface of a concrete element which has shown rapid deterioration in the form of scaling has been established. Field measurements of the microclimatic elements within the concrete surface layer throughout the winter give new insight into the understanding of the surface scaling. It was found that solar effects have a pronounced effect on the scaling of the concrete surface. Basis for a new scaling test which simulates the deterioration of concrete in the field under severe freeze-thaw conditions has been developed. It consists of partial thawing and complete refreezing of the surface. Erratum to this paper appears in 11(1).
Evaluation of Test Methods for Measuring the Bond Strength of Portland Cement Based Repair Materials to Concrete
Authors: Knab LI , Spring CB 
Published: January 2010

Abstract
Three bond strength test methods were evaluated for screening and selecting repair materials used in overlaying and patching portland cement concrete. Bond strengths of three repair materials to base concrete were investigated using two uniaxial tension bond strength test methods and a slant shear bond strength test method. The differing strengths of the repair materials caused different failure patterns, which had to be considered in the analyses of the failure stresses.
Substantial differences in the failure stresses of the uniaxial tension and slant shear test methods were attributed to their different geometries and loading conditions. These differences emphasized the need to select test method(s) with geometry, loading conditions, and stress states that are anticipated for the in-service repair material.
For the two higher strength repair materials investigated, the relative precision (repeatability) of the slant shear and one of the uniaxial tension test methods (pipe nipple grips) were comparable and relatively good (coefficient of variation values were about 5%). It was concluded that both the slant shear test method and the pipe nipple grips uniaxial tension test method are promising methods for screening and selecting repair materials of the type investigated (portland cement concrete or latex-modified concrete) for overlaying or patching portland cement concrete.
Behavior of Cement-Reduced and “Flowing” Fresh Concretes Containing Conventional Water-Reducing and “Second-Generation” High-Range Water-Reducing Admixtures
Authors: Whiting D , Dziedzic W 
Published: January 2010

Abstract
Fresh concretes were prepared using cements of high and moderate C3A contents and having a cement content of 323 kg/m3 (545 lb/yd3) and a water-to-cement ratio of 0.50. Conventional water-reducing agents based on lignosulfonates and carboxylic acids were used to reduce water and cement contents by 8 to 9%. Second generation high-range water-reducing admixtures (HRWR) were used to reduce cement and water contents by 15 to 16%. Testing included slump loss, air loss with time, setting time, and bleeding. Similar tests were carried out on flowing concretes, where cement and water contents were maintained constant and HRWR was added to increase initial slump levels to 200 to 300 mm (8 to 9 in.). In this series, testing was carried out at both 23°C (73°C) and 32°C (90°F).
Use of chemical admixtures to reduce both water and cement contents resulted in accelerated rates of slump loss and shorter working times compared to controls. When used to produce flowing concretes, working times were equivalent to those for mixes not containing the admixtures. In general, setting times were increased from 1 to 2 h at 23°C (73°F) and by lesser amounts at 32°C (90°F). Bleeding of flowing concretes was greater than that of control mixtures, especially when a copolymer-type HRWR was used. Rate of air loss was significantly greater in cement-reduced mixtures containing HRWR compared with controls; however, air loss rates in flowing concretes were roughly equivalent for all mixtures tested.
Durability of Concrete under Simulated Arctic Conditions
Authors: Moukwa M , Aitcin P-C , Regourd M 
Published: January 2010

Abstract
The durability of 0.44 W/C concrete under simulated Arctic conditions was studied. The length change of concrete specimens was monitored throughout the test. Samples taken from the concrete specimens before and after the test were analyzed to determine the effects of simulated Arctic conditions on the microstructure of the concrete. The results showed that the alternating conditions of immersion in seawater and exposure to cold air mostly affect the surface layer of the concrete and facilitate a deep migration of aggressive ions like magnesium and sulfate.
Another Look at the Portland Cement/Chemical Admixture Incompatibility Problem
Authors: Dodson VH , Hayden TD 
Published: January 2010

Abstract
Reports of incompatibility between portland cement and chemical admixtures have increased over the past ten years. Specifications written by architects and engineers calling for the use of admixtures in concrete often result in strange occurrences, that is, rapid set, accelerated stiffening, increase in time of set, lack of water reduction. This paper addresses the effect of the composition of the cement and that of the chemical admixtures on incompatibility with respect to the problems of rapid set and accelerated slump loss.
The use of natural anhydrite (CaSO4) as a substitute or partial replacement for gypsum (CaSO4 · 2H2O) in the manufacture of portland cement is gaining in popularity. Admittedly, portland cement containing large amounts of natural anhydrite will perform normally, but not necessarily so in concrete containing the common chemical admixtures.
The data presented in this paper attempt to show why large amounts of natural anhydrite in portland cement can cause incompatibility problems in the presence of chemical admixtures. The rate of solution of natural anhydrite, which is much slower than that of gypsum or calcium sulfate hemihydrate, is further retarded in the presence of chemical admixtures, which leads to a “sulfate-starved” system in the concrete, often producing rapid set and an increase in rate of concrete slump loss.
Na2SO4 Soundness Test Evaluation
Authors: Sheftick W 
Published: January 2010

Abstract
The Illinois Department of Transportation (IDOT) uses the sodium sulfate (Na2SO4) soundness test as one of its main aggregate acceptance tests. Unfortunately, many accusations concerning the lack of reproducibility and validity of the soundness test are continually voiced by aggregate producers and specifying agencies.
In order to better understand the sodium sulfate soundness test, IDOT conducted an evaluation program to identify the major problem areas in the test method. The evaluation program consisted of eight separate evaluations. Samples from a number of different Illinois aggregate sources were tested for each evaluation. The evaluations looked at (1) temperature control, (2) different Na2SO4 materials, (3) repeatability, (4) validity, (5) increased cycles, (6) cooling of samples, (7) pan versus basket soaking, and (8) the method used to interrupt the test.
Several general conclusions were drawn from the evaluations on the sodium sulfate soundness test. These conclusions identify areas of the test procedure which could produce erratic and erroneous results. One area was that temperature must be accurately controlled, both during soaking and during cool down of the samples. Another was that the specified method of interrupting the test produces results that do not correlate with running the test straight through to completion. There are also several other items that indicate potential problems and that should have additional research run on them.
The overall summary concluded that when tighter control, especially temperature, is maintained, the sodium sulfate soundness test seems to provide valid test results.
Troubleshooting Retarded Concrete: Understanding the Role of Cement and Admixtures Through an Interdisciplinary Approach
Authors: Jeknavorian AA , Hayden TD 
Published: January 2010

Abstract
This paper discusses a multidisciplinary approach used to determine the cause of a severe and erratic retardation problem. The problem involved random loads of ready-mixed concrete having extended set times of up to 40 h. Eight samples of a Type I/II portland cement, one Class F fly ash, two cylinders, a core, and a sample of Type D water-reducing admixture were evaluated using chemical, microscopic, and physical analyses, and mortar performance tests.
Six samples of the cement were tested for set time performance using a modified ASTM C 403 method. The set times of control cement-sand-water mixes ranged from 2:31 to 5:12 (h:min). When the cements were combined with only 33 mL/100 kg (0.5 oz/100 lb cement (cwt) of admixture, the difference in set time increased dramatically, 2:34 to 7:16 (h:min).
Analysis of the cement, fly ash, concrete, and admixtures did not indicate the cause of the problem. However, the sum of the individual compounds plus the LOI was unusually low, 97.5 to 98.5%, suggesting that one or more components had not been identified in the cement samples. Further analysis revealed the presence of approximately 1% zinc in all the cements. Zinc compounds are known to be powerful retarders of cement hydration.
An extensive investigation—conducted to determine why the cement samples had a wide range of initial set times and yet had a consistent 1% zinc content—indicated that two interrelated factors were responsible. First, cement samples extracted with dilute solutions of the admixture indicated that more zinc could be leached from the cement with the longest initial set time as compared to the faster setting cement. Second, the two cements had different microstructures, which could have corresponded to a variation in their zinc availability and thus the extent to which the hydration reaction was delayed.
Quantitative Petrographic Evaluation of Fine Aggregate
Authors: Hudec PP , Boateng S 
Published: January 2010

Abstract
Petrographic examination of coarse aggregate is accepted as a viable method for predicting its durability in concrete. No similar quantitative method existed for fine aggregate, although Guide for Petrographic Examination of Aggregates for Concrete (ASTM C 295) does yield preliminary information of durability of fine aggregate. This paper proposes a quantitative petrographic analysis that can be used to quickly assess the natural fine aggregate's durability when used in concrete. The method of analysis is essentially the Ministry of Transportation, Ontario LS-616, which separates the fine aggregate into silicate, carbonate, shale and chert fractions. The weighted percentages of these fractions were statistically compared to standard physical tests, including water adsorption and absorption, dry density, magnesium sulfate loss, and micro-Deval abrasion loss. Step-wise multiple regression equations were developed, which allowed calculation of expected magnesium sulfate and micro-Deval abrasion losses based on the proportion of the petrographic types. Mathematical and statistical techniques were also used to establish a petrographic number for sand (PNS) that allows the classification of aggregate into good or poor categories based on their petrographic composition.
Survey of North American Portland Cements: 1994
Authors: Gebhardt RF 
Published: January 2010

Abstract
A survey of portland cements marketed in North America was conducted in 1994 under the sponsorship of ASTM Committee C-1 on Cement. The primary purpose of the survey was to provide modern data on cement characteristics and to aid C-1 subcommittees in evaluating standard development needs. The last previous survey of similar scope was done by the National Bureau of Standards on cements procured in 1953 and 1954, with the data published during the period from 1965 through 1971 (Clifton and Mathey 1971; Blaine et al. 1965). The NBS survey differed in scope by including large amounts of testing data on concrete.
The current survey includes 387 different cements, with cements from 136 of the 140 cement-producing facilities in the United States and Canada plus several foreign cements from import terminals. The data show that modern cements differ from those produced in the 1950s, with differences in compositional and physical characteristics clearly in evidence, thus making obsolete the classification of types used in the previous survey. While an overall classification into five basic types is still applicable, the conceptual definitions of those types have changed in several respects, and there now are numerous subtypes not previously given officially recognized status.
It is expected that this snapshot of modern cement characteristics will assist ASTM committees in their development of standards relating to portland cement and may provide a basis for consideration of many topics relating to hydraulic cements.