bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Strength and Microstructure of High-Strength Paste Containing Silica Fume
Authors: Li Y , Langan BW , Ward MA 
Published: January 2010

Abstract
This paper describes the effect of silica fume on the strength and microstructure of high-strength paste. The particular tests carried out included: compressive strength, pore structure (mercury porosimetry), calcium hydroxide content, evaporable and non-evaporable water contents, and X-ray diffraction.
Water-cementitious ratios of 0.33, 0.30, 0.27, and 0.24 were tested at the ages of 14, 28, and 90 days. Silica fume contents were 5 and 10% of the total cementitious content by weight.
Results have shown that at a W/C ratio of 0.24, the strength of the paste decreased at all three test ages as the silica fume content increased. The positive influence of silica fume on the strength of paste decreased as hydration increased. The addition of silica fume did not reduce the total porosity but did reduce the maximum continuous radius significantly. X-ray diffraction results indicated that 10% silica fume virtually eliminated the calcium hydroxide content. The amount of non-evaporable water was less than would be expected by the reduction in the cement cogent.
Effect of Mixing Temperature on Slump Loss and Setting Time of Concrete Containing High-Range Water Reducers
Authors: Whiting D 
Published: January 2010

AbstractConcretes containing high-range water reducers (HRWR) based on naphthalene (NHRWR) and melamine (MHRWR) condensation products were batched, mixed, and tested at temperatures of 7, 16, 23, and 32°C (45, 60, 73, and 90°F). The amount of HRWR necessary to obtain a fixed slump and water-cement ratio was found to increase with a decrease in temperature below 23°C (73°F) and to remain fairly constant from 23 to 32°C (73 to 90°F). Slump loss showed a significant increase with an increase in temperature across the entire range studied. Mixtures containing melamine-based HRWR exhibited somewhat higher rates of slump loss than did those containing naphthalene-based HRWR when a cement containing a moderately high tricalcium aluminate (C3A) content was used. No consistent differences in slump loss were found between the two admixtures when a cement with a somewhat lower C3A content was tested. At the dosages used in this study, HRWR exhibited significant, though not excessive, retardation of set. It was found that certain combinations of HRWR and lignosulfonate or hydroxycarboxylic acid type retarders can have a moderating effect on slump loss at elevated temperatures.
Air Content of Hardened Concrete from Comparison Electron Microscope Photographs
Authors: Mullen WG , Waggoner CK 
Published: January 2010

Abstract
The purpose of the research reported in this paper is to provide a rapid means for determining the entrained air content of hardened concrete by using scanning electron microscope photographs of fractured faces of samples from hardened concrete. The method that has been developed and verified at a reasonable level of confidence consists of an array of low magnification scanning electron microscope photographs of fractured faces of concretes of known air contents. The air contents range from 0 to 20% in increments of approximately 1%. At a magnification of ×80, air-entrained bubbles interrupted by the fracture face are visible as portions of hollow spheres. To determine the air content of a concrete a random series of photographs is made of fractured faces, and these are compared as a group to the array of known air content photographs until a best match is made. With untrained personnel, 1 σ precision, where σ is the standard deviation, of less than 1.5% has been obtained in selecting the correct air content for a concrete with an unknown air content.
Roughness of Aggregates of Different Types by the Modified Fourier Method and Scanning Electron Microscopy
Authors: Czarnecka ET , Gillott JE 
Published: January 2010

Abstract
Three types of aggregates obtained by partial crushing of pebbles of different lithology and erosional history were investigated quantitatively with the modified Fourier technique. All the crushed particles were rougher, that is, more elongated and textured than the natural pebbles from which they were obtained. Surface texture increases more rapidly than the elongation. However, roughness, shape, and surface texture of the aggregates depend on the lithology of the raw material. There was also a difference in trend between changes of roughness within natural and crushed particles of different types when the size of the pebbles investigated decreased. Provided the number of profiles is representative, the modified Fourier method yields precise numerical values. These data could lead to improved control of the roughness, shape, and texture characteristics that have an important effect on the properties of aggregates in concrete. Studies with the scanning electron microscope showed conchoidal fractures on the surfaces of quartzite particles and finer textural features on limestone surfaces. These detailed features add to the surficial macrotexture of profiles investigated by the Fourier method.
Pigments for Integrally Colored Concrete
Authors:   Task Group of ASTM Subcommittee Section C09.03.08.05 on Methods of Testing and Specifications for Admixtures
Published: January 2010

Abstract
A Task Group of ASTM Subcommittee Section C09.03.08.05 has developed laboratory tests for lightfastness, alkali resistance, water wettability, and curing stability of pigments to be used to integrally color concrete. A general purpose carbon black, which was hydrophobic, did not pass the water wettability test, but a hydrophilic concrete-grade carbon black readily mixed with water. Many otherwise attractive pigments, such as chrome yellow and iron blue, did not pass the alkali resistance test. Ultramarine blue is resistant to most alkalies, but calcium hydroxide gradually decomposes it, especially at elevated temperatures; therefore, ultramarine blue did not pass the curing stability test. None of the organic pigments tested passed the lightfastness test. Of the pigments tested, only iron oxide (natural and synthetic), chromium oxide, cobalt blue, and carbon black (concrete grade) passed all four tests.
Rapid Determination of the Predominant Form of Calcium Sulfate Found in Portland Cement and Its Effect on Premature Stiffening
Authors: Buchanan CE 
Published: January 2010

Abstract
The object of this research program was to enable us to predict very rapidly the performance of portland cement in the field in relationship to abnormal setting characteristics. A cement water leach is prepared, and the filtrates are analyzed for calcium and sulfate. A sodium (DI) ethylenediaminetetraacetate acid (EDTA) titration is used for the calcium and a turbidimetric method is used for the sulfate. Based on the results obtained with this chemical procedure, quality control methods that fairly accurately predict whether a cement contains an excessive amount of either anhydrite or plaster of paris have been prepared.
Investigation of ASTM Paste and Mortar Bleeding Tests
Authors: Kemp BG 
Published: January 2010

Abstract
This report outlines the results of testing to see if 1-1-1 trichloroethane can be substituted for carbon tetrachloride as the displacement medium in the ASTM standardized cement bleeding tests. This was necessary because highly toxic carbon tetrachloride is now banned from laboratory use in the United States.
Results show that the bleeding rates and bleeding capacities of various cement pastes and mortars are not significantly affected by the use of 1-1-1 trichloroethane. This report concludes that 1-1-1 trichloroethane may be substituted for carbon tetrachloride.
It is recommended that the design of the collecting ring in the bleeding apparatus be modified to prevent unwanted water bubbles from rising inside the collecting buret.
State of Solutes in Contact with Hydrating Tricalcium Silicate Pastes
Authors: Punzet-Karpisek M 
Published: January 2010

Abstract
There have been numerous excellent studies concerned with the mechanism of the early hydration reactions of tricalcium silicate. The determination of reaction kinetics through the use of conduction calorimetry, quantitative X-ray diffraction analysis, studies of the stoichiometry of hydration, and, now, the growth of calcium hydroxide crystals in water have been done. Data concerning the liquid-phase composition in contact with hydrating tricalcium silicate also have been reported.
The present paper will only give some references concerned with electrolyte solutions and experimental procedure.
Use of the Maleic Acid Method for the Determination of Cement Content of Concrete
Authors: Marusin SL 
Published: January 2010

AbstractThe determination of cement content of hardened concrete using the maleic acid (MMA) extraction method was evaluated using laboratory-prepared samples. The effect of variations in the strength of the maleic acid solution and sample digestion time were evaluated. The method was found to be very accurate. The difference between the actual and determined cement contents of the laboratory-prepared concretes ranged from 0.0 to 0.3 bags per yd3 with an average of 0.2 bags per yd3. A test procedure for using the method to determine the cement content in concrete cores is proposed. The method is recommended as an adjunct to petrographic examination, since significant errors may occur if the cement paste is extensively carbonated, if such admixtures or aggregates as fly ash or slag are present, or if the aggregates contain carbonate minerals.
Abrasion-Erosion Resistance of Fiber-Reinforced Concrete
Authors: Liu TC , McDonald JE 
Published: January 2010

Abstract
Fiber-reinforced concrete (FRC) has been used for repair of abrasion-erosion damaged areas such as stilling basins, conduits, sluiceways, and discharge laterals in hydraulic structures. However, the resistance of such concrete subjected to abrasive action of waterborne particles has not previously been evaluated.
A recent laboratory study on the abrasion-erosion resistance of FRC is presented in this paper. Thirteen concrete mixtures of three watercement ratios ranging from 0.40 to 0.72, each containing one of four different types of steel fibers, were tested. As is true of concrete without steel fibers, the abrasion-erosion resistance of FRC increased with a decrease in water-cement ratio and consequent increase in compressive strength. The lengths of the fibers had very little effect on the abrasionerosion resistance, and the FRC containing collated and hooked fibers had better abrasion-erosion resistance than the comparable concrete containing straight fibers.
A comparison of the performance of FRC and concrete not containing fibers clearly showed that FRC was less resistant to abrasionerosion than concrete of the same aggregate type and water-cement ratio without fibers. The abrasion-erosion losses of the FRC were consistently higher than that of the concrete not containing fibers over wide ranges of water-cement ratio and, hence, compressive strength.
Based on the results of laboratory tests and field performance experience, fiber-reinforced concrete is not recommended for use in new construction or repair of hydraulic structures in which abrasion-erosion is of major concern.
The Effect of Fly Ash on Concrete Alkali-Aggregate Reaction
Authors: Dunstan ER 
Published: January 2010

Abstract
Concrete aggregates may contain reactive constituents that will react with alkalies in cement causing disruptive expansions. Concrete deterioration caused by alkali-aggregate reaction can be prevented by using nonreactive aggregate or using cement with sufficiently low alkali content. However, energy conservation and pollution controls can be expected to indirectly increase the alkali content of some cements. On the other hand, the availability of nonreactive aggregate is continually reduced. Other preventive techniques, such as the use of pozzolan admixtures, can be used. But pozzolans vary in their effectiveness in reducing alkali-aggregate reactions. This paper discusses the use of fly ash pozzolan, a finely divided material collected from the exhaust flues of coal-burning power plants, to reduce alkali-aggregate reaction. The effectiveness of fly ash to reduce this reaction appears to depend, in part, on the chemical composition of the fly ash and also on the percent weight replacement of cement by fly ash.
On the Correlation of Consistency and Strength of Concrete to the Attrition Rate of Fine Aggregate
Authors: Parka N , Hansen TC 
Published: January 2010

AbstractOn the basis of experimental studies correlations were found between attrition rate of fine aggregates on one hand and consistency of fresh concrete and compressive strength of hardened concretes on the other. For fine aggregates complying with standard requirements, differences of up to 15 MPa (2100 psi) in compressive strength were observed between concretes made with high and low quality fine aggregates when other factors are essentially identical. For identical concrete mix proportions slump values between 190 and 0 mm (7.6 and 0 in.) were observed.
On the Correlation of Strength and Elasticity of Concrete to Los Angeles Abrasion Loss and Crushing Value of Indonesian River Gravels
Authors: Parka N , Hansen TC 
Published: January 2010

AbstractOn the basis of experimental results, correlations were established between, on the one hand, aggregate crushing value and the percentage of natural Indonesian river gravels lost as per the Los Angeles abrasion test and the compressive strength and the modulus of elasticity of hardened concretes on the other. For gravels complying with standard requirements, differences of up to 11.8 MPa (1678 psi) in compressive strength and up to 10.9 GPa (1.55 × 106 psi) in modulus of elasticity were observed between concretes made with high and low quality gravels.
A Strain Control System for Relaxation Studies of Concrete
Authors: Pirtz D , Thomas K 
Published: January 2010

Abstract
This paper describes a system of automatic strain control devised to maintain constant strain in concrete specimens during stress relaxation tests. The system also makes provision for continuous monitoring of strain and stress as the testing proceeds. Evaluation of the system performance from the results of relaxation tests conducted using the system showed that the strain control achieved during these tests was remarkably effective. The maximum variation from initial strain recorded was 0.5 × 10−6 microstrain (0.5 × 10−6 in./in.)
Definition and Measurement of Flexural Toughness Parameters for Fiber Reinforced Concrete
Authors: Johnston CD 
Published: January 2010

Abstract
Current and past approaches to assessing and defining the flexural toughness of fiber reinforced concrete are reviewed, and the difficulties associated with them are discussed. Refinements needed to ensure correct analysis and interpretation of load-deflection relationships in evaluation of flexural toughness are identified. A new system of defining toughness is proposed. It comprises a series of indices based on material behavior up to specified multiples of the first-crack deflection. This system is shown to be superior to the one currently advocated by The American Concrete Institute Committee 544 based on material behavior up to a deflection of 1.9 mm (0.075 in.). It is recommended as the basis for a standard test method to evaluate toughness, and appropriate provisions for inclusion in the standard are identified.
A Critical Look at ASTM C 618 and C 311
Authors: Butler WB 
Published: January 2010

Abstract
ASTM Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete (C 618) is probably the most demanding specification for fly ash in the English-speaking world, with comprehensive provisions for both chemical and physical tests. However, the time delays involved and the cost of testing are often out of proportion to the benefits derived. ASTM Standard Methods of Sampling and Testing Fly Ash or Natural Pozzolans for Use as a Mineral Admixture in Portland Cement Concrete (C 311) does a creditable job of defining test methods to meet the needs of C 618, but neither document makes any attempt to grade testing frequencies for individual tests in a practical manner. With the new ASTM Committee C09.03.10 beginning the task of revising the documents, this seems a good time for a critical look at the status quo.
Development of High-Strength Concrete Incorporating a Large Percentage of Fly Ash and Superplasticizers
Authors: Mukherjee PK , Loughborough MT , Malhotra VM 
Published: January 2010

Abstract
In this paper results are reported of an investigation performed to develop high-strength concrete incorporating superplasticizers and a large percentage of fly ash as a replacement for normal portland cement. The concrete mix developed had a water to (cement + fly ash) ratio of 0.28, cement and fly ash contents of 390 and 230 kg/m3, respectively, and a large dosage of a superplasticizer. The 28-day compressive strength of 152- by 305-mm cylinders ranged from 51.0 to 53.8 MPa, and the 28-day flexural strength was approximately 8 MPa. The drying shrinkage and creep values were comparable to the corresponding values of the reference mix. It was concluded that the concrete developed was satisfactory in both workability and early age strength and should find uses in precast concrete operations for the production of high-strength structural units.
Durability Performance of Polymer-Modified Mortars
Authors: Ohama Y 
Published: January 2010

Abstract
Polymer-modified mortars have recently been widely used in construction work throughout the world because of their high strength, excellent adhesion, waterproofness, and chemical resistance. The durability performance of such mortars has not been extensively studied until now. Polymer-modified mortars using various polymer dispersions were prepared with different polymer-cement ratios and tested for weatherability, freezing-thawing resistance, heat resistance, and chemical resistance. The test results demonstrate that most polymer-modified mortars have better durability performance than conventional cement mortar.
Thermally Destructive Particles in Sound Dolostone Aggregate from an Ontario Quarry
Authors: Soles JA 
Published: January 2010

Abstract
A normally sound dolostone aggregate was found to be unstable in concrete during sustained heating at 150°C. Petrographic and other related investigations of the rock have indicated that the primary cause of deterioration of particles is the oxidation of iron sulfide. In this aggregate, fine pyrite is intergranular with dolomite, calcite, and clastic material, particularly in shaly sections. Analyses of disintegrated particles revealed that the granular powders consisted of unaltered carbonate and clastic grains, relict pyrite, and sub-micron material containing hygroscopic, iron-rich sulfate. It was concluded that the pyrite had oxidized to iron sulfate hydrate under these particular conditions; the resulting volume change disintegrated the permeable, often weakly bonded particles, and stresses arising from aggregate expansion ruptured the concrete. Tests revealed also that the aggregate was relatively stable at 75 and 300°C and in dry oxygen, which suggests that water vapor in a particular pressure-temperature range is critical for the reaction. Water released from the aggregate by sustained heating is in part responsible.
Ideal and Quasi-Ideal Grading of Coarse and Fine Aggregates for Mass Concrete
Authors: Ehrenburg DO 
Published: January 2010

Abstract
In an earlier publication the author presented a set of tables for proportioning continuously and gap-graded concrete of 38-mm (1.5-in.) maximum size, on the basis of Weymouth's theory of particle interference. In this paper, Weymouth's theory has been restated in algebraic form, thus making applications to mix proportioning less difficult. Moreover, tables for optimum grading of 76-mm (3-in.) maximum size coarse aggregate as well as tables for optimum grading of fine aggregate are included.
Development and Interaction of a Concrete Additive for Improved Performance and Durability
Authors: Syal SK , Kataria SS 
Published: January 2010

Abstract
Two percent of the additive lignin superplasticizer (SLC) that is developed by mixing equal amounts of alkali carbonate and black liquor sulfate/sulfite lye (that is, lignosulfonate-based material) from paper and pulp works in India can eliminate the use of gypsum and produce a cement with improved strength, lower water requirements (about 30% less) for the same consistency, and increase durability. When used as a simple additive to normal portland cement (clinker and gypsum system), it increased strength and durability to aggressive reagents and decreased the water requirement for the same consistency. Porosity, microstructural, and morphological studies suggest that the lower porosity and increased strengths observed in the presence of the additive are caused by the formation of a Type III calcium silicate hydrate gel in the early stages of hydration, instead of a Type I or a Type II calcium silicate hydrate gel that is generally observed in the normal systems. The atomistic mechanism explains that the increased durability in concretes is caused by a denser, more uniform cement matrix and a stronger matrix-aggregate bond.
Mechanical Properties, Durability, and Drying Shrinkage of Portland Cement Concrete Incorporating Silica Fume
Authors: Carette GG , Malhotra VM 
Published: January 2010

Abstract
Portland cement is a highly energy intensive material, therefore, considerable effort is being made to find substitutes for partially replacing cement in concrete. Silica fume, a byproduct in the manufacture of ferrosilicon and silicon metal is one possible substitute. Results are given of a preliminary investigation to determine the strength, freezing and thawing characteristics, and drying shrinkage of concrete incorporating various percentages of silica fume.
Eighteen 0.06-m3 air-entrained concrete mixes were made incorporating 0 to 30% silica fume as a partial replacement for cement. Some mixes were proportioned to have constant slump with water to cementitious materials ratio (W/C + S) ranging from 0.64 to 0.84 whereas others were proportioned to have a constant W/C + S of 0.40; the latter incorporated a superplasticizer. Cylinder and prism specimens were cast for determining the mechanical properties and durability of concrete.
Test data indicate that silica fume when used in concrete as a partial replacement for cement performs as a highly efficient pozzolanic material. Notwithstanding the extreme fineness of silica fume (20 000 m2/kg) and, hence, its high water demand, the compressive strength of constant slump concrete incorporating up to 30% silica fume is comparable with or higher than the strength of control concrete.
Superplasticized concrete mixes having a W/C + S maintained at 0.40 indicate some increase in compressive strength at all ages regardless of the percentage of silica fume.
Concrete prisms incorporating 0 to 15% silica fume (W/C + S = 0.40) perform satisfactorily when subjected to 300 cycles of freezing and thawing; however, prisms incorporating 20 to 30% silica fume and large dosages of superplasticizer show excessive expansion and relatively low dynamic moduli after 300 cycles. The drying shrinkage of concrete incorporating silica fume is generally comparable with that of control concrete regardless of the W/C + S.