bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Incorporation of Low Levels of By-Products in Portland Cement and the Effects on Cement Quality
Authors: Daugherty KE , Funnell JE 
Published: January 2010

Abstract
This paper has attempted to show that the cement industry in the United States can accomplish significant reductions in its total energy consumption by intergrinding industrial by-products such as slags, fly ashes, kiln dusts, and possibly other industrial by-products with cement clinker. Further, as seen in many countries this reduction can be accomplished without sacrifice in cement product quality. This study undertook an analysis and evaluation of the utilization of a variety of slags, fly ashes, and kiln dusts in combination with Type I cements from a number of cement plants. Additionally, a significant portion of the project effort was directed on fostering more widespread usage of industrial by-products in blended cement manufacture in the United States and promoting within the industry, ASTM, and other cognizant agencies the adoption of performance specifications applicable to the energy-saving blended cements.
This study was a step in the direction of energy savings that can be attained through blended cement production and use. There are potentially many additional means of further reducing the energy requirements of cement manufacture, as was discussed in the excellent report on the use of energy within the cement industry.
The Potential Use of Catalysts in the Cement Industry
Authors: Safa AI , Daugherty KE , Mallow WA , Dziuk JJ , Funnell JE 
Published: January 2010

Abstract
The calcination of calcium carbonate in a cement or a lime kiln requires approximately two to four times the theoretical quantity of energy predicted from thermodynamic analysis depending upon the type of cement kiln used. The potential for using catalysts to reduce the total energy requirements was explored. It is, of course, impossible to reduce the theoretical energy requirement for the calcination process. Two possible ways considered to reduce this total requirement were (1) to either increase the rate of calcination at a specific temperature or (2) to decrease the temperature of calcination. Several classes of catalysts show promise of doubling the calcination rate (or decreasing the energy requirement by ½).
Waste Fuels Program at the Mississauga Plant of St. Lawrence Cement, Inc.
Authors: MacDonald LP 
Published: January 2010

Abstract
Used automotive oil containing approximately 0.5% lead, 0.1% bromine, 0.1% zinc, and 0.1% phosphorus was burned in a suspension preheater kiln. Lead, zinc, and phosphorus emissions were not found to be increased. A material balance showed these elements to be retained in the process solids. No effect on cement quality was detected.
Waste chlorohydrocarbons including polychlorinated biphenyls were burned in a wet-process kiln. These compounds were destroyed in the cement kiln flame. The chlorine liberated reacted with process materials reducing the alkali content of the clinker.
Coke containing high contents of sulfur and significant levels of vanadium and nickel was burned in the wet-process kiln. Nickel and vanadium were almost entirely retained in the clinker. Sulfur retention depended strongly on burning conditions within the kiln.
The Use of Unconventional Fuels in Cement Manufacture
Authors: Capon BM , Layne PB , Watson D 
Published: January 2010

Abstract
For more than half a century combustible materials have been used to a limited extent to substitute partially for coal, oil, or gas as the main fuel for cement manufacture, and the continuing increase in price of the conventional fuels is increasing the incentive to do this wherever it is technically practicable and economic. This paper discusses and quantifies the theoretical aspects of this topic, particularly the influence of the properties, continuity of supply, delivered cost and processing cost of possible alternative fuels, the tolerance of the cement-making process according to the type of process and raw materials and cement product quality requirements. Guidelines are developed and are illustrated by reference to the results of research and development and pilot plant work and practical experiences of a number of full-scale applications including a large and novel plant and system for consuming domestic refuse (municipal garbage) in a cement works.
The Grace Factor: A New Tool for Cement Industry Process Control Engineers
Authors: Welch PW 
Published: January 2010

Abstract
A method for mill control and supervision is described that is based on measurement of the mill horsepower consumption and the bulk density of the material being ground. Control by horsepower is shown to be possible and to be a more fundamentally based scheme than other commonly used systems. A monitoring and control system is discussed that uses the relationships described to provide a visual indication of mill loading conditions that can be used effectively by nontechnically trained personnel for manual mill control or as an automatic signal for direct control interlock with programmable controllers.
Study of Alkali-Silica Reactivity Tests to Improve Correlation and Predictability for Aggregates
Authors: Heck WJ 
Published: January 2010

Abstract
Evaluation of ASTM Tests for Potential Reactivity of Chemical Aggregates (Chemical Method) (C 289), Potential Alkali Reactivity Cement-Aggregate Combination (Mortar-Bar Method) (C 227), and Petrographic Examination of Aggregates for Concrete (C 295) for predicting alkali-silica reactivity potential of aggregates was undertaken using a natural siliceous sand and a manufactured limestone sand to which 2, 5, 10, and 20% by weight of reactive materials (chert and opaline sandstone) were added. Three aggregate gradings were tried in the mortar-bar test. None of the test methods by themselves are adequate to predict alkalisilica reactivity potential; furthermore, the chemical test did not correlate well with the limit of mortar-bar expansion at an age of six months as indicative of reactive aggregate. There is a linear trend between the amount of reactive material and the amount of soluble silica by weight added to the sands and reduction of alkalinity determined by the chemical test. A similar linear relationship is shown between the amount of soluble silica and the amount of reactive material in the aggregate as determined by petrographic examination. The pessimum proportion of the reactive material was found to be around 10% by weight. Coarser graded aggregate tended to produce greater expansion, but this was not definitely established. Mortar-bar expansion tends to be highly variable with increase of amount of reactive material over 2%. The test data indicates that the limit of mortar-bar expansion of 0.1% at six months does not adequately define potentially reactive material. It is suggested that the limit should be lowered to 0.075% at six months. Because of the effect of grading and the variability of expansion, consideration should be given to replacing the mortar-bar test with a concrete-prism test. Limestone aggregate appears to have an inhibiting effect on alkali-silica reactivity, therefore, adding limestone to reactive aggregates may be a practical way to make them usable in concrete. Further testing should be conducted to establish the minimum amount of limestone required to effectively inhibit reactivity.
Some Questions Concerning ASTM Standards and Methods of Testing Fly Ash for Use with Portland Cement
Authors: Helmuth R 
Published: January 2010

AbstractAlthough the potential for substantial energy conservation by the use of fly ash in blended cements is well recognized, present test methods and standard specifications do not appear to be adequate to insure predictable performance. A review of the literature led to an analysis of the scientific bases for existing tests for water requirement for pozzolanic activity. Questions are raised concerning the use of fixed proportions in both tests. It is suggested that proportions be adjusted in the mortar flow test to take into account the 45-μm (No. 325) sieve residue of the fly ash. It is also suggested that variable proportions of fly ash and cement be used in the pozzolanic activity tests to facilitate optimization of concrete properties.
Variation of Laboratory Concrete Flexural Strength Tests
Authors: Greer WC 
Published: January 2010

Abstract
An analysis of 145 laboratory flexural-strength concrete mixes prepared for projects at the expansion of the Atlanta International Airport is presented. Typical values for within-test (within-batch) and between-test (between-batch) standard deviations are presented and compared with data published by others. Flexural strength as a function of age in the laboratory is discussed, and typical values are given for Type I cement mixes.
Alkali Reactivity of Strained Quartz as a Constituent of Concrete Aggregate
Authors: Buck AD 
Published: January 2010

Abstract
Some strained quartz may cause a deleterious alkali-silica reaction if present as a constituent of concrete aggregate in sufficient amounts. The criterion for reactive strained quartz is suggested to be more than 20% strained quartz with an average undulatory extinction angle greater than 15°. Length changes of mortar bars containing such strained quartz will be 0.025 and 0.040% or more at six and twelve months, respectively, when stored at a temperature of 60°C (140°F). Revisions to applicable ASTM standards may be appropriate.
Efficient Large Panel Roofing
Authors: Matselinsky RN , Rogatin YA , Spannut LS 
Published: January 2010

Abstract
Large panel building roofs using prestressed short cylindrical panel-shells with dimensions of 3 by 12, 3 by 18, and 3 by 24 m developed in the U.S.S.R. are presented in this paper, and their technical and economic advantages in comparison with other roofs are shown.
The Effect of Mix Design on the Properties of Sulfur Concrete
Authors: Czarnecki B , Gillott JE 
Published: January 2010

Abstract
Some sulfur concretes have been shown to expand excessively under moist conditions. The deterioration is accompanied by a decrease in dynamic modulus of elasticity with time. The durability of sulfur concretes containing glycerin and crude oil admixtures was slightly improved, but expansions were still unacceptably high. Two silane admixtures significantly decreased the moisture expansions. Silane type A was more effective when larger amounts were used, but differences in amount of silane type Z had little effect on amount of expansion. Silanes also improved the durability of sulfur concrete when assessed by the dynamic modulus of elasticity, which generally remained at the same level during water immersion. It is concluded that by changing the surface characteristics at the aggregate-sulfur interface silanes minimize the detrimental effects of moisture.
The Creep of Concrete Pipes in Kuwait
Authors: Al-Obaid YF 
Published: January 2010

Abstract
Most concrete pipes of 915-mm diameter buried 1.5 m below the surface of Kuwait highways have been examined. About 55% of these developed circumferential strains (in tension) about 30 microstrain at top and bottom as soon as they were buried. In a matter of eight weeks, due to vehicle loads, the top strains increased on 100 pipes by 10% and bottom strains remained unchanged. An experiment has been carried out on site to determine the magnitude of the creep occurring in such pipes. In a period of six months the creep strains have increased by three times the previous strains resulting from the initial application of loads. Over 60% of the concrete pipes tested show 4.75 times creep strains measured at the initial stages. On King Faisal Road some pipes on removal indicated a substantial degradation of material due to sulfur attack.
Anisotropy of Concrete Strength
Authors: Leshchinsky AM 
Published: January 2010

Abstract
Results obtained by numerous researchers concerning concrete strength anisotropy are analyzed. In some cases, the researchers have found that the compressive strength of specimens loaded at a right angle to a direction of concrete placing, f′c, is greater than for those loaded parallel to the above direction, f″c; in other cases, it is lower. This fact has been elucidated. In the cases where anisotropy is caused by the “internal” mix segregation, we come across f′c/f″c &gt; 1; when the cause is in the “external” mix segregation, the result is f′c/f″c &lt; 1. Given are recommendations for taking into account such anisotropy in core testing.
Crack Counts in Air-Entrained and Non-Air-Entrained Concrete Subjected to Accelerated and Fog-Room Curing
Authors: Gillott JE , Czarnecki B 
Published: January 2010

Abstract
Concrete cured by the accelerated steam method, at atmospheric pressure, sometimes shows a reduced rate of strength gain at later ages. This loss of potential strength has been attributed to a number of factors, including microcracking caused by differential stress within the material. This may result from differences in the thermal expansion coefficients of the solid phases themselves and from the greater differences between the coefficients of solids and water. Because entrained air voids help to protect concrete from damage by frostaction by providing void spaces that reduce the build-up of hydraulic pressure caused by migrating water, we postulated that entrained air may similarly benefit concrete subjected to accelerated steam curing. The loss of potential strength in the steam-cured specimens was assumed to result from an increase in internal microcracking.
Specimens of air-entrained and non-air-entrained concrete were made and subjected to fog-room curing and to accelerated steam curing. However, crack-counts made at ages of 1 day and 28 days under an optical microscope were similar in both air-entrained and non-air-entrained concrete. At 28 days, crack-counts were higher in the fogcured concrete than in the steam-cured concrete whether air-entrained or not. Consequently, the data did not support the suggestions that entrained air would reduce internal stresses and resulting microcracking. Also, regardless of air-entrainment, it was found that crack counts were highest in samples that had gained strength most rapidly.
Optimization of the Composition of a High-Performance Concrete
Authors: Rougeron P , Aïtcin P-C 
Published: January 2010

AbstractThe production of a high-performance concrete (HPC) is more of an art than a science, although the basic principle needed to be implemented is simple: HPC is a concrete having a low waterbinder ratio (W-B). Achieving a low water-binder ratio can be realized in many different ways. The work reported hereafter tries to answer three basic questions:• Is it better to use the least amount possible of mixing water with a high dosage of superplasticizer to obtain the desired workability, or is it better to use more water (and more cement), but less superplasticizer?• Is the use of silica fume advantageous in making HPC?• If yes, what is the maximum price that can be paid for it?A factorial design plan involving 18 laboratory concrete batches has shown that the use of silica fume is advantageous up to a price of $600/ton (CAN) (for the conditions of the experiment). Moreover, it was found that for a precast operation, it is better to increase the amount of water used in making HPC and to decrease the amount of superplasticizer; for the ready mix operation, the reverse is true.Silica fume and the superplasticizer employed were shown to be effective fluidifying agents, although they did slightly increase the time at which maximum compressive strengths were reached. Erratum to this paper appears in 17(1).
Determination of Water Content of Fresh Concrete Using a Microwave Oven
Authors: Nagi M , Whiting D 
Published: January 2010

Abstract
As part of the Strategic Highway Research Program (SHRP) contract, Optimization of Highway Concrete Technology, a microwave-oven method for measuring water content of as-delivered fresh concrete was evaluated. Water contents of a series of concrete mixes prepared in the laboratory were gravimetrically determined by drying the concrete in a microwave oven and comparing these measurements with water contents used for making these mixes. A relatively high-power microwave (900 W) equipped with a turntable to provide uniform drying was used. Mixes used in the study included conventional concrete mixes with three types of aggregates with low, moderate, and high water absorptions and mixes with silica fume, fly ash and latex. Field ruggedness of the procedure was verified by testing under actual field conditions at placements of bridge deck overlays and full-depth pavement repair sections.
Test results showed that this technique is sufficiently reproducible for purposes of field control and is independent of absorption of aggregates or consistency of concrete. The test is quite simple and does not require a skilled operator. The total test time is 16 min, including time for sample manipulation and check-weighing twice during the drying process. The method can be applied to latex-modified and silica-fume concretes, as well as more conventional mixes.
The Effects of Different Cementing Materials and Curing on Concrete Scaling
Authors: Afrani I , Rogers C 
Published: January 2010

Abstract
As part of a project to determine the long-term durability of concrete made with an alkali-silica reactive coarse aggregate, six concrete mixtures were made with a variety of cementing materials: high-alkali portland cement (HAPC), low-alkali portland cement (LAPC), 25% ground granulated blast-furnace slag (GGBFS), and 50% GGBFS with high-alkali portland cement, 18% Type F fly ash with high-alkali portland cement, and 3.8% silica fume with high-alkali portland cement and 25% GGBFS. Concrete slabs were cast and cured under three conditions: 14 days in the moist room at 23°C, 14 days outdoors covered under wet burlap and plastic sheet, and 28 days in the laboratory air after application of a curing compound. The slabs were tested at an age of 28 days for 50 freeze-thaw cycles in the scaling test using a 3% sodium-chloride (NaCl) solution. The slabs cured outside under wet burlap generally had a high resistance to scaling, with the exception of the mixture with 50% GGBFS. This concrete also exhibited scaling of a full-scale outdoor slab on grade during the first winter. The slabs cured, according to the test method, in the moist curing room generally showed a low resistance to salt scaling. Erratum to this paper appears in 17(1).
Mineral Admixtures Contribution to the Development of Heat of Hydration and Strength
Authors: Rahhal VF , Batic OR 
Published: January 2010

Abstract
The heat of hydration of normal portland cement causes an increase in concrete temperature that may result in undesired cracks on cooling after hardening. For this reason, alternatives to lowering it are sought.
This paper discusses the benefits of adding mineral admixtures, such as natural pozzolan, fly ash, and granulated blast furnace slag to control heat of hydration development. For this study, blended cements were prepared using an ordinary portland cement clinker, gypsum, and mineral admixtures, previously ground in a laboratory mill. The average fineness employed was 450 m2/kg. The percentages of mineral admixtures were: 0, 10, 20, 30, 50, 70, and 90, by mass. Tests were performed at 3, 7, 28, 90, and 180 days. Results are expressed in percentages of control cement (0% replacement) and are plotted for each replacement, percentage, and age.
Empirical coefficients of the contribution of mineral admixtures to the heat of hydration have been obtained, as well as a mathematical expression to estimate the heat of hydration of a blended cement, on the basis of the mineral admixture selected, the percentage used, and the heat of hydration of the control cement, up to 180 days.
The Effect of Mold Size and Mold Material on Compressive Strength Measurement Using Concrete Cylinders
Authors: Day RL 
Published: January 2010

AbstractFourteen concretes were cast, with and without air entrainment and fly ash, using various sizes of cylindrical mold made from different materials. Cylinders were cured in the standard manner and tested for compressive strength, primarily at an age of 28 days. The range of strengths measured was 30 to 50 MPa. Each cast consisted of 60 cylinders, with 12 replicates performed for each of the five types of mold: 150-mm diameter cardboard and plastic molds (notation, C150 and P150); 100-mm diameter plastic molds (P100); and 75-mm cardboard and plastic molds (C75 and P75). The length/diameter ratio of all cylinders was 2.0.For 150-mm cylinders, the variability of strength measurement, as indicated by the average coefficient of variation (cv), did not depend upon the type of mold material used (cardboard or plastic). For 75-mm cylinders, the same observation was made; cv did not depend upon mold-material.However, when plastic molds were used, there were significant differences in cv as cylinder size varied. The average cv for P75 cylinders was 4.9 MPa, while it was 3.2 MPa for P150 cylinders; the increase is highly significant. On the other hand, P100 cylinders gave a cv of 3.6 MPa, which is not significantly different than that for P150 cylinders.For cardboard molds, where 150- and 75-mm cylinders were tested, the cv was not a function of cylinder size.The effect of mold material and diameter on the magnitude of measured strength was also examined. No distinct trends were observed. Differences in observed strengths due to type and size of mold were influenced by the type of concrete tested and the procedure for initial storage during the first 24 h of curing. However, when all 28-day strengths were considered in paired-t analyses, the following differences were found to be significant: (1) the use of 75-mm molds (C75 and P75) resulted in a higher strength of about 1 MPa, compared to the larger molds (P100, P150, C150); (2) for 150-mm molds, the use of plastic instead of cardboard resulted in a lower strength, about 1 MPa; and (3) the strength obtained from concrete cast into plastic molds increased as the mold size decreased; the difference between P100 and P150 molds was 1 MPa, while the difference between P75 and P150 molds was, on average, 1.6 MPa.Some of the differences in strength among the mold types was traced to differences in moisture loss during the first 24 h of storage. Cylinders stored under plastic sheet (in accordance with the American Society for Testing and Materials (ASTM) specifications), were about 3 MPa stronger than those stored in sealed plastic bags (in accordance with the Canadian Standards Association (CSA) requirements). Erratum to this paper appears in 17(1).
Cement Strength Variations: Defining the Solution
Authors: Gebhardt RF 
Published: January 2010

Abstract
Strength is one of the most important properties of cement. When major strength variations occur, control actions are usually taken to mitigate the problem. The control actions taken can mask exactly when the deviations occurred and can hide their magnitude in addition to obscuring their source. It is often possible, however, to remove the effect of a known variable so that the source(s) of the problem can be located.
If strength values for individual production samples are divided by their fineness, the resulting values of strength per unit fineness (suitably indexed for readability) can be graphed versus time to determine exactly when strength deviations occurred (unrelated to fineness) and their magnitude. An example from an actual production problem illustrates the method and shows how the transformed data can be used to demonstrate the probable sources of the strength variations. Erratum to this paper appears in 17(1).