bluuebunny/crossref_metadata_2025 huggingface dataset:
Troubleshooting Retarded Concrete: Understanding the Role of Cement and Admixtures Through an Interdisciplinary Approach
Authors: Jeknavorian AA , Hayden TD
Published: January 2010

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

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

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.
Introduction to Symposium on Polymer-Modified Concrete and Mortars: Building on the Past and Moving into the Future
Authors: Bright RP , Fitzgerald PL , O'Brien MJ
Published: January 2010

The following six papers were presented as a part of a symposium on “Polymer-Modified Concrete and Mortars: Building on the Past and Moving into the Future.” The symposium was held on 20 June 1995 in Denver, Colorado and sponsored by ASTM Committee C-9 on Concrete and Aggregates and its Subcommittee C09.14 on Polymer-Modified Concrete and Mortars.
Curing Stresses in Polymer-Modified Repair Mortars
Authors: Pinelle DJ
Published: January 2010

Accurate correlation between standard test results and observed field performance of repair mortars has been difficult to achieve. A study was conducted in an attempt to understand the development of physical properties and induced tensile stresses as a repair material cures and how these affect the likelihood of early age cracking. A mathematical model was developed to predict when induced stresses may be sufficient to crack a repair mortar while curing. Using this technique, the influence of two polymers on a generic mortar was investigated in the laboratory. The laboratory study included measurements over time of tensile strength, drying shrinkage, tensile modulus of elasticity, and tensile creep. The model's predictions were checked by placing the studied mortars in a simulated repair situation.

The influence of polymers on physical properties, the stress developed while curing, and field performance were studied. Results suggest that the type of polymer has an important effect on properties, such as tensile creep and modulus of elasticity. The data also indicate a balance of certain properties is needed in order to make a repair mortar more resistant to cracking. Further, since these properties change as the material cures, their relationship over time must be understood.

The test procedures, mathematical model, and results are discussed in this paper. Cross references to a simulated field installation is also included.
Self-Smoothing Industrial Floors
Authors: Alexanderson J
Published: January 2010

Self-smoothing industrial floors have been developed in Sweden over the last 15 years.

In the beginning, the binder was portland cement, but later, high-alumina cement systems have taken over due to several reasons. Also the polymers have changed from acrylic dispersions in the early industrial floors to dispersible powders based on ethylene vinylacetate copolymers today. The dominating plasticizer in the early underlayment products was casein, but due to serious problems it has been changed to melamine-based superplasticizers.

The load-bearing properties are tested with a rolling wheel test that is more relevant than compressive strength. The polymer modification increases the performance quite substantially.

The machine systems have developed considerably over the years. In the beginning, small batch mixers and pumps were used, whereas today trucks with complete equipment can deliver the material ready-mixed on site with quite high capacity.

Field experience is positive and the use of self-smoothing floors is expected to grow.
Comparison of Liquid Dispersions with Spray-Dried Acrylic Polymers as Modifiers of a Cement-Based Patching Material
Authors: Bright RP
Published: January 2010

This study was carried out to compare the performance of dry polymers to the more conventional liquid-based polymers in a general purpose patching mortar. A series of polymer-modified mortars were thus evaluated, comparing two spray-dried redispersible acrylic powders with two water-based polymers: an acrylic dispersion and a styrene-butadiene rubber dispersion.

The results of the testing showed that the use of the redispersible powders resulted in mortars with excellent adhesion and strength properties comparable to the liquid product. The mortars modified with these dry polymers also exhibited slightly higher shrinkage than the dispersions. However, combined with their advantages over liquid product, such as ease of shipping and handling, the dry polymers are very suitable for use in the formulation of high-performance patching materials.
Performance and Correlation of the Properties of Fly Ash Cement Concrete
Authors: Al-Amoudi OSB , Maslehuddin M , Asi IM
Published: January 2010

This investigation was conducted to evaluate the performance of fly ash cement concrete specimens made by cement replacement levels of 0, 10, 20, 30, and 40% with Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Concrete (ASTM C 618) Class F fly ash. Compressive strength, pulse velocity, porosity, and water permeability were determined after 28, 90, 180, and 360 days of water curing. Reinforced concrete specimens were used to assess the corrosion-resistance of plain and fly ash cement concretes in chloride environments. The corrosion potentials on steel were measured at periodic intervals to determine the time-to-initiation of reinforcement corrosion. The data generated was statistically analyzed to ascertain the relationship between the various properties of plain and fly ash cement concretes.

Results indicated a better performance by the 20% fly ash cement concrete than plain cement concrete and those made with other cement replacement levels. A good correlation between porosity, compressive strength, permeability, and porosity was observed.
A Possible Method for Identifying Fly Ashes That Will Improve the Sulfate Resistance of Concretes
Authors: Dunstan ER
Published: January 2010

Current methods for determining sulfate resistance of fly ash concrete often require several years of testing. An accepted method that can be used to predict sulfate resistance in a few days does not exist. A hypothesis is submitted as a possible step towards development of a comprehensive theory. The sulfate reactivity of fly ash is characterized by its chemical composition. One high calcium fly ash was shown to react similarly to blast-furnace slags. Sulfate resistance of comparable fly ash concretes is shown to correlate with ash composition; therefore, based on chemical composition of fly ash, a sulfate resistance factor R is proposed. The factor is the ratio (C-5)/F, where C is calcium oxide and F is ferric oxide in percent. When R is less than 1.5, a fly ash should improve the sulfate resistance.
An Analytical Approach to Gap-Graded Concrete
Authors: Ehrenburg DO
Published: January 2010

In the mix proportioning process, the concept of minimum voids and the principle of minimum surface area are basically in conflict with each other. The former implies that a blend of several fractions of coarse aggregate is always superior to a single fraction. The latter states that for a given maximum size of aggregate a single fraction is superior to any blend. Between the two extremes—continuous gradation, on the one hand, and a single fraction of coarse aggregate, on the other—lies the vast and largely unexplored gray area of gap-graded mixes. In spite of the great variety of gradation patterns available in this area, certain general principles can be delineated and translated into a system of mix proportioning that is applicable to the total spectrum of concrete mixes.
Formula for Calculating Spacing Factor for Entrained Air Voids
Authors: Walker HN
Published: January 2010

A spacing factor only for small voids is derived from the proportion of small voids to total voids. The formula can be used with any method of air determination in hardened concrete that includes denominating some voids as large and some as small. The formula is not dependent on the size criterion used. A graphic method of estimating the spacing factors is given: ¯L for total voids and ¯Ls for the proportion of small voids.
Concrete Polymer Materials as Alternative Construction Materials for Geothermal Applications—Field Evaluations
Authors: Fontana JJ , Zeldin A
Published: January 2010

A serious problem in the development of geothermal energy is that suitable, durable, and economical construction materials are not readily available. Hot brine and other aerated geothermal fluids are highly corrosive and attack most conventional construction materials. Brookhaven National Laboratory has been investigating the use of concrete polymer materials as alternative construction materials for geothermal processes. To date, successful field tests have been demonstrated at the Geyesers, the U.S. Bureau of Mines Corrosion Facility, and the East Mesa Geothermal Facility. This report is a survey of field and laboratory evaluations of concrete polymer materials that have been shown to be durable and economical as alternative construction materials.
Quick Determination of Cement Properties Through the Use of Hot-Pressing
Authors: Gouda GR , Roy DM
Published: January 2010

By proper application of heat and pressure to a cement paste having a very low water/cement ratio W/C, a hard, strong, dense cylindrical specimen is formed in a very short time. Specimen preparation is simple and only a few grams of cement are required. Compression and splitting (modified tension) tests can be performed and the soundness of the cement can be predicted. Temperature, pressure, time, W/C, sample size, and cement fineness are the parameters that affect the degree of strength. With standardization of the hot-pressing parameters, the physical properties of the cement paste can be obtained quickly instead of after the usual waiting period of from one to four weeks.
A Method for the Determination of Consistency and Consistency Retention (Board Life) of Masonry Mortars
Authors: Conway JT
Published: January 2010

A method of field testing is presented to determine the consistency, consistency retention, and rate of stiffening of masonry mortars by the use of a modified concrete penetrometer. The equipment, procedure, and applications for the method are described.
Alkali-Silica Reactivity: Some Reconsiderations
Authors: Stark D
Published: January 2010

Numerous instances have been recorded where the use of low alkali cement with certain volcanic aggregates has failed to prevent deleterious alkali-silica reactivity. Present testing using the ASTM Test for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method) (C 227) may fail to identify this reactivity because testing is normally done with only high alkali cements. It is recommended that concurrent testing be done, using a range of both high and low alkali cements, to determine that maximum safe cement alkali level for each aggregate in question. Although the traditional limit of 0.60% alkali has prevented alkali aggregate reaction with many reactive aggregates, there are certain volcanic aggregates that require even lower alkali or the use of suitable pozzolanic materials to avoid alkali aggregate reactivity or both.
Influence of Water-Reducing Admixtures on Properties of Cement Paste—A Miniature Slump Test
Authors: Kantro DL
Published: January 2010

A miniature slump test has been developed for the evaluation of the influence of water-reducing admixtures on the workability of neat portland cement pastes. Resulting paste pat areas rather than heights are measured, and the results are expressed as the percentage of water reduction. Relative effects of various admixtures on a portland cement are illustrated, and influences of specific admixtures on different cements are also shown. Effects of different superwater-reducing admixtures and combinations of ordinary and superwater-reducing admixtures are compared. The mini-slump method has also been used for the evaluation of the loss of workability (slump loss) with time for various admixtures and admixture combinations. The simplicity of the method facilitates accurate and effective evaluation of water-reducing admixtures.
Relative Resistance of Rained-On Concrete Pavements to Abrasion, Skidding, and Scaling
Authors: Dahir SH
Published: January 2010

Cores from concrete pavements that had been exposed to rain while plastic and specimens prepared in the laboratory and exposed to artificial rain showers were tested for abrasion, skid resistance, and scaling. Companion not-rained-on cores and laboratory specimens were similarly tested. The results indicated that average skid resistance measured with the British Pendulum Tester (BPT) was similar on both rained-on and not-rained-on cores and specimens. Full-scale tire skid numbers were about 10% higher on not-rained-on untraveled pavement sections than on adjacent rained-on sections. Scaling caused by freeze-thaw exposure and abrasion loss determined with the U.S. Corps of Engineers Method of Test for Resistance of Concrete or Mortar Surfaces to Abrasion (Procedure CRD-C52-54) were consistently higher on rained-on than on comparable not-rained-on cores and specimens. Abrasion loss was higher on untraveled pavements than on those that had been in use for several years. Also, abrasion loss was higher on specimens that had been exposed to heavier rain intensity, longer rain duration, and deeper texturing.

Comparison of abrasion loss, scaling caused by freeze-thaw exposure, and frictional BPT numbers on not-rained-on and rained-on cores from untraveled pavements and on similarly prepared specimens indicates that abrasion and British Pendulum Numbers can be predetermined from specimens made and tested in the laboratory. Examination of two field sections after exposure to traffic and weathering for two years confirmed the validity of laboratory testing predictions. Two abrasion machines made to the specifications of the U.S. Corps of Engineers Procedure CRD-C52-54 gave two different levels of abrasion loss on paired specimens, but the resulting trends were similar.
Condition of Concrete in Martin Dam After 50 Years of Service
Authors: Mather K
Published: January 2010

The concrete in Martin Dam, an arch-gravity hydroelectric power dam in Alabama, completed in 1926, was sampled by three 152-mm (6-in.) cores drilled in the crest of the dam to the foundation. Samples taken from these cores were examined petrographically, tested ultrasonically to measure compressional- and shear-wave velocities, tested in unconfined compression, tested in triaxial loading in groups of three cores each at three confining pressures, and tested for strength in direct tension.

The petrographic examination yielded evidence of the occurrence of alkali-silica reaction in concrete from all three drill holes; however, alkali-silica reaction gel was not found in the lower part of one hole. The core from this zone contained large flakes of tetracalcium aluminate monosulfate-12-hydrate (C4 A¯SH12). No reference to the presence of this compound in concrete in crystals large enough to be visible to the naked eye was found in the literature. Although the evidence of alkali-silica reaction is clear, it did not extend to cracks in the mortar except to a minor extent. The mechanical tests indicated concrete in good physical condition. Despite the presence of alkali-silica reaction, the Martin Dam concrete appears to be in acceptable condition and in better condition than some younger structures that are still in service.
Inertial Effects in the Instrumented Impact Testing of Cementitious Composites
Authors: Suaris W , Shah SP
Published: January 2010

The effects of specimen inertia on the instrumented impact testing of cementitious composites are discussed and a method for reducing such effects is proposed. A two degree of freedom model capable of predicting the amplitude and period of inertial loading oscillations on the tup-load versus time-trace is presented. Results of tests conducted on asbestos cement and fiber-reinforced concrete are presented and are compared with those predicted using the analytical model. It is concluded that the model developed is satisfactory in predicting inertial loading effects.
Attack of Aggressive Fluids
Authors: Ivanov FM
Published: January 2010

This paper deals with the present state of classification of aggressive fluids. The USSR codes on rating the corrosive attack of water as an environment are given. Methods of imparting higher corrosion resistance for concrete are briefly analyzed.
Mechanical Properties and Freezing and Thawing Resistance of Non-Air-Entrained, Air-Entrained, and Air-Entrained Superplasticized Concrete Using ASTM Test C 666, Procedures A and B
Authors: Malhotra VM
Published: January 2010

This investigation was undertaken to develop data on the durability of non-air-entrained, air-entrained, and air-entrained superplasticized concrete when tested in accordance with the ASTM Test for Resistance of Concrete to Rapid Freezing and Thawing (C 666) Procedures A and B. A total of nineteen 0.06-m3 mixes were made with water-to-cement ratios ranging from 0.35 to 0.70. Apart from the control mixes, all other mixes were either air-entrained or air-entrained and superplasticized. A number of test prisms were cast and subjected to repeated cycles of freezing and thawing and air-void parameters of the hardened concrete were determined. The following conclusions were made from the test results.

1. Regardless of the test procedures used, the test prisms cast from non-air-entrained concrete disintegrated at less than 31 cycles. The only exceptions were the test prisms cast from concrete with a water-to-cement ratio of 0.35, which indicated satisfactory resistance to repeated cycles of freezing and thawing in test Procedure B, the durability factor after 300 cycles being greater than 90.

2. Regardless of the test procedure used, the concrete prisms cast from air-entrained concrete and air-entrained superplasticized concrete performed satisfactorily when subjected to repeated cycles of freezing and thawing. At the end of 300 cycles, the durability factors were greater than 90. This was in spite of the fact that the bubble spacing factor ¯L for air-entrained superplasticized concrete was, in some instances, greater than 0.20 mm.
Effect of Different Types of Crushers on Shape and Roughness of Aggregates
Authors: Czarnecka ET , Gillott JE
Published: January 2010

The shape and texture of four specimens of crushed aggregates produced by different commercial crushers were quantitatively investigated using the modified Fourier method described in earlier articles. Specimens were classified according to size (all in the range 4 to 64 mm) and type of crusher. Results show that on average the shape of different specimens of crushed aggregates vary more than their surface texture; hence, shape is the dominant factor contributing to the total roughness that combines both characteristics. Particles crushed by a jaw crusher are much more elongated and rectangular than particles that passed through a cone crusher, impactor, or rod mill. The total roughness and shape factor of crushed particles decrease in the order: jaw crusher, cone, impactor, and rod mill. Data provided by the modified Fourier technique give more precise shape as well as textural data that could lead to better control of the aggregates' characteristics; shape and texture have an important bearing upon performance of concrete.
Precision of the Proposed Test Method to Measure Slag Hydraulic Properties
Authors: Lesniak TW
Published: January 2010

A method has been developed which tests the hydraulic properties of finely ground blast furnace slag. Results from round robin testing were analyzed according to the ASTM Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction Materials (C 802). Evaluation of the data has confirmed the validity of the test method and appropriate precision statements have been developed.
Precision of Flexural Strength and Toughness Parameters for Steel Fiber Reinforced Concrete
Authors: Johnston CD
Published: January 2010

The variability of parameters used to define the toughness of fiber reinforced concrete under static flexural loading is examined to establish the precision statistics needed for ASTM standards dealing with toughness measurement. Included in the anlaysis of single-operator precision are first-crack strength, deflection, and toughness, the toughness index recommended by the American Concrete Institute Committee 544, and a number of other toughness indices that have been shown in a previous paper to define flexural toughness more completely. The single-operator 1S% value defined according to ASTM Standard Practice for Preparing Precision Statements for Test Methods for Construction Materials (C 670) is used as the measure of precision throughout, the bulk of the data being obtained from testing of 300- by 100- by 100-mm (12- by 4- by 4-in.) steel fiber reinforced beams under third-point loading. However, the effects of beam size, shape, span, and mode of loading on both the actual values of the toughness indices and their variability are also discussed. Single-operator levels of precision achievable in flexural toughness tests by an experienced operator using good equipment are summarized to provide input to precision statements for a future ASTM standard dealing with the measurement of flexural toughness under static loading.
Development of a Conductivity Probe to Monitor Setting Time and Moisture Movement in Concrete
Authors: Sriravindrarajah R , Swamy RN
Published: January 2010

The development of a three-dimensional conductivity probe, based on the measurement of electrical conductance between electrodes, to evaluate the setting time of fresh concrete and the variation of moisture content with time in hardened concrete is reported. The construction and calibration of the conductivity probe are described, and a calibration curve translating electrical conductance measurements into available moisture content is presented. Tests are then reported to evaluate the setting time of fresh concrete, and these are related to internal temperature variations. These tests are then extended to study moisture variations in hardened concrete under load and no-load conditions in both sealed and unsealed environments. These measurements taken for up to two years are related to internal humidity measurements. The results show that the conductivity probe is a simple and inexpensive device that gives quantitative information in any direction and possesses qualities of accuracy, reliability, long-term stability, and local resolution.
Accurate Rapid Analysis of Alkali Contents in Portland Cement
Authors: Syal SK , Kataria SS
Published: January 2010

Alkali contents of portland cement/clinker significantly affect the hydration reaction rate and the development of mechanical strength of cements. An accurate, rapid method has been developed for the quantitative determination of alkalies sodium oxide and potassium oxide by use of the flame photometric emission spectroscopic technique. The procedure is free from errors caused by the presence of calcium atoms and the mutual disturbance caused by the different ionization behavior of sodium and potassium salts in the flame. The determinations have been performed in a nitric acid medium with use of optimum amounts of aluminum sulfate and cesium sulfate as the controlling electrolytes. A combination of 2000 ppm of alumina +30 ppm of cesium is optimum for the analysis of ordinary portland cements and clinkers. In the procedure a wide range of alkali concentration is covered by the analysis of solutions for 1 to 10 ppm of sodium oxide and potassium oxide with the best reproducibility in the range of 4 to 8 ppm. The accuracy of the determinations is better than 0.01 ppm. The method is suitable for laboratory analysis as well as for on-line quality control determinations of alkali content.
Performance of Blast-Furnace Slag Cement
Authors: Cattaneo A , Frigione G
Published: January 2010

The sulfate resisting portland cement is obtained from a special portland cement clinker with low-tricalcium-aluminate content. In Western Europe another cement is used more for constructions in sulfate environments than portland low-tricalcium-aluminate cement, the blast furnace slag cement with slag content higher than 70%. According to ASTM standard Specification for Concrete Aggregates (C 33), when reactive alkali-aggregates are used, portland low-alkali cement is recommended. According to the European experience, the blast-furnace slag cement with slag content greater than 70% does not produce any expansion when used with stone materials of potential alkaline reactivity. This paper deals with the performances of blastfurnace slag cements tested for sulfate resistance and for alkali-aggregates reaction. The results obtained fully confirm the possibility of overcoming the risk of alkali-aggregate expansion and sulfate destruction by using blast furnace slag cements with high-slag content. The lower energy cost of blast-furnace slag cement, which can replace the special portland cement with low-tricalcium aluminate and low-alkali content, may favor its use.
Microcracking and Definition of Failure of High- and Normal-Strength Concretes
Authors: Carrasquillo RL , Slate FO
Published: January 2010

The discontinuity point is defined as that point at which an unstable progressive crack growth mechanism develops in the concrete. A criterion for defining the discontinuity point in terms of microcracking and thus for determining the stress or strain corresponding to the discontinuity point is perhaps the most relevant strength criterion for engineering design because it can identify the onset of failure when a given concrete can no longer withstand a given state of stress without unstable disruption of the structure. This paper summarizes the work done at Cornell University on the development of a criterion for determining stress and strain at discontinuity for different-strength concretes based on the observed internal microcracking at different load stages and proposes ranges of stress and strain at discontinuity for those different concretes.
Quantitative X-Ray Diffraction Analysis of Cement and Clinker: A Bibliography
Authors: Struble LJ
Published: January 2010

This comprehensive bibliography covers analysis of portland cement and concrete by quantitative X-ray diffraction. The citation and an abstract is provided for each reference. The bibliography was prepared at the request of the quantitative X-ray diffraction analysis task group of ASTM Subcommittee C01.23.
Lithological Characteristics of Concrete Aggregates as Related to Durability
Authors: Robinson RF
Published: January 2010

Popouts in concrete bridge decks prompted an investigation into the reasons for such performance in relatively new construction projects. Certain stones usually reddish in color and belonging to a lithologic unit referred to as the superior group appeared to be responsible for the popout action. Conventional tests had not revealed any excessive values or unusual properties. Several area pits were examined, sampled, and tested by different methods. There were no specific series of tests that indicated the durability of aggregates used in this study, but an indication of high absorption to greater loss in soundness tests was detected. From testing results and past performance records, a recommendation was made to require individual stone counts to isolate the amount of the suspect aggregate. It was further recommended that a soundness loss of not more than 5% of the total specimen be allowed to conform with the “deleterious substances” section 501.3.6.4.3 of the current specification.
Some Opportunities to Offset Poor Quality Characteristics of High-Alkali Cement
Authors: Spellman LU
Published: January 2010

It is to be expected that the influx of preheater/precalciner technology will result in a general increase in portland cement alkali level. High-alkali cement is associated, in general, with rapid early strength development and disproportionately lower 28 day strength in mortar cubes in accordance with ASTM Compressive Strength of Hydraulic Cement Mortars (C 109). Too, alkali cements react more readily with reactive aggregates. While portland cements tend to be increasing in alkali content, sources of unreactive aggregates tend to be decreasing.

The literature suggests that the use of fly ash can mollify the reaction of alkalies in both strength development and in alkali-aggregate reactivity. Usually it is necessary to add the fly ash in addition to portland cement to accomplish the task, to maintain adequate strength development.

The use of finely ground water-granulated blast-furnace slag as a replacement for portland cement up to 65% can markedly reduce the alkali aggregate reaction and improve compressive strengths at the age of 28 days and beyond. To a significant degree, this procedure could help offset the quality problems often associated with cements of high-alkali content produced by energy efficient kiln systems. Finely ground water-granulated blast-furnace slag can be produced using only about one fifth the energy needed to produce an equal weight of portland cement.
Evaluation of Selected Procedures for the Rapid Analysis of Fresh Concrete
Authors: Head WJ , Phillippi HM , Howdyshell PA , Lawrence D
Published: January 2010

Presented in this paper are results of a program to evaluate procedures for the rapid determination of both cement and water contents of fresh concrete. Three generations of a general method were considered. The abilities of the current (Generation II-Construction Engineering Research Laboratory/Kelly Vail [CERL/KV]) and recently evolved (Generation III-Construction Engineering Research Laboratory/Concrete Quality Monitor [CERL/CQM]) procedures to aid in predicting cement and water contents of a variety of concrete mixtures were determined in an extensive series of side-by-side laboratory tests. Evaluated in the tests were effects of sampling techniques and aggregate type. Analysis of variance techniques were used as aids in establishing accuracy statements and comparing the two procedures. Results demonstrated that accuracies of the CERL/KV and CERL/CQM methods were equivalent for identical test conditions. Further, it was determined that aggregate characteristics affect results of both cement-content tests and both water-content tests.
Chemical Analysis of Portland Cement by Energy Dispersive X-Ray Fluorescence
Authors: Wheeler BD
Published: January 2010

X-ray fluorescence techniques have been applied for the analysis of portland cement for the past 20 or more years. During this time, applications have been developed primarily with wavelength spectrometers. In the past several years, development of solid state detectors has allowed energy dispersive X-ray fluorescence to detect and measure all the elements of interest in portland cement.

Determination by energy dispersive X-ray fluorescence displays excellent precision, but a linear calibration of intensity versus concentration for many elements exhibits significant deviation from a straight line. Particle size effects that could cause errors in the calibration were minimized through fine grinding. The remaining factors responsible for nonlinear calibrations relate to interelement effects, which are usually considered as absorption and enhancement.

The purpose of this investigation is to determine the interelement effects in portland cement and demonstrate the quantitative capabilities of energy dispersive X-ray fluorescence using certified National Bureau of Standards (NBS) portland cements as standard. An additional purpose is to demonstrate the application of empirical calculations for interelement effects in obtaining quantitative results utilizing Portland Cement Association check specimens as unknowns.

Interelement effects in X-ray fluorescence are well documented with various techniques utilized. Many of these programs are complex and correct all elements for the presence of all other elements and require a large number of standards. The approach used by the author is an exponential model based on intensities of the interferring elements.

Linear least squares fit of uncorrected intensities displayed absolute errors of 0.6% for alumina and silicon oxide to 1.0% for calcium oxide. Average deviations obtained following interelement corrections ranged from a low of 0.007% for potassium oxide to a high of 0.19% for calcium oxide. Analysis of each specimen consumed 200 s. The accuracy obtained by this method is well within the limits expected by the industry and the precision possible by alternate procedures.
Production Technology of Expanded Clay Aggregate Gravel with Bulk Density Below 300 kg/m3
Authors: Yaksharov OJ , Skiba BV
Published: January 2010

Some problems of production technology of expanded clay aggregate in a rotary kiln are considered with the use of the method of dusting the particles of burning material with refractory, or highmelting, powders. A list of the main units of modernization for the rotary kiln is given. Dependence upon the consumption of dusting materials is shown, and the conditions of its usage in rotary kilns are investigated. Comparative technical indexes of operation during the industrial tests in modernized rotary kilns with the use of devices under discussion are offered. Industrial tests are given for four kinds of argillaceous raw materials.

The use of the device to regulate the feeding of secondary air, which helps to reduce a fuel consumption at the expense of a decrease of heat loss by waste gases, is considered. The main technical and economic effects of using the devices under discussion in modernized rotary kilns are included.
Effects of Initial Field Curing on Standard 28-Day Cylinder Strengths
Authors: Meininger RC
Published: January 2010

Proposed changes to the initial curing of standard strength cylinders under ASTM Making and Curing Concrete Test Speciments in the Field (C 31) were studied. Cylinders were cured for periods of one or two days under four simulated field conditions: (1) 16°C (60°F) water, (2) 16°C (60°F) air, (3) 27°C (80°F) water, and (4) 27°C (80°F) air. After this initial curring period, all cylinders were given standard curing until 28-days age. Strength results were significantly affected by initial curing environment. Initial water curing at 16°C (60°F) resulted in 28-day strengths on the order of 5 to 7 MPa (700 to 1000 psi) more than concrete from the same batch cured initially in air at 27°C (80°F). It was also found that cement source has an influence on the strength difference because of initial curing environment and, also, on the temperature rise of the concrete cylinders during the first 6 h after molding. Increasing the initial curing period from one to two days only reduced compressive strength by about 1%.
High-Strength and Flowing Concrete with a Zeolitic Mineral Admixture
Authors: Feng N-Q , Li G-Z , Zang X-W
Published: January 2010

Zeolitic mineral admixture (ZMA) is made of the finely divided powder of natural zeolite with a bit of other agent such as triethanolamine. When ZMA is used to displace about 10% (by mass) of the ordinary portland cement (OPC) (strength grade No. 525) in concrete and mixed with a suitable amount of superplasticizer (W/C = 0.31 to 0.35), then a high-strength concrete with compressive strength of about 80 MPa and a slump of about 180 mm can be obtained. The strength of this concrete is about 10 to 15% higher than that of the corresponding concrete mixed with pure OPC, and its bleeding decreases greatly. It also results in no segregation or separation of the mix, and thus it satisfies the requirement of pumping concrete in construction.

The ZMA is suitable not only for the OPC but also for the slag portland cement. The strengthening effect of the ZMA is somewhat similar to that of silica fume. But the cost is only two thirds that of OPC. Thus, when ZMA is used to displace a certain amount of the cement in the concrete, the cost of the concrete thus made will be 3 to 5% cheaper than that of the corresponding concrete with pure cement.

The ZMA can increase the amount of micropores (d < 625 Å) and decrease the amount of harmful large pores (d > 938 Å) in the cement paste. Hence, the strength of concrete is increased and its other properties are also improved. Furthermore, ZMA can raise the SiO2/CaO weight ratio in the transition zone to increase its C-S-H phase and decrease its calcium hydroxide content. Thus, the structure of the transition zone is improved. Consequently, the strength and resistance to permeability of the concrete are increased.
Mechanical Properties, Abrasion Resistance, and Chloride Permeability of Concrete Incorporating Granulated Blast-Furnace Slag
Authors: Fernandez L , Malhotra VM
Published: January 2010

This paper reports the results of an investigation to determine the mechanical properties, abrasion resistance, and chloride-ion permeability of concrete incorporating ground-granulated blast-furnace slag from a source in northern Ontario. Nine 0.06-m3 air-entrained concrete mixtures involving 18 batches were made. The water-to-cementitious materials ratio of the mixtures ranged from 0.45 to 0.70, and the percentage of the slag used as a replacement by mass for the portland cement varied from 0 to 50%.

A number of test cylinders and prisms were cast for determining the mechanical properties of concrete, its chloride-ion permeability, and the effect of initial moist curing and subsequent air curing on its compressive strength. Test blocks were also cast for determining the abrasion resistance of concrete.

The strength development characteristics of the slag concrete indicate that granulated blast-furnace slag can be satisfactorily used as a partial replacement for portland cement in concrete. The abrasion resistance of the concrete containing slag is inferior to that of the control concrete without slag. The chloride-ion permeability of concrete decreases considerably when slag is used as a partial replacement for the portland cement, especially at the 50% replacement level.
Laboratory Evaluation of Wet and Dry Abrasion Resistance of Cement Mortar
Authors: Fwa TF , Low EW
Published: January 2010

This paper describes a laboratory test program conducted to evaluate the effect of wetting and drying on the abrasion resistance of portland cement mortar. A relatively simple and speedy abrasion test procedure was adopted. Test results indicated that repeated alternating of wetting and drying treatment did not have any adverse long-term effect on the abrasion resistance of specimens. Each wetting phase, however, reduced the abrasion resistance of specimens, although the reduction was only a short-term phenomenon. The abrasion resistance was restored to the original level gradually as the specimens were allowed to dry. The effect of wetting was found to be increasingly pronounced as the water/cement ratio of the test mix was raised.
Determination of Concrete Strength by Nondestructive Methods
Authors: Leshchinsky AM
Published: January 2010

This paper considers problems of improving the non-destructive control of concrete strength from the standpoint of: selecting the most economic methods; determining the required number of individual tests at a location to obtain an average in-place test result with the same degree of confidence by various methods; and modifying the acceptance criteria of ACI 318 to reduce the consumer's risk without changing the producer's risk. The ways of reducing labor consumption of nondestructive tests are recommended.
Calorimetric Study of Cement Blends Containing Fly Ash, Silica Fume, and Slag at Elevated Temperatures
Authors: Ma W , Sample D , Martin R , Brown PW
Published: January 2010

The hydration behavior of blended cements containing fly ash, silica fume, and granulated blast furnace slag over the temperature range of 10 to 55°C was studied by isothermal calorimetry. The rates of heat evolution during the first 24 h of hydration were examined. The results were analyzed to determine the kinetics of hydration of portland and blended cements. Relationships between the reactivities of these blended cements and the curing temperature were established. The results show that the rates of hydration reactions increased with an increase in temperature in all instances. Comparison among the blends containing fly ash, silica fume, and slag was made to establish activation energies for the hydration reactions. Arrhenius activation energy Ea values obtained were 39.0, 26.7, 30.4, and 49.3 KJ/mol for portland cement, fly ash, silica fume, and slag blended cements, respectively. The relatively constant Ea values for the blended cements may be related to diffusionally controlled hydration of the mineral admixtures.
Laboratory Measurements of Corrosion Activity of Steel Reinforcement in Concrete Using Simple Equipment
Authors: Wrobel P
Published: January 2010

This paper proposes the design and operation of a laboratory instrument for measuring the corrosion activity of steel reinforcement in concrete. An instrument was constructed and its reliability and research utility assessed against six steel-reinforced concrete prisms cured in duplicate under negligible, mild, and severe conditions of corrosivity. The steel reinforced concrete prisms were measured after curing and whilst dehydrating for corrosion potentials, polarization resistances, corrosion current densities, and corrosion rates. The instrument was simple to construct and operate. The instrument was reliable since it could apply Polarization Resistance to steel-reinforced concrete and thereby distinguish between steel reinforcements of different corrosion activity with precision. Furthermore, the instrument could be used to monitor changes in the corrosion activities of the steel reinforcements and was therefore useful for researching the passivating influence of Ca(OH)2. Erratum to this paper appears in 17(1).
Proportioning of Fly Ash Cement Concrete Mixes
Authors: Shashiprakash SG , Nagaraj TS , Raviraj S , Yenagi BV
Published: January 2010

The accumulation of fly ash throughout the world is several million tons per day. The main problem with the usage of fly ash is the slow rate of strength gain, primarily due to slow pozzolanic reactions. Existing methods of proportioning fly ash concrete are lacking. These methods are involved and do not directly take into account the properties of the constituent materials. The Generalized Approach for Mix Proportioning developed at the Indian Institute of Science, Bangalore, is the basis for the development of the proposed method, which takes into account the characteristics of cement, fly ash, and aggregates. Based on the basic trial mix data obtained by using the American Concrete Institute (ACI 211.1-81) method, the proportions of fly-ash concrete mixes were arrived at using the Generalized Approach for Mix Proportioning. The method proposed was applied to and found applicable for fly-ash concretes using fly ashes from two different sources.