bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of Copper Slag and Cement By-Pass Dust as Cementitious Materials
Authors: Al-Jabri K , Taha R , Al-Ghassani M
Published: January 2010

Copper slag (CS) and cement by-pass dust (CBPD) are by-products of the production of copper and cement, respectively. In the Sultanate of Oman, large quantities of copper slag (60,000 tons/year) and cement by-pass dust (25,000 tons/year) are produced every year, most of which is not effectively utilized and disposed on-site without any reuse. The main objective of this research is to investigate the potential use of copper slag and cement by-pass dust in concrete as partial replacements for Portland cement. The physical and chemical properties of both slag and cement by-pass dust were determined. Mortar samples were prepared using different proportions of slag, cement by-pass dust and lime, which was used as an activating material. Proportions up to 15% of Portland cement replacement were used. In addition, a control mixture containing 100% Portland cement was prepared for comparison. Results obtained indicated that the increase in the proportions of copper slag and cement by-pass dust alone resulted in a decrease in the compressive strength of mortars compared with the control mix. The highest compressive strength was achieved in samples containing 5% CBPD + 95% cement, which was 41.7 MPa after 90 days. The optimum copper slag and cement by-pass dust to be used is 5%. In addition, it was determined that using cement bypass dust as an activating material will work better than using lime. Additional studies should investigate the strength and durability when copper slag and cement by-pass dust are used in concrete mixes.
Laboratory Assessment of the Potential Rate of ASR Expansion of Field Concrete
Authors: Berube M-A , Frenette J , Pedneault A , Rivest M
Published: January 2010

In-situ monitoring of concrete deformations and movements is the best way to assess the current expansion of concrete members affected by alkali-silica reactivity (ASR). However, laboratory tests on cores are less expensive and more rapid, and are commonly used to assess the potential for further expansion due to ASR. The risk of expansion and damage due to ASR can be reasonably assessed in the laboratory from: (1), the inherent expansivity of the concrete under study, which is determined by testing core samples in air at 100% RH and 38°C; (2), the residual absolute reactivity of the aggregates present in the concrete under study, which can be determined by testing core samples in 1N NaOH solution at 38°C or, even better for coarse aggregates, by testing aggregates extracted from cores through the concrete prism test CSA A23.2-14A or ASTM C 1293; (3), the amount of alkalies that are still active in the concrete, i.e. in the pore solution, which is estimated by a hot-water extraction method on ground concrete, and (4), humidity, (5), temperature, and (6), stress conditions (confinement, reinforcement, pretensioning, postensioning) in service. The individual risk indices corresponding to each of the above parameters are combined to determine the potential rate of ASR expansion of concrete members in service, either already affected by ASR or not.
Measurement of the Alkali Content of Concrete Using Hot-Water Extraction
Authors: Bérubé M-A , Frenette J , Rivest M , Vézina D
Published: January 2010

The knowledge of the active- or soluble-alkali content of concrete is useful in the diagnosis and prognosis of alkali-aggregate reactivity (AAR). A method often used for determining this content is hot-water extraction from ground concrete samples. This method was applied to 17 aggregates and 8 concretes incorporating aggregates presenting different degrees of alkali-silica or alkali-carbonate reactivity. The following conclusions can be drawn: (1) a correction must be made to take account for the alkalies released by the aggregates in the test; (2) using cold water rather than hot water has no significant effect on the results; (3) grinding to <160 μm appears more appropriate than <80 μm (lower amount of alkalies released by the aggregates); (4) the soluble-alkali content progressively decreases as alkali-silica reaction (ASR) progresses, which indicates that a significant part of alkalies, progressively incorporated in the reaction products from ASR, is not leached in the test; (5) the repeatability from one series of tests to another and the reproducibility from one laboratory to another appear relatively poor; (6) the use of a control concrete with a known soluble-alkali content may greatly improve the repeatability and the reproducibility of the method.
Review of the Thermodynamic Stability of Ettringite
Authors: Constantiner D , Farrington SA
Published: January 2010

A critical review of published solubility and thermodynamic data for ettringite is presented. Today, the data reported in the literature have variability and uncertainty that could affect the outcome of thermodynamic models. One major uncertainty arises from the fact that Kspett and ΔGfrm° for ettringite have been calculated assuming congruent dissolution even when the data indicates incongruent dissolution. Another uncertainty is the effect of the activity of water. This is an issue that exists when dealing with concentrated solutions, and has not been addressed thus far in ettringite thermodynamic studies. Proper modeling requires that the issues presented in this paper be considered to insure reliable results.
Evaluation of the Potential for Internal Sulfate Attack Through Adaptation of ASTM C 342 and the Duggan Test
Authors: Lane DS , Ozyildirim HC
Published: January 2010

The potential for distress resulting from internal sulfate attack in mortars was evaluated using a test method adapted from ASTM Test Method (C 342) and the Duggan test. While these test procedures were originally developed to evaluate the potential for cement-aggregate combinations to undergo deleterious alkali-aggregate reactions, the test scheme of temperature and moisture cycling may simulate conditions that are conducive to internal sulfate deterioration.

Length change bars were fabricated from mortars composed of various combinations of a Type I cement: the Type I cement with Class F fly ash; and a Type I/II cement. The aggregate was alkali-silica reactive. The bars were moist cured for seven days after molding at 23°C. Afterward, the bars were subjected to wet-dry, hot-cool cycles over a period of 24 days; one group subjected to a maximum temperature of 55°C and the other to a maximum of 80°C. Two additional groups received the thermal cycling to 55 or 80°C, and a final group was stored continually wet at 23°C. Following the moisture- thermal cycling period, the bars were stored immersed in water for a period of up to one year, and periodically measured for length change. Excessive expansions were noted only with the Type I cement mortars cycled to 80°C, with expansion developing more rapidly in specimens subjected to a drying cycle. Optical microscopic and scanning electron microscopic examinations of specimens indicate that the paste in expansive specimens expanded relative to aggregate particles.
Curing Practices and Internal Sulfate Attack—The European Experience
Authors: Skalny J , Locher FW
Published: January 2010

The relationships between concrete curing procedures, materials composition, and internal sulfate attack damage will be discussed in view of the experience obtained in Europe in the 1970s and 1980s. The heat-treatment procedures that were introduced and specified to eliminate or minimize the damage will be highlighted and suggestions will be made as to the needed adjustments in curing practices.
Mineralogy and Performance of Cement Based on High Sulfate Clinker
Authors: Herfort D , Rasmussen S , Jøns E , Osbæck B
Published: January 2010

The question of whether or not the release of sulfates from the clinker phases in portland cement can result in late or renewed ettringite formation has been addressed through a series of physical tests and by mineralogical examination. The cements tested contained clinker with SO3 contents ranging up to 3%, including high belite contents and sufficiently low alkali contents to ensure the presence of anhydrite. The physical testing consisted of expansion tests of mortars cured and stored at 20°C, in addition to compressive strength determinations. The mineralogical examination consisted of monitoring the consumption of anhydrous phases by X-ray diffraction and microscopy on the SEM. Linear expansion at 10 months was negligible for all cements with no significant loss in strength. No significant late, or renewed development of ettringite was observed. Calculations based on the distribution of elements between phases in the clinker included in the investigation show that the potential for late ettringite formation from the unreacted clinker is negligible, even when making the most pessimistic assumptions.
Evaluation and Mitigating Measures for Premature Concrete Distress in Texas Department of Transportation Concrete Elements
Authors: Lawrence BL , Moody ED , Guillemette RN , Carrasquillo RL
Published: January 2010

Concrete for both cast-in-place and precast construction plays a vital role in the development of the highway infrastructure in Texas. Historically, Texas has enjoyed a consistent supply of quality concrete because of the availability of economical and high-quality aggregates and cementious materials. However, recent discoveries by the Texas Department of Transportation (TxDOT) of premature concrete distress in concrete elements has raised significant concerns regarding current standards and specifications for concrete materials and construction practices.

In late 1995, 69 precast concrete box beams fabricated in San Marcos, TX became the subject of a comprehensive concrete evaluation effort to determine the cause of premature concrete distress in 56 of the 69 beams. This was TxDOT's first experience with the distress mechanism referred to as delayed ettringite formation. As a result of the investigation, the 56 distressed beams were rendered unsuitable for use.

Since the box beam case study, TxDOT has identified a number of other structures exhibiting similar signs of distress. Four of these structures have been evaluated petrographically. In each case, the distress was attributed to DEF. The increase in the number of structures with this problem has prompted TxDOT to expand its investigation. This includes conducting an extensive in-house research program, sponsoring a round-robin investigation of the box beam concrete, and funding research. As a result of the initial findings, TxDOT is presently considering changes to the cement, aggregate, and construction specifications for mitigation of this problem.

This paper addresses the key elements of TxDOT's continuing investigation and research efforts regarding the problem of premature concrete distress in Texas. Emphasis is placed on the growing nature of the problem in Texas, technological advances in evaluation techniques, and mitigating measures presently under consideration by TxDOT.
Characterization of High-Calcium Fly Ashes and Their Potential Influence on Ettringite Formation in Cementitious Systems
Authors: Tishmack JK , Olek J , Diamond S
Published: January 2010

High-calcium Class C fly ashes derived from Powder River Basin coal are currently used in many parts of the U. S. as supplementary cementing materials in portland cement concrete. These fly ashes tend to contain significant amounts of sulfur, calcium, and aluminum, thus they are potential sources of ettringite.

Detailed mineralogical characterizations of six high-calcium fly ashes originating from Powder River Basin coal have been carried out. The hydration products formed in pastes made from fly ash and water were investigated. The principal phases produced at room temperature were found to be ettringite (C6AS¯3H32), monosulfate (C4AS¯H12), and strätlingite (C2ASH8). The relative amounts formed varied with the specific fly ash. Three fly ashes were selected for further study.

Portland cement /fly ash pastes made with the selected fly ashes were investigated to evaluate ettringite and monosulfate formation. Each of the three fly ashes were mixed with five different Type I portland cements exhibiting a range of C3A and sulfate contents. The pastes had 25% fly ash by total weight of solids and a water: cement + fly ash ratio of 0.45. After mixing, the samples were sealed and placed in a curing room (R.H. = 100%, 23°C) for 28 days and were then analyzed by X-ray diffraction (XRD) and differential scanning calorimetry ( DSC) to determine the principal hydration products.

The hydration products identified by XRD were portlandite, ettringite (an AFt phase), monosulfate, and generally smaller amounts of hemicarboaluminate and monocarboaluminate (all AFm phases). Although the amount of ettringite formed varied with the individual cement, only a modest correlation with cement sulfate content and no correlation with cement C3A content was observed. DSC analyses showed that the cement/fly ash pastes generally formed less ettringite than the cement control pastes, but they formed more of the AFm phases (mainly monosulfate). It appears that the addition of high-calcium fly ash reduces the SO4/Al2O3 ratio in the system thus favoring Afm formation.
Use of Discrete Fibers for Tensile Reinforcement of an Alternative Pavement Foundation with Recycled Aggregate
Authors: Sobhan K , Ahmad T , Mashnad M
Published: January 2010

An experimental investigation consisting primarily of splitting tension and flexural tests was conducted to perform a comparative evaluation of various fibers used to reinforce a stabilized base course material containing recycled crushed concrete aggregate, Type I portland cement and ASTM Class C fly ash. Three commercially available steel and polypropylene fibers, as well as high-density polyethylene (HDPE) fiber derived from recycled plastics were used in this study as reinforcing agents. The primary objective of using fibers was to improve the tensile strength, crack resistance, and toughness characteristics of this alternative pavement foundation material, which is composed of more than 90% by weight of waste products. As an extension to the ASTM C 496 procedure for splitting tension tests, two lateral linear variable differential transformers (LVDT) were attached at the mid-height of the specimens for measuring the tensile deformation of the horizontal diameter due to vertical compressive loading in the orthogonal direction. This method enabled the determination of splitting tension load-deformation and toughness behavior of the specimens. A dimensionless toughness index is used to quantify the post-peak behavior of the specimens containing various reinforcing fibers. A new dimensionless parameter, PPSI (Post Peak Strength Index), is introduced, which combines peak tensile strength with the energy absorption capacity of the composite for evaluating the effectiveness of fibers in a lean cementitious mix. It is found that depending on the mix proportions, the specimens reinforced with recycled HDPE strips can perform as well as or sometimes better than those reinforced with commercially available fibers. These observations are certainly encouraging from economical and environmental perspectives.
Measuring the Effective Air Void Content of Portland Cement Pervious Pavements
Authors: Crouch LK , Cates MA , Dotson VJ , Honeycutt KR , Badoe DA
Published: January 2010

The current literature indicates that air voids of Portland Cement Pervious Pavements (PCPP) should be 15–25%, to achieve desired permeability. However, there is no current AASHTO or ASTM test method to determine PCPP air voids. This study is an attempt to modify currently available hot-mix asphalt (HMA) air determination techniques for PCPP. The equation used to determine air voids in HMA is Percent Air Voids=100(1−Gmb/Gmm). Where Gmb is the bulk specific gravity of the specimen and Gmm is the theoretical maximum specific gravity of loose HMA. Previous research on HMA cores at Tennessee Technological University (TTU) has shown the INSTROTEK CORELOK SYSTEM to be a most effective means of determining Gmb of a material with surface accessible voids. Therefore, it was selected for determining Gmb of the PCPP cores. Gmm of PCPP cores must be determined in a compacted condition. Therefore, three modified techniques for determining the “effective” G” of PCPP were used. Air voids calculated from the effective Gmm will be referred to as effective air voids. Specifically, effective air voids are air voids accessible from the surface, which effect PCPP permeability. Thirty-three field PCPP cores were used in the study. The “cut bag method” using the INSTROTEK CORELOK SYSTEM was found to be the most accurate in determining the effective air voids of the PCPP cores. Further, compressive strengths of all cores were also determined. As expected, compressive strength of PCPP cores was inversely related to effective air voids. Correlation coefficients ranged from 0.367–0.989.
Water Transport in Brick, Stone and Concrete
Authors: Nokken MR
Published: January 2010

In the deterioration of porous building materials, one could say that water is the root of all evil. This book covers the topic of water transport as few have with a focus on flow in commonly used construction materials. There are numerous books concerning flow through porous media, the majority of which are related to groundwater transport through soil. Certainly the extensive work done in the areas of soil physics and petroleum engineering form a sound theoretical basis. The authors draw on this knowledge and refine it to peculiarities encountered with waters interaction with brick, stone, and concrete.
The Influence of Strain Rate on Performance of Fiber-Reinforced Concrete Loaded in Flexure
Authors: Bernard ES
Published: January 2010

Fiber-reinforced concrete (FRC) is commonly used in applications in which the rate of loading exceeds quasistatic conditions by a large margin. Since the performance of materials can vary with strain rate, there is a need to determine the performance of FRC at rates of strain that approximate those occurring in actual applications. In this investigation, FRC has been tested using the round determinate panel procedure to examine the influence of low to moderate rates of strain on cracking and postcrack performance up to severe levels of deformation. The results indicate that performance can vary substantially with strain rate when some types of polymer fibers are used as reinforcement, but that this is not true for all types. Moreover, steel fiber-reinforced concrete exhibits a smaller variation in postcrack performance with rate of strain than polymer FRC.
The Influence of Thickness on Performance of Fiber-Reinforced Concrete in a Round Determinate Panel Test
Authors: Bernard ES , Pircher M
Published: January 2010

The Round Determinate panel test represents a reliable and structurally relevant alternative to beam tests for the evaluation of post-crack performance in fiber-reinforced concrete and shotcrete. However, performance assessment using panel specimens is hindered by a marked sensitivity to thickness. Failure to accurately control the thickness of a specimen can lead to a significant variation in apparent performance that may compromise the goal of reliably characterizing post-crack capacity. The present investigation was undertaken to examine the influence of thickness and diameter on the performance of round panels made with four distinctly different fiber-reinforced concretes. The objective was to develop correction factors for performance that could be used to reduce the sensitivity of test data to variations in specimen geometry and thereby improve the effectiveness of the procedure for postcrack performance assessment of fiber-reinforced concrete and shotcrete.
Effect of Controlled Environmental Conditions on Durability Index Parameters of Portland Cement Concretes
Authors: Griesel EJ , Alexander MG
Published: January 2010

Environmental conditions such as temperature and relative humidity influence the rate of evaporation of moisture from the concrete pore structure. They therefore have a direct influence on the development of transport properties, which are related to durability. Portland cement concretes of various grades were wet cured for different periods of time and exposed to controlled environmental conditions. The influences of temperature, relative humidity, and wind speed on potential durability of the cover layer were assessed by means of durability index parameters related to the transport processes of oxygen permeability, water sorptivity, and chloride conductivity.

Temperature, in the range 18 to 35°C, had the most significant influence on the results. The effect of elevated temperatures on evaporation and hydration resulted in either significant reductions or improvements of potential durability. The influence of relative humidity, in the range 50 to 65%, was less significant. Exposure to 82% relative humidity resulted in significant improvements in the indexes of poorly cured concretes, while well-cured concretes were insensitive to changes in relative humidity. The influence of wind speed on potential durability was insignificant.
A Simplified Shear Test for the Adhesion of FRP Composites to Concrete
Authors: Larralde J , Elpert MS , Weckermann D
Published: January 2010

A considerable amount of concrete structures are currently or will soon be repaired or retrofitted with external reinforcement in the form of fiber reinforced plastic composites. It is important to characterize the bond and adhesion properties of FRP materials if they are externally applied to concrete. This paper presents an alternative simple shear test that can be used to determine the adhesion of FRP materials with concrete. The effects of environmental changes such as changes in temperature and humidity as well as the effects of other harsh conditions can easily be determined with this test. The adhesion of fiberglass composite laminates to concrete was tested with the proposed procedure. Two different materials for the matrix were used and the specimens were exposed to laboratory ambient conditions as well as high temperature, freezing/thawing, and cycles of saturation in sulfate solution.
The Autoclave Soundness Test Mischaracterizes Cement-Fly Ash Blends By Introducing Alkali-Quartz Reaction
Authors: Wang H
Published: January 2010

ASTM C311 is widely used to evaluate the soundness of cement-fly ash blended systems. The soundness test is performed according to ASTM C151—an autoclave test to determine the soundness of portland cement. It has been known that excessive autoclave expansion of cement- fly ash blends occurs in some cases, but the expansion sources and mechanism are poorly understood. Present work in this paper investigated the autoclave expansion conditions of the cement—fly ash blends, major sources of the expansion and expansion mechanism. Based on the test results, it was found that the major source of autoclave expansion of cement—fly ash blend is due to alkali-quartz reaction under autoclave conditions. This excessive expansion due to alkali-quartz reaction did not occur even in the most severe test conditions in ASTM C1260. Therefore, it is reasonable to believe that ASTM C151 mischaracterizes the soundness of cement—fly ash blended systems by introducing an unintended side chemical reaction—alkali-quartz reaction.
The Relative Performance of Abrasion Apparatus In Accordance With BS 8204 (Part 2:1999)
Authors: Vassou V , Kettle RJ , Sadegzadeh M
Published: January 2010

The test apparatus was developed in the 1980s at the Cement and Concrete Association to study the in-situ abrasion resistance of concrete and, following collaboration with Aston University, it formed the basis for establishing the performance criteria in BS 8204: Part 2: 1999. The original design of these machines has been adopted by the industry and a commercial tester has been produced, which has been incorporated in the revision of the BS 8204: Part 2: 1999. It was important to investigate the three existing versions of the machines to determine whether they produce compatible results. This paper provides detailed experimental data from this investigation, discusses whether the results from the commercial abrasion tester are fully compatible with those obtained from the original machines and questions the inclusion of the commercial tester in the BS 8204: Part 2: 1999.
Non-Destructive Tests for the Evaluation of Concrete Exposed to High Temperatures
Authors: Di Maio A , Giaccio G , Zerbino R
Published: January 2010

This paper presents a discussion on the use of non-destructive tests (NDT) for the evaluation of concretes damaged by exposure to high temperatures. The main analysis is based on the relationships between strength, modulus of elasticity and ultrasonic pulse velocity. Rebound hammer, break-off, and resonant frequency were also used. Tests were performed on concretes, prepared with different types of coarse aggregates and cements, with strength levels between 20 and 60 MPa. Exposure variables included maximum temperature (150°C to 700°C), time of exposure and the cooling rate. The obtained results indicate that, contrary to what happens with strength, the ultrasonic pulse velocity is a very good tool for the estimation of the static modulus of elasticity of thermally damaged concretes.
Is ASTM C 672 Curing Procedure Still Appropriate to Test the Scaling Resistance of Blended Cements?
Authors: Saric-Coric M , Aïtcin P-C
Published: January 2010

The scaling resistance of slag-blended cements can be critical when tested according to the procedure described in the present ASTM C 672 standard. As soon as slag replacement is greater than 20 percent, the scaling resistance of concretes made with a slag-blended cement deteriorates rapidly. But when the initial water curing procedure is lengthened from 13 to 27 days, the slag-blended samples have enough time to become more fully mature and they easily pass the scaling test, even when the substitution rate is as high as 80 percent. Lengthening of the present initial water-curing period from 13–27 days should be considered in the case of slag-blended cements, and most probably for other blended cements as well. This would allow for concretes made with a blended cement to reach the same degree of maturity as concretes made with pure Portland cement when they are submitted for the first time to freezing and thawing cycles in the presence of deicing salts.
ASTM Symposium on Prescriptive and Performance Specifications for Hydraulic Cements and Their Use in Concrete: Issues and Implications for Standards Development
Authors: Wang H , Dunstan E , Chen H
Published: January 2010

ASTM C-359, a standard test method for early stiffening of Portland cement (mortar method), is used to assess false set and flash set behaviors of cement in mortar. This test method defines cement false set as “the early development of stiffness . . . . . .without evolution of much heat, which stiffness can be dispelled and plasticity regained by further mixing without addition of water,” while flash set is described as “the early development of stiffness . . . . . .usually with the evolution of considerable heat, which stiffness cannot be dispelled nor can the plasticity be regained by further mixing without addition of water.” Therefore, if penetration is regained after remixing, then the early stiffening is considered as false set. If remixing cannot restore the penetration, the early stiffening is considered as flash set. Although ASTM C-359 does not specify the causes of false set and flash set, it is generally understood that false set is mostly due to re-hydration of dehydrated gypsum in the cement, while flash set is believed to be the result of gypsum deficiency in the cement. The deficiency of gypsum allows rapid hydration of aluminate phase. Our test results indicated that in some cases ASTM C-359 alone could not be directly used to explain the origin of false set or flash set. It is found that early stiffening behavior is related to the amount of gypsum and degree of gypsum dehydration, to the clinker mineralogy and morphology, and to the physical property such as cement fineness.
Comparison of the Air Contents of Freshly Mixed and Hardened Concretes
Authors: Ozyildirim C
Published: January 2010

This study compares the air contents of freshly mixed and hardened concretes. At the fresh stage, pressure meters (Types A and B) and a volumetric meter were used to determine the air content. At the hardened stage, the air content was calculated using the linear traverse method described in ASTM C 457, which is a microscopical procedure. The unit weight and compressive strength of the concretes were also determined.

The results show that, at the ranges commonly used in the construction of pavements and bridges, the air content of fresh concrete measured by pressure meters and that determined by the microscopical method for essentially the same concrete after hardening are, for practical purposes, the same. The air content obtained by a volumetric meter as normally run in the field is generally lower than that obtained for the same hardened concretes by the microscopical method. The unit weight and compressive strength correlate well with the air content. It was also shown that adding water to concrete can significantly increase the air content as well as the slump. Thus, a higher air content in hardened concretes than that indicated by initial measurements with a pressure meter is likely to be present if water is added during placement.
Testing Fly Ash in Mortars for Air-Entrainment Characteristics
Authors: Lane DS
Published: January 2010

When fly ash is used in the production of air-entrained concrete, it can affect the dosage requirement of air-entraining admixture (AEA) needed to produce the desired air content. ASTM C 618 provides a uniformity requirement for the dosage of AEA needed with a particular fly ash, and ASTM C 311 provides a test to determine compliance with the requirement. In a study of fly ash uniformity, the C 311 test was found to be ineffective in evaluating the effect of fly ash characteristics on AEA dosage requirement. The problem with the C 311 test is traced to the high levels of AEA which are required in the test and is illustrated by the use of AEA dosage versus air content curves.

Modifications to the C 311 test are proposed wherein an admixture dosage is selected from the AEA dosage versus air content curve. This dosage is then used to test successive fly ash samples, and changes in air content of the test mix illustrate the variations in AEA requirement caused by the fly ash. An additional modification permits the evaluation of the fly ash's potential to lose entrained air over time.
Reduction in Mortar and Concrete Expansion with Reactive Aggregates Due to Alkali Leaching
Authors: Rogers CA , Hooton RD
Published: January 2010

Mortar bar expansion tests for evaluating alkali-silica reactive aggregates are not always reliable. Containers with efficient wick systems may cause excessive leaching of alkalies out of mortar bars, thus reducing the expansion. This problem has become more apparent since the introduction in 1987 of a new recommended container for the ASTM C 227 mortar bar test. It is believed that the use of this container can result in deleteriously expansive aggregates appearing to be innocuous in laboratory testing. Similar effects were found with concrete prisms made with alkali-carbonate reactive aggregate. If laboratory expansion tests are to be reliable, it is necessary to calibrate the severity of the storage condition by conducting calibration tests with known alkali-reactive aggregates as reference materials. The use of Pyrex glass is not satisfactory for calibrating storage conditions because it contributes alkalies to the reaction.
The Development of ASTM Method C 1012 with Recommended Acceptance Limits for Sulfate Resistance of Hydraulic Cements
Authors: Patzias T
Published: January 2010

With the adoption of the new standard ASTM Test Method for Length Change of Hydraulic-Cement Mortars Exposed to a Sulfate Solution (C 1012-89), it is now possible to evaluate the performance of mortars made with portland cements, blended cements, and blends of portland cement with pozzolans or slags in producing a sulfate-resisting cement mortar.

This paper is a summary of three cooperative interlaboratory testing programs conducted by ASTM Subcommittee C01.29 on Sulfate Resistance with the aim to develop a performance test method and establish its precision.

Parallel to these programs, other tests were conducted at several laboratories from industry, government agencies, and universities that participated in the Subcommittee's programs or conducted research work on their own.

Data are presented showing the expansions of the mortar bars measured at ages up to one year using both ASTM methods C 1012 and C 452. From this work valuable data were generated to conclude the suitability of both methods and propose expansion limits for the acceptance of moderate and high sulfate-resisting hydraulic cements.
Book Reviews
Authors: Klieger P , Idorn GM
Published: January 2010

Dr. Beaudoin has produced a book which is a much-needed update of the technology of fiber-reinforced concrete. It is more than a handbook, as the title states. It is a textbook that provides a distillation of the vast amount of research and development work that has been performed by many investigators, particularly in the past 25 or 30 years.
Strength Measurement of Concrete Using Different Cylinder Sizes: A Statistical Analysis
Authors: Day RL
Published: January 2010

Literature was analyzed to determine the relationship between strength of 150-mm (6 in.) diameter cylinders and smaller 100-mm (4 in.) and 75-mm (3 in.) diameter cylinders. The precision of measurement of strength when smaller cylinders are used was also examined. Almost 8000 cylinder strengths ranging from less than 20 MPa to greater than 100 MPa were analyzed. Results show: (1) over all strength ranges the coefficients of variation of strength (CV) for 100- and 150-mm cylinders are equivalent, (2) For 75-mm cylinders with strengths in the 20 to 60 MPa range, the mean CV is 5.2%, significantly higher than a mean CV of 3.0% for both 100- and 150-mm cylinders, (3) for 100- or 150-mm cylinders, the CV is significantly higher for strengths less than 60 MPa (3.0%) than for strengths greater than 60 MPa (1.8%), (4) within the range 20 to 100 MPa, the expected strength using 100-mm plastic or steel molds is 5% greater than if 150-mm plastic or steel molds are used.
Accelerated Sulfate Attack on Concrete in a Hot Climate
Authors: Wafa FF
Published: January 2010

An accelerated experimental investigation was conducted to study the effect of high sulfate concentration on concrete compressive strength. The effect of sulfate exposure on concrete compressive strength was evaluated by immersing concrete specimens (100-mm cubes) in a 10% magnesium-sulfate solution. The variable parameters were the type of cement, mixture proportions, curing period, and period of sulfate attack. Test results showed that the use of a high W-C ratio with Type I cement produced weak concrete with a loss of compressive strength up to 50% after 15 months of sulfate exposure. Using a rich mixture with Type V cement and a low W-C ratio produced dense impermeable concrete that showed no losses of strength even after 15 months of sulfate exposure in a hot humid environment.
Construction Materials Made with Coal Combustion By-Products
Authors: Wei L , Naik TR , Golden DM
Published: January 2010

A research program at the Center for By-Products Utilization, University of Wisconsin-Milwaukee, is being conducted to develop new low-cost construction materials primarily using coal combustion by-products. This paper reports results of research performed to develop concrete mixture proportions information using fly ash and bottom ash in masonry products. The influence of different types, amounts, and sources of ash on compressive strength and bulk density of concrete are given in this paper. The influence of curing temperature as well as using bottom ash as a replacement of natural aggregates is also reported. It is concluded that low-cost construction materials can be reliably developed using coal combustion by-products with potentially large savings to producers and consumers.
Effect of Curing on Shrinkage and Expansion of Surface Repair Mortars
Authors: Durand B , Mirza J
Published: January 2010

Hydro-Québec has undertaken a major study on the evaluation of repair materials for concrete surfaces damaged by erosion. Shrinkage-expansion and compressive tests, among others, were carried out on 36 different products: 12 cementitious mortars and grouts, eight cement-based mortars containing styrene-butadiene rubber (SBR), four cement-based mortars containing acrylics, and 12 epoxy mortars. For each mix, four 25 by 25 by 275-mm bars and six 51 by 51 by 51-mm cubes were prepared for shrinkage-expansion and compressive-strength tests, respectively. Specimens were demolded after 24 h and placed at 21°C and 100% relative humidity for another 24 h. After that, half the bars were put in lime-saturated water, the other half in air at 50% relative humidity (both cured at 21°C). With respect to the cubes, half were placed in air at 21°C and 50% relative humidity, the others in a moisture chamber. Among the 35 products tested, two cementitious grouts made with special cement and artificial aggregates showed the lowest shrinkage-expansion behavior and the highest compressive strength (over 80 MPa). Two polymer-modified cement-based mortars containing SBR had shown large water expansion and air shrinkage, whereas another cement-based mortar containing SBR showed little shrinkage expansion and high compressive strength. Four of the 12 high sand: epoxy ratio mixes exhibited very large water expansion, whereas most products showed little air shrinkage.
Rapid Chloride Permeability Testing of Silica-Fume Concrete
Authors: Ozyildirim C
Published: January 2010

For long-lasting, reinforced-concrete structures exposed to the environment, low permeability concretes are required. ASTM C 1202 (Electrical Indication of Concrete's Ability to Resist Chloride Ion Penetration) is a rapid test that indirectly measures the permeability of concrete. The results of the rapid test have been related to direct measurements of permeability (e.g., ponding test) and have been found to be useful and valid provided that possible interferences are accounted for. For comparisons between tests, similar concretes should be tested at similar ages.

The addition of silica fume results in a reduction in the permeability of concretes. The rapid test has been able to provide information on relative permeability of concretes with or without silica fume. This finding has been confirmed by the results of the extended ponding test.
Limits of Application of the ASTM C 2274 Mortar Bar Test. Comparison with Two Other Standards on Alkali Aggregate Reactivity
Authors: Ranc R , Isabelle H , Yves Clément J , Sorrentino D
Published: January 2010

Mortar bar expansion tests sometimes provide unreliable data concerning the potential reactivity of aggregates in an alkaline medium. The most widely used mortar bar test, known as the Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar Bar Method) (ASTM C 227) is a case in point. The alkali-carbonate reaction, which is outside the scope of this standard, will not be discussed in this paper. The procedure related to the storage conditions and the leaching of the alkalies from the bars have been the subject of several recent papers. The investigation presented in this paper covers six deleteriously expansive coarse aggregates, which were correctly evaluated when tested in concrete prisms, but not in mortar bars. The Test Method for Potential Reactivity of Aggregates (Chemical Method) (ASTM C 289) has also been used but was not found to be reliable. Based on data developed from the above tests and a complete petrographic examination, it is concluded that reducing the particle size of the materials as required in the mortar bar test contributes to a decrease in expansion.
A New Nondestructive Testing (NDT): Torsion Test to Evaluate Compressive Strength in Concrete Structures
Authors: Di Maio AA , Traversa LP
Published: January 2010

A new nondestructive test (NDT) for the in-situ compressive strength evaluation of concrete has been developed. Using a torque meter, the failure torsional moment is determined on a small cylinder formed in the structure. Test background, methodology, and results obtained in mortar and concrete are discussed. The effects of w-c ratio, particle shape, maximum size, and types of the coarse aggregates, test age, and curing conditions on the correlation relationship are also reported.

Test results (up to 90 days) showed that correlation curves between compressive strength (fc) and ultimate torsional moment (Mt) depend mainly on the size, shape, and surface texture of the coarse aggregate.
Use of Control Specimens in Freezing and Thawing Testing of Concrete
Authors: Rutherford JH , Langan BW , Ward MA
Published: January 2010

The ability to assess with confidence the potential freezing and thawing durability of concrete is important for long-term evaluations of mix designs and of in-situ concrete.

Test Method for Resistance of Concrete to Rapid Freezing and Thawing (ASTM C 666). Procedure A, which is the subject of this investigation, was designed to provide an indication of the potential freezing and thawing durability of concrete in a freezing and thawing environment. It provides a relative assessment of the frost resistance of the concrete after a given number of freeze-thaw cycles, compared to the initial condition of the specimens.

The principal objective of this investigation was to examine the use of control specimens to improve the interpretation of test data. At each test age, the control specimens are tested and these values used in the calculation of the relative dynamic modulus and weight change.

The control specimens allow the effects of the deterioration process to be separated from the changes in the internal structure due to the hydration process as measured by the transverse frequency. They provide a continuous reference for the test specimens, giving a before and after picture for visual assessment such as scaling.
Toughness Behavior of Fiber-Reinforced Rapid-Set Materials: A Preliminary Study
Authors: Ezeldin AS , Balaguru PN
Published: January 2010

This paper presents the experimental results of a preliminary investigation on fiber-reinforced rapid-set materials. The experimental study was carried out using two commercially available rapid-set materials mixed with steel fibers. The investigation was focused on the flexural strength (modulus of rupture) and toughness of the two composites. Three fiber lengths of 30, 50, and 60 mm were incorporated in this study. Their aspect ratios were: 100 (l = 50 mm, φ = 0.5 mm), 75 (l = 60 mm, φ = 0.8 mm), and 60 (l = 30 mm, φ = 0.5 mm). Three fiber contents, namely 50, 100, and 150 lb/yd3 (30, 60, and 90 kg/m3), were used.

The experimental findings indicate that the addition of steel fibers to rapid-set materials results in an increase in flexural strength and a considerable improvement in flexure toughness.
Properties of High-Strength Concrete Containing Light-, Normal-, and Heavyweight Aggregate
Authors: Nilsen AU , Aïtcin P-C
Published: January 2010

Results of an experimental study on the influence of density of aggregate on mechanical properties of high-strength concrete are presented. Using the same mixture proportions by volume, concretes with very dissimilar mechanical properties were obtained. A comparison of measured static modulus of elasticity to the calculated value obtained by using the equations from various building codes shows that the latter overestimate the modulus significantly. The influence of curing time on the drying shrinkage of concrete was also studied. The results confirm that the coarse aggregate type significantly influences the magnitude of shrinkage.
Development of a New Method for the Determination of Iron Content of Hydraulic Cementitious Materials and Pozzolans
Authors: Richter RE , Poole TS
Published: January 2010

Problems were encountered in the use of the reference method as given in ASTM Test Methods for Chemical Analysis of Hydraulic Cement C 114 for chemical determination of iron in certain cementitious materials including pozzolans, slags, and blended cements. Investigational work was done to overcome these problems. Revised procedures were developed. The revised procedures have been accepted for inclusion in ASTM C 114-88. This report documents the work that led to their development.
Sludge Ash Pellets as Coarse Aggregates in Concrete
Authors: Bhatty JI , Malisci A , Iwasaki I , Reid KJ
Published: January 2010

This work examines the potential of using sintered sludge ash pellets as a substitute for regular coarse aggregate in concrete. The mixing of concrete samples was done by replacing the coarse aggregate with sludge ash pellets in varying proportions following mixing procedures of ASTM Test Method of Making and Curing Concrete Test Specimens in the Laboratory (C 192-88). Specimens were prepared as 50 by 100-mm cylinders and tested for compressive strength for up to 28 days. The results indicate that the incorporation of pellets produced reasonably strong concrete—4900 to 5910 psi (33 to 42 MPa) after 28 days. No adverse effects on concrete strength were observed. Instead, the pellets, being round in shape, enhanced the workability of concrete and resulted in more compact concrete specimens. The net result of substituting the pellets for coarse aggregates is to yield a concrete of lower density since the pellets are formed from a material of lower specific gravity than conventional aggregates. The data show that concrete containing pellets is lighter than regular concrete and has a better strength-to-weight ratio. The peak benefits are a strength-to-weight ratio improvement of more than 15% over regular concrete observed in the specimen with 35% substitution of coarse aggregate by pellets.
Are Small Aggregates Really Better for Making High-Strength Concrete?
Authors: de Larrard F , Belloc A
Published: January 2010

It has been stated recently that 10 to 12 mm is the maximum size of aggregates preferable for making high-strength concrete. A discussion of this statement is presented herein, supported by experimental data on eight concretes (normal-strength and high-strength mixes). It is concluded that, in the range of mixes that can be made with the used components—crushed limestone aggregates, Portland cement, silica fume, and superplasticizer, the classical theory still seems to apply: 20 to 25-mm maximum size aggregates lead to better performances and economy than smaller size aggregates.
Static Modulus of Elasticity of High-Strength Concrete from Pulse Velocity Tests
Authors: Nilsen AU , Aitcin P-C
Published: January 2010

During the past few years there has been a growing interest in predicting and controlling the compressive strength and the elastic properties of concrete. In the case of high-strength concrete, the measurement of the static modulus of elasticity requires special specimen preparation and is fairly time consuming. Since the measurement of the pulse velocity is very easy and a correlation exists between static modulus of elasticity and the stiffness constant from the pulse velocity test, it is proposed to use the latter for predicting the static modulus of elasticity of high-strength concretes with very different elastic properties. The stiffness development can easily be monitored in a fast and inexpensive way, but it is not recommended to use the pulse velocity test to predict the concrete strength. The expression Ed = 1.5 Ec - 5.9 GPa provides a good correlation between the dynamic elastic modulus, Ed, and its static counterpart, Ec.
Materials Science of Concrete II
Authors: Mehta PK
Published: January 2010

The first volume of the series on the Material Science of Concrete was published in 1989. This is the second volume, and it contains ten chapters comprising state-of-the-art reviews on various subjects related to the materials science of cements and concrete.