bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.