bluuebunny/crossref_metadata_2025_split huggingface dataset:
Setting Times of Fly Ash and Slag-Cement Concretes as Affected by Curing Temperature
Authors: Eren O , Brooks JJ , Celik T 
Published: January 2010

AbstractUsing Test Method for Time of Setting of Concrete Mixtures Paste by Penetration Resistance (ASTM C 403), Proctor penetration resistance was determined under isothermal curing temperatures ranging from 6 to 80°C for concretes containing up to 50% of fly ash or ground-granulated blast-furnace slag. The results show that as the temperature increases, the initial and final setting times decrease for all types of concrete, with fly-ash concrete having the longest setting times. At high temperatures, slag concrete has shorter setting times than Type I cement concrete. Relationships are presented for setting time as a function of penetration resistance, temperature, and cement replacement level.
Efficiency of Natural Greek Pozzolan in Chloride-Induced Corrosion of Steel Reinforcement
Authors: Kouloumbi N , Batis G , Pantazopoulou P 
Published: January 2010

Abstract
This experimental work estimates the corrosion behavior in a sodium-chloride environment of steel reinforcements in mortar specimens with 0, 15, and 30% Greek natural pozzolan, cured either for 1, 7, or 28 days. The corrosion resistance was evaluated by measuring the corrosion potential development of steel rebars, their gravimetric mass loss, their anodic potentio-dynamic behavior, and the total- and free-chloride content of the mortars. Additionally, their mineralogical composition was determined by X-ray diffraction (XRD) analysis. The increase of curing time, as well as the addition of the Greek natural pozzolan, for both percentages tested, improved the corrosion behavior. The combination of the pozzolan addition with longer curing time reduces the steel rebars mass loss up to a level of about 40% after five months of exposure.
Why the Accelerated Mortar Bar Method ASTM C 1260 is Reliable for Evaluating the Effectiveness of Supplementary Cementing Materials in Suppressing Expansion Due to Alkali-Silica Reactivity
Authors: Bérubé M-A , Duchesne J , Chouinard D 
Published: January 2010

Abstract
The Accelerated Mortar Bar Method (AMBM) ASTM C 1260 (or CSA A23.2-25A) is used with success for evaluating the effectiveness of supplementary cementing materials (SCMs) in suppressing expansion due to alkali-silica reactivity in concrete (ASR). This study attempts to answer the question of why this method gives good results with SCMs. The most beneficial effects of SCMs against ASR is thought to be alkali decrease in the pore solution while the bars are immersed in 1N NaOH at 80°C. Mortar bars made with different SCMs were tested in normal conditions as well as in pure water and in air at 100% RH. The expansion results were compared with the chemistry of the mortar pore solution expressed under high pressure. The results confirmed that in the presence of an SCM, the alkali decrease in the pore solution remains the most critical mechanism involved in the AMBM. The results also confirmed that alkali equilibrium between the pore solution and the NaOH immersion solution is not achieved in the presence of an SCM at the end of the testing period of 14 days.
Determination of Silica Fume in Unhydrated, Blended, Dry-Packaged Mixture, and Hydrated Mortar
Authors: Coleman SE , Hwu S , Vogt WL 
Published: January 2010

Abstract
A test method is proposed as a quality control methodology to determine the relative amount of dry silica fume present in a prepackaged blend of dry, unhydrated, cementitious material. The method assumes availability of representative samples of each of the raw material ingredients prior to packaging, including portland cement, silica fume, fly ash, silica sand, and a representative sample of the mixed product. Known percentages of silica fume by weight of portland cement were added separately to a basic blended mixture and analyzed by combined heat treatment and X-ray diffraction (XRD) method. From a calibration curve developed from standard laboratory mixtures, an estimate of the amount of silica fume in a prepackged cement was determined with a reasonable degree of accuracy.
Additionally, a neat portland cement and portland cement + fly ash + sand mixtures containing different proportions of silica fume by weight of cement were hydrated at W-C = 0.30 and analyzed at selected periods for up to 180 days to determine residual silica fume. The diminution of calcium hydroxide (formed by the hydrating portland cement) in the cement-fly ash mixture and in the combined silica fume and fly ash cement mixtures were monitored during this period using thermogravimetric analysis and scanning electron microscopy.
Rapid Determination of the Fly Ash Content of Construction Materials
Authors: Schlorholtz SM , Dubberke W 
Published: January 2010

Abstract
Since 1989 this laboratory has had good success using X-ray fluorescence (XRF) methods to determine the amount of fly ash that is present in portland cement-fly ash mixtures. The method has been used on mixtures of dry cementitious constituents prior to batching, and also on portland cement-fly ash mortars and concretes. The method is based on the determination of the concentration of barium (Ba) and strontium (Sr) present in the construction materials. Since these two elements are greatly enriched in Iowa fly ashes they act as “finger prints” for the presence of fly ash, and if the proper criteria are satisfied, they also allow for the quantification of the amount of fly ash in a given mixture. The method works best when it can be calibrated with materials taken directly from a given jobsite. The method is very quick since samples can normally be analyzed in less than 10 min. The sample preparation process does not involve extraction techniques that use hazardous solvents. With a modern, computer-controlled X-ray fluorescence spectrometer the method can also be extended to determine many other elements present in the sample, such as sulfur (S) and chlorine (Cl), which may be of importance to investigations concerning the chemical attack of portland cement-based materials.
A New Consecutive Dissolution Method for the Analysis of Slag Cements
Authors: Goguel R 
Published: January 2010

Abstract
The best means of selective dissolution of ordinary portland cement (OPC) from ground granulated blast-furnace slag (BFS) cements has been, until now, a sodium-based alkaline aqueous solution of ethylenediamine-tetraacetate with chelating properties supplemented by the presence of 6% triethanolamine (TEA).
Selectivity of the solvent is substantially improved by replacing sodium with tetramethylammonium (TMA). This large cation has a selective decelerating effect on the release of aluminum from aluminosilicate glasses. Thus, its introduction slows down dissolution of BFS and slightly accelerates the dissolution of OPC. This improvement removes the need for careful buffering at pH 11.6. A higher pH (for example, 12.5) is used, which avoids the formation of siliceous precipitates.
Further, it was found that the use of lithium as cation makes the EDTA-TEA solution a good solvent of BFS that allows separation from aggregates based on aluminosilicate rocks. Consecutive application of the two versions of the same chelating system thus allows good separation and quantitative dissolution of OPC and BFS from the unhydrated slag-cement.
Determination of the degree of hydration of BFS could be derived from measurements of Ca and Si in the leach rather than the measurement of weight losses during leaching. This technique reduces errors from the formation of solvent resistant Mg-Al-hydroxide phases (for example, hydrotalcite) and extends the range of application.
Determination of Silica-Fume Content in Hardened Concrete by AC Impedance Spectroscopy
Authors: Gu P , Xie P , Beaudoin JJ 
Published: January 2010

Abstract
A nondestructive method based on AC impedance spectroscopy was applied to studies of the electrical behavior of hydrated portland cement concrete containing silica fume. Silica fume content significantly influenced the impedance behavior of hydrated portland cement concrete. Correlations between the high frequency arc (HFA) diameter and the silica-fume content in concrete were obtained. Empirical relationships for concrete binders at early and more advanced hydration can be expressed as 1DHFA=Koβsf+Cfor early hydration times and 2DHFA=C′(Ko′)βsffor advanced hydration times where DHFA is the high frequency arc diameter, βsf is the silica-fume content, Ko, K′o, C, and C′ are constants related to hydration times and W-C ratio, and so forth.
Trinity Square: Commentary on Concrete Test Data
Authors: Bickley JA 
Published: January 2010

Abstract
The paper describes the use of in-place testing instead of standard cylinder testing. Removal of forms and shores, and determination of concrete strength compliance with specifications were all controlled by pullout tests.
The criteria were written into the contract specification, and the relevant sections are quoted as a model for future use. Based on correlation data with standard cylinder tests, the building officials allowed the elimination of the usual mandatory standard cylinder tests. Standard tests were made however to provide comparison with the in-place tests. The paper shows that the in-place test provided an adequate measure of the quality and strength of the concrete.
Soundness Testing and Durability of Coarse Aggregates in Concrete
Authors: Cady PD 
Published: January 2010

Abstract
Throughout its long history, sulfate soundness testing of aggregates has been frequently cited for poor reliability as a predictor of concrete durability. However, its use remains widespread, even to the point of constituting an acceptance test criterion for aggregates. Sodium sulfate soundness tests of coarse aggregates are compared in this paper with freezing and thawing tests of air-entrained concretes containing the aggregates. In one case, sodium sulfate soundness displayed a relationship to durability (freezing and thawing) test results, in a statistical sense, but the level of predictability was poor. In another test series, the level of predictability fell within the range of pure chance.
The attractiveness of sulfate soundness testing is apparently derived from its simplicity and directness. However, it is shown in this paper that a combination of two aggregate property tests, specific gravity and absorption, provide a better predictor of freezing and thawing durability. Furthermore, these two tests are routinely run on aggregates and are even simpler than the sulfate soundness test.
The Maturity Method: Theory and Application
Authors: Carino NJ 
Published: January 2010

Abstract
The maturity method may be used to predict the in-place strength of hardening concrete based on its thermal history. A theoretical basis for the maturity method is presented. The general form of the time-temperature function is found to be the time integral of the rate constant. For the case of linear dependence between temperature and the rate constant, the time-temperature function becomes the traditional maturity function. The Arrhenius equation is shown to be an accurate representation of the temperature dependence of the rate constant, and the concept of equivalent age is explained for practical application of the Arrhenius equation. It is explained how the accuracy of strength prediction by the traditional maturity method can be improved by using the proper datum temperature. Results illustrate that the appropriate value of apparent activation energy or datum temperature for concrete may be obtained from strength-gain data of isothermally cured mortar specimens.
Influence of Petrography of Argillaceous Carbonates on Their Frost Resistance in Concrete
Authors: West TR , Shakoor A 
Published: January 2010

Abstract
Argillaceous carbonate rocks, when used as coarse aggregate, have been found to cause severe pitting and popouts in several Indiana highways within one winter after construction. These rocks were studied in detail petrographically to determine texture, structure, and mineral composition, and in particular the amount, type, and mode of distribution of argillaceous material.
Results of petrographic examination were compared with other test data including specific gravity, absorption-adsorption values, pore characteristics, and loss in freeze-thaw. This comparison suggests a close relationship between petrographic characteristics and freeze-thaw resistance of argillaceous carbonates. A comparison of petrographic information with field performance shows that those rocks that contain more than 20% silt and clay distributed uniformly throughout the rock mass result in pitting and popouts while those in which silt and clay are concentrated as streaks and laminations are not necessarily unsound. This is contrary to several previous investigations that concluded that laminated carbonates should be considered nondurable without specific concern for their total argillaceous content.
The Inhibition of Chloride-Induced Corrosion in Reinforced Concrete by Calcium Nitrite
Authors: Gaidis JM , Rosenberg AM 
Published: January 2010

Abstract
Reinforcing steel in portland cement concrete is subject to accelerated corrosion in the presence of chloride ions. A corrosion-inhibiting admixture based on calcium nitrite has been shown to confer protection (that is, to inhibit corrosion) if the chloride to nitrite weight ratio (Cl−/NO2−) does not exceed 1.5. Visual observations made on rebars in limewater solutions containing chloride and nitrite ions, current and potential measurements on concrete cylinders with embedded reinforcing bars (rebars), and potential measurements on simulated concrete bridge decks were in substantial agreement.
Factors Affecting the Reactivity of Fly Ash from Western Coals
Authors: Harris HA , Thompson JL , Murphy TE 
Published: January 2010

Abstract
This study of 16 fly ashes from various Colorado and Wyoming coals will show the relationship of coal and fly ash analyses to pozzolanic activity with portland cement. Samples have been followed from the coal source through the power plant combustion and collection system to show the effects upon fly ash quality for use as a mineral admixture in concrete. Each coal source is analyzed using ASTM Method for Proximate Analysis of Coal and Coke [D 3172-73(1984)] and classified by rank under ASTM Classification of Coals by Rank (D 388-84). The ash is analyzed and studied using ASTM Method for Sampling and Testing Fly Ash or Natural Pozzolans for Use as a Mineral Admixture in Portland Cement Concrete (C 311-85).
The problems associated with the present ASTM fly ash classification are shown in these samples by the conflicting data relative to their coal source and chemical analyses. Based upon the existing classifications under ASTM Specification for Fly Ash and Raw or Calcined Natural Pozzolan for Use as a Mineral Admixture in Portland Cement Concrete (C 618-85), both Class C and Class F ashes are studied.
Effect of Chemical Admixtures on Portland Cement Hydration
Authors: Odler I , Abdul-Maula S 
Published: January 2010

Abstract
The effect of selected chemical admixtures on the progress of portland cement hydration, composition of the hydration products, and strength development was studied. Calcium chloride (CaCl2) accelerated the hydration of both tricalcium silicate (C3S) and tricalcium aluminate (C3A) and increased the calcium oxide/silicon dioxide (CaO/SiO2) ratio of the formed calcium-silicate-hydrate (CSH) phase. In the presence of zinc oxide (ZnO), Na-lignosulfonate, and a melamine resin, the hydration of both C3S and C3A was retarded, while in the presence of sucrose only that of C3S. The effect of all these additives was more pronounced if pure C3S rather than portland cement was employed. Regardless of the kind and amount of admixture added (except high amounts of CaCl2) and hydration time, the bound water content, amount of liberated calcium hydroxide, and compressive strength were linear functions of the amount of hydrated C3S.
History and Use of Blended Cements in Turkey
Authors: Öztekin E , Cimilli T 
Published: January 2010

Abstract
The number of cement plants in Turkey increased from 1 in 1911 to 39 in 1985 and the yearly cement clinker production capacity from 20 000 to 21 000 000 metric tons, respectively. Production of blended cements started in the late 1960s and in 1970 accounted for 20% of the total output. However, the share of the blended cements increased to 30% in 1975, to 75% in 1979, and to 92% in 1985. Of the four types of blended cements produced (namely, modified portland cement, trass cement, iron portland cement, slag cement), modified portland cement appears to be popular, accounting for 72% of the total cement production in 1984. This paper briefly looks at the historical background, describes the types of cements produced, collates the available data on pozzolanic materials and cements, and discusses the trends in the use of blended cements.
The Use of Fly Ash in Concrete: Classification by Composition
Authors: Thomas MDA , Shehata MH , Shashiprakash SG 
Published: January 2010

Abstract
Fly ash has been used as a pozzolanic admixture in concrete for more than 50 years. Earlier uses were largely confined to low-calcium ashes from hard bituminous or anthracite coals. However, increased demand for fly ash coupled with the declining availability of suitable low-calcium ashes has attracted a wider variety of fly ashes to the marketplace in recent years. Some of these ashes are characterized by very high calcium contents (for example, &gt;25% CaO) and such materials affect the properties of concrete in a different manner than “traditional” fly ashes. The latest Canadian Standard covering fly ash for use in concrete divides fly ash into three categories strictly on the basis of its calcium content. This paper provides a rationale for this change in concept.
Use of the Accelerated Mortar Bar Test for Evaluating the Efficacy of Mineral Admixtures for Controlling Expansion due to Alkali-Silica Reaction
Authors: Thomas MDA , Innis FA 
Published: January 2010

Abstract
This paper presents data from laboratory studies to assess the suitability of the accelerated mortar bar test (CSA A23.2-25A and ASTM C 1260) as a method for evaluating the effect of mineral admixtures on expansion due to alkali-silica reaction (ASR). A wide range of materials such as fly ash, slag, silica fume and natural pozzolans have been tested at different replacement levels in combination with various reactive aggregates including siliceous limestone, greywacke, granite and sandstone. Results are presented for 70 different material combinations tested by both the accelerated test and the Canadian Standards Association concrete prism test (CSA A23.2-14A and ASTM C 1293).
For aggregates that were shown to be deleteriously reactive by both test methods there was a generally good agreement between the test results when the failure criteria used were expansion of mortar bars at 14 days &gt; 0.10% and expansion of concrete prisms at 2 years &gt; 0.040%. Only 5 out of 70 mixtures passed the mortar bar test and failed the concrete prism test and in two these 5 cases the extent of failure was insignificant (that is, 0.042% expansion at 2 years in both cases). It is concluded that combinations of pozzolans and reactive aggregates that pass the accelerated mortar bar test can be used in the field with a very low (and acceptable) risk of deleterious expansion due to ASR.
A large number of the mortar bars were subjected to pore solution expression and analysis after 14 days in 1 M NaOH at 80°C. There is a broad correlation between the pore solution alkalinity and expansion at the end of the test. This suggests that the mineral admixtures suppress expansion in this test by reducing both the alkalinity of the pore solution in the bar and the penetration (diffusion) of alkalis into the bar from the host solution.
Use of Ground Granulated Blast Furnace Slag for Reduction of Expansion Due to Delayed Ettringite Formation
Authors: Miller FMG , Conway T 
Published: January 2010

Abstract
Two cements, with a demonstrated tendency in mortars to suffer expansion related to delayed ettringite formation when cured at high temperatures ≥75°C, were tested after substitution of 5, 17.5, and 30 % with a ASTM C 989 Grade 100 ground granulated blast furnace slag. The two cements are here characterized as a “highly expansive” and a “moderately expansive” portland cement, according to the tendency of each to expand when stored in limewater after curing at elevated temperatures &gt;75°C. Expansion was reduced or delayed, but not eliminated, with 5 % slag substitution, but completely absent when 17.5 % slag substitution was used. Compressive strengths were measured on cubes cured at ambient temperatures and at 90°C. Test results indicated that no strength penalty was experienced in mortars with high slag substitution, cured at 90°C; in fact, the compressive strengths were superior for the 30 % slag mixes, at all ages tested (from 1–28 days of hydration). The conclusion is tentatively reached that the use of blast furnace slag to reduce proclivity to DEF is effective, and does not involve any sacrifice in mortar compressive strength, at least to 28 days of hydration.
Strength and Density of Laboratory-Prepared RCC Specimens: Effect of Compaction Procedure
Authors: Shihata SA 
Published: January 2010

Abstract
Appropriate compaction is essential in producing roller-compacted concrete (RCC). An experimental program was conducted to study the effect of compaction on the strength and den-sity of RCC specimens. Compaction was achieved by tamping the sample with a hammer similar to that of ASTM D 1557. The main variables were the magnitude of compaction energy, number of lay-ers per mold, and cement content. The compaction energy ranged from 300 to 2700 kN-m/m3. The test results show that the decrease of the unit weight by 7.7% decreases the compressive and splitting tensile strengths by 73 and 71%, respectively. Increasing the cement content compensates for the reduction in compaction energy. The average degree of compaction of the cores taken from the field RCC test slabs was 99% of the unit weight of field samples prepared with a 2700 kN-m/m3 compaction energy.
Kinetics and Microstructural Changes Associated with Mortar Expansion
Authors: Pade C , Struble LJ 
Published: January 2010

Abstract
Mortar expansion data have been fitted to various kinetic models. The expansion tests utilized several aggregates (Pyrex glass, Vycor glass, calcined flint, Spratt's aggregate, and Beltane opal) and cements with various alkali contents. A very good fit was observed using a model developed to describe autocatalytic chemical reactions, and a fairly good fit was observed using a model for topochemical reactions. Microstructural studies showed that the reaction of Pyrex and Vycor involved highly localized attack of the glass, while reaction of calcined flint was less localized and appeared to be associated with preexisting internal fractures. For all three aggregates, the mortar expansion appeared to be associated with expansion of individual aggregate particles.