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Showing 1-9 of 9 Abstracts search results

Document: 

SP263-08

Date: 

October 1, 2009

Author(s):

M.N. Soutsos, S.J. Barnett, S.G. Millard, and J.H. Bungey

Publication:

Special Publication

Volume:

263

Abstract:

The early age strength development of concretes containing slag cement (ggbs) at levels of up to 70% of the total binder have been investigated to give guidance for their use in fast track construction. 28-day target mean strength for all concrete specimens was 70 MPa (10,150 psi). Although supplementary cementitious materials such as slag cement (ggbs) are economical, their use has not gained popularity in fast track construction because of their slower strength development at early ages and at standard cube curing temperatures. There are however indications that supplementary cementitious materials are heavily penalised by the standard cube curing regimes. Measurements of temperature rise under adiabatic conditions have shown that high levels of cement replacement by ggbs, e.g. 70% are required to obtain a significant reduction in the peak temperature rise. Even though the temperature rise using slag cement is lower than from using portland cement, it is still sufficient to provide the activation energy needed for a significant reaction acceleration. Maturity measurements are needed to take advantage of the enhanced in-situ early age strength development of ggbs concrete. The contractor should confirm that the actual compressive strength of the concrete in the structure at the time of formwork removal exceeds the required strength. Maturity functions like the one proposed by Freiesleben Hansen and Pedersen (FHP), which is based on the Arrhenius equation, have been examined for their applicability to ggbs concrete. Activation energies, required as input for the FHP equation, have been determined according to ASTM C1074-98.

10.14359/51663256


Document: 

SP263-07

Date: 

October 1, 2009

Author(s):

C.-M. Aldea, B. Cornelius, J. Balinski, B. Shenton, and J. Sato

Publication:

Special Publication

Volume:

263

Abstract:

The experimental program presented in this paper was a technical evaluation of an alternative cement and high-density (HD) concrete mixture design for HD concrete at mid-range temperature to meet specific target properties. The cement industry has moved away from manufacturing ‘special use’ portland cements, which were approved for some applications of mass HD concrete, for which temperature rise in the concrete is of importance. Potential replacement of these ‘special use’ portland cements by blending varying amounts of supplementary cementitious materials (SCMs) with ‘general use’ portland cement to provide ‘blended cements’ was investigated. The paper focuses on experimental results obtained in the laboratory showing the effect of the addition of high volume slag blended cement for HD concrete on temperature rise, as well as on mechanical properties and microstructure after aging and mid-range temperature exposure. Slag-blended cement was evaluated and determined to have acceptable properties in HD concrete, meeting or exceeding performance requirements.

10.14359/51663255


Document: 

SP263-06

Date: 

October 1, 2009

Author(s):

R.D. Hooton, K. Stanish, J.P. Angel, and J. Prusinski

Publication:

Special Publication

Volume:

263

Abstract:

This report details the results of a critical review of the literature on the effect of ground, granulated, blast-furnace slag (slag cement) and slag-blended cements on the drying shrinkage of concrete. Drying shrinkage values from the literature were collected, and concretes containing slag were compared to otherwise identical concretes that did not contain slag. Overall, while individual data may indicate a higher drying shrinkage, on average, the drying shrinkage for concretes containing slag cement was the same as concretes without slag. From examination of the data it was determined that the only parameter of the mixture design that had a significant influence on the drying shrinkage was the total aggregate volume. Any increase in drying shrinkage of the slag cement concrete was typically reduced with increasing aggregate content. The level of slag replacement and the w/cm of the concrete mixture were not found to affect the relative drying shrinkage, at least over the typical range used for concrete mix designs. The relative values of the drying shrinkage were also unaffected by whether slag cement was added as a separate ingredient or if a blended hydraulic cement containing slag was used. The aggregate content of concretes made with slag was often lower than a comparable concrete made without slag due to the lower density of the slag relative to portland cement when slag cement was used as a replacement on an equal mass basis, rather than on an equal volume basis. A correction for this would reduce any additional shrinkage attributable to the use of slag cement. In addition, the increase in relative shrinkage of some slag-containing concretes may, in several cases, also be partially due to the reduced gypsum content of the cementitious mixture, although this is unclear and needs further investigation. Although the data are limited, the restrained shrinkage cracking of concrete containing slag appears to be less than that of concrete without slag. Cracking was delayed to later ages and resulted in smaller total crack widths. The effect of the inclusion of slag on restrained cracking needs to be further investigated.

10.14359/51663254


Document: 

SP263-05

Date: 

October 1, 2009

Author(s):

L.J. Wilhite, J.T. Vetter, and W.M. Hale

Publication:

Special Publication

Volume:

263

Abstract:

Synopsis: Economic and environmental considerations have promoted the use of supplementary cementing materials (SCMs) such as slag cement (SC) and fly ash (FA). Ternary mixtures containing both slag cement and fly ash have gained popularity due to environmental issues and shortages in the supply of cement. However, in the 2003 Arkansas State Highway and Transportation Department (AHTD) Standard Specifications, ternary mixtures were prohibited for use in Portland Cement Concrete Pavement (PCCP). Previous research conducted by the University of Arkansas examined ternary mixtures containing SC and FA and cured at 70°F (21°C). This research program examined the strength gain and time of setting characteristics of ternary mixtures cured at lower temperatures. In the study, SC contents ranged from 0 to 40%, and the FA contents ranged from 0 to 60%. Six different mixtures containing Class C FA and Grade 100 SC were batched and tested at temperatures of 70°F (21°C) and below. The curing temperatures for the study were 40, 50, 60, and 70°F (4, 10, 16, and 21°C). The concrete properties measured were concrete temperature, slump, unit weight, air content, time of setting, and compressive strength.

10.14359/51663253


Document: 

SP263-04

Date: 

October 1, 2009

Author(s):

P.R. Rangaraju

Publication:

Special Publication

Volume:

263

Abstract:

The Federal Highway Administration (FHWA) under its Testing and Evaluation program (TE-30) on High-Performance Concrete (HPC) pavements had initiated several field demonstration projects to evaluate the use of new technology to improve the long-term performance of the pavements. Under this program, the Minnesota Department of Transportation (Mn/DOT) has successfully completed the construction of the first 60-year design life HPC pavement in the state along Interstate I-35W. Significant changes to materials-related specifications that affect the long-term performance of the concrete pavement were implemented in this project. This paper will provide a brief description of the Mn/DOT’s first HPC pavement project along with key design features of the pavement, including use of slag cement in high-performance concrete mixtures, higher level of entrained air content than that is conventionally used, and stainless steel dowel bars. Also, the results of quality control tests conducted on field concrete during construction are presented.

10.14359/51663252


Document: 

SP263-03

Date: 

October 1, 2009

Author(s):

D.D. Higgins and G. McLellan

Publication:

Special Publication

Volume:

263

Abstract:

To investigate the relationship between the alkali content of concrete and the expansion caused by alkali-silica reaction, several hundred concrete prisms containing reactive natural aggregate, were regularly measured over a period of ten years. These prisms contained between 0 and 70% slag cement in combination with portland cements, and had concrete alkali contents between 4.5 and 11 kg/m3 (0.3 and 0.7 lb/ft3). The alkali content of the Portland cements ranged from 0.54 to 1.15% and that of the slag cements from 0.58 to 0.83%. Prisms were moist-stored at 20°C (68 °F) and at 38°C (100°F). Storage at the higher temperature accelerated the rate of expansion, and slightly increased the ultimate expansion. The correlation between the two temperatures was very good in terms of classifying mixtures as either ‘expanding’ or ‘non-expanding’. It is concluded that storage at 38°C (100°F) is an accelerated test that can be used to reliably predict what would happen at ‘normal’ temperature. The mixtures containing slag cement, tolerated much greater alkali contents in the concrete, without expansion. This effect was more pronounced for higher proportions of slag cement.

10.14359/51663251


Document: 

SP263-02

Date: 

October 1, 2009

Author(s):

M.D. Luther, P. Bohme, and W. Wilson

Publication:

Special Publication

Volume:

263

Abstract:

This paper is a collection of over 30 brief case studies about mass-concrete projects using ASTM C989 (AASHTO M302), or similar, slag cement (formerly called ground granulated blast-furnace slag) - undertaken to learn more about concrete mixtures and considerations as they are applied in the field. With the exception of some ternary mixes, generally, the slag cement amounts equaled or exceeded the amounts of Portland cement employed in the mixtures. The information showed that a broad spectrum of proportions featuring slag cement of all grades have been used to achieve desired mass-concrete properties and outcome, including staying under a maximum core temperature, holding within a maximum differential temperature, and achieving specified strength.

10.14359/51663250


Document: 

SP263-01

Date: 

October 1, 2009

Author(s):

C. Ozyildirim

Publication:

Special Publication

Volume:

263

Abstract:

Slag cement was introduced to Virginia Department of Transportation (VDOT) in the early 1980s. Laboratory investigations showed that slag cements can be used as an alternative to conventional portland cement concretes in replacement rates up to 50% for pavements and bridge structures. Concrete containing slag cement had lower permeability than the conventional portland cement concrete. Since the mid 1980s, slag cement has been successfully used by VDOT in bridge structures and pavements to reduce permeability and improve the durability of concrete. In large footings, slag cement has been used at a replacement rate of 75% to control the temperature rise and to reduce permeability. Currently, slag cement is used in high-performance concretes to obtain high compressive strength and low permeability. Slag cement is also used in ternary blends with portland cement and fly ash or silica fume to lower permeability, improve durability, and obtain the desired early strengths.

10.14359/51663249


Document: 

SP263

Date: 

October 1, 2009

Author(s):

Editor: Corina-Maria Aldea / Sponsored by: ACI Committee 233

Publication:

Special Publication

Volume:

263

Abstract:

This CD-ROM contains eight papers that provide insight on recent slag cement concrete developments in academia, the concrete industry, and in real life applications of slag cement concrete. Topics include materials aspects related to the benefits of adding slag in concrete to prevent alkali-silica reactions, reducing drying shrinkage, and reducing the potential for thermal cracking during the curing period. Also covered are high-volume applications of slag cement in: concrete for transportation structures, high-performance concrete pavements, mass concrete, and high-density concrete. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-263

10.14359/51663196


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