International Concrete Abstracts Portal

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  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-10 of 36 Abstracts search results

Document: 

SP206-35

Date: 

April 1, 2002

Author(s):

K. P. Chong

Publication:

Special Publication

Volume:

206

Abstract:

Mechanics and materials are essential elements in all of the transcendent techynologies in the twenty first century and in the New Economy. Information technology and biotechnology. Research opportunities and challenges in theoretical and applied mechanics as well as engineering materials, including cement-based materials, in the exciting information age are presented and discussed.

10.14359/12276


Document: 

SP206-34

Date: 

April 1, 2002

Author(s):

D. C. Jansen

Publication:

Special Publication

Volume:

206

Abstract:

In most curricula, students have numerous opportunities to work as part of a team, but they are seldom instructed on how to function as part of a team, a valuable skill in the corporate environment. As part of a larger initiative to develop five fundamental skills, Tufts University's School of Engineering has implemented a program to introduce teamwork skills to all engineering students. This program is designed to develop good habits for functioning as part of a team. In context of the work being presented, the team working skills were introduced into a sophomore level civil entgineering materials course (including concrete, of course!). Students were given two lectures followed by laboratory exercises to emphasize the teamwork concept of defining and working towards a common goal and not being so driven by the task. The students then practiced their skills throughout the course by functioning as teams in all their laboratory exercises and report writing. Through roper functioning teams, cooperative learning is promoted, and students learn the material beeter and more efficiently. Team performances were periodically assessed. Overviews of the School of Engineering's five fundamental skills program and teamwork initiative are presented. Outcomes from the teamwork program incorporated into the civil engineering materials course were assessed at several stages uring the class and are reported.

10.14359/12275


Document: 

SP206-33

Date: 

April 1, 2002

Author(s):

S. H. Kosmatka

Publication:

Special Publication

Volume:

206

Abstract:

This paper reviews the opportunities that the Portland Cement Association has taken to address part of the education needs of the cement and concrete industries. Addressed are current educational efforts and a review of how research at universities addresses both the educational and technical needs of the industry. A. list of concrete related web sites is included. Through education the concrete industry can meet the need for informed professionals who are necessary to sustain concrete as the building material of choice for this century.

10.14359/12274


Document: 

SP206-32

Date: 

April 1, 2002

Author(s):

E. N. Landis and W. P. Manion

Publication:

Special Publication

Volume:

206

Abstract:

An intoductory construction materials course was developed for first year civil and environmental engineering students at the University of Maine. Because it is typically the first engineering course in which most civil engineering students enroll, the course also serves as an introduction to principles of engineering aalysis and desing. We have adopted a materials science approach in our coverage of construction materials. That is, we emphasize how material properties are a function of their microstructure, and that we control microstructure through processing. We have found concrete to be an ideal material with which to illustrate this concept. Students are easily able to observe the processing-microstructure-properties links through laboratory and homework exercises in concrete mix design and testing. In the broader context we have found materials in general, and concrete in particular, to be excellent model topics for intoducing the general topics of engineering analysis and design.

10.14359/12273


Document: 

SP206-31

Date: 

April 1, 2002

Author(s):

C. Meyer

Publication:

Special Publication

Volume:

206

Abstract:

The United States is a country known for its wasteful use of natural resources. Effort so correct the results of past transgressions as well as to balance economic development against legitimate concerns of conservation are pervading almost all aspects of life, including the construction industry. Concrete, being the most widely used material worldwide, is a natural target for greenhouse gases and energy user. Recent research has led to the point where substituted partially fror cement, such as fly ash and ground granulated blast furnace slag. Also other recycled materials are finding increased application in concrete produciton. For example, recycled concrete has been used successfully in numerous projects, and crushed waste glass is now available as a valuable source of aggregate, since the problem of alkali-silicate reaction has been solved. The key to commercial success is beneficiation, ie.e. the targeted utilizaion of specific properties of the recycled material, which adds value to the end product.

10.14359/12272


Document: 

SP206-30

Date: 

April 1, 2002

Author(s):

Z. P. Bazant, F. C. Caner, and J. Cervenka

Publication:

Special Publication

Volume:

206

Abstract:

A newly developed powerful version of microplane model, labeled model M4, is exploited to study two basic phenomena in fracturing concrete:(a) The vertex effect, I.e., the tangential stiffness for loading increments to the side of a previous radial loading path in the stress space, and (b) the effect of confinement by a steel tube or a spiral on the suppression of softening rsponse of columns. In the former problem, the microplane model is used to simulate the torsional response of concrete cylinders after uniaxial compression preloading to the peak compression load or to a post peak softening state. Comparisons with new tests carried out at Northwestern University show the microplane model to predict the initial torsional stiffness very closely, while the classical tensorial models with invariants overpredict this stiffness several times (in plasticity of metals, this phenomenon is called the vertex effect because its tensorial modeling requires the yield surface to have a vertex or corner at the current state point of the stress space). In the latter problem, microplane model simulations of the so called tube squash tests are presented and analyzed. In these tests, recently performed at Northwestern University, steel tubes of different thicknesses filled by concretre are squashed to about half of their initial length and very large strains with shear angles up to about 70 degrees are achieved. The tests and their simulations show that in order to prevent softening and thus brittle failure and size effect, the cross section of th etube must be at least 16% of the total cross section area, and the volume of the spiral must be at least 14% of the volume of the column. When these conditions are not met, which comprises the typical contemporary designs, one must expect localization of damage and size effect to take place.

10.14359/12271


Document: 

SP206-29

Date: 

April 1, 2002

Author(s):

S. Mindess

Publication:

Special Publication

Volume:

206

Abstract:

Fracture mechanics concepts were first applied to concrete in 1959, and since then several thousand papers have been published on this topic. Professor Shah himself has contributed many papers in this area, dating back to 1971. The first attemps at utilizing fracture mechanics in concrete research dealt with linear elastic fracture mechanics in concrete research dealt with linear elastic fracture mechanics. However, it soon became apparent that this was insufficient to characterize a heterogeneous, non-linear elastic material such as concrete. Thus, a variety of non-linear fracture mechanics models were developed to try to better describe the fracture and failure of concrete. Unfortunately, despite a great deal of researh, both theoretical and experimental, fracture mechanics concepts are still seldom used in the design of concrete structures, particularlay in North America. For instance, they are not even mentioned in the current ACI 318 Building kCode Requirements for Structural Concrete, or in the kCanadian CSA Standard A23.3 Design of Concrete Structures. It is the purpose of this paper to review briefly the current position of fracture mechanics in concrete applications, and then to look to possible future developments.

10.14359/12270


Document: 

SP206-28

Date: 

April 1, 2002

Author(s):

N. Krstulovic-Opara and V. Kilar

Publication:

Special Publication

Volume:

206

Abstract:

High-Performance Fiber Reinforced Cocndrete (HPFRC) exhibits features particularly desirable for increasing earthquake resistance such as high tensile strength and ductility. However, since HPFRC is substantially different from conventional materials, using existing design and construction procedures does not lead to the most cost-effective solutions. To address this issue, this paper presents a way of selectively using Slurry Infiltrated Mat Concrete (SIMCON), Slurry Infiltraded Fiber Concrete (SIFCON) and high Strength Lightweight Aggregate Fiber kReinforced Concrete (HS_LWA FRC) to construct is to improve cost effectiveness by simplifying both construction and postearthquake repair, increasing the construction speed, lowering seismically induced forces and increasing overall seismic resistance. This is achieved by fuses with cast in place HS-LWA FRC. First, the paper presents experimentally evaluated behavior of HPCF members. Next the seismic response of a four story HPCF building is investigated analytically and compared to that of a seismically designed R.C. frame. HPCF reached an overall good seismic response. As compared to the reference building, it exhibited slower strength and stiffness degradation, lower top displacements and story drifts. Overall building damage was lower for the HPCF building, and even under 33% higher seismic excitations the HPCF building had higher seismic resistance than the reference R. C. Building.

10.14359/12269


Document: 

SP206-27

Date: 

April 1, 2002

Author(s):

Y. Shao and S. Moras

Publication:

Special Publication

Volume:

206

Abstract:

The use of extrusion technology for the production of cement boards with unbleached kraft pulps I sevaluated in this paper. Cement boards reinforced both by hardwood and softwood pulp of different percentages were fabricated using an auger type lab extruder. The moisture contnet, water absorption and density of all batches were measured. The flexural response of the cement boards was used to investigate the strength, the toughness, the anisotropy, the age effect and the resistance to natureal weathering as well as to freeze-thaw cycling. With a relative ease of manufacture and a much claener production, extrusion was found to be a suitable means for making cement boards with up to 8% pulp by weight. Higher pulp content increased the toughnessof the material but didn’t enhance the flexural strength appreciably due to a higher water content required for extrudability. Anisotropic behavior and age effect were observed. The extruded products exhibited good resistance to weathering and freeze-thaw cycling. Hardwood pulps, cheaper and more available than the softwood ones, were found to be more suibalbe for extrusion production in terms of extrudability, finished surface and long term mechanical properties.

10.14359/12268


Document: 

SP206-26

Date: 

April 1, 2002

Author(s):

F. Reza, G. B. Batson, J. A. Yamamuro, and J. S. Lee

Publication:

Special Publication

Volume:

206

Abstract:

The incorporation of a small volume of carbon fibers into a concrete mixture produces a strong, durable concrete and at the same time lends the crack resistance and the carbon fiber's hight resistance to wear, heat and corrosion. The smart property is a damage-sensing ability. This intrinsic capability can be tapped by using simple electrical resistance techniques. There is the potential for these techniques to be used as nondestructive testing methods to assess the integrity of the ocmposite. The results of some fundamental investigations on the bulk electrical properties of carbon fiber cement composites (CFCC) under compressive loading are presented. Well-defined patterns are exhibited in the electircal resistance behavior that can be correlated with the stres-strain behavior. The resistance behavior was evaluated for various fiber volume contents. The effects of taking resistance measurements both parallela nd perpendicular to the axis of loadin were investigated.

10.14359/12267


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