International Concrete Abstracts Portal

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International Concrete Abstracts Portal

Showing 1-10 of 703 Abstracts search results

Document: 

CI4102Powell

Date: 

February 1, 2019

Author(s):

Leahann E. Powell, Timothy Barnard, and Shiraz Tayabji

Publication:

Concrete International

Volume:

41

Issue:

2

Abstract:

The article provides details of rapid rehabilitation of a bridge approach slab on I-10 near Quincy, FL, using precast concrete panels. The existing cast-in-place approach slab had been in service since the bridge was constructed in 1976, and it was exhibiting cracking and settlement. The rehabilitation only required a total of 2.5 days to allow for continuous construction during the two travel lane panel placements, all the time maintaining one lane open for traffic.


Document: 

SP327-39

Date: 

November 1, 2018

Author(s):

Mohanad M. Abdulazeez, Ahmed Gheni, Omar I. Abdelkarim, and Mohamed A. ElGawady

Publication:

Special Publication

Volume:

327

Abstract:

This paper presents the seismic behavior of two large-scale hollow-core fiber-reinforced polymer-concrete-steel (HC-FCS) precast columns having two different footing connections. The precast HC-FCS column consists of a concrete shell sandwiched between an outer fiber-reinforced polymer (FRP) tube and an inner steel tube. The steel tube was embedded 635 mm (25 inches) into a reinforced concrete footing, while the outer FRP tube confined the concrete shell only i.e. it was truncated at the top surface of the footing. One connection included embedding the steel tube into the footing. The other one included using a corrugated steel pipe (CSP) embedded into the concrete footing outside the steel tube to achieve better confinement. This study showed that the connection including the CSP is deemed satisfactory and was able to develop the plastic flexural capacity of the HC-FCS column providing good ductility and energy dissipation compared with the other connection type.


Document: 

SP327-33

Date: 

November 1, 2018

Author(s):

Mamdouh El-Badry, Mohammad Moravvej, and Parham Joulani

Publication:

Special Publication

Volume:

327

Abstract:

An experimental evaluation of a hybrid FRP-concrete slab-on-truss girder bridge system is presented. The girders consist of pretensioned top and bottom concrete chords connected by vertical and diagonal truss members made of concrete-filled fiber-reinforced polymer (FRP) tubes. The truss members are connected to the chords by means of long double-headed glass FRP (GFRP) bars. The chords are also reinforced with GFRP longitudinal bars and transverse stirrups. The deck slab is connected to the top chords of the girders using double-headed GFRP studs. The truss girders are thus lighter and more durable than the conventional precast I-girders. The experimental program consisted of fabricating and testing eight full-scale truss girders including four 2.83-m (9.28-ft) long 2-panel trusses and four 9.82-m (32.22-ft) long 8-panel trusses, all having the same cross-section dimensions with 1.32-m (4.33-ft) overall depth. Two of the 2-panel and two of the 8-panel girders were reinforced with GFRP reinforcement. The remaining four were reinforced with steel and used as control specimens. Two of the 2-panel and two of the 8-panel girders were covered with a one-meter wide concrete slab connected to the girder top chord by either steel or GFRP double-headed studs. Tests under static loading showed excellent performance of the system in terms of strength and stiffness.


Document: 

CI4010Gillen

Date: 

October 1, 2018

Author(s):

Steve Gillen, Daniel J. Gancarz, and Shiraz Tayabji

Publication:

Concrete International

Volume:

40

Issue:

10

Abstract:

This article describes a recently implemented method for making rapid, full-depth repairs of continuously reinforced concrete pavement. The method is based on the use of precast concrete panels and it results in continuous longitudinal reinforcement throughout the repair area, making it suitable for the repair of multiple lanes or large areas, with minimal impact on traffic.


Document: 

SP-330-12

Date: 

September 26, 2018

Author(s):

Ricardo Remus, Christiane Roessler, and Horst‑Michael Ludwig

Publication:

Special Publication

Volume:

330

Abstract:

Power Ultrasound (PUS) is widely used in various technical processes (from pharmaceutic to ceramic and fuel industry) to disperse suspensions and to control crystallization processes. Previous investigations by the authors have shown that a short PUS treatment during mixing process effectively accelerates the growth of strength determining C-S-H phases and thus hydration and setting of Portland cement pastes.

The present study concerns the workability, the strength development and the durability of sonicated concretes. Results of study shows, that flowability is increased after sonication and stiffening of cement paste can be fully compensated. The strength development is significantly accelerated and durability testing on sonicated concretes reveals that negative effects of PUS on carbonation behaviour, freezing/thawing- and sulphate-resistance can be excluded. The advantage of using PUS to accelerate early-strength development of concrete is that little or no chemical accelerators or heat treatment are required. Enhancement of cement reactivity by PUS application during mixing possibly paves the way for application of cements with low CO2-footprint for precast concrete production.


Document: 

SP328-01

Date: 

September 12, 2018

Author(s):

Rico J. Massa, William D. Cook and Denis Mitchell

Publication:

Special Publication

Volume:

328

Abstract:

An experimental program was carried out on full-scale precast pretensioned I-girders to study the influence on the shear response of carbon fiber reinforced polymer (CFRP) shear strips epoxied to the sides of the girders. The test program demonstrated that the CFRP shear strips were effective in increasing the shear strength of the webs and in controlling the shear crack widths. The shape of the I-girders makes it difficult to properly anchor the vertical shear strips. The curved epoxy transitions between the web and the flanges at the re-entrant corners together with the use of horizontal CFRP strips in the regions of the re-entrant corners helped to improve the anchorage of the vertical CFRP strips. The shear resistance components from the concrete, the stirrups and the CFRP shear strips, were determined experimentally and compared with analytical predictions. The results from this experimental study are compared with the test results from other researchers. The design approach of the 2014 Canadian Highway Bridge Design Code provides conservative estimates of the shear strength of the webs.


Document: 

CI4009Klinger

Date: 

September 1, 2018

Author(s):

James Klinger, Frank Salzano, Tim Manherz, and Bruce A. Suprenant

Publication:

Concrete International

Volume:

40

Issue:

9

Abstract:

Embedded steel plates with headed studs (embeds) serve as connections to structural steel framing, façade and curtain wall systems, elevator rails, steel or precast stairs, mechanical-electrical-plumbing components, and miscellaneous additional items. The need to coordinate with other trades, tolerance conflicts, and other issues can make embed placement difficult for the concrete contractor. Members of the American Society of Concrete Contractors (ASCC) provide recommendations directed at ways that design and construction teams can improve the constructability of embeds.


Document: 

SP326-87

Date: 

August 10, 2018

Author(s):

Daman K. Panesar and Duo Zhang

Publication:

Special Publication

Volume:

326

Abstract:

The precast concrete industry is considering approaches with respect to mix design constituents and manufacturing methods to reduce the environmental impact of concrete products without compromising the desired properties and performance. The specific focus of this study is to examine the effect of using limestone filler and ground granulated blast furnace slag as cement replacement on the early age (one-day) compressive strength of steam cured precast concrete. Although it is known that a potential risk of incorporating such material may compromise the rate of hydration reactions and result in an inferior compressive strength gain which could delay demolding and prestressing operations reducing the rate of product production. This study explores the interplay between steam curing variables and mix design constituents to identify the variables that most significantly control the one-day strength of precast concrete. Key outcomes of this research reveal that the GU (general use) cement content (504 – 600 kg/m3) [31.5-37.5 lb/ft3], and the percentage of slag (up to 16.7%) has a greater effect on the one-day strength than does the cementitious material content for GU-slag blends, the stream curing duration (16-24 hours), the type of cement used (high early (HE) or GU), and the steam curing temperature (60-70°C) [140-158°F].


Document: 

SP326-84

Date: 

August 10, 2018

Author(s):

Roberto Torrent, Marco di Prisco, Veronica Bueno, and Fabio Sibaud

Publication:

Special Publication

Volume:

326

Abstract:

An investigation in an industrial building devoted to manufacturing equipment for the pharmaceutical industry was carried out. Stringent requirements were set for the building, in particular a very low permeability was required against the relatively high water-table. The design of the building, as well as the quality of the concrete, was concerned with providing an impermeable barrier, besides structural safety and functionality.

Different concrete qualities were used for different parts of the building. The most critical areas were built with steel fiber reinforced concrete (SFRC), both precast and cast in situ. In particular, some slabs were cast in situ with self-compacting (SCC-SFRC). Concrete samples were cast on site and taken to the laboratory for testing mechanical and durability performance. In order to verify the degree of impermeability reached in the end product, on site air-permeability measurements were conducted on representative elements of the structure. The paper presents and analyzes the air-permeability results obtained on several different elements, concluding that the cast on site SCC-SFRC presents a unique extremely low permeability and that the external wall tested has an air-permeability low enough to withstand the environment to which it is exposed. On the contrary, some non-critical internal elements, both cast on site and precast, present rather high and scattered air-permeability values.


Document: 

SP326-69

Date: 

August 10, 2018

Author(s):

Petr Hajek and Ctislav Fiala

Publication:

Special Publication

Volume:

326

Abstract:

Structures and the built environment should be better prepared for changing climatic conditions – as they should be sustainable and resilient. The specific properties of concrete like affordability, availability and variability in connection with strength and durability have made concrete the most used construction material in the world; and represents a material with high level of safety and resiliency, and high potential for environmental impact reduction. The use of new types of advanced concrete composites represents an especially important potential towards future sustainable and resilient built environment.

Results of a long-term research project on the development of an optimized light precast construction system based on high performance silicate composites are presented as an example of sustainability construction. The concept is based on a combination of slender concrete load-bearing frame structure and timber elements which can lead to advantageous structural and environmental solutions. Slender demountable high performance concrete (HPC) frame represents an effective alternative to timber-based load bearing structures by providing the possibility to build buildings with higher spatial stiffness, better fire safety and acoustic properties of concrete floor structures, while allowing the other structural elements to be constructed of renewable material source – especially wood.


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