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 1176 Abstracts search results

Document: 

SP-337_08

Date: 

January 23, 2020

Author(s):

Anthony Devito; Alex Krutovskiy and Leszek Czajkowski

Publication:

Special Publication

Volume:

337

Abstract:

The purpose of the LaGuardia Runway Extension Project is to extend existing runways 4-22 and 13-31 into Flushing Bay, at the inshore end of Long Island Sound, to support Engineered Material Arresting System (EMAS) - a crushable material installed at the end of each runway to reduce the risk of a plane overrun during takeoff.

The new runway deck extensions are marine concrete structures which utilize precast prestressed pile caps with a pre and post-tensioned composite precast deck and cast-in-place concrete topping slab. The concrete decks are supported by 250 ton (227 tonnes) 24 inch (61cm) diameter epoxy coated closed end concrete filled steel pipe piles with specialized wraps and sacrificial zinc anodes for corrosion protection. The piles are approximately 100 feet (30m) long and driven in about 30 feet (9m) of water through soft organic clay and dense glacial soils and founded on bedrock.

This paper provides an overall description of the runway extensions and a detailed account of both the technical and logistical challenges. Challenges included a prestressed composite deck design for both the aircraft impact and braking loads. Maintaining and replacing the lightbars of the Approach Lighting Systems (ALS) used to visually identify the runways was required, along with optimizing the pile hammer selection and driveability with wave equation analyses and dynamic pile driving PDA testing. Extensive coordination was necessary with the PANYNJ, FAA and various other stakeholders involved in this fast-paced design build project.


Document: 

SP-337_04

Date: 

January 23, 2020

Author(s):

Mohammad S. Khan

Publication:

Special Publication

Volume:

337

Abstract:

Offshore and marine structures present special testing and inspection challenges due to their difficult accessibility and lack of visibility below water. Some of the testing and inspection personnel need to be divers, and some of the testing and inspection techniques become impractical in submerged conditions even with a diver. Thus, non-destructive evaluation (NDE) techniques that can be applied from above water, coupled with limited underwater inspections, offer the most practical solution for the testing and inspection of offshore and marine structures. This paper reviews and analyzes various above-water and underwater techniques that can be used for offshore and marine structures. Above-water techniques include visual inspections, chloride ion analysis, carbonation depth measurement, half-cell potential measurement, corrosion rate measurement, strength testing, and petrographic analysis. Whereas, the underwater techniques include diver-assisted visual inspections, real-time video imaging, modified versions of some of the above-water techniques, sonic-echo, impulse response, ultrasonic guided waves (UGW), and limited semi-destructive testing. Advantages and limitations of various techniques have been discussed. Finally, areas of future research have been identified, which can improve the efficiency, effectiveness, cost, and safety of testing and inspection techniques used in offshore and marine structures.


Document: 

SP-336_02

Date: 

December 11, 2019

Author(s):

Nidhi M Modha and Pratanu Ghosh

Publication:

Special Publication

Volume:

336

Abstract:

In this research, a natural pozzolanic cementitious material known as zeolite is being utilized to investigate the performance of High-Performance Concrete (HPC). Several binary (cement+zeolite) and ternary (cement+zeolite+other supplementary cementitious material) based concrete mixtures including a control mixture of Ordinary Portland Cement (OPC) with water - cementitious (w/cm) ratios of 0.40 and 0.44 are cast by replacing cement with different percentage level of zeolite material. The purpose of this study is to investigate effectiveness of zeolite material by means of long term compressive strength (7 to 91 days), tensile strength, modulus of elasticity and corrosion resistance in several concrete mixtures from 7 to 28 days. The compressometer is utilized for the measurement of the modulus of elasticity and Universal Testing Machine (UTM) is utilized to measure the compressive and tensile strength of concrete. In addition, a 4-point Wenner Probe resistivity meter is tested to determine the surface electrical resistivity of concrete, which provides an indirect indication of permeability and in turn, chloride induced corrosion durability in reinforced concrete structures. Overall, zeolite based concrete mixtures with 0.40 w/cm ratio and ¾ inch aggregate size provide promising results in terms of compressive strength, tensile strength and remarkable improvement on corrosion resistance in terms of achievement of surface resistivity data.


Document: 

SP333

Date: 

October 9, 2019

Author(s):

Yail J. Kim, John J. Myers, and Antonio Nanni

Publication:

Special Publication

Volume:

333

Abstract:

Concrete bridges play an important role in the efficiency and reliability of transportation civil infrastructure. Significant advancements have been made over the last decades to enhance the performance and durability of bridge elements at affordable costs. From an application perspective, novel analysis techniques and construction methods are particularly notable, which have led to the realization of more sustainable built-environments. As far as the evaluation and rehabilitation of constructed bridges are concerned, new nondestructive testing approaches provide accurate diagnosis and advanced composites, such as carbon fiber reinforced polymer (CFRP), have become an alternative to conventional materials. This Special Publication (SP) contains nine papers selected from two technical sessions held at The ACI Concrete Convention and Exposition – Spring 2018, in Salt Lake City, UT. The objective of the SP is to present technical contributions aimed to understand the state of the art of concrete bridges, identify and discuss challenges, and suggest effective solutions for both practitioners and government engineers. All manuscripts were reviewed in accordance with the ACI publication policy. The Editors wish to thank all contributing authors and reviewers for their rigorous efforts. The Editors also gratefully acknowledge Ms. Barbara Coleman at ACI for her knowledgeable guidance in the development of the SP.


Document: 

SP-333_09

Date: 

October 1, 2019

Author(s):

Tarek Omar and Moncef L. Nehdi

Publication:

Special Publication

Volume:

333

Abstract:

Bridge deck condition rating systems commonly use measurements of obvious defects recorded through visual investigation. Accordingly, the condition of bridge decks is rated linguistically with inherent vagueness in the description of the deck condition. Although several advanced non-destructive testing (NDT) technologies have emerged for inspecting bridge decks, their results have yet to be incorporated in the condition rating process. The present study establishes a unique link between NDT technologies and inspector findings by developing a novel bridge deck condition rating index (BDCI). The proposed procedure captures the integrated results of infrared thermography (IRT) and ground-penetrating radar (GPR), along with visual inspection judgement deployed to evaluate a full-scale aging concrete bridge deck. The information sought to identify the parameters affecting the integration process was gathered from bridge engineers with extensive experience and intuition. The analysis process utilized the fuzzy set theory, thus overcoming the inherent scientific uncertainties and imprecision in the measurements of bridge deck subsurface defects by IRT and GPR testing along with surface defects identified through bridge inspector observations. Integrating the proposed BDCI procedure with existing bridge management systems can provide a detailed and reliable appraisal of bridge health, thus helping transportation agencies in optimizing budgets and prioritizing maintenance, repair, and rehabilitation efforts.


Document: 

SP-333_08

Date: 

October 1, 2019

Author(s):

Needa Lingga, Yasir Saeed, Anas Yosefani, and Franz Rad

Publication:

Special Publication

Volume:

333

Abstract:

This research focused on concrete beams with voids simulating beams with fully corroded steel that were repaired with CFRP laminates. The experimental program included testing five, approximately one-third-scaled simply supported rectangular concrete beams. In three beams, the oiled steel rebars for flexure and shear were safely pulled out of the formwork after the concrete had cured for six hours, leaving voids. This technique was used to represent an extreme case of corrosion, albeit non-realistic, that is even worse than being exposed to the most corrosive environment. The aim was to investigate the extent of improvement by CFRP to flexural and shear capacity of beams that contain fully corroded steel bars, simulated by voids. The first specimen was with voids representing completely deteriorated steel. The second was a plain concrete beam without voids. The third beam was a typical code-designed reinforced concrete (RC) beam, that represented the “original undeteriorated” beam. The two remaining deteriorated beams were repaired by externally bonding one and two layers of CFRP. Load carrying capacity, deflection, and ductility were measured and compared. The novel results of this investigation were that test results showed that one layer of CFRP increased the load capacity to slightly higher than the RC beam, and two layers of CFRP increased it by a factor of two. Finally, a computer model was created to estimate the performance of the tested beams and to carry out a parametric study to investigate the effects of CFRP longitudinal reinforcement ratio and CFRP transverse confinement ratio on the flexural performance of CFRP-repaired concrete beams. The predicted contribution of CFRP to flexure and shear capacities was in good agreement with test results.


Document: 

SP-333_02

Date: 

October 1, 2019

Author(s):

Junwon Seo and Jharna Pokhrel

Publication:

Special Publication

Volume:

333

Abstract:

This paper investigates the effects of material constituents on fresh and hardened properties of Self-Consolidating Concrete (SCC) mixture necessary for efficient prestressed bridge girder fabrication using a surrogate modeling technique. Response surface methodology (RSM)-based surrogate models consisting of input parameterssuch as density of coarse and fine aggregate were created based upon the past laboratory testing results for differentSCC mixture trials. These models were used to estimate various SCC material characteristics, including slump flow, J-ring flow, passing ability, filling capacity, Visual Stability Index (VSI), T50 (concrete spread time to reach the 50.8 cm [20 in] mark), column segregation, 16-hour compressive strength, and 28-days compressive strength, while examining the correlation between the input parameters on each material characteristic. To observe the effect of core input parameters in an efficient manner, 2D contour plot and 3D surface plot for material characteristics were also created. Then, statistical analyses with the testing results were performed to determine the accuracy of the surrogate models in terms of coefficient of regression (R2). Most of the R2 values are higher than 90%, indicating a higher degree of correlation among the testing and surrogate data. Average predicted-to-measure ratios of the surrogate models were almost equal to or slightly greater than 1.00, showing good agreement with the testing results, and specifically, the surrogate and testing values for J-ring flow and 28-days compressive strength were nearly identical. Key findings indicate that the coarse aggregate content significantly affected the characteristics of the SCC mixtures.


Document: 

SP-334-01

Date: 

September 30, 2019

Author(s):

Yuan Tian and Ardavan Yazdanbakhsh

Publication:

Special Publication

Volume:

334

Abstract:

Due to their unique mechanical characteristics, glass fiber reinforced polymer (GFRP) composite materials are difficult to recycle at the end of their service lives. In the present work, a specific approach of recycling GFRP waste for use in concrete is investigated. Scrap from GFRP rebar and waste from a GFRP wind turbine blade shell were processed into slender elements, referred to as “needles,” with a length of 100 mm and used in concrete to replace 5% and 10% of natural coarse aggregate. The results of testing various concrete specimens revealed that the incorporation of needles with longitudinally aligned glass fibers increased the splitting tensile strength of concrete significantly. Both types of recycled needles, regardless of the source of waste and orientation of glass fibers, increased the tensile toughness of concrete significantly. In addition, it was observed that incorporating needles did not reduce concrete’s slump, due to the relatively high specific surface area of the needles. The findings suggest that recycling GFRP waste into needles as concrete reinforcement may be a viable GFRP waste management strategy and deserves further research.


Document: 

SP-335_09

Date: 

September 20, 2019

Author(s):

A. M. Yasien, A. Abayou, and M. T. Bassuoni

Publication:

Special Publication

Volume:

335

Abstract:

In cold regions, freezing temperatures limit the construction season to few months, usually between May and September. The use of nanoparticles, which have high specific surface and vigorous reactivity, may potentially enhance the performance of concrete placed at low temperatures. Therefore, this study focused on developing concrete mixtures incorporating nano-silica which were mixed, placed and cured at -5°C (23°F) without any insulation or protection targeting field applications in late fall and early spring periods. Eight mixtures incorporating general use (GU) cement, fly ash (up to 25%), and nano-silica (up to 4%) were tested for this purpose, with water-to-binder ratios of 0.32 and 0.4. All mixtures contained a combination of calcium nitrate and calcium nitrite as an antifreeze admixture. Testing involved concrete setting time (placement), 7 and 28 days compressive strengths (hardened properties) and resistance to freezing-thawing cycles (durability). Moreover, mercury intrusion porosimetry, thermal analysis and scanning electron microscopy were performed to corroborate the trends from the macro-scale tests. It was found that nano-silica significantly improved the overall performance of concrete placed and cured at -5°C (23°F), which implicates its promising use for construction applications under low temperatures.


Document: 

SP-335_06

Date: 

September 20, 2019

Author(s):

Su-Jin Lee, Shiho Kawashima, and Jong-Pil Won

Publication:

Special Publication

Volume:

335

Abstract:

In this study, nanosilica was applied to the surface of polypropylene (PP) fibers to introduce self-healing abilities when incorporated into cement-composites. When the fiber is at the site of a crack, the nanosilica can form additional hydration products through pozzolanic reaction to effectively seal the crack. Nanosilica was synthesized onto the fibers through a sol-gel process. Then the fibers were dried at room temperature or 50°C (122°F) to remove the excess solution and adhere the nanosilica particles onto the fiber surface. The existence of nanosilica was confirmed by observing the mass change before and after the sol-gel process, water absorption, soluble matter loss and microscopy. The self-healing performance of cement-composites reinforced with treated and untreated macro and micro PP fibers at dosages of 1.8kg/m3 (3.0lb/yd3) and 0.9kg/m3 (1.5lb/yd3), respectively, were evaluated through flexural strength testing according to ASTM C348. To evaluate strength recovery, samples were loaded to 60% of the peak load to induce cracking. The cracked specimens were cured for 28 days under laboratory conditions to undergo self-healing. A significant recovery in flexural strength (112.8%) was observed by using nanosilica treated micro PP fibers dried at room temperature.


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