Applying Statistical Methods for Further Improvement of High-Performance Concrete for New York State Bridge Decks

1997 ◽  
Vol 1574 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Peter Bajorski ◽  
Donald A. Streeter ◽  
Robert J. Perry
Keyword(s):  
New York ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks ◽  
New York State ◽  
Cementitious Materials ◽  
Concrete Mixture ◽  
Successful Implementation ◽  
York State

A new concrete mixture designated “Class HP” for high-performance has been developed for bridge decks in New York State. A modification of the state’s standard Class H concrete, it has better handling and workability characteristics, reduced permeability, and greater resistance to cracking and displays little or no surface scaling. These improvements have potential to result in twice the previously expected concrete service life. The mixture incorporates substitutions for cement of 20 percent Class F fly ash and 6 percent microsilica. It has now been established as the required concrete mixture for all decks built by the New York State Department of Transportation. Its successful implementation has triggered further research toward an even better mixture. An experiment was designed and performed to investigate the effects on cracking and permeability of microsilica and fly ash content, as well as the effects of total weight of cementitious materials. Experimental designs allowed investigation of a broad range of possible combinations while only a limited number of mixtures were tested. Statistical analysis of experimental data is presented and some concrete mixes are recommended for further study, especially those having 10 to 25 percent fly ash, 11 to 12 percent microsilica, and 327 to 375 kg/m3 (550 to 630 lb/yd3) of cementitious materials, and also those with 20 to 35 percent fly ash, 4 to 6 percent microsilica, and 392 to 428 kg/m3 (660 to 720 lb/yd3) of cementitious materials.

Developing High-Performance Concrete Mix for New York State Bridge Decks

1996 ◽  
Vol 1532 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Donald A. Streeter
Keyword(s):  
New York ◽  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks ◽  
New York State ◽  
Concrete Mixture ◽  
Primary Concern ◽  
Increased Strength ◽  
Testing Field ◽  
Class F Fly Ash

The development and implementation of a more durable concrete mixture for bridge decks are described. The work began with review and evaluation of published results of research conducted by others and resulted in a new concrete mixture that has been designated Class HP for high performance. It has better handling and workability characteristics, improved resistance to chloride intrusion, and greater resistance to cracking, and it displays little or no surface scaling. Increased strength was not a primary concern in producing a high-performance concrete for bridge decks, but greater ultimate strength was nevertheless achieved. Class HP concrete is a modification of New York State's standard Class H concrete, incorporating two pozzolan substitutions for cement—20 percent Class F fly ash and 6 percent microsilica. On the basis of satisfactory laboratory testing, field trial, and field production it is being recommended for use statewide. Initial increases in cost are expected to be minimized as concrete producers and contractors become familiar with its mixing and placement. The first-cost increase will be easily offset by more than doubling service life expectancy. Further investigation is progressing to optimize performance of Class HP concrete in bridge decks and for its use in other concrete applications.

In-Service Performance of High-Performance Concrete Bridge Decks

2000 ◽  
Vol 1696 (1) ◽  
pp. 193-196 ◽  
Author(s):  
Sreenivas Alampalli ◽  
Frank Owens
Keyword(s):  
New York ◽  
High Performance ◽  
Recent Literature ◽  
High Performance Concrete ◽  
Bridge Decks ◽  
New York State ◽  
Crack Density ◽  
Transverse Cracking ◽  
Concrete Bridge Decks ◽  
Better Than

The current statewide standard for New York State bridge decks is Class HP (high-performance) concrete. This mix was introduced in April 1996 to increase deck durability by reducing cracking and permeability. Since its introduction, more than 80 bridge decks have been built with Class HP concrete. To compare the performance of Class HP concrete with that of previously specified concrete, the decks were visually inspected. Results indicated that Class HP decks performed better than previously specified concrete in resisting both longitudinal and transverse cracking. Furthermore, of the 84 decks inspected, 49 percent exhibited no cracking at all, but of those that had cracked, 88 percent exhibited equal or less longitudinal cracking and 80 percent exhibited equal or less transverse cracking than previously specified concrete. A final result showed that average transverse crack density on Class HP decks, excluding uncracked decks, was 6.9 cm/m2. This value is comparable with crack densities for other decks (not using HP mix) that were reported in recent literature.

Optimization of Amount and Blending of Cementitious Materials in High-Performance Concrete

2000 ◽  
Vol 1698 (1) ◽  
pp. 30-35
Author(s):  
Peter Bajorski ◽  
Donald A. Streeter
Keyword(s):  
New York ◽  
High Performance ◽  
High Performance Concrete ◽  
New York State ◽  
Cementitious Materials ◽  
York State Department ◽  
Linear Regression Models ◽  
Local Regression ◽  
Concrete Mixtures ◽  
Transportation Research

In recent years, there has been a demand by the traveling public for longer-lasting, more durable transportation structures. One of the biggest problems encountered is the corrosion of reinforcing steel used in concrete applications. To reduce the damage caused by the ingress of chlorides, and the subsequent corrosion, the New York State Department of Transportation (NYSDOT) has developed and used a high-performance concrete, designated Class HP. As part of a continuous improvement effort to produce longer-lasting structures, research has been ongoing to further improve the characteristics of Class HP concrete. The study is a continuation of the previous experimental work performed by the NYSDOT and reported in Transportation Research Record 1574. During that study, the effects of microsilica, fly ash, and the total cementitious mass in a mixture on cracking and permeability of the resulting concrete were studied. The experimental design used in the investigation resulted in testing a minimal number of concrete mixtures yet allowed the analysis of a broad range of possible combinations. Statistical analysis of experimental data is presented, and examples of a scientific approach to experimentation are shown. The Response Surface Methodology was used with the appropriate statistical experimental designs, including the Box–Behnken design. In addition to the traditional linear regression models, a modern technique of the local regression was used.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

Factors Influencing the Successful Implementation of HIV Linkage and Retention Interventions in Healthcare Agencies Across New York State

2018 ◽  
Vol 23 (S1) ◽  
pp. 105-114 ◽  
Author(s):  
Diane Addison ◽  
◽  
Abigail Baim-Lance ◽  
Lauren Suchman ◽  
Benjamin Katz ◽  
...  
Keyword(s):  
New York ◽  
New York State ◽  
Successful Implementation ◽  
York State ◽  
Factors Influencing

scholarly journals Mental health education in New York state schools : the teachers' perspective

2020 ◽  
Author(s):  
◽  
Neethu Arikupurathu
Keyword(s):  
Mental Health ◽  
New York ◽  
Health Education ◽  
Qualitative Content Analysis ◽  
New York State ◽  
Successful Implementation ◽  
Health Issues ◽  
Mental Health Education ◽  
York State ◽  
Mental Health Issues

In response to the rise in mental health issues among youth, New York State (NYS) now requires all schools' curriculums to include mental health education. The purpose of this study was to understand the perspectives of high school teachers in NYS -- on school-based mental health education, its implementation, its effectiveness, and its impact on student and teacher mental health outcomes. The Theory of Organizational Readiness for Change can be used in an organization, such as a school system, to determine if the necessary factors are present for the successful implementation of new policies as incorporating a mental health educational program into the existing curriculum. Participants (N=20) with a minimum of 3 years of classroom experience were recruited through Facebook and snowball sampling. Using a qualitative descriptive approach, a semi-structured, open-ended interview guide was developed and used to interview participants. Qualitative content analysis was used to analyze interviews and derive common themes. The main themes that emerged included the following: (a) a broken system, (b) mental health issues impact teachers and the classroom environment, (c) student mental health challenges in schools are complex and multifaceted, and (d) effective school mental health education needs a multi-faceted approach. Teachers play a pivotal role in the academic, social, and emotional development of students. This study highlights a need for policy changes that will support teachers in dealing with mental health issues in the classroom.

scholarly journals Effects of Combined Usage of Supplementary Cementitious Materials on the Thermal Properties and Microstructure of High-Performance Concrete at High Temperatures

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1833 ◽  
Author(s):  
Dong Lu ◽  
Zhuo Tang ◽  
Liang Zhang ◽  
Jianwei Zhou ◽  
Yue Gong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Fly Ash ◽  
High Temperatures ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Amorphous Phases ◽  
Micro Cracks

Concrete has low porosity and compact microstructure, and thus can be vulnerable to high temperature, and the increasing application of various types of supplementary cementitious materials (SCMs) in concrete makes its high-temperature resistant behavior more complex. In this study, we investigate the effects of four formulations with typical SCMs combinations of fly ash (FA), ultra-fine fly ash (UFFA) and metakaolin (MK), and study the effects of SCMs combinations on the thermal performance, microstructure, and the crystalline and amorphous phases evolution of concrete subjected to high temperatures. The experimental results showed that at 400 °C, with the addition of 20% FA (wt %), the thermal conductivity of the sample slightly increased to 1.5 W/(m·K). Replacing FA with UFFA can further increase the thermal conductivity to 1.7 W/(m·K). Thermal conductivity of concrete slightly increased at 400 °C and significantly reduced at 800 °C. Further, combined usage of SCMs delayed and reduced micro-cracks of concrete subjected to high temperatures. This study demonstrates the potential of combining the usage of SCMs to promote the high-temperature performance of concrete and explains the micro-mechanism of concrete containing SCMs at high temperatures.

scholarly journals Study on using maximum amount of fly ash in producing ultra-high performance concrete

2018 ◽  
Vol 12 (3) ◽  
pp. 51-61
Author(s):  
Van Viet Thien An
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Cementitious Materials ◽  
Maximum Amount ◽  
Ultra High Performance Concrete ◽  
Design Expert ◽  
High Volume Fly Ash

In the present study, the synergic effects of cementitious materials in the ternary binder containing cement, silica fume, fly ash on the workability and compressive strength were evaluated by using the D-optimal design of Design-Expert 7. The ternary binder composed of 65 vol.-% cement, 15 vol.-% SF and 20 vol.-% FA at the W/Fv ratio of 0.50 is the optimum mixture proportions for the highest compressive strength of the UHPC. To produce the sustainable UHPC, high-volume fly ash ultra high performance concrete with a good flowability and 28-d compressive strength over 130 MPa can be produced with fly ash content up to 30 vol.-% in the binder. Article history: Received 21 March 2018, Revised 06 April 2018, Accepted 27 April 2018

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