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.

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.

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.

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.

Homogenization Procedure Effect on Microscopical Performance of Concrete Containing Supplementary Cementitious Materials

2020 ◽  
Vol 995 ◽  
pp. 168-173
Author(s):  
Zdeněk Prošek ◽  
Vladimír Hrbek ◽  
Petr Bílý ◽  
Lukáš Vráblík
Keyword(s):  
High Performance ◽  
Chemical Resistance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Macro Level ◽  
Homogenization Procedure ◽  
Homogenization Process ◽  
Concrete Mixtures ◽  
Major Factors

The advantages of supplementary cementitious materials (SCM) use in concrete, such as reduced cement consumption and overall material improvement (durability, chemical resistance, etc.), are widely known. Our research focuses on two major factors connected to high performance concrete (HPC) containing SCM, the content of selected SCM and the homogenization process used for concrete mixture. Both of these aspects of this research were addressed by the authors from macro-level of the material. In this contribution, the focus is directed on microscopical performance of concrete mixtures with highest macro-mechanical features with respect to both homogenization procedure and SCM containment.

New Paradigm for State Department of Transportation Environmental Initiatives: New York State’s Guidelines and Procedures

2000 ◽  
Vol 1702 (1) ◽  
pp. 92-96 ◽  
Author(s):  
Gary McVoy ◽  
Mark Sengenberger ◽  
Elizabeth Novak
Keyword(s):  
New York ◽  
New York State ◽  
Cost Effective ◽  
State Department ◽  
Regulatory Compliance ◽  
Environmental Benefits ◽  
Environmental Damage ◽  
York State Department ◽  
Department Of Transportation ◽  
New Paradigm

Public-works agencies have an obligation to enhance the environment as opportunities arise. The New York State Department of Transportation (NYSDOT) has developed an environmental initiative to make an affirmative contribution to the environment, using the department’s organizational strengths. The environmental initiative is a paradigm shift applicable to all departments of transportation (DOTs). Conventional reactive regulatory compliance can reduce unnecessary environmental damage and sometimes gain grudging regulatory agency cooperation; however, it is not a positive, satisfying way of doing the people’s work. Through proactive steps, NYSDOT has become an important part of the state’s environmental solution (often at little or no additional cost) and has changed its working relationships with environmental agencies and groups. As these agencies and groups have become partners, instead of adversaries, permit-approval times have improved, mitigation costs have declined, morale has improved, and cost-effective environmental benefits are being realized. Procedures are outlined to apply the engineering capabilities of a DOT to the environmental-stewardship responsibilities shared by all governmental organizations.

scholarly journals Durability Study on High-Performance Fiber-Reinforced Mortar under Simulated Wastewater Pipeline Environment

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3781
Author(s):  
Tianyu Wang ◽  
Yahong Zhao ◽  
Baosong Ma ◽  
Cong Zeng
Keyword(s):  
Mass Loss ◽  
Pore Volume ◽  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Economic Losses ◽  
Structural Deterioration ◽  
Simulated Wastewater ◽  
Corrosive Environments

The acid–alkaline-inducd corrosive environments inside wastewater concrete pipelines cause concrete structural deterioration and substantial economic losses all over the world. High-performance concrete/mortar (HPC) was designed to have better resistance to corrosive environments, with enhanced service life. However, the durability of HPC in wastewater pipeline environments has rarely been studied. A high-performance mortar mixture (M) reinforced by supplemental materials (including fly ash and silica fume) and polyvinyl alcohol (PVA) fibers, together with a mortar mixture (P) consisting of cement, sand and water with similar mechanical performance, were both designed and exposed to simulated wastewater pipeline environments. The visual appearance, dimensional variation, mass loss, mechanical properties, permeable pore volume, and microstructure of the specimens were measured during the corrosion cycles. More severe deterioration was observed when the alkaline environment was introduced into the corrosion cycles. Test results showed that the M specimens had less permeable pore volume, better dimensional stability, and denser microstructure than the P specimens under acid–alkaline-induced corrosive environments. The mass-loss rates of the M specimens were 66.1–77.2% of the P specimens after 12 corrosion cycles. The compressive strength of the M specimens was 25.5–37.3% higher than the P specimens after 12 cycles under corrosive environments. Hence, the high-performance mortar examined in this study was considered superior to traditional cementitious materials for wastewater pipeline construction and rehabilitation.

scholarly journals Response of an Obstetric Unit during the Coronavirus Disease of 2019 (COVID-19) Pandemic: Experiences from a Tertiary Care Center

2020 ◽  
Vol 10 (03) ◽  
pp. e281-e287
Author(s):  
Sangeeta Kumaraswami ◽  
Tana S. Pradhan ◽  
Sorana Vrabie-Wolf ◽  
Sadaf Lodhi ◽  
Geetha P. Rajendran ◽  
...  
Keyword(s):  
New York ◽  
Care Center ◽  
Tertiary Care ◽  
New York State ◽  
York State Department ◽  
Obstetrical Care ◽  
Expert Opinions ◽  
Department Of Health ◽  
Delivery Unit ◽  
Westchester County

Abstract Objective To describe our experiences in preparing our obstetric unit in Westchester County, New York, during the COVID-19 (coronavirus disease of 2019) pandemic. We focus on describing our timeline, continuously evolving actions, observations, and challenges. Methods With guidance from the New York State Department of Health (NYSDOH), our institutional epidemiologist, and key multidisciplinary faculty members, we evaluated emerging national data as well as expert opinions to identify issues and challenges to create action plans. Results We created and modified policies for our patients presenting for obstetrical care on the labor and delivery unit to accommodate their unique needs during this pandemic. Conclusion The COVID-19 pandemic has posed many unique challenges. Balancing communication, risks of infection to providers, patient autonomy and rights, and resources for testing and personal protective equipment were among the valuable lessons learnt. We have shared our experiences and described our observations and challenges in Westchester County, New York.

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