Influence of Pumping Parameters on the Freeze-thaw and Scaling Resistance of Highly Workable Concrete PDF Download
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Author: Alexandra Nicole Wehar
Publisher:
ISBN:
Category :
Languages : en
Pages : 141
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Book Description
"Over the past 60 years, pumping concrete has gained popularity due to the economic and technical benefits that typically accompanies it. However, boom configuration and flow rate can adversely affect freeze-thaw and scaling resistance of concrete due to the effects of pressure on the air-void system. Therefore, the objective of this research is to assess the influence of different pumping parameters on the durability of hardened self-consolidating concrete. Self-consolidating, flowable, and conventional concrete mixtures were tested during large scale pumping experiments positioning the pump boom in an 'A' and a flat shape as well as using different pumping speeds. In addition, the effect of adding a reducer and submerging the discharge hose into concrete to minimize the impact on the concrete air-void system was also explored. While pumping, the concrete fresh properties, including the air content were measured. The freeze-thaw durability and scaling resistance were tested for both pumped and non-pumped samples. Furthermore, the air-void size distribution in the hardened state was measured. During pumping, considerable changes in fresh air content were observed from sample to sample. Hardened results indicated that different pumping parameters induced different changes in the air-void system, most importantly the spacing factor. The most notable increases in spacing factor were observed when increasing the flow rate in the A configuration for self-consolidating and flowable mixtures and adding a reducer in the A configuration with self-consolidating concrete. The changes in air-void system corresponded to changes in the severity of scaling. A poor air-void system led to lower scaling resistance. Mixtures with higher air content showed fewer signs that pumping affects the freeze-thaw or scaling resistance"--Abstract, page iii.
Author: Alexandra Nicole Wehar
Publisher:
ISBN:
Category :
Languages : en
Pages : 141
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Book Description
"Over the past 60 years, pumping concrete has gained popularity due to the economic and technical benefits that typically accompanies it. However, boom configuration and flow rate can adversely affect freeze-thaw and scaling resistance of concrete due to the effects of pressure on the air-void system. Therefore, the objective of this research is to assess the influence of different pumping parameters on the durability of hardened self-consolidating concrete. Self-consolidating, flowable, and conventional concrete mixtures were tested during large scale pumping experiments positioning the pump boom in an 'A' and a flat shape as well as using different pumping speeds. In addition, the effect of adding a reducer and submerging the discharge hose into concrete to minimize the impact on the concrete air-void system was also explored. While pumping, the concrete fresh properties, including the air content were measured. The freeze-thaw durability and scaling resistance were tested for both pumped and non-pumped samples. Furthermore, the air-void size distribution in the hardened state was measured. During pumping, considerable changes in fresh air content were observed from sample to sample. Hardened results indicated that different pumping parameters induced different changes in the air-void system, most importantly the spacing factor. The most notable increases in spacing factor were observed when increasing the flow rate in the A configuration for self-consolidating and flowable mixtures and adding a reducer in the A configuration with self-consolidating concrete. The changes in air-void system corresponded to changes in the severity of scaling. A poor air-void system led to lower scaling resistance. Mixtures with higher air content showed fewer signs that pumping affects the freeze-thaw or scaling resistance"--Abstract, page iii.
Author: J. Marchand
Publisher: CRC Press
ISBN: 0203627091
Category : Architecture
Languages : en
Pages : 323
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Book Description
Concrete durability in climates where freezing and thawing occurs is a continuing problem. It is particularly acute for highway and bridge structures, where de-icing salts are used to combat the effects of frost, snow and ice. These salts can cause damage to concrete and accelerate corrosion of reinforcements. This book presents the latest international research on this area, with contributions from North America and Europe which were presented at an international RILEM workshop.
Author: JA. Jonsson
Publisher:
ISBN:
Category : Compressive strength
Languages : en
Pages : 5
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Book Description
As a part of a comprehensive study to evaluate the effects of elevated curing temperatures on hardened concrete properties, four non-air-entrained high-strength concrete (HSC) mixtures were prepared at temperatures ranging from 10 to 35°C. After mixing, 5.5 liters of concrete were placed inside a large polystyrene block to simulate temperature development in HSC structural members. The concrete temperature inside the block was continuously monitored with thermocouples, and collected temperature information was used to simultaneously temperature-match-cure (TMC) a series of compressive strength, scaling, and freeze-thaw specimens. The maximum recorded temperatures ranged from 59 to 69°C, depending on the fresh concrete temperature. Control specimens from each of the four mixtures were cured at room temperature. Based on the amount of residue collected during scaling tests in the presence of 3% NaCl solution, the TMC specimens were 7-63 times less resistant than the control specimens. However, during the freezing and thawing tests, seven of the eight TMC specimens outperformed their respective control specimens.
Author: Max J. Setzer
Publisher: RILEM Publications
ISBN: 9782912143303
Category : Concrete
Languages : en
Pages : 408
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Book Description
Author: Donald J. Janssen
Publisher: Strategic Highway Research Program (Shrp)
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 228
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Book Description
This study, aimed at improving the freeze-thaw resistance of concrete, consists of three parts. Part I evaluates parameters affecting the freeze-thaw durability of concrete. A modification of the existing standard of method for determining the durability factor of concrete specimens is proposed, and a new procedure for fundamental transverse frequency (used in durability factor calculations) has been developed. Part II focuses on developing better methods for identifying nondurable aggregates, and has resulted in a rapid new test based on the hydraulic fracture of aggregates. Part III describes field experiments to evaluate the freeze-thaw resistance of a number of specified concrete mixes and the use of sealants to mitigate D-cracking. Preliminary field performance results are presented.
Author: Shaopeng Wu
Publisher: MDPI
ISBN: 3039210165
Category : Technology & Engineering
Languages : en
Pages : 270
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Book Description
Construction materials are the most widely used materials for civil infrastructure in our daily lives. However, from an environmental point of view, they consume a huge amount of natural resources and generate the majority of greenhouse gasses. Therefore, many new and novel technologies for designing environmentally friendly construction materials have been developed recently. This Special Issue, “Environment-Friendly Construction Materials”, has been proposed and organized as a means to present recent developments in the field of construction materials. It covers a wide range of selected topics on construction materials.
Author:
Publisher:
ISBN:
Category : Concrete
Languages : en
Pages : 792
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Book Description
Author: Thomas Dyer
Publisher: CRC Press
ISBN: 0203862112
Category : Technology & Engineering
Languages : en
Pages : 447
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Book Description
Written specifically for the young professional and addressing a growing need for a long service life with minimal maintenance, Concrete Durability takes a whole new look at the whole-life performance of structures. This text examines physical and chemical issues that can threaten the durability of concrete. It explores available options for achiev
Author: Committee on Nonconventional Concrete Technologies for Renewal of the Highway Infrastructure
Publisher: National Academies Press
ISBN: 0309562317
Category : Technology & Engineering
Languages : en
Pages : 125
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Book Description
Nonconventional Concrete Technologies: Renewal of the Highway Infrastructure identifies research and development opportunities in innovative, nonconventional materials and processes that have the potential to accelerate the construction process, improve the durability of highway pavement and bridges, and enhance the serviceability and longevity of new construction under adverse conditions.
Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 1024
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Book Description
