The Influence of Steam Curing on the Chloride Resistance of High Performance Concrete

The Influence of Steam Curing on the Chloride Resistance of High Performance Concrete
Author: Melissa Prevey Titherington
Publisher:
Total Pages:
Release: 1998
Genre:
ISBN:

Steam curing is often used in the production of precast concrete. The elevated temperature of steam curing increases the initial rate of strength development allowing for earlier removal of the formwork. Although elevated curing temperatures result in high early strength, long-term strength and durability may be adversely affected. In this study, the chloride penetration resistance of steam-cured concretes containing silica fume alone or in combination with slag was investigated. The water to cement ratio was kept constant, at 0.3, for all concretes. Testing included: (1) Compressive Strength, (2) Rapid Chloride Permeability, (3) Water Sorptivity, (4) Bulk Diffusion, and (5) Chloride Migration. For a given mixture, steam curing was found to decrease chloride resistance. However, the use of supplementary cementing materials significantly reduced the negative effects of steam curing. The performance of a 4% silica fume steam-cured concrete was comparable to that of a 100% OPC ambient-cured concrete.

The Effect of Steam Curing on High-Early Strength Portland Cement Containing Carbonate Addition

The Effect of Steam Curing on High-Early Strength Portland Cement Containing Carbonate Addition
Author: C. Bédard
Publisher:
Total Pages: 9
Release: 1990
Genre: Carbonate addition
ISBN:

In 1981 the Canadian Standards Association (CSA) Committee A5 on Hydraulic Cements approved carbonate addition to normal portland cement Type 10 to a maximum of 5%. The decision was based on a considerable amount of data indicating no adverse effects on the properties of concrete and even improvements at optimum level of carbonate addition. The CSA Committee is now considering a proposal for extending carbonate addition to high-early strength portland cement Type 30 that has essentially the same chemical composition as Type 10 cement. Since Type 30 cement is used primarily in precast and prestressed concrete operations, a project has been initiated at the Research and Technical Center of Lafarge Canada Inc. to study the effect of steam curing conditions on the properties of concrete made with Type 30 cement containing carbonate addition. The main parameters will be the tricalcium aluminate (C3A) content of the cement, the presence of carbonate addition, and the curing temperature. The properties investigated will be compressive strength, freezing and thawing resistance ASTM Test for Resistance of Concrete to Rapid Freezing and Thawing (C 666, Procedure A), and volume change ASTM Test for Length Change of Hardened Hydraulic Cement Mortar and Concrete (C 157).

Proceedings of the Third International Conference on Sustainable Civil Engineering and Architecture

Proceedings of the Third International Conference on Sustainable Civil Engineering and Architecture
Author: J. N. Reddy
Publisher: Springer Nature
Total Pages: 1973
Release: 2024-01-12
Genre: Architecture
ISBN: 9819974348

This book includes articles from the Third International Conference on Sustainable Civil Engineering and Architecture (ICSSEA 2023), held at Da Nang City, Vietnam, on July 19-21, 2023. The conference brings together international experts from both academia and industry to share their knowledge and expertise, facilitate collaboration, and improve cooperation in the field. The book focuses on the most recent developments in sustainable architecture and civil engineering, including offshore structures, structural engineering, building materials, and architecture.

Assessing the Impact of Curing on Chloride Penetration Resistance of the Concrete Cover Zone

Assessing the Impact of Curing on Chloride Penetration Resistance of the Concrete Cover Zone
Author: Majed Karam
Publisher:
Total Pages: 0
Release: 2020
Genre:
ISBN:

There is a lack of rapid test methods for accurately assessing the impact of curing on the differential hydration through the depth of the concrete cover as well as the impact on chloride penetration resistance. In the absence of adequate performance assessment tools, prescriptive curing specifications have been adopted for concretes exposed to chlorides and other exposures, such as in CSA A23.1-19. There is a desire to switch to a performance specifications for curing, particularly by the precast concrete industry, that could be used to assess the impact of using of accelerated heat curing methods widely used to obtain high early-strength gain and maturity. Two methods are presented and evaluated in this thesis. The first involves proling the initial rate of absorption of a sodium chloride solution. The second makes use of embedded arrays of electrodes to map the formation factor with depth, enabling a multi-mechanistic approach to the problem.

Effect of Constituent Materials and Curing Methods on the Abrasion Resistance and Durability of High Performance Concrete for Pre-cast Pre-stressed Bridge Deck Slabs

Effect of Constituent Materials and Curing Methods on the Abrasion Resistance and Durability of High Performance Concrete for Pre-cast Pre-stressed Bridge Deck Slabs
Author: Shweta Keshari
Publisher:
Total Pages: 486
Release: 2010
Genre: Concrete bridges
ISBN:

This thesis is the consequence of a research effort undertaken by the School of Civil and Construction Engineering at Oregon State University and funded by the Oregon Department of Transportation (ODOT) and the Federal Highway Administration (FHWA). The principal objective of the effort was to reduce the life cycle cost of bridges by developing one or more materials systems for precast and pre-stressed bridge deck components that improve the studded tire wear (abrasion) resistance and durability of bridge decks. Degradation of the concrete bridge decks due to abrasion caused by the studded tires and accelerated corrosion of the reinforcing steel in the concrete often triggers costly, premature rehabilitation or replacement of these bridges. High performance concrete (HPC) can provide improved abrasion resistance, but is more costly than ordinary concrete and can exhibit early age cracking when used for cast-in-place concrete members, which can accelerate corrosion of embedded reinforcing steel. However, several studies have suggested that HPC developed for precast members offers a viable alternative to cast-in-place concrete deck slabs due in part to improved control of the curing process. The scope of this research was to develop one or more mixture designs for HPC that improve the durability and abrasion resistance of the bridge decks through careful selection and proper proportioning of the constituent materials and improved control of the curing process. The materials investigated in this research included silica fume, slag, and fly ash as partial replacement of Type I and Type III portland cement mixed with crushed aggregate and river gravel. Phase I of the study included development of 15 mixture designs incorporating various combinations of the materials. Mixtures were cast under controlled laboratory conditions and cured using a variety of methods. The results of tests conducted on the cured samples indicated that the mixture with silica fume and slag had greater strength than the mixture with silica fume and fly ash mixture, and that mixtures with crushed rock provided better abrasion resistance than those with river gravel. Results from the chloride ion penetration test for permeability indicated that mixtures cured in saturated lime water for 28 days exhibited reduced permeability in comparison to mixtures which were steam cured followed by ambient curing. Following phase I, a pilot study was undertaken to identify the best curing method to apply during production at precast yards to assist high early strength gain so that the concrete member can be removed from the casting bed in a matter of several hours as well as to facilitate high ultimate strength, improved abrasion resistance, and low permeability. The pilot study indicated the best curing method to be steam curing followed by application of a curing compound. Phase II of the research study included seven mix designs and focused on various levels of supplementary cementitious materials. It adopted the curing method suggested by the pilot study. Results from phase II indicated that slag was better in enhancing durability of the concrete than fly ash. Increasing the proportion of silica fume did not improve the properties of high performance concrete significantly. Some other interesting results indicated that compressive strength was inversely proportional to wear rate and chloride ion penetration. Wear rate was directly proportional to chloride ion penetration. There was no relationship between durability factor (freeze-thaw test) and compressive strength or chloride ion penetration. Two mixtures were identified as having significantly improved abrasion and permeability characteristics over the control mixture (ODOT bridge deck mixture). Both included slag and silica fume as supplementary cementitious materials as a partial replacement of portland cement and one did not contain an air entraining admixture.

Advances in Civil Engineering and Building Materials

Advances in Civil Engineering and Building Materials
Author: Shuenn-Yih Chang
Publisher: CRC Press
Total Pages: 974
Release: 2012-10-31
Genre: Technology & Engineering
ISBN: 0203388070

Advances in Civil Engineering and Building Materials presents the state-of-the-art development in: - Structural Engineering - Road & Bridge Engineering- Geotechnical Engineering- Architecture & Urban Planning- Transportation Engineering- Hydraulic Engineering - Engineering Management- Computational Mechanics- Construction Technology- Buildi