Early-Age Strength Development of Concrete Incorporating Fly Ash and Condensed Silica Fume
Author(s): G. Carette and V.M. Malhotra
Published By:ACI
Published Year:5/1/1983
Quality:Unspecified
Abstract:
ACI/ Volume: 79 Appears on pages(s): 765-784
Early-age strength development of concrete in which part of the portland cement has been replaced by low-calcium fly ash tends to be slow, because fly ash acts as a relatively inert component during this period of hydration, though at later ages it contributes significantly to strength development. It was considered that the problem of low early-age strength of portland cement-fly ash concrete could be overcome by the incorporation of small amounts of condensed silica fume, a very fine and more rapidly reactive pozzolan. This report presents the results of an investigation on the early-age strength development of concrete incorporating 30% low-calcium fly ash, and to which small amounts of condensed silica fume have been added. The amounts of the fume ranged from 0 to 20% by combined weight of the portland cement plus fly ash. A total of thirty 0.06-m3 concrete mixtures with water-(cement + fly ash) ratios ranging from 0.40 to 0.80 were made; 240 cylinders were tested in compression and 180 prisms were tested in flexure. A supplementary series of six concrete mixtures was made to deter-mine the effect of silica fume and fly ash on the long-term strength development of concrete. Test data showed that the incorporation of condensed silica fume increased the compressive strength of concrete at all ages as compared with the compressive strength of the control concrete (70% portland cement + 30% fly ash). At 7 days, the loss of compressive strength due to the partial replacement of cement by fly ash was completely overcome by the addition of 10% condensed silica fume for concretes with water-(cement + fly ash) ratios ranging from 0.40 to 0.60; 15 to 20% was required for concretes with higher water-(cement + fly ash) ratios, At 28 days, regardless of the water-(cement + fly ash) ratio, the effect was generally achieved with less than 5% silica fume addition. The laterage strength development of portland cement-fly ash concrete did not appear to be impaired by the use of condensed silica fume indicating availability of sufficient lime for the fly ash pozzolanic activity.
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If civil engineering were a game, Karl Terzaghi had a right to lay down the rules—he had invented and established much of the groundwork. Terzhaghi (1883-1963) is one of the leading civil engineers of the 20th century and is widely known as the father of soil mechanics. His lifelong application of the principles established in his work took him throughout the world to engineering challenges in Communist Russia, Nazi Germany, America, and the entire post-war world.
Terzaghi's fame as a master engineer is well known but the story of his development, both personal and professional, has remained unexplored by most people. This first full-length, critical biography of a complex man draws upon his publications, hundreds of unpublished reports, thousands of private letters, and 82 volumes of previously private personal diaries.
This narrative shows Terzaghi's struggle to understand the phenomena observed on many major engineering projects. Through his own words we explore friendships, conflicts, jealousies, frustrations, and enormous successes. Terzaghi was an artist with constant focus, commitment, and genius. The exploration of his life, much of it amid the backdrop of turbulent Europe between the Wars, becomes an adventure that unfolds to entertain, educate, and stimulate.
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Determination of the Fracture Energy of Concrete: A comparison of the three-point bend test on notched beam and the wedge-splitting test
Editor: Hassanzadeh, Manouchehr
Sveriges Provnings- och Forskningsinstitut - Byggnadsteknik
Author: Hansen, Ernst Jan De Place
Department of Structural Engineering and Materials, Technical University of Denmark
Author: Aassved Hansen, Einar
SINTEF
Author: Stang, Henrik
Department of Structural Engineering and Materials, Technical University of Denmark, Denmark
Abstract:
In a NORDTEST project two methods for determination of the fracture energy of concrete are compared; the Three-Point Bend Test (TPBT) and the Wedge Splitting Test (WST). The methods involve notched beams and notched, grooved cubes, respectively. The two methods are compared in relation to handling and precision (repeatability, reproducability). Concrete with a water/cement ratio of 0.43 including fly ash as well as silica fume is investigated. The results show that WST is significantly faster to work with compared to TPBT, although the sawing procedure is more time consuming. Only when using laboratory prepared specimens cast in moulds with a negative groove time can be saved. With the experimental setup used in the majority of the testing, the GF determined according to the TPBT method is generally higher than the GF determined according to the WST method. The results however seem to indicate that care should be taken in designing the supports in the beam test (TPBT) in order to minimize the resistance to axial movements.
Original language English
Number of pages 53
State Published - 1998
This book marks the 60th anniversary of ICE's world leading journal, Géotechnique. It includes a set of seminal papers published in Géotechnique over the past 60 years as well as all the papers from the specially commissioned June 2008 Diamond Jubilee issue.
CONTRIBUTIONS TO THEORY AND PRACTICE
The book highlights the important contributions that Géotechnique has made, and continues to make, to the theory and practice of ground engineering and provides a glimpse into the future.
Since it was first published in 1948, the journal has continued to ignite international interest, providing readers with the best original papers and technical notes on soil and rock mechanics, engineering geology and environmental geotechnics.
THE SOURCE OF MODERN GEOTECHNICS
Nine seminal Géotechnique papers from 1950-1990 have been reproduced in their original format alongside the discussions that they provoked. Many of these papers set the direction of modern geotechnics and the origins of current theory and practice can be retraced to them.
Contents
Preface
Editorial
Géotechnique: Past, present and future
Géotechnique 1948–2008: more than just a journal
The founders of Géotechnique
Geotechnical publications before Géotechnique
Geotechnics: the next 60 years
Contributions to Géotechnique 1948–2008
Foundation engineering
Retaining structures
Slope stability and embankment dams
Tunnelling
Ground improvement
Constitutive and numerical modelling
Physical modelling
Laboratory and field testing
Soil behaviour
Groundwater
Soil science and interdisciplinary aspects of geotechnical engineering
Engineering geology, rock mechanics and rock engineering
Dynamics
Seminal papers and discussion: 1950–1990
The measurement of the shear strength of soils
The sensitivity of clays
The movement and distribution of water in soils
The use of the slip circle in the stability analysis of slopes
Stability of strutted excavations in clay
On the yielding of soils
A discrete numerical model for granular assemblies
A computer model for the analysis of ground movements in London Clay
A constitutive model for partially saturated soils
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Author(s): David Darwin, Shawn Barham, Rozalija Kozul, and Shuguang Luan
Published By:ACI Materials Journal
Published Year:9/1/2001
Quality:PDF
Abstract: The effects of water-cementitious materials ratio, age, and aggregate type on the compressive strength, flexural strength, and fracture energy of concretes with compressive strengths ranging from 20 to 99 MPa (2900 to 14,400 psi) are studied. Concrete mixtures contain either basalt or crushed limestone aggregate with maximum sizes of 12 or 19 mm (1/2 or 3/4 in.). Mixtures are tested at ages ranging from 5 to 180 days and have water-cementitious (w/cm) ratios ranging from 0.24 to 0.50. High-strength concrete containing the higher-strength, basalt coarse aggregate attains higher compressive and flexural strengths than high-strength concrete containing limestone. The compressive and flexural strengths of medium and normal-strength concretes (fc¢ up to approximately 60 MPa [9000 psi]) are affected little by aggregate type. Concrete containing basalt yields significantly higher fracture energy than concrete containing limestone, with fracture energy governed principally by aggregate properties, independent of compressive strength, w/cm ratio, and age. Overall, as compressive strength increases, the energy stored in the material at the peak tensile load increases while the ability of the material to dissipate energy remains approximately constant. The result is increasingly brittle behavior as compressive strength increases.
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Published By:Hydrology Research, An International Journal
Published Year:Published February 2017
DOI:10.2166/nh.2016.169
Quality:PDF
Ordinary kriging and genetic programming for spatial estimation of rainfall in the Middle Yarra River catchment, Australia
Author(s): Sajal Kumar Adhikary, Nitin Muttil, Abdullah Gokhan Yilmaz
Published By:Hydrology Research, An International Journal
Published Year:Published December 2016
DOI:10.2166/nh.2016.196
Quality:PDF
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hi. I need following paper from AISC Engineering Journal.I would appreciate to share this & other articles available from AISC Engineering Journal.Thanck u.
Chi, B., and Uang., C. M. 2004. “Effect of Straightening Method on the Cyclic
Behavior of k-Area in Steel Rolled Shapes,” Engineering Journal, American
Institute of Steel Construction, first quarter, 2004, 15–22.
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Hi,
I am looking for Norwegian National Annexes to Eurocode: NS-EN.
Maybe someone have any and can share?
The most necessary are annexes to the parts of EN 1990, 1991 and 1993 (steel structures, especially 1993-1-1 and 1993-1-8).
Thank You in advance.
The book establishes sewer processes as an integral part of managing, designing, and operating an urban wastewater system. It presents in-sewer processes from a fundamental and conceptual point of view for easy understanding by students. Both engineers and students will find the book's models and practical examples useful. It demonstrates a range of sewer and treatment issues, such as odor control, corrosion, and integrated wastewater treatment. It also explains how environmental process engineering principles can be applied to sewer design, resulting in better wastewater treatment and cleaner water entering receiving areas.
Sewer Processes
Microbial and Chemical Process Engineering of Sewer Networks, 2nd Edition
Sewer Processes: Microbial and Chemical Process Engineering of Sewer Networks, Second Edition, provides a basis for up-to-date understanding and modeling of sewer microbial and chemical processes and demonstrates how this knowledge can be applied for the design, operation, and the maintenance of wastewater collection systems. The authors add chemical and microbial dimensions to the design and management of sewer networks with an overall aim of improved sustainability for the system itself and the surrounding environment.
1st & 2nd Edition in single 9.9MB rar archive
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1. An evaluation framework for identifying the optimal raingauge network based on spatiotemporal variation in quantitative precipitation estimation
Che-Hao Chang, Shiang-Jen Wu, Chih-Tsung Hsu, Jhih-Cyuan Shen, Ho-Cheng Lien
Published February 2017, 48 (1) 77-98; DOI: 10.2166/nh.2016.169
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2. Ordinary kriging and genetic programming for spatial estimation of rainfall in the Middle Yarra River catchment, Australia
Sajal Kumar Adhikary, Nitin Muttil, Abdullah Gokhan Yilmaz
Published December 2016, 47 (6) 1182-1197; DOI: 10.2166/nh.2016.196
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