Creep and shrinkage of high strength concrete

2010 ◽  
pp. 191-196
Author(s):  
S Chowdhury
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Creep And Shrinkage

Creep, shrinkage, frost, and sulphate resistance of high strength concrete

1995 ◽  
Vol 22 (3) ◽  
pp. 621-636 ◽  
Author(s):  
Sujit Ghosh ◽  
K. W. Nasser
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Frost Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Air Entrainment ◽  
Strength Concrete ◽  
Binder Ratio ◽  
Matrix Morphology ◽  
Creep And Shrinkage

A comprehensive study was undertaken to determine the shrinkage, creep, and durability of high strength concrete (50–70 MPa) containing silica fume and lignite fly ash. The concrete mixtures contained normal CSA type 10 (ASTM type 1) portland cement, 10% condensed silica fume, and different amounts of fly ash that varied between 0 and 80% of the weight of binder in the mixture. The aggregates-to-binder ratio by weight was maintained at 5 and the weight of the superplasticizer was varied between 1.5% and 2.2% of the binder while the water-to-binder ratio was maintained at 0.27. The test program consisted of compressive strength tests at various ages on concrete cylinders; drying shrinkage tests at room temperature; creep tests of sealed and unsealed concrete at room temperature (21 °C (70°F)) and at high temperatures (up to 232 °C (450°F)) under three different stress regimes; frost resistance tests on concrete prisms up to 300 freezing and thawing cycles; and sulphate resistance tests on concrete prisms immersed in 5% Na2SO4 solution for up to 10 months. The results indicated that up to 60% fly ash replacement with 10% silica fume showed either superior or similar 28- and 56-day compressive strengths when compared with the 100% cement control mixture. Fly ash + silica fume concrete indicated lower shrinkage and long-term creep. Creep increased with increase in temperature due to physico-chemical processes, which were confirmed by microstructure analysis using the scanning electron microscope. The creep and shrinkage data of high fly ash + silica fume concrete fitted well to the current ACI creep and shrinkage model. Replacement of cement by up to 35% fly ash and 10% silica fume indicated enhanced frost resistance, without any air-entrainment. The addition of 8% air-entrainment to the 20% fly ash + 10% silica fume mixture increased the durability factor by about 10%. For the 50% fly ash + 10% silica fume mixture, the frost durability factor was found comparable to that of the 100% cement control mixture, and air entrainment did not improve its value appreciably. Sulphate resistance of concrete made with 100% CSA type 10 cement was found satisfactory; however, with increasing fly ash contents (up to 50%), the expansion due to sulphate action was suppressed. A study of matrix morphology and microstructure bonding, using the scanning electron microscope, helped to explain the observed results in a comprehensive manner. Key words: creep, shrinkage, compressive strength, frost resistance, durability factor, sulphate resistance, fly ash, silica fume, high-strength concrete, SEM micrograph, matrix morphology.

Influence of creep and shrinkage on cracking in high strength concrete

1992 ◽  
Vol 22 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Vincent Sicard ◽  
Raoul Francois ◽  
Erick Ringot ◽  
Gérard Pons
Keyword(s):  
High Strength Concrete ◽  
High Strength ◽  
Strength Concrete ◽  
Creep And Shrinkage

The Experimental Study on Creep and Shrinkage of High Strength Concrete with Fly Ash

2013 ◽  
Vol 639-640 ◽  
pp. 423-426 ◽  
Author(s):  
Jian Qun Wang ◽  
Zhi Fang ◽  
Zhi Jian Tang
Keyword(s):  
Fly Ash ◽  
Prestressed Concrete ◽  
High Strength Concrete ◽  
Large Scale ◽  
Influence Factor ◽  
Concrete Structures ◽  
High Strength ◽  
Strength Concrete ◽  
Shrinkage And Creep ◽  
Creep And Shrinkage

Shrinkage and creep characteristics of concrete are significant factors in the design of prestressed concrete structures. With large scale/span concrete structures developed, the fly ash or other blends are added into high strength concrete to improve the mechanical properties and workability. As a result, the existing shrinkage and creep predicting models have certain limitations. The creep and shrinkage behavior of high strength concrete with fly ash are studied in this paper. Proper predicting model for shrinkage and creep of high strength concrete is recommended. The influence factor of fly ash is proposed as well. These conclusions would be of great useful for structures with fly ash concrete.

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