Drying Shrinkage Behavior of Mortars Made with Ternary Blends

2012 ◽  
Vol 2290 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Xuhao Wang ◽  
Fatih Bektas ◽  
Peter Taylor ◽  
Kejin Wang ◽  
Paul J. Tikalsky
Keyword(s):  
Fly Ash ◽  
Response Surface ◽  
Silica Fume ◽  
Surface Analysis ◽  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Response Surface Analysis ◽  
Ternary Blends ◽  
Free Shrinkage ◽  
Shrinkage Behavior

Ternary cementitious blends are widely used in today's concrete mixtures, particularly when high performance is needed. This paper discusses drying shrinkage behavior of mortar mixtures made with various ternary blends. Ternary blends consisting of different combinations of portland or blended cement, slag, fly ash, and silica fume were considered. The amounts of slag, fly ash, and silica fume ranged from 15% to 35%, 13% to 30%, and 3% to 10% by mass of cementitious materials, respectively. Mortar bars were made with the ternary blends and subjected to drying (i.e., temperature = 73° ± 3°F and relative humidity = 50% ± 4%) after standard moist curing for 28 days. Free shrinkage of the bars was assessed at 56 days of age after 28 days of drying. A response surface analysis was done to examine the effects of blend proportions on shrinkage behavior of the mortars. To validate this model, an independent group of mortar mixtures with different ternary combinations was cast, and the measured values were compared with the predicted shrinkage values. The results indicated that of the three supplementary cementitious materials in the ternary blends studied, slag showed a dominant effect on increasing mortar shrinkage. The contribution of Class C fly ash to the shrinkage was slightly less than that of slag. An increase in silica fume or in Class F fly ash content slightly increased free shrinkage. There is a good correlation between the measured shrinkage strain and the strain predicted from the shrinkage model developed from the response surface analysis.

scholarly journals Characterizing the Performance of Ternary Concrete Mixtures Involving Slag and Metakaolin

2020 ◽  
Vol 5 (2) ◽  
pp. 14
Author(s):  
Matthew S. Sullivan ◽  
Mi G. Chorzepa ◽  
Stephan A. Durham
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Fly Ash ◽  
Coefficient Of Thermal Expansion ◽  
Drying Shrinkage ◽  
Chloride Ion ◽  
Cementitious Materials ◽  
Ternary Mixtures ◽  
Modulus Of Rupture ◽  
Ternary Blends

Ternary blends of cementitious materials are investigated. A cement replacement level of 45% is used for all ternary mixtures consisting of 15% metakaolin and 30% slag replacements. Three metakaolin and two blast furnace slag, referred to as ‘slag’ for short, products commercially available are used to compare performance in ternary blends. A mixture with a 45% fly ash replacement is included to serve as a benchmark for performance. The control mixture contains 422 kg of cement per cubic meter of concrete, and a water-to-cementitious material ratio of 0.43 is used for all mixtures with varying dosages of superplasticizer to retain workability. Mixtures are tested for mechanical properties, durability, and volumetric stability. Mechanical properties include compression, split-cylinder tension, modulus of rupture, and dynamic Young’s modulus. Durability measures are comprised of rapid chloride-ion penetrability, sulfate resistance, and alkali–silica reactivity. Finally, the measure of dimensional stability is assessed by conducting drying shrinkage and coefficient of thermal expansion tests. Results indicate that ternary mixtures including metakaolin perform similarly to the control with respect to mechanical strength. It is concluded that ternary blends perform significantly better than both control and fly ash benchmark in tests measuring durability. Furthermore, shrinkage is reduced while the coefficients of thermal expansion are slightly higher than control and the benchmark.

scholarly journals Response surface analysis of nozzle parameters at supersonic flow through microjets

2021 ◽  
pp. 1-16
Author(s):  
Turki Al-Khalifah ◽  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muhammad Hanafi Bin Azami ◽  
Muneer Baig
Keyword(s):  
Supersonic Flow ◽  
Response Surface ◽  
Surface Analysis ◽  
Response Surface Analysis ◽  
Flow Through

scholarly journals In vitro synergy of isavuconazole in combination with colistin against Candida auris

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Patrick Schwarz ◽  
Anne-Laure Bidaud ◽  
Eric Dannaoui
Keyword(s):  
Response Surface ◽  
Surface Analysis ◽  
Concentration Index ◽  
Inhibitory Concentration ◽  
Response Surface Analysis ◽  
Fractional Inhibitory Concentration ◽  
Candida Auris ◽  
Fractional Inhibitory Concentration Index ◽  
Agar Diffusion

AbstractThe in vitro interactions of isavuconazole with colistin were evaluated against 15 clinical Candida auris isolates by a microdilution checkerboard technique based on the EUCAST reference method for antifungal susceptibility testing and by agar diffusion using isavuconazole gradient concentration strips with or without colistin incorporated RPMI agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index and by response surface analysis based on the Bliss model. By checkerboard, combination was synergistic for 93% of the isolates when interpretation of the data was done by fractional inhibitory concentration index, and for 80% of the isolates by response surface analysis interpretation. By agar diffusion test, although all MICs in combination decreased compared to isavuconazole alone, only 13% of the isolates met the definition of synergy. Essential agreement of EUCAST and gradient concentration strip MICs at +/− 2 log2 dilutions was 93.3%. Antagonistic interactions were never observed for any technique or interpretation model used.

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