SITE IMPLEMENTATION REPORT OF CAST-IN-SITU PRESTRESSED CONCRETE ROAD BRIDGE DECK USING BOTH EARLY-HIGH-STRENGTH PORTLAND CEMENT AND FLY ASH

2021 ◽  
Vol 77 (2) ◽  
pp. 65-77
Author(s):  
Naoki SAKAKIBARA ◽  
Shota TOMIZUKA ◽  
Atsushi YOSHIDA ◽  
Takuya MAESHIMA ◽  
Yasuhiro KODA ◽  
...  
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Prestressed Concrete ◽  
Bridge Deck ◽  
High Strength

scholarly journals In Situ Effectiveness of Alkaline and Cementitious Amendments to Stabilize Oxidized Acid-Generating Tailings

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 314 ◽  
Author(s):  
Abdellatif Elghali ◽  
Mostafa Benzaazoua ◽  
Bruno Bussière ◽  
Thomas Genty
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Surface Runoff ◽  
Ordinary Portland Cement ◽  
Control Cell ◽  
Water Infiltration ◽  
Gold Mine ◽  
Mine Site ◽  
In Situ Stabilization

This study investigates the effectiveness of alkaline and cementitious additives in the in situ stabilization of localized acid-generating tailings from a closed gold mine in Abitibi–Témiscamingue, Québec (Eagle/Telbel mine site). Five field cells (including one control) were constructed and equipped with mechanisms for collecting vertical water infiltration and surface runoff. The five cells included: (C1) Control cell; (C2) 5 wt % limestone amendment; (C3) 10 wt % limestone amendment; (C4) 5 wt % half ordinary Portland cement and half fly ash amendment; and (C5) 5 wt % ordinary Portland cement amendment. The control cell showed an acidic behavior (pH < 4.5) with variable concentrations of Fe, Al, Zn, and Cu. The amendments were used to neutralize the acidic leachates and decrease dissolved metal concentrations. Leachates from surface runoff samples of amended cells were less loaded with metals compared to samples of vertical infiltration. All amendment formulations increased the pH of the leachates from approximately 4 to circumneutral values. Furthermore, metal and metalloid concentrations were greatly limited, except for Cr and As for the carbonate-based amendments. Metal(-oid) stabilization was successfully achieved using the different amendment formulations, with the exception of C2, which still released As.

scholarly journals Efficiency of Rice Husk Ash as Cementitious Material in High-Strength Cement-Admixed Clay

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Pornkasem Jongpradist ◽  
Watee Homtragoon ◽  
Raksiri Sukkarak ◽  
Warat Kongkitkul ◽  
Pitthaya Jamsawang
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cement Content ◽  
High Strength ◽  
Compression Tests ◽  
Cement Replacement ◽  
Soil Cement ◽  
Partial Cement Replacement

The potential and efficiency of using rice husk ash (RHA) to add up or partially replace Portland cement in deep cement mixing technique are examined. A series of unconfined compression tests on cement-RHA-stabilized clay are conducted to investigate the influence of RHA on the mixture properties. Special attention is paid to its efficiency for increasing the strength by partial cement replacement to obtain high-strength soil cement, and it is compared with fly ash. Test results indicate that up to 35% of RHA could be advantageously added up to enhance the strength if the cement content in the mixture is larger than 10%. The RHA enhances the strength of cement-admixed clay by larger than 100% at 28 days. For curing time of 14 and 28 days, the RHA exhibits higher efficiency on Portland cement replacement when the cement and overall cementitious contents are not less than 20 and 35%, respectively. The optimum condition for high-strength mixture is achieved when RHA is added to the 20% cement content mixture. When compared with fly ash of similar grain size, the efficiency of RHA is higher when the content to be added is greater than 15%. This indicates the suitability of RHA for use in high-strength soil-cement.

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.

Consistency of Performance of Concretes With and Without Fly Ash

1986 ◽  
Vol 86 ◽  
Author(s):  
Weston T. Hester
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Fresh Concrete ◽  
High Strength ◽  
High Compressive Strength ◽  
Measures Of Performance ◽  
Construction Practice ◽  
Design And Construction

ABSTRACTFly ash and other pozzolans are increasingly used in concretes that must consistently achieve high compressive strength and other measures of performance. In contemporary design and construction practice, however, there is some concern as to whether or not use of commercial fly ash materials contribute to or reduce variations observed in field compressive strengths and properties of the fresh concrete. Regardless of its potential for improving the performance of the concrete, if the daily ongoing use of commercial fly ash will decrease the consistency of the concrete produced, the use of fly ash will be curtailed. In this paper, the experiences of geographically diverse, specific concrete suppliers using their respective sources of fly ash are summarized in detail. The nominal compressive strength of concretes, made with and without fly ash, are analyzed statistically. Special attention is given to moderate- and high-strength concretes. In conclusion, it is shown that concretes made with fly ash may not be more consistent than concretes with only portland cement.

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