Evaluation of fly ash effect on the durability of prestressed concrete cylindrical pipe in aggressive soil by electrochemical method

2021 ◽  
Vol 32 ◽  
pp. 100656
Author(s):  
K. Berrami ◽  
A. Ech-chebab ◽  
M. Galai ◽  
A. Ejbouh ◽  
S. Hassi ◽  
...  
Keyword(s):  
Fly Ash ◽  
Prestressed Concrete ◽  
Electrochemical Method ◽  
Cylindrical Pipe

scholarly journals Long-Term Vibration Monitoring of the Effects of Temperature and Humidity on PC Girders with and without Fly Ash considering ASR Deterioration

2017 ◽  
Vol 2017 ◽  
pp. 1-23
Author(s):  
Tuan Minh Ha ◽  
Saiji Fukada ◽  
Kazuyuki Torii
Keyword(s):  
Fly Ash ◽  
Prestressed Concrete ◽  
Weather Conditions ◽  
Element Model ◽  
Vibration Monitoring ◽  
Mode Shapes ◽  
Numerical Verification ◽  
Evaluation Procedures ◽  
Temperature And Humidity ◽  
Vibration Responses

Structural responses have been used as inputs in the evaluation procedures of civil structures for years. Apart from the degradation of a structure itself, changes in the environmental conditions affect its characteristics. For adequate maintenance, it is necessary to quantify the environment-induced changes and discriminate them from the effects due to damage. This study investigates the variation in the vibration responses of prestressed concrete (PC) girders, which were deteriorated because of the alkali–silica reaction (ASR), concerning ambient temperature and humidity. Three PC girders were exposed to outdoor weather conditions outside the laboratory, one of which had a selected amount of fly ash in its mixture to mitigate the ASR. The girders were periodically vibration tested for one and a half years. It was found that when the temperature and humidity increased, the frequencies and damping ratios decreased in proportion. No apparent variation in the mode shapes could be identified. A finite element model was proposed for numerical verification, the results of which were in good agreement with the measured changes in the natural frequencies. Moreover, the different dynamic performances of the three specimens indicated that the fly ash significantly affected the vibrations of the PC girders under ASR deterioration.

Investigating the influence of fly ash on the hydration behavior of cement using an electrochemical method

2019 ◽  
Vol 222 ◽  
pp. 41-48 ◽  
Author(s):  
Jianchao Zhang ◽  
Biqin Dong ◽  
Shuxian Hong ◽  
Xiaojuan Teng ◽  
Gui Li ◽  
...  
Keyword(s):  
Fly Ash ◽  
Electrochemical Method

scholarly journals Experimental Evaluation of Shrinkage, Creep and Prestress Losses in Lightweight Aggregate Concrete with Sintered Fly Ash

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3895
Author(s):  
Rafał Stanisław Szydłowski ◽  
Barbara Łabuzek
Keyword(s):  
Fly Ash ◽  
Prestressed Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Lightweight Aggregate Concrete ◽  
Clear Correlation ◽  
Aggregate Concrete ◽  
Normal Weight Concrete ◽  
Creep Coefficient ◽  
Shrinkage And Creep

The paper presents the experimental results of shrinkage, creep, and prestress loss in concrete with lightweight aggregate obtained by sintering of fly ash. Two concrete mixtures with different proportions of components were tested. Concrete with a density of 1810 and 1820 kg/m3, and a 28-day strength of 56.9 and 58.4 MPa was obtained. Shrinkage and creep were tested on 150 × 250 × 1000 mm3 beams. Creep was tested under prestressing load for 539 days and concrete shrinkage for 900 days. The measurement results were compared with the calculations carried out according to the Eurocode 2 as well as with the results of other research. A very low creep coefficient and lower shrinkage in relation to the calculation results and the results of other research were found. It was also revealed that there is a clear correlation between shrinkage and creep, and the amount of water in the concrete. The value of the creep coefficient during the load holding period was 0.610 and 0.537, which is 56.0 and 49.3% of the value determined from the standard. The prestressing losses in the analyzed period amounted to an average of 13.0%. Based on the obtained test results, it was found that the tested lightweight aggregate concrete is well suited for prestressed concrete structures. Shrinkage was not greater than that calculated for normal weight concrete of a similar strength class, which will not result in increased loss of prestress. Low creep guarantees low deflection increments over time.

scholarly journals Characterization of Fabricated FG Pipe with Natural Fiber-Flyash-Epoxy using Centrifugal Casting

2019 ◽  
Vol 8 (11) ◽  
pp. 734-741 ◽  
Keyword(s):  
Fly Ash ◽  
Functionally Graded Materials ◽  
Natural Fiber ◽  
Centrifugal Casting ◽  
Functionally Graded ◽  
Powder Materials ◽  
Optimized Design ◽  
Cylindrical Pipe ◽  
Graded Materials ◽  
Banana Stem

This research presents the design of fabrication technique for hollow pipe made up of functionally graded materials and its characterization. In the first part, a horizontal centrifugal casting model is designed and developed using CATIA package. After getting an optimized design the fabrication work is performed in workshop. Different powder materials (Banana stem fiber, Jute fiber and Fly ash) are prepared by considering different chemical treatment and physical process. Different powder sizes (300µ, 150µ, 75µ, 53µ, 45µ) are considered to fabricate current functionally graded cylindrical pipe by altering their weight percentage. The different weight percentages (5%, 7.5%, 10%, 12.5%, 15% of Banana stem and 2.5%, 5%, 7.5%, 10%, 12.5% of Fly Ash) of constituents are considered for fabricating FGM cylindrical pipe. By altering the constituent of FGM material composition, twelve numbers of various functionally graded materials (FGMs) pipes are fabricated. In the second part, the material characterization is performed using different testing machines in Laboratories. Mechanical properties (Compression test and Micro hardness test) and physical properties (Density test, Water absorption test and thermal conductivity test) are investigated. Furthermore, the microstructures of the fabricated FGNF pipes are examined using Scanning Electron Microscope (SEM).

scholarly journals Full-scale test of precast prestressed concrete double-tee girder for rural bridges

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Dinh Hung Nguyen ◽  
Hong Nghiep Vu ◽  
Thac Quang Nguyen
Keyword(s):  
Fly Ash ◽  
Prestressed Concrete ◽  
Rural Areas ◽  
Full Scale ◽  
Concrete Aggregate ◽  
Span Length ◽  
Natural Sand ◽  
Linear Elastic ◽  
Bridge Structures ◽  
Concrete Blocks

AbstractIncreasing the number of small and medium-sized bridges is a need to improve accessibility in rural areas of the Mekong River Delta of Vietnam. Many types of bridge structures can be the suitable selection for rural bridges, on which the overall load of the operating truck is about 100kN. An objective of this paper is to propose a double-tee (DT) girder with the span length varying from 12 m to 15 m for the rural bridge types B and C in the Vietnamese standard. New concrete aggregate using crushed sand and fly ash for the DT girders is also examined to solve the scarcity of natural sand and environmental problem from industrial waste. A full-scale DT girder with a span length of 12 m is tested to confirm the capacity of the proposed design. Result finds out that the concrete sand, which the natural sand is replaced by 90% of the crushed sand and 10% of the fly ash by weight, could be well applied for the proposed DT girders. Another finding is a linear elastic uncracked response of the tested DT girder under loads of a rural vehicle and concrete blocks of 306kN. Therefore, the proposed DT girders are suggested to the rural bridges.

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.

Sign in / Sign up

Export Citation Format

Share Document