TENSILE CREEP OF FLY ASH CONCRETE AT EARLY AGE CONSIDERING THE YOUNG'S MODULUS DEVELOPMENT

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Yoichi Mimura ◽  
Vanissorn Vimonsatit ◽  
Yuki Watanabe ◽  
Itaru Horiguchi ◽  
Isamu Yoshitake
Keyword(s):  
Fly Ash ◽  
Tensile Properties ◽  
Young’S Modulus ◽  
Creep Test ◽  
Elastic Strain ◽  
Young's Modulus ◽  
Tensile Creep ◽  
Early Age ◽  
Fly Ash Concrete ◽  
Dog Bone

Tensile properties are important for predicting tensile stress which causes thermal cracking. Fly ash, a by-product from coal-fired power plants, has been recently used to reduce such thermal cracks. However, investigations dealing with tensile properties of fly ash concrete are still limited. This study focuses on the tensile properties of concrete mixed with fly ash at an early age. Fly ash was mixed in general purpose concrete with a cement-replacement ratio of 20% by mass to simulate fly ash concrete used in Japan. To examine tensile Young's modulus and tensile creep, direct tension test was conducted using dog-bone shaped specimens. The tensile creep tests were conducted at the age of 3 days or 7 days, and the loading (30% of splitting tensile strength at the loading age) was sustained for 14 days. Past investigations usually assumed a constant elastic strain during creep test. It should be noted however that elastic strain at early age decreases with the age of concrete as hydration continues. This study takes a consideration of Young's modulus development during creep test to distinguish actual creep and elastic strains. Test results show that creep strain has been underestimated when assuming constant elastic strain.

scholarly journals Tensile Mechanical Properties of Fly Ash Concrete at Early Age for Thermal Stress Analysis

2020 ◽  
Author(s):  
Yoichi Mimura ◽  
Vanissorn Vimonsatit ◽  
Itaru Horiguchi ◽  
Isamu Yoshitake
Keyword(s):  
Fly Ash ◽  
Young’S Modulus ◽  
Compression Test ◽  
Creep Test ◽  
Elastic Strain ◽  
Young's Modulus ◽  
Tensile Creep ◽  
Early Age ◽  
Secant Modulus ◽  
Fly Ash Concrete

Abstract The present study investigates tensile properties of concrete with and without fly ash at early age, such as tensile Young’s modulus, strength and creep. Some Young’s modulus of fly ash concrete for thermal crack analysis was compared with the tensile Young’s modulus, secant modulus, initial tangent modulus and linear modulus obtained from the direct tension test and compression test. The tensile creep test was also performed to obtain the specific creep behavior considering decrease in elastic strain due to stiffness development at early age during creep test. The results show that the Young's modulus for crack evaluation can be obtained from the compression test based on the stress range less than the splitting tensile strength, while the compressive secant modulus was smaller than the tensile Young's modulus. The decrease of the elastic strain at early age contributes more to the evaluation of the tensile creep than the use of the fly ash mixing.

scholarly journals Tensile mechanical properties of fly ash concrete at early age for thermal stress analysis

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yoichi Mimura ◽  
Vanissorn Vimonsatit ◽  
Itaru Horiguchi ◽  
Isamu Yoshitake
Keyword(s):  
Fly Ash ◽  
Young’S Modulus ◽  
Compression Test ◽  
Creep Test ◽  
Elastic Strain ◽  
Young's Modulus ◽  
Tensile Creep ◽  
Early Age ◽  
Secant Modulus ◽  
Fly Ash Concrete

AbstractThe present study investigates tensile properties of concrete with and without fly ash at early age, such as tensile Young’s modulus, strength and creep. Some Young’s modulus of fly ash concrete for thermal crack analysis was compared with the tensile Young’s modulus, secant modulus, initial tangent modulus and linear modulus obtained from the direct tension test and compression test. The tensile creep test was also performed to obtain the specific creep behavior considering decrease in elastic strain due to stiffness development at early age during creep test. The results show that the Young’s modulus for crack evaluation can be obtained from the compression test based on the stress range less than the splitting tensile strength, while the compressive secant modulus was smaller than the tensile Young’s modulus. The decrease of the elastic strain at early age contributes more to the evaluation of the tensile creep than the use of the fly ash mixing.

scholarly journals Tensile Mechanical Properties of Fly Ash Concrete at Early Age for Thermal Stress Analysis

2020 ◽  
Author(s):  
Yoichi Mimura ◽  
Vanissorn Vimonsatit ◽  
Itaru Horiguchi ◽  
Isamu Yoshitake
Keyword(s):  
Fly Ash ◽  
Young’S Modulus ◽  
Compression Test ◽  
Creep Test ◽  
Elastic Strain ◽  
Young's Modulus ◽  
Tensile Creep ◽  
Early Age ◽  
Secant Modulus ◽  
Fly Ash Concrete

Abstract The present study investigates tensile properties of concrete with and without fly ash at early age, such as tensile Young’s modulus, strength and creep. Some Young’s modulus of fly ash concrete for thermal crack analysis was compared with the tensile Young’s modulus, secant modulus, initial tangent modulus and linear modulus obtained from the direct tension test and compression test. The tensile creep test was also performed to obtain the specific creep behavior considering decrease in elastic strain due to stiffness development at early age during creep test. The results show that the Young's modulus for crack evaluation can be obtained from the compression test based on the stress range less than the splitting tensile strength, while the compressive secant modulus was smaller than the tensile Young's modulus. The decrease of the elastic strain at early age contributes more to the evaluation of the tensile creep than the use of the fly ash mixing.

EXPERIMENTAL STUDY ON COMPRESSIVE YOUNG’S MODULI AND TENSILE YOUNG’S MODULUS OF FLY ASH CONCRETE

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Yoichi Mimura ◽  
Vanissorn Vimonsatit ◽  
Yuki Watanabe ◽  
Itaru Horiguchi ◽  
Isamu Yoshitake
Keyword(s):  
Fly Ash ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Tangent Modulus ◽  
Early Age ◽  
Secant Modulus ◽  
Tensile Stresses ◽  
Fly Ash Concrete ◽  
Young’S Moduli ◽  
Initial Tangent Modulus

Initial cracks due to volume changes at an early age affect the durability of concrete structures, so numerical simulations are often conducted in order to predict cracks. Such prediction requires some mechanical properties of early age concrete. Tensile Young's modulus is directly dependent on the prediction of tensile stress and is one of the important input data for FEM analysis. However, direct tension test for tensile Young's modulus needs a unique apparatus and specimen, and such test is not suitable for evaluating Young's modulus at early ages of concrete. The present study compared tensile Young's modulus with compressive Young's moduli of Fly ash concrete. Compressive Young's moduli used in this study were secant modulus and initial tangent modulus. In addition, linear modulus taken from a regression line of a compressive stress-strain curve in the range of stresses less than the splitting tensile strength was also evaluated. It is found that the secant modulus, which is generally used as Young's modulus in Japan was clearly smaller than the tensile Young's modulus, which means that, tensile stresses evaluated using a secant modulus might be underestimated. On the other hand, linear modulus and initial tangent modulus were almost equal to the tensile Young's modulus. This result indicates that tensile stresses can be evaluated using Young's modulus obtained from a compression test with general apparatus and specimens.

Relationship between tensile Young’s modulus and strength of fly ash high strength concrete at early age

2016 ◽  
Vol 123 ◽  
pp. 317-326 ◽  
Author(s):  
Dejian Shen ◽  
Xiang Shi ◽  
Shuaishuai Zhu ◽  
Xiaofang Duan ◽  
Jinyang Zhang
Keyword(s):  
Fly Ash ◽  
Young’S Modulus ◽  
High Strength Concrete ◽  
Young's Modulus ◽  
High Strength ◽  
Early Age ◽  
Strength Concrete

scholarly journals Enhancement of the Thermomechanical Properties of a Fly Ash- and Carbon Black-Filled Polyvinyl Chloride Composite by Using Epoxidized Soybean Oil as a Secondary Bioplasticizer

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Toan Duy Nguyen ◽  
Chinh Thuy Nguyen ◽  
Van Thanh Thi Tran ◽  
Giang Vu Nguyen ◽  
Hai Viet Le ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Carbon Black ◽  
Soybean Oil ◽  
Young’S Modulus ◽  
Polyvinyl Chloride ◽  
Young's Modulus ◽  
Epoxidized Soybean Oil ◽  
Melt Mixing ◽  
Elongation At Break

Plasticized polyvinyl chloride (PVC) was fabricated using epoxidized soybean oil (ESBO) as a secondary bioplasticizer with dioctyl phthalate (DOP). The PVC/MFA/CB composites were prepared by melt mixing of the plasticized PVC with modified fly ash (MFA), carbon black N330 (CB), and polychloroprene (CR) in a Haake Rheomix mixer using a rotation speed of 50 rpm at 175°C for 6 min and then compressed by Toyoseiki pressure machine under 15 MPa. The effect of ESBO content on morphology, melt viscosity, tensile properties, and flame retardancy of PVC/MFA/CB composites was investigated. The obtained results showed that the incorporation of ESBO has significantly enhanced the processing ability, Young’s modulus, tensile strength, and elongation at break of the PVC/MFA/CB composites. The torque of PVC/MFA/CB composites was increased to approximately 12% when 50 wt% of DOP was replaced by ESBO. When ESBO was 20 wt% in comparison with DOP weight, the elongation at break, tensile strength, and Young’s modulus of the composites were increased to 48%, 24%, and 4.5%, respectively. Correspondingly, thermogravimetric analysis results confirmed that ESBO had improved the thermostability of the PVC composites. The ESBO have potential as a secondary bioplasticizer replacement material for DOP owing to their better thermomechanical stability.

scholarly journals Experimental Investigation on Mechanical Properties of In Situ Cemented Paste Backfill Containing Coal Gangue and Fly Ash

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xinguo Zhang ◽  
Shichuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Friction Angle ◽  
Coal Gangue ◽  
Cemented Paste Backfill ◽  
Paste Backfill

Cemented paste backfill containing coal gangue and fly ash (CGFACPB) is an emerging backfill technique for coal mines that allows environmentally hazardous coal gangue and fly ash to be reused in the underground goaf. Meanwhile, CGFACPB can provide an efficient ground support and reduce the surface subsidence. Due to the difference of consolidation environment between the laboratory and the field, the mechanical properties of the cemented paste backfill vary significantly. In this paper, the core specimens were collected from an underground coal mine where the CGFACPB was used for coal mining, and the mechanical properties of the collected specimens were investigated. The cores were obtained from the underground coal mine, and then the standard cylinders or discs were prepared in laboratory. The uniaxial compressive strength (UCS), Young’s modulus, and Poisson’s ratio were determined by the compression tests, and the tensile strength was achieved by the Brazilian test. Then the internal friction angle and cohesion were calculated using the improved Mohr–Coulomb strength criterion. The results showed the development of UCS can be divided into four stages, and the final long-term stable value was about 5.1 MPa. The development of Young’s modulus had similar trend. Young’s modulus had a range from 550 MPa to 750 MPa and the mean value of 675 MPa. Poisson’s ratio gradually increased with the underground curing duration and eventually approached the stable value of 0.18. The failure type of compression samples was mainly single-sided shear failure. The development of tensile strength can be divided into two stages, and the stable value of the tensile strength was about 1.05 MPa. The development of cohesion can be divided into four stages, and the stable value was about 1.75 MPa. The stable value of the internal friction angle was about 25°. This study can provide significant references for not only the long-term stability evaluation of CGFACPB in the field but also the design of optimal recipe of the cemented paste backfill (CPB).

scholarly journals Effective reinforcements for thermoplastics based on carbon nanotubes of oil fly ash

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Numan Salah ◽  
Abdulrahman Muhammad Alfawzan ◽  
Abdu Saeed ◽  
Ahmed Alshahrie ◽  
Waleed Allafi
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Raw Materials ◽  
Young's Modulus ◽  
Weight Fraction ◽  
Low Weight ◽  
Oil Fly Ash

AbstractCarbon nanotubes (CNTs) are widely investigated for preparing polymer nanocomposites, owing to their unique mechanical properties. However, dispersing CNTs uniformly in a polymer matrix and controlling their entanglement/agglomeration are still big technical challenges to be overcome. The costs of their raw materials and production are also still high. In this work, we propose the use of CNTs grown on oil fly ash to solve these issues. The CNTs of oil fly ash were evaluated as reinforcing materials for some common thermoplastics. High-density polyethylene (HDPE) was mainly reinforced with various weight fractions of CNTs. Xylene was used as a solvent to dissolve HDPE and to uniformly disperse the CNTs. Significantly enhanced mechanical properties of HDPE reinforced at a low weight fraction of these CNTs (1–2 wt.%), mainly the tensile strength, Young’s modulus, stiffness, and hardness, were observed. The tensile strength and Young’s modulus were enhanced by ~20 and 38%, respectively. Moreover, the nanoindentation results were found to be in support to these findings. Polycarbonate, polypropylene, and polystyrene were also preliminarily evaluated after reinforcement with 1 wt.% CNTs. The tensile strength and Young’s Modulus were increased after reinforcement with CNTs. These results demonstrate that the CNTs of the solid waste, oil fly ash, might serve as an appropriate reinforcing material for different thermoplastics polymers.

Fly-Ash Concretes of 50% of the Replacement Ratio to Reduce the Cracking in Concrete Structures

2013 ◽  
Vol 405-408 ◽  
pp. 2665-2670 ◽  
Author(s):  
Ming Jie Mao ◽  
Qiu Ning Yang ◽  
Wen Bo Zhang ◽  
Isamu Yoshitake
Keyword(s):  
Fly Ash ◽  
Concrete Structures ◽  
High Volume ◽  
Pozzolanic Reaction ◽  
Strength Development ◽  
Early Age ◽  
Replacement Ratio ◽  
Fly Ash Concrete ◽  
Massive Concrete ◽  
Normal Strength

Fly-ash concrete used in massive concrete structure has superior advantages to reduce hydration heat. On the other hand, the fly-ash concrete has negative property of low strength development at early age because pozzolanic reaction of fly-ash activates at mature age, such as after 28 days. To investigate these characteristics of fly-ash used in concrete, the present study discusses thermal cracking possibility of fly-ash concrete by using FE analysis software. The present study employs prediction formulae proposed by Zhang and Japanese design code in the simulations. The objects in this study are normal strength concrete mixed of fly-ash up to 50% of replacement ratio to cement. The comparative investigations show that temperature effect is more significant than strength development at early age. Based on the analytical study, high volume fly-ash concretes of 30-50% of the replacement ratio can be concluded as effective and useful materials to reduce the cracking possibility in massive concrete structures. Keywords-Fly-ash concrete; Early Age, Prediction Formulae for Strength; Thermal Stress Analysis

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