Irradiation Duration Effect of Gamma Ray on the Compressive Strength of Reactive Powder Concrete

2020 ◽  
Vol 857 ◽  
pp. 15-21
Author(s):  
Nesreen B. Najib ◽  
Shatha D. Mohammed ◽  
Wasan Z. Majeed ◽  
Nada Mahdi Fawzi A. Jalawi
Keyword(s):  
Compressive Strength ◽  
Fiber Volume Fraction ◽  
Gamma Ray ◽  
Volume Fraction ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Gamma Ray Irradiation ◽  
Duration Effect ◽  
Reactive Powder ◽  
The Impact

Reactive Powder Concrete (RPC) could be considered as the furthermost significant modern high compressive strength concrete. In this study, an experimental investigation on the impact of micro steel fiber volume fraction ratio and gamma ray irradiation duration influence upon the compressive strength of RPC is presented. Three volume fraction ratios (0.0, 1.0 and 1.5) % was implemented. For each percentage of the adopted fiber ratios, six different irradiation duration was considered; these are (1, 2, 3, 4, 5 and 6) days. Gamma source (Cs-137) of energy (0.662) MeV and activity (6) mci was used. In a case of zero volume fraction ratio, the experimental results showed that gamma ray had a significant influence on the reducing of the compressive strength varies between (1.2-8.6)% for a period of (1-6) days, respectively. Although there was a decrease in the compressive strength for a state of non-zero volume fraction ratio (1 and 1.5) % varies between (1.0-3.1 and 0.4-1.6) %, respectively, the attained results indicated that gamma ray had no significant effect to reduce the compressive strength of the RPC that’s included micro steel fibers as a volume fraction.

scholarly journals Influence of MgO and Hybrid Fiber on the Bonding Strength between Reactive Powder Concrete and Old Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Mo Jinchuan ◽  
Ou Zhongwen ◽  
Wang Yahui
Keyword(s):  
Tensile Strength ◽  
Bonding Strength ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Drying Shrinkage ◽  
Splitting Tensile Strength ◽  
Reactive Powder Concrete ◽  
Fiber Volume ◽  
Reactive Powder

The reactive powder concrete (RPC) was used as concrete repair material in this paper. The influence of steel fiber, steel fiber + MgO, and steel fiber + MgO + polypropylene fiber (PPF) on the mechanical properties of RPC repair materials and the splitting tensile strength between RPC and old concrete was studied. Influences of steel fiber, MgO, and PPF on the splitting tensile strength were further examined by using scanning electronic microscopy (SEM) and drying shrinkage test. Results indicated that the compressive and flexural strength was improved with the increasing of steel fiber volume fraction. However, the bonding strength showed a trend from rise to decline with the increasing of steel fiber volume fraction. Although MgO caused mechanical performance degradation of RPC, it improved bonding strength between RPC and existing concrete. The influence of PPF on the mechanical properties of RPC was not obvious, whereas it further improved bonding strength by significantly reducing the early age shrinkage of RPC. Finally, the relationship of drying shrinkage and splitting tensile strength was studied, and the equation between the splitting tensile strength relative index and logarithm of drying shrinkage was obtained by function fitting.

Research on Impact Behavior of Reactive Powder Concrete

2010 ◽  
Vol 150-151 ◽  
pp. 779-782
Author(s):  
Qing Xin Zhao ◽  
Zhao Yang Liu ◽  
Jin Rui Zhang ◽  
Ran Ran Zhao
Keyword(s):  
Compressive Strength ◽  
Impact Toughness ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Impact Behavior ◽  
Reactive Powder Concrete ◽  
Flexural Toughness ◽  
Reactive Powder ◽  
The Impact

By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.

Effect of Polypropylene Fiber on Strength and Flexural Properties of Concrete Containing Silica Fume

2011 ◽  
Vol 346 ◽  
pp. 30-33
Author(s):  
Hong Wei Wang
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Silica Fume ◽  
Modulus Of Elasticity ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Flexural Modulus ◽  
Polypropylene Fiber ◽  
Flexural Properties ◽  
Fiber Volume

A designed experimental study has been conducted to investigate the effect of polypropylene fiber on the compressive strength and flexural properties of concrete containing silica fume, a large number of experiments have been carried out in this study. The flexural properties include flexural strength and flexural modulus of elasticity. On the basis of the experimental results of the specimens of six sets of mix proportions, the mechanism of action of polypropylene fiber on compressive strength, flexural strength and flexural modulus of elasticity has been analyzed in details. The results indicate that there is a tendency of increase in the compressive strength and flexural strength, and the flexural modulus of elasticity of concrete containing silica fume decrease gradually with the increase of fiber volume fraction.

Experimental Study on Impact Behavior of Flax Fiber Reinforced PP Laminates

2011 ◽  
Vol 332-334 ◽  
pp. 735-738 ◽  
Author(s):  
Li Yan Liu ◽  
Yong Liang Han ◽  
Fei Zhang
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Flax Fiber ◽  
Impact Behavior ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Technical Parameters ◽  
The Impact

This paper is aiming to research the impact behavior of flax fiber reinforced PP laminates considering the end use of the products. Flax yarn and Polypropylene (PP) filaments were twisted together with three fiber volume fraction 0.45, 0.50 and 0.60 to form the commingled yarns which were woven into fabrics as prepreg with plain and twill structures respectively. The prepregs of different layers were pressed into flax reinforced PP composites in the process of hot-pressing. The laminates with different fiber volume fraction, layer, and woven structure were tested and analyzed respectively aiming at the impact resistibility in succession. SEM micrograph of the impact fracutured surface was observed and analyzed as well. The results reveal that the impact properties of laminates with twill structures are prior to those of laminates with plain structures when other technical parameters are the same. The ability of impact resistibility of flax reinforced PP laminates improves with the increase of the fibre volume fraction, layer amount and impact velocity respectively in this research.

Analysis of Bending Behavior of Laminated Composite Beam

2015 ◽  
Vol 786 ◽  
pp. 421-425
Author(s):  
R. Arravind ◽  
M. Saravanan ◽  
K. Balasubramanian
Keyword(s):  
Composite Beam ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laminated Composite ◽  
Layered Composite ◽  
Fiber Volume ◽  
Bottom Side ◽  
Bending Behavior ◽  
Laminated Composite Beam ◽  
The Impact

This paper discusses about the impact of fiber volume fraction on the bending behavior of a laminated composite beam. A two layered composite beam with upper layer made of glass fiber epoxy resin and reinforced with Kevlar at the bottom side of the beam is modeled and structural analysis is carried out. The analysis shows that the tensile strength increases with increase in fiber volume fraction. The compression strength decreases with increase in fiber volume fraction in the upper fiber where as increases in the bottom fiber and the obtained results are correlating with the experimental and analytical studies.

scholarly journals The Effect of Various Polynaphthalene Sulfonate Based Superplasticizers on the Workability of Reactive Powder Concrete

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Anthony Torres ◽  
Federico Aguayo ◽  
Srinivas Allena ◽  
Michael Ellis
Keyword(s):  
Compressive Strength ◽  
Fresh Concrete ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Chemical Admixture ◽  
Lower Viscosity ◽  
Reactive Powder ◽  
The Impact ◽  
Polycarboxylate Ether ◽  
High Range

A superplasticizer is a type of chemical admixture used to alter the workability (viscosity) of fresh concrete. The workability of fresh concrete is often of particular importance when the water-to-cement (w/c) ratio is low and a particular workability is desired. Reactive Powder Concrete (RPC) is a high-strength concrete formulated to provide compressive strengths exceeding 130MPa and made of primarily powders. RPC materials typically have a very low w/c, which requires the use of a chemical admixture in order to make the material workable for placing, handling and consolidating. Superplasticizer are commonly used for this purpose. Superplasticizers are developed from different formulations, the most common being Polynaphthalene Sulfonate (PNS), Polymelamine Sulfonate (PMS) and Polycarboxylate Ether (PCE). This study investigates the impact of various PNS based superplasticizers on the compressive strength and rheological performance of a RPC mixture. Six different types of PNS based superplasticizers were used; three of various compositional strengths (high, medium, low range) from a local provider, and three of the same compositional strengths (high, medium, low) from a leading manufacturer. Specific properties assessed were the superplasticizers viscosity, concrete workability through the mortar-spread test, concrete rheology, and 7, 14, and 28 day RPC compressive strengths. Two mixtures were produced with two w/cm (0.20 and 0.15), which would subsequently increase the amount of superplasticizer needed, from 34.7L/m3 to 44.5L/m3. The results show that the name brand high range composition produced the overall highest spread, lowest viscosity, and a highest compressive strength at all ages tested. However, the local provider outperformed the name brand in the mid and low range compositions. Additionally, the rheology test also demonstrated that the name brand high range, and RPC produced with the name brand high range, had a lower viscosity at all angular speeds than the others tested.

scholarly journals Peningkatan Sifat Mekanik Komposit Serat Alam Limbah Sabut Kelapa (Cocofiber) yang Biodegradable

2021 ◽  
Vol 6 (1) ◽  
pp. 30-37
Author(s):  
Sri Hastuti ◽  
Herru Santosa Budiono ◽  
Diki Ilham Ivadiyanto ◽  
Muhammad Nurdin Nahar
Keyword(s):  
Mechanical Properties ◽  
Fiber Volume Fraction ◽  
Bending Strength ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Fiber Composites ◽  
Coconut Fiber ◽  
Fiber Volume ◽  
Coconut Coir ◽  
The Impact

Inovasi baru serat dari sabut kelapa dimanfaatkan untuk meningkatkan nilai ekonomis dari serat sabut kelapa, oleh karena itu dirancanglah pendayagunaan serat dari sabut kelapa untuk penguat komposit dengan material serat alam yang biodegradable. Hal ini untuk mendukung penggunaan komposit yang ramah terhadap lingkungan dan mengurangi penggunaan material komposit serat sintetis yang polutan. Tujuan penelitian adalah menganalisis sifat mekanik pada komposit serat alam bermaterial serat dari sabut kelapa yang ramah lingkungan. Metode penelitian pembuatan komposit berpenguat serat dari sabut kelapa dilakukan treatment NaOH 15% selama 5 jam dan fraksi volume serat 10 %, 15 %, dan 20 %. Komposit  serat dari sabut kelapa dengan matriks UPRs 157 BQTN dengan hardener MEXPO. Pengujian mekanik dilakukan uji bending menggunakan standar ASTM D790 dan uji impak  menggunakan standar ASTM D5941.  Pengujian impak komposit serat alam menunjukkan ketangguhan impak komposit pada fraksi volume serat 20% dengan nilai 0.017588J/mm2. Hasil pengujian menunjukkan peningkatan fraksi volume serta berpengaruh terhadap peningkatan kekuatan bending komposit serat dari sabut kelapa  dengan kekuatan optimum bending pada fraksi volume serat 10% dengan nilai 44,33N/mm2. Hal ini menunjukkan peningkatan fraksi volume serat dengan perendaman NaOH 15% akan meningkatkan sifat mekanik bending dan impak komposit. Perendaman NaOH memberikan pengaruh daya serap sabut kelapa terhadap matrik Unsaturated Polyester yang dapat meningkatkan daya rekat antara penguat serat dengan matrik sehingga meningkatkan sifat mekanik bending dan impak komposit. ABSTRACT The innovation of coco fiber is used to increase the economic value of coconut coir, therefore the utilization of coconut fiber for reinforcing composites with biodegradable natural fiber material is designed. This is to support the use of composites that are friendly to the environment and reduce the use of pollutant synthetic fiber composite materials. The research objective was to analyze the mechanical properties of natural fiber composites with environmentally friendly coconut fiber as material. The research method of making fiber-reinforced composites from coconut coir was carried out by 15% NaOH treatment for 5 hours and a fiber volume fraction of 10%, 15%, and 20%. Composite fiber from coconut coir with UPRs 157 BQTN matrix with MEXPO hardener. Mechanical testing is carried out using the ASTM D790 standard and the impact test using the ASTM D5941 standard. The impact test of natural fiber composites showed the impact toughness of the composite at a fiber volume fraction of 20% with a value of 0.017588 J/ mm2. The test results showed an increase in volume fraction and an effect on the increase in the bending strength of coconut fiber composites with the optimum bending strength at a fiber volume fraction of 10% with a value of 44.33N /mm2. This shows that the increase in fiber volume fraction by immersion in 15% NaOH will increase the bending mechanical properties and the impact of the composite. Soaking NaOH has an effect on the absorption power of coconut coir on the Unsaturated Polyester matrix which can increase the adhesion between the fiber reinforcement and the matrix thereby increasing the bending mechanical properties and impact of the composite.

Self-Hardening Calcium Phosphate Composite Scaffold for Bone Tissue Engineering

2009 ◽  
Vol 79-82 ◽  
pp. 19-22 ◽  
Author(s):  
Hua Liu ◽  
Chang Ren Zhou
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Compressive Strength ◽  
Liquid Phase ◽  
Calcium Phosphate ◽  
Bone Tissue Engineering ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Large Diameter ◽  
Fiber Volume

Calcium phosphate cement (CPC) sets in situ to form solid hydroxyapatite, can conform to complex cavity shapes without machining, has excellent osteoinductivity, and is able to be resorbed and replaced by new bone. Therefore, CPC is promising for craniofacial and orthopaedic repairs. However, its low strength and lack of macroporosity limit its use. This study investigated CPC reinforcement with absorbable fibers, the effects of fiber volume fraction on mechanical properties and macroporosity, and the biocompatibility of CPC-fiber composite. The liquid phase of CPC in this study was the weak acidic solution of chitosan. Chitosan has favourable biocompatibility, which has high viscosity in solution. The incorporation of chitosan could improve the handling properties of CPC. The liquid phase contained citric acid could strongly improve the hydration rate of CPC, which shortened the setting time and increased the compressive strength of CPC. In addition, the weak acidic environment around the biomaterials could accelerate the degradation of CPC, which was important to bone tissue engineering. The rationale was that large-diameter absorbable fibers would initially strengthen the CPC graft, then dissolve to form long cylindrical macropores for colonization by osteoblasts. Compressive strength was measured vs. fiber volume fraction from 0% (CPC Control without fibers) to 70%. Animal experiment showed that the material had osteoinductivity and biodegradability when the material was implanted into the muscle pouches in the thigh of rabbits. Compressive strength (mean ± SD; n=3) of CPC with 70% fibers was 0.8± 0.1 MPa. Long cylindrical macropores 100~300 μm in diameter were created in CPC after fiber dissolution, and the CPC-fiber scaffold reached a total porosity of 75.1±1.2% with 70% fibers. The new CPC-fiber formulation had good potentiality of ectopic bone induction. The method of using large-diameter absorbable fibers in bone graft for mechanical properties and formation of long cylindrical macropores for bone ingrowth may be applicable to other tissue engineering materials.

Properties of Polymeric Fiber-Reinforced Concrete

1996 ◽  
Vol 1532 (1) ◽  
pp. 27-35
Author(s):  
P. Balaguru ◽  
Anil Khajuria
Keyword(s):  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Strength ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Modulus Of Rupture ◽  
Unit Weight ◽  
Fiber Reinforced ◽  
Fiber Volume

The mechanical properties of lightweight and normal concrete containing nylon polymeric fibers are presented. Fiber reinforced concrete made with nylon fibers was evaluated. The 19-mm-long fibers were in single filament form. The control concrete was designed for a compressive strength of 20 MPa. The primary independent variable was fiber volume fraction. The response variables were air content, unit weight of fresh concrete, compressive strength, modulus of rupture (flexural strength) and toughness, splitting tensile strength, and impact strength. The addition of fibers decreased the slump values. The decrease was negligible at fiber contents of 0.45 and 0.6 kg/m3. The fibers distributed well in the matrix. Fibers could be directly added in the mixer. The effect fibers had on unit weight of concrete is negligible. Addition of fibers up to 2.4 kg/m3 did not change the compressive, flexural, and splitting tensile strengths appreciably. Impact strength and flexural toughness increased consistently with the increase of fiber volume fraction.

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