scholarly journals Influence of Cooling Methods on the Behavior of Reactive Powder Concrete Exposed to Fire Flame Effect

Fibers ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Hadeel K. Awad
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Splitting Tensile Strength ◽  
Reactive Powder Concrete ◽  
Absorbed Energy ◽  
Fire Flame ◽  
Reactive Powder ◽  
Cooling Methods

The construction of highly safe and durable buildings that can bear accident damage risks including fire, earthquake, impact, and more, can be considered to be the most important goal in civil engineering technology. An experimental investigation was prepared to study the influence of adding various percentages 0%, 1.0%, and 1.5% of micro steel fiber volume fraction (Vf) to reactive powder concrete (RPC)—whose properties are compressive strength, splitting tensile strength, flexural strength, and absorbed energy—after the exposure to fire flame of various burning temperatures 300, 400, and 500 °C using gradual-, foam-, and sudden-cooling methods. The outcomes of this research proved that the maximum reduction in mechanical properties is detected in case of 0% addition at burning temperature of 500 °C using sudden cooling to be 63.90%, 55.77% and 53.8% for compressive, splitting tensile, and flexural strength, respectively, while using 1.5% produced a modification in compressive strength, splitting tensile strength, and flexural strength to 6.67%, 4.15%, and 7.00% respectively, and 7.10 kN·mm for the absorbed energy for gradual cooling at 300 °C. From the results, the adopted cooling methods can be ordered according to their negative influence by sudden, foam, and gradual, while the optimum percentage of (Vf) is 1.5% when burning at 300 °C for all methods of cooling. 1.0% is considered the optimum percentage for all burning temperatures that exceed 400 °C using sudden-cooling method.

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.

scholarly journals Experimental Behaviour of Fiber Reinforced Reactive Powder Concrete

2019 ◽  
Vol 9 (1S3) ◽  
pp. 454-459 ◽  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Polypropylene Fiber ◽  
Chloride Diffusion ◽  
Sisal Fiber ◽  
Reactive Powder Concrete ◽  
Coir Fiber ◽  
Split Tensile Strength ◽  
Reactive Powder

In this paper various mix proportions of Reactive Powder Concretes were formulated using ordinary Portland cement, Fly ash, Micro silica, Silica Fume, Quartz powder etc and these concretes were subjected to strength test. The best mix was selected for further in depth study with fibers like Sisal fiber, Coir fiber, Hair fiber and Polypropylene fiber mixed Reactive Powder Concrete and the various tests have been performed Cube Compressive strength, Cylinder Compressive strength, Flexural strength, Split Tensile strength, Shear test, Water absorption, Sorptivity and Chloride diffusion etc. As a result, fiber incorporated concrete shows increasing Flexural strength, splitting tensile strength, and shear strength up to 30% as compared to control RPC and gives minimal decrease in compressive strength by the addition of fibers. These characteristics make it as a promising material for casting non structural elements such as pressure pipes, flooring tiles, Partition panels, door and window frames. It can also be used as repair materials.

scholarly journals Mechanical Properties of Mortar Using Polypropylene Fibers

2020 ◽  
pp. 1-4
Author(s):  
Eethar Thanon Dawood ◽  
◽  
Tamara Waleed Ghanim ◽  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Polypropylene Fiber ◽  
Splitting Tensile Strength ◽  
Experimental Results ◽  
Polypropylene Fibers ◽  
Low Volume

In the present paper the behavior of mortar reinforced with polypropylene fibers was studied. Different percentages of polypropylene fibers such as 0, 0.2, 0.4, 0.6 and 0.8% as volumetric fractions were used. Different properties which are flowability, density, compressive strength, flexural strength and splitting tensile strength were evaluated for all mix combinations. The experimental results indicated that a reduction in flowability was obtained with increased polypropylene fibers content. Besides, it can be concluded that the incorporation of polypropylene fiber may significantly reduce the density of mortar. The use of low volume fraction of polypropylene fiber improves the mechanical properties of HPM. Thus, the use of 0.2% of such fiber increases compressive strength by about (4-10%), at various ages.

scholarly journals Effect of Steel Fibers and Temperature on the Mechanical Properties of Reactive Powder Concrete

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud Ahmed Ali Abdelrahim ◽  
Aboelwafa Elthakeb ◽  
Usama Mohamed ◽  
Mohamed Taha Noaman
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elevated Temperatures ◽  
Fine Sand ◽  
Splitting Tensile Strength ◽  
Steel Fibers ◽  
Reactive Powder Concrete ◽  
Strain Relationship ◽  
Reactive Powder

Abstract Reactive Powder Concrete (RPC) is a concrete of the modern generation it mainly contains a high percentage of cement and a small percentage of water For cement as well as the presence of fine sand, ground quartz and silica dust. This research aims Studying the behavior and mechanical characteristics of RPC exposed to elevated temperatures. The key variables in this study are steel fibers content and the high temperatures of different levels 25, 200, 300, 400 ºC. Mechanical properties of concrete behavior including compressive strength, splitting tensile strength, stress-strain relationship (modulus of elasticity), and flexural strength. The test findings indicated that the Output strength of RPC specimens decreased when the high temperature increases. At a temperature of 400 °C, all samples lost the compressive strength and splitting tensile strength.

Strength Development of Concrete Incorporating Metakaolin and PVA Fibres

2014 ◽  
Vol 567 ◽  
pp. 505-510 ◽  
Author(s):  
Sadaqat Ullah Khan ◽  
Muhd Fadhil Nuruddin ◽  
Nasir Shafiq
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Aspect Ratio ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Splitting Tensile Strength ◽  
Strength Development ◽  
Increasing Trend ◽  
Better Than

Study has been conducted to investigate the effect of aspect ratio and volume fraction of PVA fibres on the mechanical properties of concrete. Total eighteen (18) mixes of concrete have been examined using metakaolin up to 5% and PVA fibres of aspect ratio 45, 60, 90 and 120 with volume fraction 1 to 2%. Compressive strength, splitting tensile strength and flexural strength at 7 days and 28 days have been determined to check the effect of volume fraction and the aspect ratio of PVA fibres. It has been found that 2% volume fraction is better than 1% and there is increasing trend up to a certain value of aspect ratio in the strengths of concrete.

GLASS FIBER POLYMER ON THE FRESH AND HARDENED PROPERTIES OF CONCRETE

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed Jobaer Uddin ◽  
Ariful Hasnat ◽  
Mohammad S Islam ◽  
Syed F Ahmad
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Glass Fiber ◽  
Volume Fraction ◽  
Splitting Tensile Strength ◽  
Fiber Reinforced Concrete ◽  
Glass Fiber Reinforced ◽  
Fiber Fractions ◽  
Hardened Properties

The study describes an experimental study into the relationship among incorporation of Glass Fiber on the fresh and hardened properties of concrete. The effect of fiber fractions on the slump, compressive strength, splitting tensile strength and flexural strength of Glass Fiber Reinforced Concrete (GFRC) were investigated for volume fraction (VF) of 0%, 1%, 2% and 4%. In order to serve the purpose, concrete cylindrical and prism specimens were made with various rates of fiber-glass polymer. The cylinder specimens were tested at 7 and 28 days for compressive strength and at 28 days for splitting tensile strength, whereas the prism specimens were tested at 28 days for flexural strength. The experimental test results show that the additions of glass fiber polymer to concrete decrease slump, but increase compressive strength, splitting tensile strength and flexural strength. In addition, an analytical model has been proposed to predict slump of fresh concrete.

Effect of using magnetic water on the mechanical properties of concrete exposed to elevated temperature

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wasim Barham ◽  
Ammar AL-Maabreh ◽  
Omar Latayfeh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elevated Temperature ◽  
Flexural Strength ◽  
Tap Water ◽  
Splitting Tensile Strength ◽  
Content Type ◽  
Normal Water ◽  
Magnetic Water

PurposeThe influence of using magnetic water instead of tap water in the mechanical properties of the concrete exposed to elevated temperatures was investigated. Two concrete mixes were used and cast with the same ingredients. Tap water was used in the first mix and magnetic water was used in the second mix. A total of 48 specimens were cast and divided as follows: 16 cylinders for the concrete compressive strength test (8 samples for each mix), 16 cylinders for the splitting tensile strength (8 specimens for each mix) and 16 beams to test the influences of magnetized water on the flexural strength of concrete (8 specimens for each mixture). Specimens were exposed to temperatures of (25 °C, 200 °C, 400 °C and 600 °C). The experimental results showed that magnetic water highly affected the mechanical properties of concrete. Specimens cast and curried out with magnetic water show higher compressive strength, splitting tensile strength and flexural strength compared to normal water specimens at all temperatures. The relative strength range between the two types of water used was 110–123% for compressive strength and 110–133% for splitting strength. For the center point loading test, the relative flexural strength range was 118–140%. The use of magnetic water in mixing concrete contribute to a more complete hydration process.Design/methodology/approachExperimental study was carried out on two concrete mixes to investigate the effect of magnetic water. Mix#1 used normal water as the mixing water, and Mix#2 used magnetic water instead of normal water. After 28 days, all the samples were taken out of the tank and left to dry for seven days, then they were divided into different groups. Each group was exposed to a different temperature where it was placed in a large oven for two hours. Three different tests were carried out on the samples, these tests were concrete compressive strength, flexural strength and splitting tensile strength.FindingsExposure of concrete to high temperatures had a significant influence on concrete mechanical properties. Specimens prepared using magnetic water showed higher compressive strength at all temperature levels. The use of magnetic water in casting and curing concrete can increase the compressive strength by 23%. Specimens prepared using magnetic water show higher splitting tensile strength at all temperatures up to 33%. The use of magnetic water in casting and curing can strengthen and increase concrete resistance to high temperatures, a significant enhancement in flexural strength at all temperatures was found with a value up to 40%.Originality/valuePrevious research proved the advantages of using magnetic water for improving the mechanical properties of concrete under normal conditions. The potential of using magnetic water in the concrete industry in the future requires conducting extensive research to study the behavior of magnetized concrete under severe conditions to which concrete structures may be subjected to. These days, there are attempts to obtain stronger concrete with high resistance to harsh environmental conditions without adding new costly ingredients to its main mixture. No research has been carried out to investigate the effect of magnetic water on the mechanical properties of concrete exposed to elevated temperature. The main objective of this study is to evaluate the effect of using magnetic water on the mechanical properties of hardened concrete subjected to elevated temperature.

scholarly journals The Mechanical Properties of Steel-Polypropylene Fibre Composites Concrete (HyFRCC)

2015 ◽  
Vol 773-774 ◽  
pp. 949-953 ◽  
Author(s):  
Izni Syahrizal Ibrahim ◽  
Wan Amizah Wan Jusoh ◽  
Abdul Rahman Mohd Sam ◽  
Nur Ain Mustapa ◽  
Sk Muiz Sk Abdul Razak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Volume Fraction ◽  
Concrete Strength ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Polypropylene Fibre ◽  
Experimental Results

This paper discusses the experimental results on the mechanical properties of hybrid fibre reinforced composite concrete (HyFRCC) containing different proportions of steel fibre (SF) and polypropylene fibre (PPF). The mechanical properties include compressive strength, tensile strength, and flexural strength. SF is known to enhance the flexural and tensile strengths, and at the same time is able to resist the formation of macro cracking. Meanwhile, PPF contributes to the tensile strain capacity and compressive strength, and also delay the formation of micro cracks. Hooked-end deformed type SF fibre with 60 mm length and fibrillated virgin type PPF fibre with 19 mm length are used in this study. Meanwhile, the concrete strength is maintained for grade C30. The percentage proportion of SF-PPF fibres are varied in the range of 100-0%, 75-25%, 50-50%, 25-75% and 0-100% of which the total fibre volume fraction (Vf) is fixed at 0.5%. The experimental results reveal that the percentage proportion of SF-PPF fibres with 75-25% produced the maximum performance of flexural strength, tensile strength and flexural toughness. Meanwhile, the percentage proportion of SF-PPF fibres with 100-0% contributes to the improvement of the compressive strength compared to that of plain concrete.

scholarly journals Influence of Partial Replacement of Micro-Silica by Fly-Ash on Strength Properties of Reactive Powder Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 2932-2937
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Partial Replacement ◽  
Reactive Powder Concrete ◽  
Experimental Investigations ◽  
Reactive Powder ◽  
Micro Silica

Reactive powder concrete (RPC) is the ultra-high strength concrete made by cementitious materials like silica fumes, cement etc. The coarse aggregates are completely replaced by quartz sand. Steel fibers which are optional are added to enhance the ductility. Market survey has shown that micro-silica is not so easily available and relatively costly. Therefore an attempt is made to experimentally investigate the reduction of micro-silica content by replacing it with fly-ash and mechanical properties of modified RPC are investigated. Experimental investigations show that compressive strength decreases gradually with addition of the fly ash. With 10 per cent replacement of micro silica, the flexural and tensile strength showed 40 and 46 per cent increase in the respective strength, though the decrease in the compressive strength was observed to be about 20 per cent. For further percentage of replacement, there was substantial drop in compressive, flexural as well as tensile strength. The experimental results thereby indicates that utilisation of fly-ash as a partial replacement to micro silica up to 10 per cent in RPC is feasible and shows quite acceptable mechanical performance with the advantage of utilisation of fly-ash in replacement of micro-silica.

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