scholarly journals Reactive Powder Concrete Mix Ratio and Steel Fiber Content Optimization under Different Curing Conditions

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3615 ◽  
Author(s):  
Yunlong Zhang ◽  
Bin Wu ◽  
Jing Wang ◽  
Mo Liu ◽  
Xu Zhang
Keyword(s):  
Tensile Strength ◽  
Steel Fiber ◽  
Orthogonal Experiment ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Mixture Ratio ◽  
Curing Conditions ◽  
Compressive Performance ◽  
Binder Ratio ◽  
Reactive Powder

In this paper, a practical reactive powder concrete mixture ratio is created on the basis of an orthogonal experiment. Previous studies have combined the compressive and splitting tensile strengths of four categories of reactive powder concrete (RPC) for major materials. These categories include water/binder ratio, silica fume volume content, sand/binder ratio, and dosage of fly ash volume. The optimal mixing proportion of each factor was determined by analyzing the compressive strength of the RPC matrix. For this purpose, steel fiber was used as a reinforcing agent. The compressive and splitting tensile strength test results of steel fiber RPC were analyzed by comparing compound, standard, and natural curing. This was conducted to explore the improvement effect of different steel fiber contents on compressive performance, especially tensile strength of the RPC matrix. According to the results, the optimal steel fiber content was found to be 4% under the three curing conditions. The effect of compound curing on early strength was found to be greater in RPC than by natural or standard curing. However, the effect of late improvement is not obvious. Although standard curing is slightly stronger than natural curing, the performance under the latter can still meet engineering requirements.

scholarly journals Study on Mix Proportion Optimization of Manufactured Sand RPC and Design Method of Steel Fiber Content under Different Curing Methods

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1845 ◽  
Author(s):  
Chunling Zhong ◽  
Mo Liu ◽  
Yunlong Zhang ◽  
Jing Wang
Keyword(s):  
Steel Fiber ◽  
Design Method ◽  
Fiber Content ◽  
Orthogonal Experimental Design ◽  
Curing Conditions ◽  
Practical Applications ◽  
Manufactured Sand ◽  
Binder Ratio ◽  
Curing Methods ◽  
Reactive Powder

This study investigated four factors (water/binder ratio, silica fume, fly ash, and sand/binder ratio) using the orthogonal experimental design method to prepare the mix proportions of a manufactured sand reactive powder concrete (RPC) matrix to determine the optimal matrix mix proportions. On this basis, we assessed the compressive and splitting tensile strengths of different steel fiber contents under natural, standard, and compound curing conditions to develop an economical and reasonable RPC for various engineering requirements. A calculation method for the RPC strength of the steel fiber contents was evaluated. The results showed that the optimum steel fiber content for manufactured sand RPC is 4% under natural, standard, and compound curing conditions. Compared with standard curing, compound curing can improve the early strength of manufactured sand RPC but only has a small effect on the enhancement of late strength. Although the strength of natural curing is slightly lower than that of standard curing, it basically meets project requirements and is beneficial for practical applications. The calculation formula of 28-day compressive and splitting tensile strengths of manufactured sand RPC steel fiber at 0%–4% is proposed to meet the different engineering requirements and the flexible selection of steel fiber content.

Tensile Properties of Steel Fiber-Reinforced Reactive Powder Concrete after High Temperature

2011 ◽  
Vol 413 ◽  
pp. 270-276 ◽  
Author(s):  
Wen Zhong Zheng ◽  
Hai Yan Li ◽  
Ying Wang ◽  
Heng Yan Xie
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Steel Fiber ◽  
Heating Temperature ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Fiber Reinforced ◽  
Critical Temperatures ◽  
Reactive Powder ◽  
The Relationship

87 prismatic flexural steel fiber-reinforced reactive powder concrete (RPC) specimens with the size of 40mm×40mm×160mm were tested as well as 87 dumbbell-shaped axis tensile RPC specimens after being exposed to different high temperatures. The effect of steel fiber content and heating temperature on the flexural and tensile strength of steel fiber-reinforced RPC was analyzed. With the steel fiber content increasing, the flexural and tensile strength of steel fiber-reinforced RPC after high temperature improve significantly, and they increase first and then decrease with the heating temperature elevated, and the critical temperatures are 200¡æ and 120¡æ, respectively. Equations are established to express the relationship between the flexural and tensile strength of steel fiber-reinforced RPC and the heating temperature. The theoretical curves are in good agreement with the test data.

scholarly journals A Study on Optimum Mixture Ratio of Reactive Powder Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Mingyang Chen ◽  
Wenzhong Zheng
Keyword(s):  
Compressive Strength ◽  
Steel Fiber ◽  
Raw Materials ◽  
Reactive Powder Concrete ◽  
Mixture Ratio ◽  
Curing Methods ◽  
Main Components ◽  
Cement Strength ◽  
Reactive Powder ◽  
Design Factors

To optimize the main components of reactive powder concrete (RPC) for various curing methods, based on the fluidity and compressive strength, an inclusive experimental research is conducted on 58 different mixture ratios. The results indicate that owing to the increase of the cement strength, the RPC fluidity decreases and the cement strength is not proportional to the compressive strength. The addition of the fly ash and the nano-microbead is an effective way to improve the fluidity, and it is required at the low W/B ratio. However, the influence of the SF grade on the strength and fluidity is almost negligible. By considering the fluidity, strength, and economy of RPC as crucial design factors, SF90 is suggested. The contribution of the steel fiber to the compressive strength cannot be ignored. The upper envelope value of the steel fibers is required for the structure to resist appropriately against the fire. According to the test results, the mixture ratio formula is proposed through considering the characters of different compositions and curing methods. The strength coefficient k1 is introduced to verify the influence of the steel fiber content, and the parameters fb, αa, and αb in the formula are reevaluated. A reasonably good agreement between the calculated strength and those obtained from the tests is reported, except for the case of W/B = 0.16 with P.O.52.5 cement. The basic steps for preparations of different RPC strengths are given, which provide a valuable reference to choose appropriate raw materials and mixture ratio design for different strength values.

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.

Study of RPC Mechanical Properties and Anti-Freeze-Thaw Resistance

2010 ◽  
Vol 168-170 ◽  
pp. 1742-1748
Author(s):  
Yan Zhong Ju ◽  
Feng Wang ◽  
De Hong Wang
Keyword(s):  
Mechanical Properties ◽  
Silica Fume ◽  
Steel Fiber ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Freeze Thaw ◽  
Early Strength ◽  
Reactive Powder

To study the mechanical properties of RPC performance and freeze-thaw resistance，through the experimental study discussed the water-cement ratio, silica fume cement ratio, steel fiber content, curing system and other factors on the mechanical properties of reactive powder concrete and anti-freezing properties. Research indicates that many factors in the RPC, the water cement ratio is the most important factor, followed by the silica fume cement ratio, finally the steel fiber content, and curing system for the growth of its early strength also have a greater role.

scholarly journals Study on Mechanical Properties of Hybrid Polypropylene-Steel Fiber RPC and Computational Method of Fiber Content

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2243
Author(s):  
Chunling Zhong ◽  
Mo Liu ◽  
Yunlong Zhang ◽  
Jing Wang ◽  
Dong Liang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Steel Fiber ◽  
Polypropylene Fiber ◽  
Area Ratio ◽  
Fiber Content ◽  
Splitting Tensile Strength ◽  
Optimum Content ◽  
Pore Area ◽  
Reactive Powder

On the basis of determining the optimum content of polypropylene fiber reactive powder concrete (RPC), the influence of different steel fiber content on the compressive strength and splitting tensile strength of hybrid polypropylene-steel fiber RPC was studied. The particle morphology and pore parameters of hybrid polypropylene-steel fiber RPC were analyzed by combining scanning electron microscope (SEM) with image-pro plus (IPP) software. The results showed that the RPC ductility can be further improved on the basis of polypropylene fiber RPC, the compressive strength and splitting tensile strength of polypropylene fiber. The optimum content of hybrid polypropylene-steel fiber RPC is 0.15% polypropylene fiber, 1.75% steel fiber. Hybrid polypropylene-steel fiber RPC is mainly composed of particles with small particle size. The particle area ratio first increased and decreased with the increase of steel fiber content, and the maximum steel fiber content is 1.75%. The pore area ratio first decreased and increased with the increase of steel fiber content, and the pore area ratio is the smallest when the steel fiber content is 1.75%. The calculation methods of polypropylene fiber content and steel fiber content and 28-day RPC compressive strength and splitting tensile strength are proposed to select polypropylene fiber content and steel fiber content flexibly according to different engineering requirements, which can provide important guidance for the popularization and application of RPC in practical engineering.

scholarly journals Direct Shear Strength of RPC Member

2021 ◽  
Vol 39 (1A) ◽  
pp. 22-33
Author(s):  
Shahad Q. Madhlom ◽  
Hussein A. Aziz ◽  
Ammar A. Ali
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Steel Fiber ◽  
Shear Loading ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Direct Shear ◽  
Steel Rebar ◽  
Transverse Steel ◽  
Reactive Powder

In this research paper, results are obtained from Reactive Powder Concrete (RPC) push-off specimens - double L shape subjected to direct shear loading. Different parameters considered are compressive strength, percentages of steel fiber, presence of aggregate and shear reinforcement. The results show that increasing in steel fiber content starting from 0.0% and ending with 1.5% leads to increases in the shear strength by (261%) and attempt to decrease its brittleness. The presence of steel fiber content enhances and improves the tensile strength and  the shear strength. Using RPC in constructing the specimens enhances the shear strength by 29.6% compared with NSC specimen. Shear strength increased by 25% when the compressive strength increased from 75 to 90MPa. The presence of transverse steel rebar in the direction of shear line increased the shear strength by (108.3%) as compare with the specimen without shear rebar. The presence of small aggregate in RPC mix creates an increase in the shear strength by (9.1%).

Experimental Investigation on Stress-Strain Curves of Reactive Powder Concrete under Uniaxial Compression

2011 ◽  
Vol 261-263 ◽  
pp. 192-196 ◽  
Author(s):  
Yan Zhong Ju ◽  
De Hong Wang ◽  
Fei Jiang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Uniaxial Compression ◽  
Steel Fiber ◽  
Strain Curve ◽  
Fiber Content ◽  
Reactive Powder Concrete ◽  
Stress Strain ◽  
Reactive Powder

Based on experiments of uniaxial compression and flexural experiments, the basic mechanical properties (compressive strength and flexural strength) of reactive powder concrete (RPC) were investigated, the effect of the steel fiber content on mechanical properties of RPC was studied in this work. The resu1ts indicate that the axial compressive strength of RPC had no obvious change with the change of steel fiber content. When the steel fiber content varied from 1.0% to 2.0%, the flexural strength of RPC had no obvious change.When the steel fiber content varied from 2.0% to 5.0%, the flexural strength of RPC increased dramaticlly with the increase of steel fibers content. According to experiment curves, an equation for the compressive stress-strain curve of RPC was deduced with different stee1 fiber content.

The Effect on Dynamic Properties of Reactive Powder Concrete under High Temperature Burnt and its Micro-Structure Analysis

2010 ◽  
Vol 452-453 ◽  
pp. 109-112 ◽  
Author(s):  
Bao Jun Pang ◽  
L.W. Wang ◽  
Z.Q. Yang ◽  
Run Qiang Chi
Keyword(s):  
High Temperature ◽  
Steel Fiber ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Reactive Powder Concrete ◽  
Micro Structure ◽  
Essential Change ◽  
Binder Ratio ◽  
Reactive Powder ◽  
Water Binder Ratio

In this paper, the dynamic macroscopical properties of reactive powder concrete (RPC) are studied by using the split Hopkinson pressure bar (SHPB) system. The effect on dynamic properties of RPC material with different water binder ratio (W/B) and steel fiber influence under high temperature burnt is discussed. And scanning electron microscope (SEM) technology is also used to investigate the micro-structure change under high temperature burnt. The experiment result shows: without high temperature burnt, the higher water binder ratio, the lower dynamic compression strength of RPC material. With high temperature burnt, strength decreases exquisite. However, steel fiber can prevent micro-crack from generating, the toughness effect still alive after high temperature burnt. From SEM analysis: the inner part of RPC will have a series of physical chemistry changing, such as: micro-crack generation, C-S-H gel damage. This essential change is the basic reason for dynamic properties degrade.

scholarly journals Effect of Fly Ash on Some Properties of Reactive Powder Concrete

2021 ◽  
Vol 27 (11) ◽  
pp. 32-46
Author(s):  
Zahraa F Muhsin ◽  
Nada Mahdi Fawzi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Industrial Wastes ◽  
Experimental Program ◽  
Reactive Powder Concrete ◽  
Binder Ratio ◽  
Reactive Powder ◽  
Water To Binder Ratio

To achieve sustainability in the field of civil engineering, there has become a great interest in developing reactive powder concrete RPC through the use of environmentally friendly materials to reduce the release of CO2 gas produced from cement factories as well as contribute to the recycling of industrial wastes that have a great impact on environmental pollution. In this study, reactive powder concrete was prepared using total binder content of 800 kg/m3, water to binder ratio (0.275), and micro steel fibers  1% by volume of concrete. The experimental program included replacing fly ash with (8, 12, 16) % by cement weight to find the optimal ratio, which achieved the best mechanical properties of (RPC) at 7, 28, and 90 days with standard curing. Some mechanical properties of reactive powder concrete (flow, compressive strength, tensile strength, and density) were verified. The results at 28 days showed that the compressive strength (96.5) Mpa, tensile strength (9.38) Mpa, and density (2395 kg/m3). The results showed that the percentage of replacement of 8% of fly ash with cement is the optimal percentage, which achieved the highest resistance compared to the others. The results also indicated that it is possible to develop RPC using fly ash with a high withstand stress, tensile strength, and density.

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