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Article

The Influence of Aspect Ratio of Steel Fibers on the Conductive and Mechanical Properties of Compound Cement Reactive Powder Concrete

by
Zhao Liang
1,2,
Xi Peng
2,3,* and
Hui Wang
1,*
1
School of Civil Engineering and Geographical Environment, Ningbo University, Ningbo 315000, China
2
School of Civil Transportation Engineering, Ningbo University of Technology, Ningbo 315000, China
3
Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang, Ningbo University of Technology, Ningbo 315000, China
*
Authors to whom correspondence should be addressed.
Coatings 2023, 13(2), 331; https://doi.org/10.3390/coatings13020331
Submission received: 5 January 2023 / Revised: 27 January 2023 / Accepted: 29 January 2023 / Published: 1 February 2023
(This article belongs to the Special Issue Surface Treatment and Mechanical Properties of Sustainable Pavement Materials)
Browse Figures
Versions Notes

Abstract

:
The performance of steel fibers reinforced RPC has a great relationship with the aspect ratio of the fibers. It is necessary to systematically study the relationship between the aspect ratio and the mechanical properties of RPC and the force-electricity response. In this paper, the flexural strength, the compressive strength and the flexural toughness and AC electrical resistance and AC impedance spectroscopy of reactive powder concrete are investigated. The flexural strength, compressive strength, and flexural toughness with the curing age of 1 day and 28 days are tested. The cement is the compound cement in this study, and the mass ratio of ordinary portland cement and sulphoaluminate cement is 1:1, and two kinds of steel fibers with aspect ratios of 30(AR-30) and 75(AR-75) are used. The fiber content is 2% of the concrete volume. Scanning electron microscope (SEM) and scanning electron microscope energy spectrum analysis (EDS) are investigated to analyze the composition of the hydration products. It can be obtained from the research results that the flexural strength and the compressive strength of reactive powder concrete decrease with the increase of steel fibers content with an aspect ratio of 30. The decreasing rates of the flexural strength and the compressive strength with the curing age of 1 d and 28 d are 14.93%~83.26% and 0.40%~46.36% with the incorporation of steel fibers with an aspect ratio of 30. The flexural toughness decreases in the form of a quadratic function with the mass ratio of steel fibers with an aspect ratio of 30. The electrical resistance of reactive powder concrete increases with the increase of steel fibers with an aspect ratio of 30. The maximum decreasing rate of electrical conductivity is 91.16%. The AC impedance spectrum is obtained, and the electric circuit of reactive powder concrete accords with the series conduction model, which parallel electrical resistance and capacitance of pore solution, rapid strength RPC and steel fibers respectively connect with a contact resistance of the electrode and specimens. It is found that the steel fibers network with an aspect ratio of 75 is closer by studying the equivalent circuit diagram.

1. Introduction

Ordinary portland cement (OPC) has a history of nearly 200 years since it is manufactured. The invention of OPC has brought significant changes to the building materials industry. The performance of the concrete has also been greatly improved by the changes in the type, amount of cement, and admixtures. With the rapid repairing of damaged structures in engineering, special requirements for early strength, and rapid setting of cement are required, and OPC can not meet the requirements in terms of technology and performance [1].
Coastal cities are economically developed. At the same time, trade requires a lot of transportation. The bridge is an important part of transportation. However, due to the erosion of the sea-crossing bridge in the marine environment and traffic loading [2], the pavement of the bridge is more prone to cracking, and the scene of repairing the damaged bridge will not have too much time to close. For example, Beijing Xizhimen Interchange has a large number of cracks due to chloride erosion and the freeze-thaw cycle. Many port projects in some coastal countries will appear cracking and peeling in a short period of time. The decks of 9700 bridges in Wisconsin, USA, were damaged due to chloride corrosion [3]. The damaged roads should be repaired in time [4,5,6]. Furthermore, the repairing materials of the bridge deck should have good corrosion resistance.
The electric conductivity of concrete has been used for intelligent detection and evaluation of hydration and mechanical properties [7,8]. Wang’s article points out that using electrical properties to characterize mechanical properties is an effective method for the nondestructive evaluation of concrete mechanical properties [9]. This nondestructive evaluation method has been applied to bridges such as Qinglong Bridge in Ningbo City, Zhejiang Province [10].
Sulfoaluminate cement (SAC) has been used for repairing roads and bridges due to its fast-hardening characteristics in recent years [11,12]. Feng’s article points out that SAC mortar reinforced with ultra-fine steel fibers displays a maximum compressive strength (fcu) of 19 MPa and flexural strength (ft) of 5.3 MPa after curing for 3 h. SAC has excellent impermeability and corrosion resistance [13]. However, SAC has a high cost and the phenomenon of late strength recession.
Reactive powder concrete (RPC) is a special cement concrete material with ultra-high strength, high toughness, and durability [14,15]. Moreover, as described in Hui’s research that RPC with the silica fume and fly ash demonstrates fcu of 124.2 MPa and ft of 19.2 MPa. Additionally, after standard curing, the fcu and ft of steel fibers reinforced RPC can reach 130 MPa and 52.9 MPa. The autogenous shrinkage rate decreases by 29.9% [16,17].
The compound cement has more advantages than single cement [18,19]. Scholars have optimized the deficiency of single cement by compositing SAC and OPC. Hong’s article points out that the initial setting time and final setting time after the combination of SAC and OPC are 30 min and 55 min respectively. The fcu and ft of 5 h are 34.8 MPa and 3.7 MPa. The strength decline in the later stage will also be improved [20].
The addition of fibers has a significant influence on mechanical performance and durability [21,22,23]. Several types of research about the fibers reinforced cement concrete have been reported. Scholars have reported that steel fibers, plant fibers, and polypropylene fibers are effective to improve the mechanical strength of RPC [24,25]. Plant fibers and polypropylene fibers have excellent corrosion resistance and cracking resistance. However, they are difficult to disperse in cement-based materials [26,27,28,29]. Meanwhile, the effect of plant fibers and polypropylene fibers on the mechanical strength and toughness of RPC is not obvious. The steel fibers have been proven to improve the mechanical strength of RPC [30]. As reported in some research, the increasing rates of the splitting tensile strength, ft, and tension compression ratio by steel fibers are 74%, 119%, and 75% respectively [31,32]. The dispersion and aspect ratio of steel fibers will have a considerable impact on the performance of RPC. At present, few people have carried out systematic research on the area of the dispersion and aspect ratio of steel fibers.
In this experiment, the mechanical properties (ft, fcu, and the flexural toughness (α)) and the electrical properties (AC electrical resistance (Re) and AC impedance spectrum) of reactive powder concrete with 2% fibers content of steel fibers with different ratio of the aspect ratios of 30 and 75 are determined. In addition, the mechanical properties of RPC with different aspect ratio fibers are characterized by electrical properties. Scanning electron microscope (SEM) and scanning electron microscope energy spectrum analysis (EDS) are investigated to reveal the mechanism of the macro performances. This paper will provide a reference for rapid repairing materials for bridge decks by adjusting the aspect ratio of steel fibers in the future.

2. Experimental

2.1. Raw Materials

Rapid hardening SAC and OPC with strength grades of 42.5 MPa are employed in the research. The initial setting time and final setting time of SAC are 20 min and 205 min (GBT1346-2011). OPC and SAC are produced by Anhui Conch Group Co., Ltd. (Wuhu, China) The specific surface area of SAC is 365 m2/g. Silica fume (SF) with a specific surface area and density of 15 m2/g and 2.2 g/cm3 is used for this research. SF is produced by Shanggao Mingzheng Plastic Co., Ltd. The density and specific surface area of granulated blast furnace slag powder (GGBS) are 2.9 g/cm3 and 436 m2/g respectively. GGBS is provided by Lingshou Qiangdong Mineral Products Processing Plant. Table 1 and Table 2 show the particle size distribution and chemical composition of the cementitious materials. Aggregate is the quartz sand produced by Ling Shou County Yongshun Fruit Products Processing Co., Ltd., LingShou, China. The particle sizes are 0.99~0.72 mm, 0.60~0.34 mm, and 0.14~0.299 mm. And the mass ratio of sand is 1:1.5:0.8. The copper-plated steel fibers produced by Chongqing Yingzhi Building Materials Co., Ltd., Jiulongpo District, China are used in the experiment. The average length and diameter of steel fibers with an aspect ratio of 75(AR-75) are 1.5 cm and 0.2 mm. The average length and diameter of steel fibers with an aspect ratio of 30(AR-30) are 1.5 cm and 0.5 mm. The tensile strength and the nonbreaking rate at one bending of 90° of steel fibers with AR-30 and AR-75 are 3000 MPa and 98%, respectively. The density and the resistivity of steel fibers are 7.85 g/cm3 and 9.78 × 10−8 Ω·m. The polycarboxylate-based (SP) that has a water-reducing rate of 40% provided by Shenteng Co., Ltd., Lingshou, China is used as a water-reducing agent. Li2SO4, tartaric acid, and polyether defoamer (The purity of these drugs is 99%) are regarded as early-strength agent, retarder and defoamer in this research. The densities of Li2SO4, tartaric acid, and polyether defoamer are 2.06 g/cm3, 1.90 g/cm3, and 1.00 g/cm3, respectively. The mixing proportion of specimens is shown in Table 3. “C-RPC” represents the composite reactive powder concrete group.

2.2. Specimen Preparation

All weighed raw materials are poured into a stirring UJZ-15 mortar stirring pot, stirring in the mixture for 480 s. The specimens are prepared according to GB/T 50081-2019. The preparation of the specimens can be divided into the following steps.
First of all, the dry materials are stirred in the UJZ-15 for 30 s. The materials are mixed in a mixture of water-reducing agents and water. Mixing materials are continuously stirred in the UJZ-15 for 480 s.
After the materials are stirred, the mixed concrete is poured into the oiled plastic molds obtaining the specimens with sizes 40 mm × 40 mm × 160 mm and 50 mm × 50 mm × 50 mm. These two sizes of specimens are used for measurements of mechanical and electrical properties. The numbers of specimens for measurement of mechanical and electrical parameters are 3 and 6, respectively. The difference between the data and the average value exceeds ±10% of the average value, which is regarded as unreasonable data (GB/T17671-1999). The average values after removing the unreasonable data are treated as the testing values. All specimens are cured at a temperature of 20 ± 2 °C and a relative humidity above 95% (GB50204-2015) after demolding.

2.3. Measurement Method

2.3.1. The Experiments of Mechanical Strengths

fcu and ft of specimens are tested by the YAW-300 automatic pressure testing machine with the hydraulic pump rated pressure of 25 kN provided by Jinan Rutong Testing Technology Factory. The control pattern is force control, and the 2400 N/s and 60 N/s are used for compressive and flexural tests. The specific operation process refers to GB/T 17671-1999 Chinese standard [33]. Figure 1 shows the photos of the compressive and flexural tests.

2.3.2. The Experiments of Flexural Toughness

CMT5205 microcomputer-controlled electronic universal testing machine is employed to measure α. The specimens with a size of 40 mm × 40 mm × 160 mm are used for the measurement of α. Linearly varying displacement transducer (LVDT) produced by Zhengzhou Muchen Automation Technology Co., Ltd., Zhengzhou, China is applied to measuring the mid-span displacement. The loading speed is 0.5 mm/min in the experiment as shown in Figure 2 (The force exerted by the press is expressed in “F”. The bottom edge width and thickness of the sample are expressed in “b” and “h” respectively). The detailed measurement steps can be followed in Wang’s paper [34]. In the force-displacement curve, the integral value from 0 to the highest of the force is used as α. Figure 2 is the schematic diagram for measuring α.

2.3.3. The Experiments of Electrical Properties

TH2810D LCR digital electric bridge with a testing standard frequency of 100 Hz, 120 Hz, 1 kHz, and 10 kHz provided by Changzhou Tonghui Factory is used for measuring AC Re. Additionally testing voltage and frequency of TH2810D are 1 V and 10 kHz, respectively. The specific connection and method refer to Wang’s article [34]. For the reason that the AC Re measurement of concrete can minimize Re instability caused by polarization, in this study, so the two electrodes are applied in the measurement of Re.
Parstat3000 electrochemical workstation with a testing frequency of 1~105 Hz provided by Shanghai Princeton Instrument Co., Ltd., Shanghai, China is used for recording the AC impedance spectrum. Figure 3 is the schematic diagram of the connection between the specimen and TH2810D LCR digital electric bridge and Parstat3000 electrochemical workstation respectively.

2.3.4. The Experiments of Micro Analysis

The following is the procedure of SEM and EDS.
After the samples are cured, the samples are soaked in absolute ethanol for 5 days to prevent cement hydration. YZF-6050 vacuum drying oven with an output power of 1200 W (Shanghai yaoshi Co., Ltd., Shanghai, China) is used to dry the samples at 105 °C for 2 days. Then, the bean-sized and pebble-free particles are removed from the oven-dried samples. The collected particles are pasted on the aluminum plate with conductive tape. The particle surfaces are sputtered with a layer of gold film in a vacuum environment. The prepared samples are used for measuring SEM and EDS. The analysis method of the hydration products analyzed by results of SEM and EDS is based on Wang’s article [9].

3. Results and Discussions

3.1. Mechanical Performance Analysis

Figure 4 shows fcu and ft of specimens with different steel fiber content with AR-30. It can be found that the mechanical performance decreases with the increase of steel fibers with AR-30 (The maximum rate of decline is 80%). Meanwhile, the decline in fcu with the curing age of 28 d is more obvious than fcu with the curing age of 1 d. However, the decline in ft with the curing age of 28 d is lower than ft with the curing age of 1 d. The dramatic declines in fcu with the curing age of 28 d and ft with the curing age of 1 d are observed with the ratio of the steel fibers with AR-30 from 50% to 75%. When the total amount of fibers remains unchanged, the increase of steel fibers content with AR-30 will reduce the number of fibers. Thus affecting the bridging effect of fibers in RPC. In addition, steel fibers with AR-30 tend to sink to the bottom, resulting in uneven dispersion of fibers [35]. The degree of hydration of the specimen is low after curing for 1 day, and ft is mainly provided by steel fibers. Therefore, ft decreases with the increase of steel fibers content with AR-30.

3.2. Flexural Toughness Analysis

Figure 5 and Figure 6 show the flexural stress (Pt) and mid-span deflection (wm) of specimens. It can be found from Figure 5 and Figure 6, wm decreases with the ratio of steel fibers with AR-30 from 0% to 100%. At the same time, the maximum Pt decreases. Figure 7 and Figure 8 show the fitting curves of Pt, wm, and the fitting results of Pt and wm curves. The curves of Pt and wm with the curing age of 1 d extremely fit a quadratic parabola. α in Figure 9 is calculated. It can be found from Figure 9, α decreases with the increase of steel fibers with AR-30. Meanwhile, a dramatic decrease in α is observed with the ratio of steel fibers with AR-30 from 0% to 25%. However, the decreasing rate decreases with the increase of steel fibers with AR-30, which can be attributed to the fact that the decrease of α will slow down when the ratio of steel fibers with AR-30 reaches a value. Furthermore, the number of steel fibers with AR-75 will be more at the same ratio, which is more uniformly distributed in the RPC. The fibers are more tightly embedded in the concrete, resulting in improving α of RPC [36]. Additionally, ft with a curing age of 28 d is higher than ft with a curing age of 1 d, indicating the accuracy of experimental data.

3.3. Electrical Performance Analysis

Figure 10 shows Re, the increasing rate, and the ratio of steel fibers with AR-30. The steel fibers with AR-30 induce the ascending in Re. However, the increase of R seems to be irregular. Re of specimens with the curing age of 1 d and 28 d are measured reaching the maximum value at 25% and 75%, respectively. The increase of steel fibers with AR-30 will reduce the tightness of the electric grid composed of fibers in RPC. However, the gaps increase with the increase of steel fibers with AR-30. The free ions in the specimens produce electrophoresis during electrification, and the electrophoresis phenomenon leads to the enhancement of the electric conductivity of the specimens, leading to the instability of Re.
Figure 11 shows the electrical resistance of specimens with different content of steel fibers with AR-30. As shown in Figure 11, the electrical resistance of pore solution (Rp) decreases with the increase of steel fibers with AR-30, and its decrease is gradual. The steel fibers with AR-30 lead to increasing inner pores’ volume, so the pore solution increases, resulting in the decline of Rp. Moreover, when the fiber content is 0%~25%, the electrical resistance of steel fibers (Rs) increases slowly. However, when the fiber content exceeds 50%, Rs increases rapidly. The increasing ratio of steel fibers with AR-30 will lead to the decreasing dispersion of steel fibers in RPC. Furthermore, the number of steel fibers decreases with the increase of steel fibers content with AR-30 leading to a sparse electrical conductive network. Rs decreases [37]. The fitting curves fit the quadratic function, and the fitting degrees are 0.99823 and 0.97846, respectively, indicating that the fitting function is very reasonable.
Figure 12 displays the electrochemical impedance spectroscopy of specimens. The imaginary component (-Zi) and the real component (Zr) represent electrical reactance and Re respectively. Table 4 shows the abscissa of the extreme point after removing individual points. It can be found that Re increases with the increasing ratio of steel fibers with AR-30. Moreover, the distribution of points becomes dispersed. The reason for this phenomenon may be that the increase of steel fibers with AR-30 will reduce the number of steel fibers, leading to the decrease of dispersion of steel fibers. The electrical conductivity decreases in RPC [38].
Figure 13 shows the circuit schematic and equivalent circuit diagram of electrochemical impedance spectroscopy. It can be seen that the electric circuit diagram of RPC with compound cement accord with the series conduction model. Re and capacitance include steel fibers, plain RPC, and pore solution, and these three parts respectively connect with contact resistances of the electrode and specimens [39]. The Chi-squared is less than 2.324 × 10−3, indicating that the equivalent circuit is reasonable.

3.4. Micro Analysis

Figure 14 shows SEM-EDS photos of samples cured for 28 days. The samples are plain samples without any steel fibers. The dense hydration products, the flocculent hydration products, and the agglomerate hydrate can be observed in the photos. Table 5 shows the element distribution obtained by EDS. As depicted in Figure 14 that the element of carbon (C), oxygen (O), silicon (Si), sulfur (S), aluminium (Al), calcium (Ca), tellurium (Te), kalium (K), and magnesium (Mg) in Table 5 can be found. As observed in Table 5, the content of the elements decreases in this order of O > Si > S. This is attributed to the fact that the contents of S and Si in the part A and part B are low indicating that the parts are mainly other substances. Furthermore, the content of Si is significantly higher than the content of S in part C and part D indicating that the parts are mainly composed of hydrated calcium silicate and other substances [9].

4. Conclusions

In this experiment, the mechanical properties and electrical parameters of RPC with sulfoaluminate compound cement are studied. The experimental conclusions are as follows.
The max ft and fcu of 1 d are 22.1 MPa and 50 MPa. The max ft and fcu of 28 d are 26.8 Mpa and 87.32 MPa. The increase of steel fibers with an aspect ratio of 30 fibers leads to the decline of the mechanical properties of RPC. The decreasing rates of ft and fcu with the curing age of 1 d and 28 d are 14.93%~83.26% and 0.40%~46.36%.
The addition of steel fibers with an aspect ratio of 30 can weaken α of RPC. The decreasing rates with the curing age of 1 d and 28 d are 85.48% and 84.77%, respectively.
The increase of steel fibers with an aspect ratio of 30 leads to the decrease of electrical conductivity in RPC. The max Rc of 28 d is 2033.9 Ω. The electrical conductivity of specimens of steel fibers with an aspect ratio of 30 is 1/10 of the electrical conductivity of specimens of steel fibers with an aspect ratio of 75.
The electric circuit of reactive powder concrete accords with a series conduction model, which parallel electrical resistance and capacitance of pore solution, rapid strength RPC and steel fibers respectively connect with the contact resistance of the electrode and specimens.
The main hydration product of SAC and OPC composite cement is hydrated calcium silicate.
In this study, the effect of steel fibers’ aspect ratio on the electrical performance and mechanical strength has been reported. However, the influence of steel fibers’ aspect ratio on the durability needs further investigation in the future.

Author Contributions

Conceptualization, Z.L. and H.W.; methodology, X.P.; software, Z.L.; validation, H.W., X.P. and Z.L.; formal analysis, X.P.; investigation, H.W.; resources, X.P.; data curation, H.W.; writing—original draft preparation, Z.L.; writing—review and editing, H.W.; visualization, Z.L.; supervision, X.P.; project administration, H.W.; funding acquisition, H.W. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by [the Natural Science Foundation of China] grant number (52008215) and [the Natural Science Foundation of Zhejiang Province, China] grant number [LY22E080005].

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data used to support the findings of this study are available.

Conflicts of Interest

The authors declare no conflict of interest.

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Coatings 13 00331 g001 550
Figure 1. The diagram of ft and fcu.
Figure 1. The diagram of ft and fcu.
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Figure 2. The schematic diagram of the loading regime and electrode layout.
Figure 2. The schematic diagram of the loading regime and electrode layout.
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Figure 3. Electrical parameters measurement.
Figure 3. Electrical parameters measurement.
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Figure 4. Mechanical strength is a relation of the ratio of fibers with an aspect ratio of 30.
Figure 4. Mechanical strength is a relation of the ratio of fibers with an aspect ratio of 30.
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Coatings 13 00331 g005 550
Figure 5. Pt and wm curve for 1 d.
Figure 5. Pt and wm curve for 1 d.
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Coatings 13 00331 g006 550
Figure 6. Pt and wm curve for 28 d.
Figure 6. Pt and wm curve for 28 d.
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Coatings 13 00331 g007 550
Figure 7. The fitting curve of 1 d Pt and wm.
Figure 7. The fitting curve of 1 d Pt and wm.
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Coatings 13 00331 g008 550
Figure 8. The fitting curve of 28 d Pt and wm.
Figure 8. The fitting curve of 28 d Pt and wm.
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Coatings 13 00331 g009 550
Figure 9. α of specimens.
Figure 9. α of specimens.
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Coatings 13 00331 g010 550
Figure 10. Re of specimens.
Figure 10. Re of specimens.
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Coatings 13 00331 g011 550
Figure 11. The relationship between Rp, Rs, and steel content of RPC.
Figure 11. The relationship between Rp, Rs, and steel content of RPC.
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Coatings 13 00331 g012 550
Figure 12. Electrochemical impedance spectroscopy.
Figure 12. Electrochemical impedance spectroscopy.
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Coatings 13 00331 g013 550
Figure 13. The equivalent circuits of RPC.
Figure 13. The equivalent circuits of RPC.
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Coatings 13 00331 g014 550
Figure 14. SEM-EDS of samples for 28 d.
Figure 14. SEM-EDS of samples for 28 d.
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Table
Table 1. The passing rate of the particle size distribution (%).
Table 1. The passing rate of the particle size distribution (%).
Particle Size (%)0.30.614864360
Types
OPC00.342.6715.0028.7693.60100
SAC00.341.9016.3730.1395.16100
GGBS0.0260.23.5419.6535.0597.7100
SF31.158.582.1100100100100
Table
Table 2. Chemical composition (%).
Table 2. Chemical composition (%).
TypesChemical Composition (%)
SiO2Al2O3Fe2O3MgOCaOSO3Ti2O
OPC20.905.463.931.7162.225.78/
SAC13.9622.452.662.9342.0114.331.64
GGBS35.6214.750.259.7235.910.243.50
Table
Table 3. Mixing proportion of specimens (g).
Table 3. Mixing proportion of specimens (g).
TypesH2OOPCSACSFGGBSSandWater-Reducing AgentLi2SO4Calcium FormateTartaric AcidDefoamerAspect Ratio of 75 Steel FibersAspect Ratio of 30 Steel Fibers
C-RPC-1244.42740.7740.7370.3111.1977.920.30.62.61.90.615.80
C-RPC-2244.42740.7740.7370.3111.1977.920.30.62.61.90.611.853.95
C-RPC-3244.42740.7740.7370.3111.1977.920.30.62.61.90.67.97.9
C-RPC-4244.42740.7740.7370.3111.1977.920.30.62.61.90.63.9511.85
C-RPC-5244.42740.7740.7370.3111.1977.920.30.62.61.90.6015.8
Table
Table 4. The abscissa of the extreme point after removing individual points.
Table 4. The abscissa of the extreme point after removing individual points.
TpyesC-RPC-1C-RPC-2C-RPC-3C-RPC-4C-RPC-5
Zr230.11582.2803.2953.52033.9
Table
Table 5. The element distribution obtained by EDS (%).
Table 5. The element distribution obtained by EDS (%).
PartCOSiSAlCaTeKMg
A11.5748.441.291.402.7330.084.49--
B12.4253.710.22-0.7232.93---
C7.1249.9325.080.905.039.360.741.200.64
D7.1249.9325.080.905.0310.10-1.200.64
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Liang, Z.; Peng, X.; Wang, H. The Influence of Aspect Ratio of Steel Fibers on the Conductive and Mechanical Properties of Compound Cement Reactive Powder Concrete. Coatings 2023, 13, 331. https://doi.org/10.3390/coatings13020331

AMA Style

Liang Z, Peng X, Wang H. The Influence of Aspect Ratio of Steel Fibers on the Conductive and Mechanical Properties of Compound Cement Reactive Powder Concrete. Coatings. 2023; 13(2):331. https://doi.org/10.3390/coatings13020331

Chicago/Turabian Style

Liang, Zhao, Xi Peng, and Hui Wang. 2023. "The Influence of Aspect Ratio of Steel Fibers on the Conductive and Mechanical Properties of Compound Cement Reactive Powder Concrete" Coatings 13, no. 2: 331. https://doi.org/10.3390/coatings13020331

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