Basalt Fiber Content Research Articles

Experimental Study on the Impermeability and Micromechanisms of Basalt Fiber-Reinforced Soil-Cement in Marine Environments

In coastal areas, structures such as cement-soil dams are often eroded by seawater, so it is significant to study how to improve the impermeability of cement-soil. Basalt fiber with a strong tensile property, good stability and a high-performance price ratio was selected as the additive to study the influence of the basalt fiber content on the permeability of soil-cement. The permeability test and the chloride ion permeability test were used to evaluate the best mixing amount. The results of the permeability test showed that, although the permeability coefficient of soil-cement decreased with the increase in the basalt fiber content, the decreased rate of the permeability coefficient showed a slowing trend. The results of the chloride ion permeability test indicated that the chloride ion-related impermeability of soil-cement was enhanced with the increase in the basalt content, which was confirmed by the consistent findings of the contrast permeability test. The comprehensive analysis shows that the optimal content ratio of the basalt fiber was 1.5%. Furthermore, a SEM analysis established that the addition of the basalt fiber reduced the soil-cement porosity, improved the structural compactness and formed a more stable whole. This study could serve as a valuable reference for soil-cement used in projects with impermeability requirements.

Damage Model of Basalt-Fiber-Reinforced Cemented Soil Based on the Weibull Distribution

This study investigates the mechanical performance and a constitutive model of basalt-fiber-reinforced cemented soil (BFRCS) containing 0%, 0.1%, 0.3%, 0.5%, and 0.7% basalt fibers with lengths of 3, 6, 12, 20, and 35 mm, respectively. Unconfined compressive strength tests were used to examine the mechanical performance of BFRCS with varying basalt fiber contents and lengths. The test results demonstrate that the basalt fiber content of optimal quality is 0.1%, and that the fiber distribution uniformity and density have a significant impact on the strength of BFRCS. Based on the Weibull distribution of BFRCS for the degree of damage, a damage model for BFRCS, accounting for the fiber length and fiber content, is proposed here. Moreover, in this study we explored the relationship between the scale parameter as well as shape parameter of the Weibull distribution and fiber content as well as length. Furthermore, the evaluation methods for the mechanical properties of BFRCS according to the scale and shape parameters of the Weibull distribution are discussed. The results suggest that the proposed constitutive model captures the compressive stress–strain relationship of BFRCS; the theoretical results are in strong agreement with the data obtained.

Compressive-Tensile Mechanics and Energy Consumptions of a Cementitious Composite with High Utilization of Steel Slag

In response to the National Development and Reform Commission's “Guiding Opinions on Comprehensive Utilization of Large Solid Wastes during the Fourteenth Five Year Plan”, further expand the use of steel slag as concrete admixture in construction projects and other fields, and gradually improve the comprehensive utilization ratio, a cementitious composite with high utilization of steel slag (CHS) was developed, which is with the cement replaced by high-content super-fine steel slag powder (SSP) (replacement ratio υ ≥ 30%) as the cementitious materials, steel slag sand (SS) as the only aggregate and environmentally basalt fiber (BF) for toughening. It improves the utilization percentage of steel slag (SSP and SS) and reduces the consumption of natural resources such as cement and natural sand. Use BF to achieve better strength and toughness. In order to better understand the performance of CHS and make it better used in the engineering field. Study the influence of each component on the strength and energy consumption of compression and splitting tension, and strive to find the optimal proportion and lay the theoretical foundation for its application. Through the tests, the effects of high replacement ratio υ (30%–50%), low binder-aggregate ratio γ (0.31–0.44), and BF content ρv (0%–2%) on the aspects of peak strength, force-deformation curve and energy consumption were analyzed. The results show that the standard curing fck and ft,s can reach 40 MPa and 5 MPa respectively. With the increase of υ, the maximum axial compressive strength fck and splitting tensile strength ft,s decreased insignificantly. The γ has an important influence on fck and ft,s. When it increases from 0.31 to 0.44, fck increases linearly by 63.1% to 40.4 MPa, while ft,s increases by 52.8% to 5.18 MPa. As ρv increases, fck and ft,s show a trend of first increasing and then decreasing. ρv exerts a significant impact on the descending segments of stress-strain response curves of the compression which expressed as bilinear and trilinear models with different ρv after normalization. The energy consumptions of peak, total, and residual (Epeak, Edisp, Eres) show a slight downward trend with the increase of υ, a significantly upward trend with the increase of γ. With the increase of γv, and Edisp increase first and then tend to be flat, while Eres always increases and the percentages of Eres/Edisp in the compressive test increase from 22.6% to 38.5%, reflecting the improvement of the compressive toughness of BF.

Reinforcement Mechanism and Erosion Resistance of Loess Slope Using Enzyme Induced Calcite Precipitation Technique

The disaster of loess slope seriously threatened the safety of people and property. Enzyme Induced Calcite Precipitation (EICP) was demonstrated as an environmentally friendly soil improvement method. However, few studies have focused on the improvement effect of EICP on loess slopes. In this study, a series of tests were conducted to investigate the effect of EICP and added either basalt fiber (BF) to the loess or polyvinyl acetate emulsion (PVAC) to the solution on the erosion resistance of loess slopes. The results showed that all of the EICP, EICP-BF, and EICP-PVAC treatments could improve surface strength (SS). The addition of 50 g/L PVAC achieved high SS because the network structure formed by PVAC promoted the affixation of CaCO3. The thickness of the crust layer decreased with the increasing BF content or PVAC concentration. With the increasing number of EICP treatment cycles, the CaCO3 content increased progressively, but the increase rate decreased. For rainfall erosion, the time until erosion occurred was delayed and the stability was improved for loess slopes treated with EICP, EICP-BF, and EICP-PVAC. The high erosion resistance of loess slopes treated with EICP-0.5% BF, EICP-30 g/L PVAC, and EICP-50 g/L PVAC was attributed to the stable spatial structure formed by CaCO3 precipitation and the additional cementation provided by high BF content and PVAC concentration. The addition of 0.5% BF effectively inhibited the development of surface cracks in loess slope after dry–wet cycles. With the increasing number of dry–wet cycles, the accumulative loess loss weight of slopes treated with various methods increased gradually. Among all treatment methods, the number of dry–wet cycles had less effect on EICP-30 g/L PVAC treated loess slopes. This study provided guidance for loess slopes prevention.

Efficient reception of introducing basalt fiber in cement matrix of fiber concrete

The article is devoted to solving the problem of the distribution of basalt fiber in the environment of the filled cement paste and the total volume of basalt fiber-reinforced concrete, which is one of the most important in the preparation of basalt fiber-reinforced concrete. This article presents the results of experimental studies to establish the most effective technological method of introducing basalt fiber into the cement matrix of the composite from the point of view of increasing the strength characteristics of fiber-reinforced concrete. In the experimental studies performed, standardized methods for the study of cement paste and stone were used. As a result of the research, graphical dependences of the strength and water demand of a dispersed-reinforced cement stone on introducing basalt fiber into the composite and the quantitative content of basalt fiber in the composite were obtained. The analysis of the obtained results made it possible to establish that of the various methods for introducing basalt fiber into the cement matrix of basalt fiber-reinforced concrete, the most effective in terms of increasing the strength of the composite material, provided that the water demand of the fiber-reinforced concrete mixture remains unchanged, is preliminary dry mixing of cement with basalt fiber in a spring mill. The most favorable environment for the mechanical activation of basalt fiber in a spring mill has also been established, which makes it possible to achieve high rates in terms of the preservation of basalt fiber during joint grinding. The scientific novelty of the performed research lies in the fact that the issue of studying the distribution of basalt fiber was first studied at the level of the microstructure of basalt fiber-reinforced concrete.

Effect of basalt fiber on properties of asphalt and asphalt mixture

Asphalt mixture is the surface material of flexible pavement and semi-rigid pavement. It directly bears the influence of climate conditions and traffic load, and is prone to aging and fatigue damage. Therefore, using reinforcing agent to improve the performance of asphalt mixture is the long-term goal of researchers.This paper aims to study the effect of basalt fiber on asphalt viscosity and mechanical properties of asphalt mixture. Firstly, by testing the basic properties of asphalt binder with different fiber content, the viscosity characteristics of fiber + asphalt composites are analyzed by using the modified Einstein viscosity equation. The research shows that basalt fiber has obvious toughening effect on asphalt, and the penetration and softening point indexes are suitable to evaluate the viscosity properties of fiber + asphalt composites.Secondly, the effects of different fiber content on the water stability and splitting tensile strength of asphalt mixture are analyzed. The results show that the maximum content of basalt fiber should not be greater than 0.4%; With the increase of fiber content, the splitting strength of asphalt mixture increases, but the increase is not obvious when the content is > 0.30%, while the stiffness modulus continues to increase, indicating that the deformation resistance of asphalt mixture is enhanced after adding fiber. Based on the micromechanics theory of composite materials, the basic principle of basalt mineral fiber improving the strength performance of asphalt mixture is explained. The research shows that basalt mineral fiber can significantly improve the performance of asphalt mixture.

Development of Basalt Fiber Reinforced Fine-Grained Cementitious Composites for Textile Reinforcements

Cementitious composites have been the prevalent field of research in recent eras due to their excellent bending and high strains. However, textile reinforcement requires materials with fine grain size to make proper binding between the yarns in the textile reinforcement and improve the strength characteristics. This concern has led to the development of fine-grained cementitious composites by dispersing chopped basalt fiber to improve strain-hardening capabilities with reduced voids. The basalt fiber content is varied by 0, 0.2, 0.4, 0.5 and 1% to the volume of the cementitious matrix. Various testing methods have evaluated the mechanical and microstructural properties of fine-grained cementitious composites with basalt fiber. Adding basalt fiber up to 0.4% to the volume of the matrix improves the compressive, split tensile, flexural strength and dynamic modulus of elasticity compared to the controlled cementitious matrix. Also, higher fiber content escalated the impact resistance and degree of carbonation. From the results, obtained basalt fiber reinforced fine-grained cementitious composites have higher mechanical characteristics, and the particles are densely packed compared to cementitious composites. Thus it provides good bonding between the textile reinforcement and helps to construct thin structural elements.

Study of eco-friendly fabricated hydrophobic concrete containing basalt fiber with good durability

Basalt fiber reinforced concrete often works in marine environments. The wettability of the basalt fiber reinforced concrete directly affects its corrosion resistance and durability. In this paper, hydrophobic basalt fiber reinforced concrete was fabricated by using non-toxic stearic acid. The influence of the stearic acid on the wettability of basalt fiber reinforced concrete was studied. The surface free energy of hydrophobic basalt fiber reinforced concrete was calculated using the Owens-Wendt, Neumann, and Fowkes methods, and the corresponding results were compared. The impact of the stearic acid on the cement hydration, surface free energy, water absorption, and corrosion resistance of basalt fiber reinforced concrete with different basalt fiber contents was also analyzed. It was deduced that the water absorption decreased with the increase of the basalt fiber content. Compared with the basalt fiber reinforced concrete without stearic acid, the water absorption of the modified fiber concrete was reduced by 10%. In addition, the surface wettability of the samples with the added stearic acid was decreased, which increased the corrosion resistance. The proposed method is eco-friendly and it can be expanded for the use in the application of basalt fiber reinforced concrete in marine environment.

Effect of mixed basalt fiber and calcium sulfate whisker on chloride permeability of concrete

Rapid chloride migration (RCM) test was used to determine the non-steady-state chloride migration coefficient (DRCM) of concrete mixed with calcium sulfate whisker (CSW) and basalt fiber (BF). Meanwhile, the microscopic morphology of CSW and BF in concrete was observed through scanning electron microscope (SEM), and the microstructural parameters were determined by the nuclear magnetic resonance (NMR) method. Results show that mixes with 3.0 kg/m3 CSW or BF alone outperformed in terms of chloride penetration reduction. However, by considering the strength factors comprehensively, the effect of enhancing concrete strength and chloride permeability resistance is better when 3.0 kg/m3 CSW and 4.5 kg/m3 BF are mixed. Binary problem optimal analysis results show that the optimal admixture dosage for improving the chloride impermeability and the optimum admixture dosage for enhancing the compressive strength (fc) of concrete are not consistent. According to SEM results, CSW is evenly distributed in the matrix and BF is wrapped by concrete matrix. The addition of BF and CSW to concrete reduced its porosity according to NMR tests. Increasing the content of BF would increase the contributive porosity (φ) of macro pores in concrete, while CSW could reduce the φ of macro pores. The DRCM has the strongest correlation with φ with a pore size of 100–1000 nm, followed by porosity.

Optimize the design by evaluating the performance of asphalt mastic reinforced with different basalt fiber lengths and contents

The excellent mechanical properties of fibers contribute to the properties of asphalt materials. However, the current research is mainly focused on fiber-modified asphalt mixtures, and there is a lack of understanding of the effect of fibers on the functions of asphalt mastics. This study aims to obtain the optimal design of basalt fiber-modified asphalt mastics based on their rheological properties. Basalt fibers with three lengths (3, 6 and 9 mm) and four proportions (0 %, 3 %, 6 % and 9 % of asphalt mass) were used in this study. Dynamic shear and bending beam rheometer tests were conducted to evaluate their rheological performance. The experimental results showed that basalt fibers enhanced the stiffness, rutting resistance and cracking potential of asphalt mastics while reducing their fatigue performance. However, the S value gradually decreased, and the m value gradually increased as the temperature was changed from −18 °C to −12 °C and then to −6°C, representing that the temperature was favorable to enhancing the low-temperature performance of asphalt mastics. Besides, an analysis of fatigue cracking results showed that the asphalt mastic materials followed a two-phase crack growth model, exhibiting identical crack initiation phases and different crack propagation behavior. Finally, a modification design with the optimal overall performance was obtained through statistical analysis: the fiber length was 6–9 mm, and the fiber content was 3 %–6%.

Experimental Study on the Performance of Basalt Fiber Modified Pervious Concrete Based on Entropy Method

In order to solve the problem the permeability coefficient and strength of pervious concrete pavement are difficult to coordinate. In this paper, the basalt fiber was incorporated into pervious concrete, and the single factor control variable method was used to carry out the test of basalt fiber modified pervious concrete, and combined with the microstructure image, the influence law of different diameters, lengths, and dosages of basalt fibers on mechanical properties and pervious properties of pervious concrete were studied. The optimal incorporation index of basalt fiber was determined by a new analysis method—the entropy method. Finally, it is concluded that basalt fiber can improve the mechanical and pervious properties of pervious concrete by changing the internal structure of pervious concrete. In addition, when the diameter of basalt fiber increases from 14 μm to 20 μm, the compressive strength of pervious concrete decreases by 17.79%. The splitting tensile strength showed a trend of increasing to decreasing. The porosity and water permeability increased by 2.55% and 48.66%, respectively. When the basalt fiber length increases from 12 mm to 24 mm, the compressive strength of pervious concrete increases by 20.54%, and the splitting tensile strength increases first and then decreases. The porosity and water permeability increased by 6.40% and 57.68%, respectively. When the content of basalt fiber increases from 2 kg/m3 to 6 kg/m3, the compressive strength of pervious concrete decreases by 16.25%. The splitting tensile strength increases by 23.72%. The porosity and permeability decreased by 7.75% and 39.36%, respectively. Finally, the entropy method is used to comprehensively analyze the optimum incorporation indexes of basalt fiber, which can achieve the optimal mechanical properties and water permeability at the same time with, 20 μm in diameter, 24 mm in length, and 2 kg/m3 in dosage, and it provides a reference value for the popularization and application of basalt fiber pervious concrete in practical engineering.

Experimental study and mechanism analysis on basic mechanical properties of basalt fiber reinforced concrete

AbstractIn order to comprehensively examine the influence of basalt fiber on the basic mechanical properties of concrete, the axial compression, axial tension and direct shear tests were carried out on basalt fiber reinforced concrete (BFRC) with different fiber contents and fiber lengths. The failure modes and stress–strain curves under different loading modes were obtained from the test data, and the basic mechanical parameters of BFRC were extracted from the curves. Based on the results, the following conclusions were drawn. With the increase of fiber content, both the compressive strength and tensile strength showed an upward trend first followed by a downward trend. In general, the shear strength of BFRC was lower than that of ordinary reinforced concrete with no fiber (RC). All BFRC specimens had an increased peak strain and significantly improved deformability compared to RC. Based on a comprehensive analysis, the specimen with a fiber content of 0.2% and a fiber length of 6 mm (BFRC‐0.2%‐6) exhibited the best mechanical properties. In addition, mathematical regression analysis was performed on the normalized stress–strain curves of BFRC, and the influencing parameters model of basalt fiber was proposed based on the fiber content and fiber length. Moreover, scanning electron microscopy (SEM) and computed tomography were utilized to analyze the influencing mechanism of basalt fiber content and fiber length on the mechanical properties of concrete from the microcosmic and mesoscopic perspectives.

Fracture behavior of basalt fiber‐reinforced concrete subjected to high temperatures

AbstractThe three‐point bending test was conducted and the digital image correlation (DIC) technique was used to observe the full‐field displacement and strain of the notched beam. The initial cracking load and the crack mouth opening displacement were determined based on the deformation field near the tip and mouth of the notch. The initial cracking toughness Kini and the unstable fracture toughness Kun calculated according to the double‐K fracture model, the fracture energy GF and the ductility index Du determined with a modified method, and the equivalent fracture toughness K at four different deformation stages, were analyzed under different temperatures and basalt fiber contents. The results showed that Kini exhibited a monotonic decrease trend with the increasing temperature, indicating that the notched beam was prone to initial cracking after high temperatures. However, Kini rose slowly with the increase of the fiber content, suggesting that the basalt fiber had little influence on Kini. At the temperatures below 400°C, the Kun, GF, Du, and K at each deformation stage increased with the rise of temperature. At the temperatures above 400°C, the Kun, GF, Du, and K at each deformation stage apparently decreased with the increase of temperature. Under the current test conditions, the basalt fiber content of 0.4% by volume had the greatest improvement on the fracture performances of concrete after high temperatures.

Effect of Basalt Fiber Content on Mechanical and Tribological Properties of Copper-Matrix Composites

The basalt-fiber-reinforced copper-matrix composites were fabricated using spark plasma sintering. The effect of basalt fiber content on the mechanical and tribological properties of copper-matrix composites was investigated. The results show that the relative density decreased, the hardness increased and the tensile strength first increased and then decreased with the increase in fiber content. The optimal tensile strength of 276 MPa was obtained when the content of basalt fiber was 1.5 wt.%. The friction coefficient of the composites decreased, and the wear volume first decreased and then increased with the increase in the fiber content. The addition of basalt fibers reduced the plastic deformation of the copper matrix during the friction test due to its strengthening effect. Moreover, the detached basalt fibers from the Cu matrix were ground into fine particles and were helpful for forming a mechanical mixing layer, which can decrease the friction coefficient of composites.

Research on the Bearing Performance of Prefabricated New Type Subway Track Slab with Basalt Fiber

Currently, most ballastless tracks in Chinese subways are traditional cast-in-situ concrete structures, which require long construction progress. In contrast, prefabricated ballastless tracks can greatly reduce the construction period. However, there are few theoretical and experimental analyses on the prefabricated new type of subway slab track. Hence, to study the mechanical properties of the new type of subway track slab, static bending crack tests of one standard slab track and nine prefabricated full-scale track slabs with basalt fiber were carried out in this paper. The influence of the reinforcement arrangement method and the basalt fiber content on the performance of the track slabs was studied. Results showed that with the increase in the basalt fiber content in the range of 0.1–0.3%, the load–strain curve growth rate increased, the stiffness decreased, and the flexural resistance reduced. All the specimens exhibited a linear portion (elastic) and then a nonlinear portion (plastic) followed by flexural failure. During the elastic stage, the basalt fiber helped to improve the rigidity of the track slab. During the plastic stage, the influence of the basalt fiber content on the failure load varied with different reinforcement arrangements. With the reinforcement arrangement F2 and 0.1% basalt fiber content, the specimen had the smallest load–strain curve growth rate and the best overall flexural performance and crack resistance, and its strain was 23.35 με at an elastic limit of 95 kN. The results can provide a reference for the design of the prefabricated slab ballastless track.

Synergistic reinforcement mechanism of basalt fiber/cellulose nanocrystals/polypropylene composites

Abstract In this article, we prepared novel basalt fiber (BF)-reinforced polypropylene (PP) composites based on the synergistic reinforcement of cellulose nanocrystals (CNCs). First, we compared the enhancement effect of CNCs and silane coupling agent-modified BFs on PP, showing that the enhancement effect of the former was more significant. Subsequently, to further improve the mechanical properties of the composites, CNCs were introduced into the BF-reinforced PP composite system as the third phase, and the results suggested that their combination with BFs could synergistically strengthen the PP matrix composites. Simultaneously, the study also shows that when the mass percentage of CNCs and BFs are 1 and 30%, respectively, the composite achieves the highest mechanical strength, which is 64.31% higher than that of the PP matrix. The systematic characterization revealed the synergistic enhancement mechanism: on the one hand, CNCs not only promoted the improvement of PP crystallinity by heterogeneous nucleation but also formed a wedge-shaped structure between them and BFs through hydrogen bonding to prevent PP molecular movement; on the other hand, the BFs promote not only the extrusion crystallization of the resin matrix but also the network structure formed by the appropriate content of BFs can realize the rapid transmission of external stress.

Study on Mechanical Properties and Microstructure of Basalt Fiber Reactive Powder Concrete

In order to promote the wide application of reactive powder concrete (RPC) in practical engineering. In this paper, RPC was prepared using conventional and economical natural river sand instead of quartz sand and economical and environmentally friendly basalt fiber (BF) instead of steel fiber, and the macroscopic properties of basalt fiber reactive powder concrete (BFRPC) with different fiber content, such as flowability, failure mode, compressive strength and splitting tensile strength were studied, and the strength calculation formula of BFRPC was established based on the mechanical property results. The microscopic morphology and structure of BFRPC were characterized by scanning electron microscope (SEM) and Image Pro Plus (IPP) image processing software. The results show that BF has a small effect on the compressive strength of RPC, while it has a significant increase on the splitting tensile strength. When BF content is at 2 kg/m3, the 28-day compressive strength reaches 95.2 MPa and splitting tensile strength reaches 7.78 MPa. Compared with the RPC with BF of 0 kg/m3, the BFRPC shows an improvement in its 28-day compressive strength by 25.70% and an increase in its splitting tensile strength by 83.92%. According to the microscopic analysis, reasonable fiber content can optimize the internal microstructure of BFRPC, but excessive BF content will produce agglomeration and overlap, resulting in strength loss. Based on the gray correlation analysis method, it was concluded that the particle area ratio and pore fraction dimension were the most correlated with the mechanical properties of BFRPC. In addition, the feasibility and applicability of the BFRPC strength calculation formula were summarized. This research results of this paper provides a valuable reference for the further research and promotion of BFRPC.

Orthogonal experimental and theoretical study on mechanical properties of fiber-reinforced recycled powder concrete

With the goal of "low cement, low cost, high environmental protection and high performance", building solid wastes are applied to concrete manufacture. This study investigated the mechanical properties of fiber-reinforced recycled powder concrete (FRPC) by orthogonal test, and optimized the mix proportion of FRPC. The research variables included water-binder ratio, sand-binder ratio, the volume content and aspect ratio of basalt fiber (BF), and recycled concrete powder (RCP) replacement rate. The results showed that the ductility of FRPC is the best when the replacement rate of RCP is 45%. The mechanical properties of FRPC are the best when the volume content of BF is 0.1% and the aspect ratio is 1059. A trilinear model and constitutive equation of tensile stress-strain curve of FRPC were proposed. Additionally, the microscopic mechanism of fibers in FRPC was analyzed by scanning electron microscope (SEM).

Mechanical performance of basalt and PVA fiber reinforced hybrid-fiber engineered cementitious composite with superimposed basalt fiber content

• PVA/basalt HF-ECC with multiple cracking behavior was achieved by superimposition of basalt fiber. • Increasing basalt fiber superimposing content improved overall strength of PVA/basalt HF-ECC. • The advised optimal superimposing volume fraction of basalt fiber is 0.8%. • The effect of basalt fiber on tensile strain capacity was analyzed by micro-mechanical analysis. The large-scale application and popularity of engineered cementitious composites (ECC) is hindered by the relatively high price and increased CO 2 footprint of PVA fiber. PVA and basalt fiber reinforced hybrid-fiber ECC (PVA/basalt HF-ECC) is a promising way to deal with such drawbacks. Hence, this study focused on the influence of basalt fiber superimposing content on the properties of PVA/basalt HF-ECC. Compressive tests indicated basalt fiber could elevate compressive strength and its corresponding strain, the obtained maximum values were 46.37 MPa and 0.47 % as basalt fiber content increased up to 1.2 %. Tensile tests showed that first cracking strength and ultimate tensile strength increased up to 6.62 MPa and 7.85 MPa as basalt fiber content increased up to 1.2 %. Although tensile strain capacity continuously decreased to 0.62 %, all specimens showed multiple cracking behavior due to the superimposed performances derived from PVA and Basalt fibers. Mercury intrusion porosimetry test showed volume fraction of large capillary pore that influences strength decreased up to 31.65 % when basalt fiber content increased to 1.2 %. Based on test results, predicting equations of mechanical properties were proposed by curve fitting and showed good agreement with test results. Micro-mechanical analysis was conducted based on modified crack bridging model, and its results further interpreted change mechanism of tensile strain capacity. This study explores the feasibility of developing PVA/basalt HF-ECC by basalt fiber superimposition and facilitates the popularity of ECC.

Study on Evolution Law of Pore Structure and Frost Resistance of High-Performance Activated Cement-Based Composites in Severe Cold Area

In order to explore the frost resistance of high-performance activated cement-based composites(HACC), The freeze-thaw cycle test of HACC with different water-binder ratio and basalt fiber content was carried out, the mass loss rate, relative dynamic elastic modulus and related pore structure parameters of different freeze-thaw cycles were measured, and the influence of different factors on the frost resistance of HACC was studied, and the variation law of pore structure parameters with freeze-thaw cycles was explored. The results show that the mass loss rate of high performance cement-based composites has a small range, the maximum is less than 1% during failure, and the relative dynamic modulus changes significantly, which is the main indicator to evaluate the freeze-thaw failure of HACC; The frost resistance of HACC decreased gradually with the increase of the water-binder ratio, and showed a change rule of first increasing and then decreasing with the increase of basalt fiber content; HACC have good frost resistance when the air content is 3% ~ 4%. The bubble chord length is directly related to the freeze-thaw deterioration characteristics of HACC, and the bubble chord length reflects the frost resistance of HACC to some extent.