Addition Of Basalt Fiber Research Articles

Influence of basalt fiber on pore structure, mechanical performance and damage evolution of cemented tailings backfill

To study the influence of the addition of basalt fibers on the mechanical properties, pore structure, and damage evolution characteristics of the cemented tailings backfill (CTB), the uniaxial compression tests, nuclear magnetic resonance tests and scanning electron microscopy analysis were conducted on the CTB with four different content and lengths of basalt fibers. Test results show the following. (1) An increase in the content of basalt fibers will lead to an increase in the proportion of micropores and secondary pores in the CTB, while a decrease in the proportion of macropores. The influence of basalt fiber length on pore structure is not as significant as the content. (2) With the increase of basalt fiber content and length, the peak stress and peak strain of the CTB increase, but the elastic modulus decreases. Basalt fiber can significantly improve the ductility and bearing time of the CTB, with a length of 12 mm and a content of 1.5 % having the best effect. The length of basalt fibers affects macroscopic mechanics more than content. (3) The CTB without fiber have fewer cracks and faster crack propagation speed, while the CTB with fiber have more cracks and slower crack propagation speed. Basalt fibers mainly play a bridging role between hydration products, delaying the failure process of the sample. (4) A damage constitutive model was constructed. The rationality and reliability of the model were verified, and the damage evolution law of CTB was analyzed. The content and length of basalt fibers have a positive impact on damage evolution.

Identifying the influence of basalt fiber reinforcement on the deformation and strength characteristics of cement stone

The object of the research is the quality of cementing oil and gas wells with increasing the strength and deformation capacity of cement stone using basalt fibers. Cement slurry used in cementing oil and gas wells faces the problem of failure under the influence of hydraulic fracturing and perforation procedures. This failure leads to the formation of cracks and may require remedial cementing, which increases operating costs and complicates the process of oil and gas production. Moreover, this problem can lead to premature well water breakthrough and cause serious damage such as oil and gas shows and blowouts, which poses a threat to the environment and safety. To solve the problem of the destruction of cement stone under external influences, the study proposed the approach of reinforcing with basalt fiber. During the study, a cementing material based on Portland cement, reinforced with various concentrations of basalt fibers (0.1 %, 0.5 %, 1 % and 2 %), was developed and tested. Cement strength tests at 2, 7, and 14 days, along with deformation monitoring under load, were performed. The addition of basalt fibers to cement stone significantly improved its strength characteristics. The most successful results were achieved with the addition of 0.5 % basalt fibers, resulting in an 11 % increase in compressive and flexural strength. Basalt fibers complement the structure of cement stone, increasing its ability to deform. One of the key features of the obtained results is the possibility of improving the strength of the cement stone without losing its fluidity as a cement slurry. The results obtained are applicable in the development and production of cement materials based on basalt fibers. This will improve the quality of well cementing and reduce the risks of complications

Mechanical performance study of basalt-polyethylene fiber reinforced concrete under dynamic compressive loading

In order to enhance concrete's impact resistance, this study investigates the effects of single basalt fiber and basalt-polyethylene hybrid fiber on concrete through split Hopkinson pressure bar (SHPB) tests, emphasizing their significance in engineering applications. A comparative analysis of the failure modes, dynamic compressive strength, dynamic compressive toughness, and dynamic growth factor of specimens was conducted under different strain rates and polyethylene fiber volume fractions. The study considered concrete damage, strain rate effect, and the toughening effect of fibers, introducing the damage factor, and establishing a dynamic damage constitutive model for fiber-reinforced concrete. The results showed that basalt-polyethylene fiber reinforced concrete (BPFRC) exhibited better impact resistance and deformation capability. There were improvements observed in dynamic compressive strength, dynamic compressive toughness, and dynamic growth factor. The addition of basalt fiber (BF) and polyethylene fiber (PE) played a buffering role in inhibiting crack propagation and slowing down the damage process. The optimum PE volume fraction for dynamic compressive strength was 0.1% at a strain rate of 60 s−1, 0.15% at a strain rate of 95 s−1, and 0.05% at a strain rate of 120 s−1, all with a BF volume fraction of 0.25%. The optimum fiber volume fractions for dynamic compressive toughness and dynamic peak toughness were consistent, both at 0.25% BF and 0.1% PE. The established dynamic damage constitutive model for fiber-reinforced concrete can effectively describe the impact resistance performance of BPFRC, and the experimental curves fit well with the constitutive curves. Furthermore, it was observed that BF acted as macrofibers, bridging to restrain the post-hardening cracking of concrete, while PE acted as microfibers, inhibiting the propagation of plastic cracks, reducing internal defects in concrete, and enhancing the ductility and toughness of concrete. Consequently, BPFRC holds significant potential value in engineering applications.

Mechanical properties and microscopic characteristics of fly ash–slag composite backfill

The strength of the backfill is crucial for safe and efficient mining, and the cementing material is the key to obtaining a strong backfill. In this paper, industrial waste was used as a raw material, into which basis basalt fibres of different lengths and dosages were incorporated. First, the influencing factors were determined through orthogonal test designs. The optimal ratio of solid–liquid ratio of 2 and basalt fiber content of 2% and length of 6 mm was obtained, and thereby the complete proportion of the backfill material was obtained. The compressive strength and slump of the backfill material mixed with basalt fibres were investigated, and the interfacial mechanism of the backfill material was analysed at the microscopic level using scanning electron microscopy and X-ray diffraction. The results indicated that the degrees of influence of the different factors on the mechanical properties of the backfill material decreased in the following order: Solid–liquid ratio > fibre dosage > fibre length. Furthermore, there were different degrees of interaction among them. Under the best test proportion, that is, when the Solid–liquid ratio was 2, the fibre dosage was 2%, and the fibre length was 6 mm, the slump was 210 mm, and the compressive strength was 5.03 MPa. The mechanical properties were the best at this time. Through data regression, the relationship between the fibre dosage and the average peak stress was established, and the full curve expression for the uniaxial compressive stress–strain of the BFGF specimen was obtained. According to a microscopic characterisation analysis, the slag formed C–S–H gel, which contributed to the early-stage strength of the filling material; fly ash and coal gangue contained a large amount of aluminium, which formed hydrated aluminosilicate with a framework structure, and this contributed significantly to the later-stage strength of the backfill material. The addition of basalt fibres reduces the internal defects of the backfill, allowing the internal pore structure of the backfill to be optimised and the compressive strength to be increased. The results of this study have been successfully implemented in actual projects. Additionally, they provide a reference for similar mine management projects and have considerable promotion and application value.

Experimental and Numerical Behavior of Basalt Fiber Reinforced Short Concrete Columns Under Axial Loading

This paper presents experimental and numerical investigations to reveal effecting of incorporating basalt fibers into a concrete matrix on the structural behavior and loading capacity of axially loaded short columns. Six volume fractions of chopped basalt fibers are added to the same concrete mixture to prepare six identically reinforced columns. The results illustrate that the bonding forces between microfilaments and matrix increase to provide good internal confinement for concrete ingredients, which enhances compressive strength and column loading capacity. The 0.3 % basalt fiber awarded the best compressive strength, while 0.15 % and 0.3 % awarded the best load capacity to the column. The Addition of basalt fibers delays cracking to increase the cracking load by about 50 % more than no fiber column, which indicates that it needs more energy to overcome the bonding strength between filaments and matrix. At the ultimate state, the loading capacity increases by 15 % and 17 % for 0.15 % and 0.3 % of basalt fibers and by 10 % and 12 % for 0.45% and 0.6% of basalt fiber. The 0.75 % decreased compressive strength by about 6 % but raised the column's ultimate load by 18 %. Therefore, basalt fiber benefits the cracking load more than the maximum load. The finite element showed approaching the peak load in numerical and experimental results. The longitudinal rebars and ties do not yield at the ultimate state. Increasing the reinforcement ratio raises loading capacity while lowering the yield stress of bars minimizes the maximum load.

Performance, Mechanical Properties and Durability of a New Type of UHPC-Basalt Fiber Reinforced Reactive Powder Concrete: A Review.

The advent of reactive powder concrete (RPC) has brought about the era of ultra-high performance concrete (UHPC), and the incorporation of fiber has brought about more possibilities for its application. Basalt fiber reinforced reactive powder concrete (BFRPC), as the product of the combination of RPC and fiber, has become a new engineering material that has received much attention from scholars in recent years. Compared with traditional UHPC, BFRPC is superior in corrosion resistance, material compatibility, cost performance, environmental protection, and other aspects; therefore, it is destined to have a wide range of applications in the future. In this article, we extensively reviewed the literature on basalt fiber reinforced RPC in the past decade from the perspective of work performance, mechanical properties, and durability. Moreover, we summarized the research progress and achievements on BFRPCs in the following points: (1) The performance of BFRPCs is mainly influenced by three factors: the frictional resistance between fine aggregates, the consistency of the cement slurry, and the three-dimensional random interweaving of basalt fibers; (2) the mechanical properties of BFRPC are mainly influenced by curing conditions, the design of the RPC matrix proportional mix, and the addition of basalt fibers up to a threshold; (3) thanks in part to RPC's density and the filling and bridging of fibers, BFRPC exhibits uniform and good performance in durability indicators. However, there are still some problems in the current development of BFRPC, such as inconsistent test conclusions among different scholars and a lack of scenarios in which to apply BFRPC. This paper also puts forward the prospect from the aspects of theoretical research and practical application, and provides a reference for subsequent related work.

Effect of basalt fibers on fracture properties of nanoclay reinforced polymer concrete after exposure to elevated temperatures

The present study evaluates the effect of basalt fiber reinforcement on the fracture properties of polymer concrete (PC) after exposure to different temperatures. First, 1, 2, 3, 4, and 5 wt% basalt fiber are introduced to the nanoclay reinforced PC. Three-point bending tests are conducted on the cracked semi-circular bending (SCB) specimens to determine the fracture toughness and fracture energy of mode I and mode II, as well as the optimum weight content of the fibers. The addition of basalt fibers improves KIc, KIIc, GIf, and GIIf by 55.8%, 90.2% 28.5%, and 486.6%, respectively. Then, the influences of exposure to the temperatures of 24, 40, 60, 80, 100, 120, and 140 °C on the fracture parameters of both unreinforced and basalt fiber reinforced PCs are studied. The load-displacement curves of both unreinforced and fiber reinforced PCs confirm the brittle fractures, before and after subjecting to high temperatures. Field emission scanning electron microscopy (FESEM) study is conducted to investigate the fracture surface of the fiber reinforced PC. The presented results will be useful in the design and optimization of the PCs exposed to high temperatures.

Prediction of chloride ion concentration distribution in basalt-polypropylene fiber reinforced concrete based on optimized machine learning algorithm

The distribution characteristics of chloride ion concentration in basalt-polypropylene fiber reinforced concrete (BPFRC-CC) are important for assessing the durability of concrete structures under marine environment. This study collected the distribution data of BPFRC-CC in three different environments: tidal, submersible, and salt spray. Several optimized machine learning models were developed to predict the distribution of BPFRC-CC. The performance of these models was evaluated based on a comparison between actual and predicted values, residual distribution histograms, and performance indicators. The research results of this article showed that the particle swarm optimization support vector regression (PSO-SVR) model exhibits significant accuracy and generalization ability, with closer proximity to the actual values in both the training and testing sets. The residual distribution histogram of the PSO-SVR model approximated a normal distribution with a smaller mean and standard deviation. Evaluation indicators, including R2, MSE, RMSE, MAE, and MAPE, for the PSO-SVR model were 0.994, 6.92e-5, 0.0083, 0.0062, and 0.0453, respectively. The SHAP values revealed that depth and age were the most critical influencing factors. The decrease in age, water-cement ratio, and water-binder ratio, the addition of basalt fibers and polypropylene fibers, and the increase in depth reduced the BPFRC-CC. In addition, BPFRC-CC in tidal, salt spray, and submersible areas decreased in that order. Finally, a graphical user interface for BPFRC-CC was developed, providing researchers and production personnel with an intuitive, efficient, and visual production experience. This study has important implications for the optimization of BPFRC formulations and the prediction and assessment of the life of BPFRC structures.

Interpretable Predictive Modelling of Basalt Fiber Reinforced Concrete Splitting Tensile Strength Using Ensemble Machine Learning Methods and SHAP Approach

Basalt fibers are a type of reinforcing fiber that can be added to concrete to improve its strength, durability, resistance to cracking, and overall performance. The addition of basalt fibers with high tensile strength has a particularly favorable impact on the splitting tensile strength of concrete. The current study presents a data set of experimental results of splitting tests curated from the literature. Some of the best-performing ensemble learning techniques such as Extreme Gradient Boosting (XGBoost), Light Gradient Boosting Machine (LightGBM), Random Forest, and Categorical Boosting (CatBoost) have been applied to the prediction of the splitting tensile strength of concrete reinforced with basalt fibers. State-of-the-art performance metrics such as the root mean squared error, mean absolute error and the coefficient of determination have been used for measuring the accuracy of the prediction. The impact of each input feature on the model prediction has been visualized using the Shapley Additive Explanations (SHAP) algorithm and individual conditional expectation (ICE) plots. A coefficient of determination greater than 0.9 could be achieved by the XGBoost algorithm in the prediction of the splitting tensile strength.

Mechanical and permeability properties of basalt fibre Reinforced concrete

Concrete, the most consumed construction material, is capable to resist under compressive force but not in tension. To improve this inherent defect in concrete, several methods have been adopted. One of these methods is the addition of fibres in concrete. The addition of Basalt Fibres (BF) improves the tensile strength of concrete and considerably reduces the development and propagation of cracks. By hindering the propagation of cracks, the permeability of the concrete is also reduced considerably. BF, a fibre produced from naturally occurring basalt rock, has improved chemical and thermal stability and higher elastic modulus, with improved compressive, tensile and flexural strength. This study primarily emphases on the effect of the addition of BF in concrete. First, the optimum dosage of BF is found through multiple strength test on hardened concrete. From the BF dosages of 0.2%, 0.3%, 0.4%, 0.5% and 0.6% of volume of concrete, 0.3% is obtained as optimum. The permeability properties, water and chloride ion penetrability of Basalt Fibre Reinforced Concrete (BFRC) are also tested and concluded that optimum addition reduces the permeability. The behaviour of BFRC beams on the flexural loading is studied experimentally and determined that BFRC has significant increase in the cracking load, ultimate load carrying capacity and reduced propagation of cracks.

Rheological and Mechanical Properties of Bentonite-Cement Paste Reinforced with Basalt Fibers.

Bentonite cement paste (BCP) is among the grouting materials used widely in large-pore grouting and karst cave treatment. The mechanical properties of bentonite cement paste (BCP) will be improved by additional basalt fibers (BF). In this study, the effects of basalt fiber (BF) contents and their lengths on the rheological and mechanical properties of bentonite cement paste (BCP) have been examined. Yield stress (YS), plastic viscosity (PV), unconfined compressive strength (UCS), and splitting tensile strength (STS) were used to evaluate the rheological and mechanical properties of basalt fiber-reinforced bentonite cement paste (BFBCP). Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) characterize microstructure development. The results indicate that the Bingham model can provide the rheological behavior of basalt fibers and bentonite cement paste (BFBCP). The yield stress (YS) and plastic viscosity (PV) increase as the content and length of basalt fiber (BF) increase. The effect of fiber content on yield stress (YS) and plastic viscosity (PV) is greater than that of fiber length. The addition of basalt fiber (BF) enhanced the unconfined compressive strength (UCS) and splitting tensile strength (STS) of basalt fiber-reinforced bentonite cement paste (BFBCP) at the optimum basalt fiber (BF) content of 0.6%. The optimum basalt fiber (BF) content tends to increase as curing age increases. The basalt fiber length of 9 mm is the most effective for improving unconfined compressive strength (UCS) and splitting tensile strength (STS). The large increments in unconfined compressive strength (UCS) and splitting tensile strength (STS) were 19.17% and 28.21% for the basalt fiber-reinforced bentonite cement paste (BFBCP), with a basalt fiber length of 9 mm and content of 0.6%. Scanning electron microscopy (SEM) shows that the randomly distributed basalt fiber (BF) forms a spatial network structure in basalt fiber-reinforced bentonite cement paste (BFBCP), which composes a stress system under the action of cementation. Basalt fibers (BF) used in crack generation processes slow down the flow through bridging and occur in the substrate to improve the mechanical properties of basalt fiber-reinforced bentonite cement paste (BFBCP).

ТРІЩИНОСТІЙКІСТЬ БЕТОНІВ З ПОЗИЦІЇ МЕХАНІКИ РУЙНУВАННЯ (ОГЛЯД)

This paper presents the generalized results of the analysisand synthesis of scientific and technical sources of investigation the heavy concrete on the basis of fracture mechanics for the last 25-30 years.New criteria and models for heavy concrete, which were obtained during this period have been described and generalized, in particular, a new deformation model of concrete crack resistance on the basis of fracture mechanics. The analysis of results of experimental and theoretical researches of heavy concrete crack resistance on disk-shaped samples at eccentric stretching by concentrated forces has been presented. A number of methods have been elaborated i.e. a method for experimental determination of the concrete crack resistance characteristics under static loads, a method for determining the length of the fracture zone in the crack, the relationship between the mechanical characteristics of heavy concrete and the parameters of acoustic emission measurement. The method of concrete cracking resistance with the addition of basalt fiber was also developed and the influence of basalt fiber on crack resistance and crack opening was studied in field tests. The generalized results have been presented.It has been stated about the significant development over the last three decades of methods for determining the strength, crack resistance and deformation of concrete in reinforced concrete elements from the standpoint of reinforced concrete mechanics and mechanics of concrete destruction. The conclusions about the expediency of using the Leonov-Panasyuk deformation model for concrete and the prospects for fictitious crack model have been made.On the basis of the generalized data given in the specified publications the technique of technical diagnostics and a technique of repair and restoration works at strengtheningwith use of modern technologies and materials has been developed that gives the chance to increase considerably a resource and reliability of reinforced concrete buildings and constructions

Effect of the addition of basalt fiber on life-cycle anti-cracking behavior of concrete

Effect of the addition of basalt fiber on life-cycle anti-cracking behavior of concrete

Study of the Compressive Properties of Heavy Calcium Carbonate-Reinforced Epoxy Composite Spheres (HC-R-EMS) Composite Lightweight Concrete.

Lightweight concrete is one of the effective means to solve the problems of structural component weight, energy efficiency, and fire safety in modern civil engineering. Heavy calcium carbonate-reinforced epoxy composite spheres (HC-R-EMS) were prepared by the ball milling method, and HC-R-EMS, cement, and hollow glass microspheres (HGMS) were mixed into the mold by the molding method to prepare composite lightweight concrete. The relationship between the HC-R-EMS volumetric fraction, the initial inner diameter of the HC-R-EMS, the number of layers of HC-R-EMS, the HGMS volume ratio, the basalt fiber length and content, and the multi-phase composite lightweight concrete density and compressive strength was studied. The experimental results show that the density of the lightweight concrete ranges between 0.953-1.679 g/cm3 and the compressive strength ranges between 1.59-17.26 MPa, where the volume fraction of HC-R-EMS is 90%, the initial internal diameter is 8-9 mm, and the number of layers of HC-R-EMS is three. The lightweight concrete can meet the requirements of high strength (12.67 MPa) and low density (0.953 g/cm3). In addition, the addition of basalt fiber (BF) can effectively improve the compressive strength of the material without changing the density of the material. From a micro-level perspective, HC-R-EMS is closely combined with the cement matrix, which is conducive to increasing the compressive strength of concrete. Basalt fibers connect the matrix into a network, improving the maximum limit force of the concrete.

Mechanical and Thermo-Mechanical Performance of Natural Fiber-Based Single-Ply and 2-Ply Woven Prepregs.

This paper presents a study conducted on prepregs manufactured by a novel method for the impregnation of a thermoplastic matrix. Different composite prepregs based on polypropylene and reinforced with natural fibers (e.g., basalt and jute fibers) were developed. The mechanical and dynamic mechanical properties were investigated. DMA tests were conducted at 1 Hz frequency and properties such as storage modulus and damping (tan δ) were evaluated. The overall mechanical properties of the basalt fiber composites were found to be superior to that of the jute fiber-based samples. Thermo-gravimetric analysis (TG/DTG) of the composite samples showed that the thermal degradation temperatures of the basalt-based composites shifted to higher temperature regions compared to the PP or jute fiber composites. The addition of basalt fiber considerably improved the thermal stability of the composite samples. Microscopic images of the tensile fractured composite samples illustrated better fiber-matrix interfacial interaction due to the novel technology of prepregs. Single-ply and 2-ply prepregs showed significantly superior mechanical, thermal, and thermo-dynamical performance compared to the control sample (pure PP). 2-Ply composites demonstrated higher modulus, tensile strength, and storage modulus due to the higher fiber volume fraction. Basalt-based samples showed a minimum weight loss of about 57% up to 700 °C in contrast to 96.05% weight loss in the jute-based samples and 98.4% in the case of pure PP. The heat resistance index (THRI) is more than twice for basalt compared to jute and PP. Furthermore, the superior thermal stability of basalt is reflected in its DSC curves, showing the highest endothermic peak. The technique of using the resin in the form of thermoplastic yarns offers cost effective and efficient alternatives for composite manufacturing.

Experimental study on compression failure characteristics of basalt fiber-reinforced lightweight aggregate concrete: Influences of strain rate and structural size

This paper presents systematic experimental investigations on the combined influences of loading strain rate and structural size on uniaxial-compression failure characteristics of LAC and basalt fiber-reinforced lightweight aggregate concrete (BFLAC), in terms of workability, failure morphology, deformation curve, failure strength, elastic modulus and energy absorption, with a special focus on the size-dependence of strain rate effect. Results indicate that the uniaxial-compression strength, elastic modulus, compression toughness as well as specific toughness are increased when the basalt fibers with 0.3% volume content is added in LAC, which can be ascribed to the synergistic effect of three working modes of basalt fibers in restricting the crack propagation and fracture failure. As the strain rate increases, specimens with larger size perform a stronger strain rate effect, resulting in that the influence of structural size on uniaxial-compression failures is weakened. The addition of basalt fibers can also weaken the size-dependence on uniaxial-compression strength, compression toughness and specific toughness, which contributes to the promotion and application of basalt fibers in LAC, especially for large-scale engineering structures. The dynamic increase factor (DIF) empirical formulas of LAC and BFLAC with various structural sizes have been obtained, which can provide a reasonable reference for structure safety design and numerical computation of LAC and BFLAC.

Engineering, Mechanical and Dynamic Properties of Basalt Fiber Reinforced Concrete.

This study investigates the engineering and mechanical properties of basalt fiber-reinforced (FRF) concrete, giving special attention to residual flexural strength and dynamic modal parameters. These properties, which have not been thoroughly investigated elsewhere, are a precursor to structural design applications for dynamic compliant structures (i.e., bridges, offshore platforms, railways, and airport pavement). Accordingly, the standard notched flexural tests have been carried out to assess the basalt fiber-reinforced concrete's residual flexural strength with an additional 0.125%, 0.25%, 0.375%, and 0.5% of volume fraction of basalt fiber. In addition, dynamic modal tests were then conducted to determine the dynamic modulus of elasticity (MOE) and damping of the FRF concrete beams. The results indicate that concrete's toughness and crack resistance performance are significantly improved with added fiber in basalt fiber reinforced concrete, and the optimum fiber content is 0.25%. It also exhibits the highest increment of compressive strength of 4.48% and a dynamic MOE of 13.83%. New insights reveal that although the residual flexural performance gradually improved with the addition of basalt fiber, the damping ratio had an insignificant change.

The Effect of Basalt Fiber Addition on Physical Dry Wear in Al-Cu Alloy Used in the Automotive Industry

In this study, AlCu alloy was produced by the powder metallurgy method used in many stages of the automotive industry. In addition to the AlCu alloy, basalt fiber was added. Thus, it is aimed to increase wear resistance. A mixture was obtained with Al and Cu elements used in a 1:1 ratio by weight. Samples that were pressed and sintered at 600°C were examined. Microstructure (scanning electron microscopy), hardness (Vickers), chemical analysis (energy dispersive X-ray), and physical reciprocating wear tests were applied to the samples. Porosity status was observed in the microstructure. The porosity ratio increased with the addition of fiber. With this process, a slight decrease in hardness occurred. During the chemical analysis process, the oxide level of the grains and the alloy was determined to be at most 1%. In the physical dry abrasion test, the abrasion resistance increased by about 6 times with the addition of basalt fiber. Thus, with the addition of fiber in the AlCu alloy, an adhesive wear mechanism has been developed and the wear rate has decreased.

Experimental Study on Mechanical Properties of Basalt Fiber Concrete after Cryogenic Freeze-Thaw Cycles.

Basalt fiber (BF) has received much attention in recent years for engineering practice and scientific research related to basalt fiber reinforced concrete (BFRC) due to its advantageous mechanical properties and cost-effectiveness. By researching its performance characteristics after cryogenic freeze-thaw cycles, the advantages of BFRC's mechanical properties can be further exploited in order to expand its application scope. The effects of the fiber volume fraction, temperature gradient, and number of freeze-thaw cycles on the compressive strength, toughness index, splitting tensile strength, flexural strength, etc., of BFRC were investigated. Additionally, the damage mechanism of BFRC after freeze-thaw cycles was analyzed via scanning electron microscopy (SEM). The results show that the compressive strength of BFRC reaches its peak value when the fraction reaches 0.1% under the conditions of freezing and thawing cycles from room temperature to -80 °C. When the fraction of BFRC is 0.1%, and the maximum reduction is 17.1%, the splitting tensile strength decreased most sharply when the fraction was 0.1%, and the decrease amplitude was 40.9%, and the flexural strength decreased most acutely when the fraction was 0.3%, and the maximum decrease was 44.62%. The addition of basalt fibers can reduce the damage to the microstructure of concrete and improve its plastic degradation characteristics to a certain extent. With a decrease in the minimum temperature of the cryogenic freeze-thaw cycle, the optimal fiber content for compressive strength increases. Nevertheless, the splitting tensile strength and flexural strength of BFRC is improved as the fiber content increases under the cryogenic freeze-thaw environment.

Effects of Basalt Fiber on Strength of Alkali-Activated Slag-Tailing Cement Bodies

The influences of different quantity of basalt fiber and lead–zinc tailings on the strength of alkali-activated slag-tailings cement bodies were studied. After adding basalt fiber, the uniaxial compressive strength of the 50 and 60 g per unit tailing cement bodies increased before decreasing throughout a 7-day curing period. During a 28-day curing period, the uniaxial compressive strength of the 50 g per unit tailings cement decreased gradually, while the uniaxial compressive strength of the 60 g per unit tailings cement increased first and then decreased. Furthermore, after adding basalt fiber, the flexural strength of the 50 g per unit tailings cement body decreased gradually during a 7-day curing period, while the 60 g per unit tailings cement increased first and then decreased. Under a 28-day curing period, the flexural strength decreased first and then increased for both cement bodies. Finally, At the confining pressures of 2, 4 and 6 Mpa, the increase amplitude of the triaxial compressive strength of the cementation body was different with the addition of basalt fiber. The increase amplitude of the triaxial confining pressure from 2 to 4 Mpa was higher than that of the triaxial compression from 4 to 6 Mpa.