Brucite Fiber Research Articles

Mechanical behavior and damage constitutive relationship of basalt-brucite hybrid fiber reinforced low-heat cement concrete

In this study, the mechanical properties and microstructure of basalt-brucite hybrid fiber reinforced low heat cement concrete was explored. The results indicated that the mechanical properties of low heat cement concrete first increase and then decrease with the increase of hybrid fibers volume fraction, and the cubic compressive strength, splitting tensile strength, and axial compressive strength of the optimal strengthening group, that volume fraction is 0.20% for basalt fiber and 0.15% for brucite fiber, respectively, increased by 40.16%, 70.61%, and 56.16%, respectively. Under a reasonable volume fraction of hybrid fibers, the mechanical properties of concrete could be significantly improved. By comparing the bonding effect between fibers and concrete, fibers exhibited different distribution patterns in concrete matrix, that could improve the compactness of concrete matrix through filling effect, optimize internal structure, and delay the connection and expansion of microcracks. The causes of the bonding effect between fibers and concrete was discussed from the perspective of chemical bonding effects. Based on the above analysis, the reinforcement mechanism of hybrid fibers on concrete was explored. Based on statistical damage theory, a damage constitutive equation for hybrid fiber reinforced low heat cement concrete considering fiber volume fraction was established by modifying the model parameters, and the model curve fitted well with the experimental curve.

Properties of magnesium phosphate cement reinforced with natural brucite fiber

Magnesium phosphate cement (MPC) is widely utilized owing to its excellent properties. However, MPC is a chemically bonded material; therefore, it has the disadvantage of being highly brittle. The introduction of fibers is a simple and effective way to improve its toughness. Therefore, this study was focused on the effects of brucite fiber (BF) on the working properties, mechanical properties, hydration products, and microstructure of MPC. X-ray diffraction, thermogravimetric (TG) analysis, mercury intrusion porosimetry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared (FTIR) spectroscopy were used to analyze the hydration products and microscopic morphology of the specimens. The results showed that the addition of BF reduced the fluidity of the MPC slurry, slightly prolonged the setting time, and reduced the hydration temperature. BF significantly enhanced the mechanical properties of MPC, particularly its flexural strength, which increased with an increase in BF content. The 7-d and 28-d strengths of the specimens with 20 % BF content increased by 72.5 % and 70.0 %, respectively, compared with the reference group. TG analysis showed that BF promoted the production of the hydration product K-struvite, and K-struvite production was almost saturated at 20 % BF doping. The SEM, EDS, and FTIR spectroscopy results showed that the MPC composite matrix containing BF had a denser structure. Moreover, bonding between the fibers and matrix was enhanced, owing to the involvement of BF in the hydration reaction. Additionally, the structure was more solid, which led to a significant decrease in brittleness and an improvement in other properties of the MPC.

Fiber-Reinforcing Effect in the Mechanical and Road Performance of Cement-Emulsified Asphalt Mixtures

Cement-emulsified asphalt mixture (CEAM), a kind of cold mix asphalt mixture, has the advantages of energy conservation and emission reduction as well as easy construction. However, the performance of CEAM is not as good as hot mixed asphalt mixtures. Hence, in this study, two different fibers were adopted as the reinforcing phase to improve the comprehensive properties of CEAM. The results indicated that the addition proportion and curing time were crucial to fiber-reinforced cement-emulsified asphalt mixture (FRCEAM). The compressive strengths, water stability, and raveling resistances of FRCEAM preparations with polyester or brucite fibers (FRCEAM-PF and -BF, respectively) were enhanced significantly. FRCEAM-PF had the maximum flexural tensile strength and strain, which meant that its low-temperature performance was the best compared to FRCEAM-PF and CEAM. However, the contribution of PF to CEAM high-temperature stability was greater than that of BF. Fiber addition to CEAM not only enhanced the cycles of fatigue loading but also reduced sensitivity to changes in stress level. Furthermore, FRCEAM-BF durability was slightly better than that of FRCEAM-PF. SEM analysis indicated that fibers provided bridging and meshing effects. Although PF and BF showed different enhancement effects, both mixtures met the requirements for hot mixed asphalt mixtures.

Brucite fibers on performance improvement and mechanism of high-temperature slag cementing slurries

At temperatures greater than 70 °C, the introduction of air in the slurry preparation process in slag hydration of solidified stone produces cracking and thermal stresses. In the study, slag cementing slurries at 90 °C were used to join brucite fibers. The mechanical performance, toughening mechanism, and microstructural changes were studied using tensile tests, XRD, TGA, SEM, IR, and triaxial tests. After curing for 14 and 28 days, the compressive and tensile strengths of 6 wt% brucite fiber-reinforced slag increased by 69.08 and 45.98% and 73.58 and 69.08%, respectively, while the elastic modulus decreased 8.4% compared to the control samples The brucite fibers were randomly distributed in the slag cementing slurries, resulting in a toughened material via energy dissipation caused by bridging peel and pulling-out. This result provides theoretical background to solve strength attenuation and cracking phenomenon at high temperature in solidified slag stones.

Effect of brucite fibers and early strength agent on cement stabilized macadam in Alpine regions

This paper aims to study the mechanical performance and durability properties of the brucite fiber reinforced cement stabilized base at the low-temperature condition. Five type samples with different fiber content were prepared, and the related mechanical performance and durability properties were examined. The test results indicated that the added brucite fiber could enhance both the mechanical and durability performance of the cement stabilized base. Specifically, it was found that the unconfined compressive/splitting tensile strength can reach at 3-day age and 7-day age could reach 41%/37% and 67%/67% respectively compared to the results at 28-day age. Furthermore, the added brucite fiber can reduce the drying shrinkage of the cementitious material and also improve its resistance to frost damage. The X-ray diffraction and Scanning Electron Microscopy tests were further conducted to examine the improvement mechanism of the brucite fiber reinforcement. It is found that the hydration degree of cement paste was enhanced with the added brucite fiber. The designed brucite fiber cement stabilized sample in this study is suitable for pavement construction in alpine regions.

Uniaxial compression mechanical properties and fracture characteristics of brucite fiber reinforced cement-based composites

In this work, the mechanical properties, stress-strain behaviors, and microstructure of brucite fiber reinforced cement-based composites are determined. The results reveal that the incorporation of brucite fiber limits the compressive strength reinforcement of cement-based composite but leads to a significant increase of tensile strength by 136% and flexural strength by 73%. The employment of brucite fiber increases the fracture toughness KIcS and KIcQ of the cement-based composite by 450% and 98%. The incorporation of brucite fiber increases the linear elastic fracture toughness energy GF by 455% and elastic-plastic fracture toughness energy JC by 279%. The constitutive model of brucite fiber reinforced cement paste is also established. The diameter of the brucite fiber bundle is 1.5–16.3 μm, and the diameter of the single dispersed fiber is around 45–110 nm. There are about 15–363 single fibers in a bundle. Due to the brucite fiber possesses an intrinsic fibrous anisotropy, and network topology, the brucite fiber reinforced cement composites exhibit advantages of greater bending strength and crack bridging, as well as better crack resistance properties.

The interface interaction behavior between E. coli and two kinds of fibrous minerals.

In the present, studies of interaction between human normal flora and fibrous mineral are still lacking. Batch experiments were performed to deal with the interaction of Escherichia coli and two fibrous minerals (brucite and palygorskite), and the interface and liquid phase characteristics in the short-term interaction processes were discussed. The bacterial concentrations, the remnant glucose (GLU), pyruvic acid, and the activity of β-galactosidase and six elements were measured, and the results show that the promoting effect of brucite on the growth of E. coli was more significant than that of palygorskite. FTIR and XRD analysis results also confirmed E. coli has obviously dissolved on brucite and damage effect on palygorskite silicon structure. SEM results show that the interfacial contact degree between E. coli cells and brucite fibers was higher than that of palygorskite. These may be due to the zeta potential difference between E. coli and palygorskite was 14.57-22.37mV, while it of brucite was 44.04-64.24mV. The elements dissolving of two fibrous minerals not only increased regularly to liquid EC but also had a good buffer effect to the decrease of liquid pH. Studies of short-term interaction between E. coli and brucite and palygorskite can help to understand the effect of fibrous minerals on microeubiosis of human normal flora and the contribution of microbial behaviors on the fibrous minerals weathering in the natural environment.

Study of Pre-Dispersive Technology of Brucite Fiber and the Composite Insulation Board <sup></sup>

This paper has compared different kinds of dispersive technologies for brucite fiber mineral, and researched the industrial application of composite insulation board. Compared with the ball-milling treatment and the ultrasonic disperser craft techniques, the high speed mechanical stirring is preferential. The dispersive degree of three dispersants shows a trend as OT > FDN > PCA ®(IV), and the system of suspension with OT penetrant is stable under the designed ratios. The optimal fabrication progress is as the ratio of water and fiber is 18:1, the dosage of OT is 15 wt.% of brucite fiber, the stirring time is 60 min, and the stirring speed is 1200 r/min. Whit the appropriate dosage of brucite fiber (down to 15 wt.% of total fibers mass ) can improve the pore structure of the insulation board, which is benefit to the thermal insulation properties. The results revealed that the brucite fiber could partially replace chrysotile fibers in the composition of insulation board.

Laboratory investigation on the brucite fiber reinforced asphalt binder and asphalt concrete

To investigate the modification of brucite fiber, fiber reinforced asphalt binder and asphalt mixtures were prepared and tested. Lignin fiber, basalt fiber and polyester fiber were used for comparative studies. Water absorption, oven heating, mesh-basket draindown were designed to evaluate the fiber wettability, thermostability, asphalt absorption and stabilization. Cone penetration test and dynamic shear rheometer test were applied to research the shear resistance rheological property and rutting resistance of fiber reinforced asphalt. In addition, the microstructure of fibers and reinforced asphalt binders were analyzed via scanning electron microscopy. Moreover, the engineering properties, containing high temperature stability, low temperature cracking resistance and moisture susceptibility, were conducted. Results show that brucite fiber has a better state of preservation in humid environment and thermostability than lignin fiber. It obtains a better effect on asphalt absorption and stabilization than basalt fiber and polyester fiber. Besides, the brucite fiber can effectively improve the rutting resistance and shear prevention of asphalt binders. The brucite fiber obtains a spatial networking to enhance the adhesion and stabilization of asphalt binders. The results also indicate that the asphalt mixture mixed with brucite fiber shows great high temperature stability, low temperature cracking resistance and moisture susceptibility.

Laboratory Investigation of Brucite Fiber in Stabilizing and Reinforcing Asphalt Binder

The purpose of this study is to evaluate brucite fiber's properties, stabilizing and reinforcing effects, and corresponding mechanism when used for asphalt binder. Commonly used fibers such as lignin fiber, basalt fiber, and polyester fiber were chosen for comparative studies. Laboratory tests of water absorption, oven heating, and mesh-basket draindown were designed and performed to evaluate their wettability, thermostability, asphalt absorption, and stabilization, respectively. The cone penetration test was applied to study the resistance to shear of fiber modified asphalt; the standard dynamic shear rheometer test was conducted to evaluate the rheological properties and rutting resistance of fiber modified asphalt; and Scanning Electron Microscopy (SEM) analyses was introduced to observe fiber's microstructure characteristic and its spatial network in asphalt binder. The results indicate that brucite fiber has improved the moisture susceptibility property and thermostability more than lignin fiber. It has better asphalt absorption and stabilization effects than basalt fiber and polyester fiber. Meanwhile, brucite fibers can effectively improve asphalt binder's resistance to rutting and shear, and dynamic shear modulus. Brucite fiber can effectively reinforce the asphalt matrix through its functions of spatial networking, adhesion and stabilization of asphalt binder.

Investigation of Usability of Brucite Fiber in Asphalt Mixture

The objective of this study is to investigate the usability of brucite fiber in asphalt mixture. In order to compare the characteristics of brucite fiber with other fibers usually used in asphalt mixtures, the water absorption test, oven heating test, Mesh-basket draindown test, and scanning electron microscopy are conducted on brucite fiber, lignin fiber, basalt fiber, and polyester fiber. Also, the Marshall test, wheel tracking test, low temperature bending test, water sensitivity test, and fatigue test are used to evaluate the performance of different fiber-reinforced asphalt mixtures. These experimental results show that brucite fiber has a good state of preservation in the moist storage environment, and its thermo-stability is better than lignin fiber. Its absorption and adhesion of asphalt is better than basalt fiber and polyester fiber. The best performance of asphalt mixtures are obtained for 0.40% brucite fiber content. Asphalt mixture prepared with brucite fiber also has excellent high temperature stability, water sensitivity, and fatigue property, especially low temperature properties. Addition of brucite fiber is feasible to improve major performance properties of asphalt mixture.

Structural characteristics, dispersion, and modification of fibrous brucite

Fibrous brucite has very unique structure and physical properties. Brucite fibers were exfoliated into single nanofibers by using dioctyl sodium sulfosuccinate (AOT) as a dispersant through mechanical agitation and ultrasonic dispersion; and then, the nanofibers were modified by stearic acid and (3-aminopropyl)triethoxysilane (γ-APS) compound modification agent. The nanofibers were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis. It is found that AOT has good effect on the dispersion. The single fiber has a consistent morphology, and fibrous brucite is dispersed and modified without destroying the crystal structure. Infrared and thermal analysis shows that the surface modification of fibrous brucite is achieved by forming chemical bonds between the coupling agent and magnesium hydroxide.

Mechanical Property of Brucite Fiber Reinforced Composite Material

In this paper, microstructure of brucite fiber was introduced briefly and its physical and chemical properties were given. Disperse method of fiber applied in concrete has been introduced. The effect of compressive strength, flexural strength of concrete and cement mortar by the addition of brucite fiber have also been discussed. The mechanism that fiber can reinforce concrete has been discussed. The results showed that the diameter of brucite fiber changes from micrometer scales to nanometer dimension with the dispersing action of water reducers. Brucite fiber can exert its high tensile strength on concrete and improve the mechanical property of cement motar and concrete. Life of bructie fiber reinforced composite material can be prolonged by the addition of brucite fiber.

High Temperature Rheological Characteristics of Brucite Fiber Modified Asphalt Mastics

The rheological properties of brucite fiber asphalt mastics are studied by the Brookfield viscosity test in this paper. The results show that at 105°C and 120°C, brucite fiber asphalt mastics shows the characteristics of non-Newtonian fluid. At 135°C and 150°C, it shows the characteristics of Newtonian fluid gradually. When the temperature is higher than 150°C, the asphalt mastics has fully manifested the characteristics of Newtonian fluid. The viscosity increases with the increasing of the dosage of brucite fiber. The value of ZSV increases with the increasing of the dosage of brucite fiber. According to the change law of ZSV, the anti-rutting performance of asphalt mastics is improved by the addition of brucite fiber.

Low Temperature Anti-Cracking Performance of Brucite-Fiber-Reinforced Asphalt Concrete

As a naturally occurring fibrous mineral abundant in China, it is not common to use the brucite fiber as the reinforcement in asphalt concrete to improve its anti-cracking property in low temperature until now. Laboratory experiments are made on the brucite fiber asphalt binder and the brucite fiber asphalt concrete in this paper. Effects of the dosage of the brucite fiber on anti-crack properties of asphalt binder and brucite fiber asphalt concrete in low temperature are also studied. The contrast test is made between brucite fiber, lignin fiber and basalt fiber. Test results show that the value of the ductility, the compliance in extension and the yield strain energy of asphalt binder decreases with the increasement of the dosage of brucite fiber. However, the temperature sensitivity property of asphalt binder in low temperature can be improved. The anti-crack properties especially the maximum bending stress and the maximum bending strain are improved by adding the proper quantity of brucite fiber in asphalt concrete. According to the test results, the optimum quantity of brucite fiber was about 0.4 wt.% of asphalt. Based on the contrast test, the brucite fiber is better than the lignin fiber on improving the anti-crack properties of the asphalt concrete, but which is similar to the basalt fiber.

Preparation of natural brucite nanofibers by the dispersion method

The preparation of natural brucite nanofibers through dispersion by the wet process is described. The test results indicate that brucite fibers can be well dispersed by using sodium dioctyl sulfosuccinate (OT) as the dispersant at a dispersant/fiber mass ratio of 0.15:1, dispersing for 30 min at a water/solid mass ratio of 20:1. The prepared nanofibers were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). It is shown that the prepared single brucite nanofiber is around 30 nm in diameter and the talus of the nonsingle brucite nanofibers is about 50-150 nm in diameter. Natural brucite mineral fibers were treated by the dispersion method to obtain nanomaterials. These fibers have significant advantages over artificial nanofibers both in yield and in cost.

Investigation of brucite-fiber-reinforced concrete

Laboratory experiments were made on the brucite-fiber-reinforced concrete composites. Effects of brucite fiber grades and the dosage on flexural strength, compressive strength, impact strength, sulfate corrosion resistance and the slump, cohesiveness, as well as the water retentiveness were also investigated. Different water reducers were tested. The particle-size characteristics of brucite fibers, the densities of the concrete, and the viscosities of the fiber/water-reducer suspensions were also measured. Results show that proper addition of brucite fibers in concrete can improve the mechanical properties, especially the flexural strength. In the test, the optimum quantity was about 0.5 wt.% of concrete. With the dosage increase of brucite fibers in concrete, the fluidity and the density of the concrete decrease. The performance of the concrete strengths is the collective interactions of the fiber reinforcement and the density reduction. The aspect ratio and the surface area of brucite fibers are the important affecting factors to the workability and the mechanical properties of the fiber concrete. Larger aspect ratios and smaller surface areas benefit the reinforcement. Water reducers with lower fiber suspension viscosities are favorable in improving the workability and strengths of the brucite fiber concrete.