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This paper presents the modification results and effects of reinforcing green polyethylene terephthalate matrix composites (bioPET ECOZEN® T120) with basalt fibers of two different lengths. Five types of composites with two filling levels of 7.5 and 15 wt% of each fiber were produced by injection molding. Basic mechanical and processing properties, microstructure photographs, and reinforcement effects were analyzed and low- and high-cycle fatigue tests were performed. A significant increase in strength and stiffness was observed (especially for short fibers) proportional to the amount of fibers; longer fibers would also increase the deformation capacity of the composite. Furthermore, longer fibers would reduce relaxation processes (creep) but would not increase the dissipation capacity and mechanical energy. Predictability of fatigue effects enables optimal environmentally friendly materials to be designed. [ABSTRACT FROM AUTHOR]

This paper presents the modification results and effects of reinforcing green polyethylene terephthalate matrix composites (bioPET ECOZEN® T120) with basalt fibers of two different lengths. Five types of composites with two filling levels of 7.5 and 15 wt% of each fiber were produced by injection molding. Basic mechanical and processing properties, microstructure photographs, and reinforcement effects were analyzed and low- and high-cycle fatigue tests were performed. A significant increase in strength and stiffness was observed (especially for short fibers) proportional to the amount of fibers; longer fibers would also increase the deformation capacity of the composite. Furthermore, longer fibers would reduce relaxation processes (creep) but would not increase the dissipation capacity and mechanical energy. Predictability of fatigue effects enables optimal environmentally friendly materials to be designed.

The effect of using basalt fibers on the fresh, mechanical, durability, and corrosion properties of reinforced concrete was investigated in this study. The study was performed using different basalt fiber volume fractions of 0.15%, 0.30%, 0.45%, and 0.50%, while two different water/cement (w/c) ratios of 0.35 and 0.40 were utilized. The results were compared to conventional concrete (PC) as well as steel fiber concrete (SFC) with 0.30% and 0.50% steel fibers volume fractions. An extensive experimental program of 336 samples was conducted in four stages as follows: testing for fresh properties included slump and unit weight tests; mechanical properties testing included compressive strength tests, split tensile strength tests, flexural strength tests, and average residual strength tests; durability testing included unrestrained shrinkage and surface resistivity tests; and a Rapid Macrocell corrosion evaluation test for corrosion properties. The test results showed that the use of basalt fibers reduces slump values as the fiber volume fraction increases; however, with the use of the appropriate amount of High Range Water Admixture (HRWA), target slump values can be achieved. Moreover, a considerable improvement in the compressive, tensile, flexural, average residual strength and durability properties was achieved in case of using basalt fibers. On the other hand, corrosion rates increased with the increase in fiber volumes. However, it can be concluded that utilizing a 0.30% fibers volume fraction is the optimum ratio with an overall acceptable performance with respect to mechanical and corrosion properties.

In an attempt to increase the low-velocity impact response of natural fiber composites, a new hybrid intraply woven fabric based on flax and basalt fibers has been used to manufacture laminates with both thermoplastic and thermoset matrices. The matrix type (epoxy or polypropylene (PP) with or without a maleated coupling agent) significantly affected the absorbed energy and the damage mechanisms. The absorbed energy at perforation for PP-based composites was 90% and 50% higher than that of epoxy and compatibilized PP composites, respectively. The hybrid fiber architecture counteracted the influence of low transverse strength of flax fibers on impact response, irrespective of the matrix type. In thermoplastic laminates, the matrix plasticization delayed the onset of major damage during impact and allowed a better balance of quasi-static properties, energy absorption, peak force, and perforation energy compared to epoxy-based composites.

Nowadays, innovative materials are more frequently adopted for strengthening historical constructions and masonry structures. The target of these techniques is to improve the structural efficiency with retrofitting methods while having a reduced aesthetical impact. In particular, the use of basalt fiber together with a cementitious matrix emerges as a new technique. This kind of fiber is obtained by basalt rock without other components, and consequently it could be considered a natural material, compatible with masonry. Another innovative technique for strengthening masonry columns consists of applying steel wires in the correspondence of mortar joints. Both techniques have been recently proposed and some aspects of their structural performances are still open. This paper presents the results of an experimental study on the compressive behavior of clay brick masonry columns reinforced either with Basalt Fiber–Reinforced Cementitious Matrix (BFRCM) or with steel wire collaring. Uniaxial compressive tests were performed on eight retrofitted columns and four control specimens until failure. Two masonry grades were considered by varying the mix used for the mortar. Results are presented and discussed in terms of axial stress-strain curves, failure modes and crack patterns of tested specimens. Comparisons with unreinforced columns show the capability of these techniques in increasing ductility with limited strength enhancements.

The effect of using basalt fibers on the fresh, mechanical, durability, and corrosion properties of reinforced concrete was investigated in this study. The study was performed using different basalt fiber volume fractions of 0.15%, 0.30%, 0.45%, and 0.50%, while two different water/cement (w/c) ratios of 0.35 and 0.40 were utilized. The results were compared to conventional concrete (PC) as well as steel fiber concrete (SFC) with 0.30% and 0.50% steel fibers volume fractions. An extensive experimental program of 336 samples was conducted in four stages as follows: testing for fresh properties included slump and unit weight tests; mechanical properties testing included compressive strength tests, split tensile strength tests, flexural strength tests, and average residual strength tests; durability testing included unrestrained shrinkage and surface resistivity tests; and a Rapid Macrocell corrosion evaluation test for corrosion properties. The test results showed that the use of basalt fibers reduces slump values as the fiber volume fraction increases; however, with the use of the appropriate amount of High Range Water Admixture (HRWA), target slump values can be achieved. Moreover, a considerable improvement in the compressive, tensile, flexural, average residual strength and durability properties was achieved in case of using basalt fibers. On the other hand, corrosion rates increased with the increase in fiber volumes. However, it can be concluded that utilizing a 0.30% fibers volume fraction is the optimum ratio with an overall acceptable performance with respect to mechanical and corrosion properties. [ABSTRACT FROM AUTHOR]

Textile Reinforced Mortar (TRM) composite systems are gaining consensus within the scientific and technical communities as a viable and advantageous alternative to the most conventional Fibre-Reinforced Polymer (FRP) composites. Due to the good compatibility both in terms of stiffness and vapor permeability between the inorganic matrix and the substrate, the TRMs appear to be particularly well suited for strengthening masonry members and enhancing their capacity to withstand tensile and shear stresses, such as those induced by seismic shakings. This paper aims to investigate the mechanical response of a TRM system featuring an internal reinforcement made of basalt fiber textile. Therefore, the paper reports the results of an experimental campaign carried out by single-lap shear bond tests on masonry substrate reinforced by TRM strips. Three different kinds of TRM have been taken into account, each one characterized by a variable number of fabric plies. The results show that, in all cases, TRMs fail prematurely due to debonding between fabric and matrix. However, the aforementioned premature failure is the main concern emerging from these test results, and further work is requested in reformulating the matrix composition towards enhancing their tensile strength and, hence, restraining the occurrence of fabric-to-matrix debonding. [ABSTRACT FROM AUTHOR]

In an attempt to increase the low-velocity impact response of natural fiber composites, a new hybrid intraply woven fabric based on flax and basalt fibers has been used to manufacture laminates with both thermoplastic and thermoset matrices. The matrix type (epoxy or polypropylene (PP) with or without a maleated coupling agent) significantly affected the absorbed energy and the damage mechanisms. The absorbed energy at perforation for PP-based composites was 90% and 50% higher than that of epoxy and compatibilized PP composites, respectively. The hybrid fiber architecture counteracted the influence of low transverse strength of flax fibers on impact response, irrespective of the matrix type. In thermoplastic laminates, the matrix plasticization delayed the onset of major damage during impact and allowed a better balance of quasi-static properties, energy absorption, peak force, and perforation energy compared to epoxy-based composites. [ABSTRACT FROM AUTHOR]