Basalt fibres: Mechanical properties and applications for concrete structures

Durability of GFRP and BFRP reinforcing bars in simulated seawater sea sand calcium sulfoaluminate cement concrete pore solution

Experimental investigation of tensile, compression, shear and flexural behaviour of basalt fibre and glass fibre reinforced polymer bars

Environmental impact on the durability of FRP reinforcing bars

This paper focuses on the interlaminar shear behavior of basalt fiber reinforced polymer (FRP) laminates impregnated with epoxy and vinyl ester resins as well as hybrid basalt and carbon FRP laminates. Meanwhile, the interlaminar shear behavior of carbon and E-glass FRP laminates was also studied for comparison. The experiments were conducted according to the ASTM-D-2344 standard, and the failure modes, load–deformation (L–D) relationships, and interlaminar shear stress to normalized deformation relationships of various FRP laminates were analyzed. The differences in interlaminar shear behavior among different fibers and resins were identified. The fracture surfaces of the laminate specimens with different fibers were examined by scanning electron microscopy. Furthermore, the hybrid effect on interlaminar shear behavior was discussed and the interlaminar shear strength was predicted based on above analysis. The results show that the L–D relationships of FRP laminates can be classified into three types, which are determined by the interlaminar shear strength between fiber layers and the resin as well as by the failure modes. The interlaminar shear strength of basalt FRP with vinyl ester resin is higher than that of the glass FRP but less than that of the carbon FRP. The adoption of epoxy resin and the hybridization of basalt and carbon fibers can enhance the interlaminar shear strength of basalt FRP. In addition, the scanning electron microscopy images of fracture surfaces of the laminate specimens confirm the differences of interlaminar behavior of various composites. The hybrid effect on the interlaminar shear behavior is reflected in the integration of both advantages of basalt FRP and carbon FRP in the interlaminar shear stress to nominal deformation relationship, which results in both higher interlaminar shear strength at the cracking and the final stages. Finally, the interlaminar shear strength of different FRP laminates can be accurately predicted by the proposed model.

Durability study of concrete-covered basalt fiber-reinforced polymer (BFRP) bars in marine environment

Purpose Building elements that are damaged by fire are often strengthened by fiber wrapping techniques. Self-compacting concrete (SCC) is an advanced building material that is widely used in construction due to its ability to flow and pass through congested reinforcement and fill the required areas easily without compaction. The aim of the research work is to examine the flexural behavior of SCC subjected to elevated temperature. This research work examines the effect of natural air cooling (AC) and water cooling (WC) on flexural behavior of M20, M30, M40 and M50 grade fire-affected retro-fitted SCC. The results of the investigation will enable the designers to choose the appropriate repair technique for improving the service life of structures. Design/methodology/approach In this study, an attempt has been made to evaluate the flexural behavior of fire exposed reinforced SCC beams retrofitted with laminates of carbon fiber reinforced polymer (CFRP), basalt fiber reinforced polymer (BFRP) and glass fiber reinforced polymer (GFRP). Beam specimens were cast with M20, M30, M40 and M50 grades of SCC and heated to 925ºC using an electrical furnace for 60 min duration following ISO 834 standard fire curve. The heated SCC beams were cooled by either natural air or water spraying. Findings The reduction in the ultimate load carrying capacity of heated beams was about 42% and 55% for M50 grade specimens that were cooled by air and water, respectively, in comparison with the reference specimens. The increase in the ultimate load was 54%, 38% and 27% for the specimens retrofitted with CFRP, BFRP and GFRP, respectively, compared with the fire-affected specimens cooled by natural air. Water-cooled specimens had shown higher level of damage than the air-cooled specimens. The specimens wrapped with carbon fiber could able to improve the flexural strength than basalt and glass fiber wrapping. Originality/value SCC, being a high performance concrete, is essential to evaluate the performance under fire conditions. This research work provides the flexural behavior and physical characteristics of SCC subjected to elevated temperature as per ISO rate of heating. In addition attempt has been made to enhance the flexural strength of fire-exposed SCC with wrapping using different fibers. The experimental data will enable the engineers to choose the appropriate material for retrofitting.

The behavior of fiber-reinforced polymer (FRP) bars under compression is not fully understood yet due to the limited research in this area. However, the long-term durability, weathering resistance, and exceptional mechanical properties of FRP bars justify the need for their use in compression members. The main objectives of this study are to evaluate the mechanical properties of glass FRP (GFRP) and basalt FRP (BFRP) bars under compression and examine their performances as main longitudinal reinforcements in reinforced concrete (RC) columns. In the first part of this research, a series of static compression tests were conducted on GFRP and BFRP bars of different diameters. The second part of this research numerically investigated the behavior of FRP-RC columns under concentric and eccentric loading using the mechanical properties of the FRP bars obtained experimentally. Nonlinear finite element models were developed to simulate the compressive behavior of the concrete columns reinforced with GFRP and BFRP bars. The FE models were verified with the experimental results conducted previously. The verified FE models are then utilized to conduct a parametric analysis considering two different column geometries and cross-sections, five reinforcement ratios, two concrete compressive strengths, three types of ties materials, and several loading eccentricities to develop a set of interaction diagrams that may provide valuable data for design purposes. The results indicated that the FRP bars could have a significant contribution to the overall capacity of FRP-RC columns by up to 35% of the total force at failure, depending on the reinforcement ratio. The performance of both the GFRP- and BFRP-RC columns was almost similar in terms of capacity, deflection, and bar strength contribution.

Experimental investigation on the flexural behaviour of basalt fibre reinforced polymer rebar concrete

Flexural behavior of basalt fiber-reinforced concrete slab strips reinforced with BFRP and GFRP bars

Experimental study on the fire resistance of RC beams strengthened with near-surface-mounted high-Tg BFRP bars

Experimental investigation into the flexural behaviour of basalt FRP reinforced concrete members

This study evaluates the static and fatigue bond behavior in basalt fiber-reinforced polymer (BFRP) bars embedded in concrete. For bond behavior under a mono-tensile load, BFRP bars with four types of surface patterns (round, rectangular, cross-winding, and spiral-winding) were adopted, and 20 groups of rib parameters were introduced for round-type BFRP bars. The bond–slip relationships and the influences of the above parameters on bond behavior were investigated. An analytical model for simulating the relationships of full bond slip was studied by data fitting. For bond behavior under cyclic loads, the relationship between stress levels and the number of cycles was investigated, and the slip of round-ribbed BFRP bars was studied with respect to the number of cycles. The results showed that the rectangular, cross-winding, and spiral-winding ribbed bars experienced serious wear, and that the average bond strength was approximately 80.6% of that of the round-ribbed bars. Thus, the bond behavior of the round rib is superior to those of the other surfaces. In addition, a bond–slip constitutive model for a BFRP bar is proposed, representing four main stages: a micro-slip stage, a slip stage, a descending stage, and a residual stage. Under cyclic loads, an equation was proposed for predicting fatigue life with a regression coefficient of 0.880, and a development law of slip was characterized as three stages: the linear increase stage, the steady increase stage, and the sharp increase stage, respectively.KeywordsBasalt fiber-reinforced polymer (BFRP)Rib parametersBond behaviorBond–slip constitutive lawFatigue life

Wood is a heterogeneous and anisotropic material, and its mechanical properties are different from other building materials. It is necessary to know the mechanical properties of wood materials in buildings, such as carriers, floor beams, roof timber, plywood roof covers, laminated beams, stair or wire poles, yacht poles, and furniture frames. Tensile strength is the resistance of wood material to two forces applied in opposite directions, trying to break and separate the fibers. This study aimed to determine the tension strength perpendicular to fibers of beech timber reinforced with basalt fiber-reinforced polymer (BFRP), glass fiber-reinforced polymer (GFRP), and plaster mesh (PSM). One component polyurethane (PUR-D4) and polyvinyl acetate (PVAc-D4) were used as the adhesive. The BFRP, GFRP, and PSM were added as one layer of reinforced materials. Experimental materials reinforced with BFRP, GFRP, and PSM were tested in the unreinforced locations, of reinforced lumber with BFRP, GFRP, and PSM. Tests were performed to investigate the tensile strength perpendicular to fiber (┴σt). The test results showed that the reinforcement process increased the (┴σ). The ┴σt value of samples reinforced with BFRP was 13%, 32%, and 66% higher than those reinforced with GFRP, unreinforced, and reinforced PSM, respectively. Accordingly, the BFRP shows potential to serve as an option for reinforced wood structural members.

The sudden occurrence of an earthquake induces a liquefaction effect on foundation soil, which causes a substantial increase in the uplift pressure acting on piles and causes structural damage to superstructures. This forms the basis of the necessity of experimenting with the behaviour of piles subjected to uplift loads and predicting their load-carrying capacity or resistance. Fibre-reinforced polymer (FRP) wraps are widely used for strengthening and retrofitting piles subjected to damage. The current study is aimed at determining the uplift load-carrying capacity or resistance of piles wrapped with basalt fibre-reinforced polymer (BFRP) and glass fibre-reinforced polymer (GFRP) sheets by experiment. Preliminary tests were conducted to identify the influence of BFRP and GFRP wraps on the mechanical strength properties of concrete. The mechanical strength of the specimen with the double wrapping of basalt and glass fibres in the perpendicular direction outperformed all other specimens. Moreover, the piles were wrapped with laminates and experimented on for their uplift capacity in dry and submerged conditions. The results indicate a considerable improvement in the uplift resistance of the piles compared with the unconfined piles. The BFRP and GFRP wraps improved the uplift resistance of the piles by 35.56% and 15.56%, respectively, higher than the unconfined pile for dry conditions. The angle of the interfacial friction in dry and submerged states was observed to be the maximum for the perpendicular direction for both of the FRP wraps, and the failure modes were compared. The simulated model showed a significant correctness for determining the uplift resistance of FRP-wrapped piles in dry and submerged states. The degree of agreement in the dry condition for the experimental results and finite element method was more than 94% for all fibre wraps.

Continuously reinforced concrete pavement (CRCP) does not require any contraction joints which is a high-performance pavement structure type that just need a sufficient number of reinforced pavement longitudinal configuration to constrain sideway random crack width. With continuous basalt fiber as reinforced material and synthetic resin as the matrix material and adding appropriate adjuvants, basalt fiber reinforced polymer (BFRP) bar form a new type of material after pultrusion processing and surface treatment technologies. BFRP on the mechanical properties were studied by two kinds of test methods which are using extensometer strain detection and fiber optic strain sensing and the parameter of homegrown BFRP bars mechanical properties. Because of the lower tensile elastic modulus of BFRP bars compared with rebar, the mechanical properties of basalt fiber-steel wire composite bar has been studied along with the research corrosion and flexural properties of BFRP bar.