Ductility and flexure of lightweight expanded clay basalt fiber reinforced concrete slab

Relevance. The load on a reinforced concrete slab with high strength lightweight aggregate concrete leads to increased brittleness and contributes to large deflection or flexure of slabs. The addition of fibers to the concrete mix can improve its mechanical properties including flexure, deformation, toughness, ductility, and cracks. The aims of this work are to investigate the flexure and ductility of lightweight expanded clay concrete slabs reinforced with basalt fiber polymers, and to check the effects of basalt fiber mesh on the ductility and flexure. Methods. The ductility and flexural/deflection tests were done on nine engineered cementitious composite (expanded clay concrete) slabs with dimensions length 1500 mm, width 500 mm, thickness 65 mm. These nine slabs are divided in three reinforcement methods types: three lightweight expanded clay concrete slab reinforced with basalt rebars 10 mm (first slab type); three lightweight expanded clay concrete slab reinforced with basalt rebars 10 mm plus dispersed chopped basalt fiber plus basalt fiber polymer (mesh) of cells 2525 mm (second slab type); three lightweight expanded clay concrete slab reinforced with basalt rebars 10 mm plus dispersed basalt fiber of length 20 mm, diameter 15 m (third slab type). The results obtained showed physical deflection of the three types of slab with cracks. The maximum flexural load for first slab type is 16.2 KN with 8,075 mm deflection, second slab type is 24.7 KN with 17,26 mm deflection and third slab type 3 is 32 KN with 15,29 mm deflection. The ductility of the concrete slab improved with the addition of dispersed chopped basalt fiber and basalt mesh.

The Effectiveness of Basalt Fiber in Lightweight Expanded Clay to Improve the Strength of Concrete Helicoidal Staircase

Staircase is a very important structural element found in mostly buildings of more than a floor. The properties of materials and designs used in constructing this structural element are very important. This study addresses the development of ultra-lightweight concrete. How ultra-lightweight concrete can effectively work in helicoidal structure. The flexural strength of this staircase was analysed on a finite element software SCAD. The designed lightweight aggregates concrete is targeted to be used in staircase of a structure having the shape of helicoid. In the concrete, chopped basalt fiber portion was added to each concrete mixture specimen reinforced as reinforcement. The basalt fiber percentages used are 0, 0.45, 0.9, 1.2 and 1.6. The developed lightweight expanded clay basalt fiber concrete showed significant increase in the flexural strength. The loads applied on this helicoidal concrete staircase in SCAD were derived from the laboratory experiments conducted on the concrete specimens on the 28 days curing period. This combination of values exceeds, to the researchers' knowledge, the performance of all other lightweight building materials. Furthermore, the developed lightweight concrete possesses excellent durability properties.

Improving the compressive strength of lightweight cylindrical concrete column with basalt fiber reinforced polymer acting under imposed load

Relevance. The brittleness of lightweight concrete has developed concern among structural engineers. This concern led to the search on how to improve the strength of lightweight concrete and still retain the weight lightness. Researches are ongoing to solve the strength challenges noticed in lightweight concrete, but at the moment there are few works on solving the issues regarding expanded clay concrete, thus it served as a motivation for studying this issue. The aim of the work is to analyze the effects of basalt fiber polymers on lightweight expanded clay concrete columns acting under imposed loads. Methods. To achieve this process, a total number of nine expanded clay cylindrical concrete columns were experimentalized and analyzed. 1.6 % of dispersed chopped basalt fiber was used in the concrete mixture which serves as reinforcement. Also, basalt fiber mesh was used in the experimental analysis. Results. The expanded clay cylindrical column without basalt fiber polymer withstood strength up to 19.6 tons at 58 minutes, the column with dispersed chopped basalt fiber withstood strength up to 26.67 tons at 61 minutes while the column with dispersed chopped basalt fiber and basalt mesh confinement got destroyed at 29 tons at 64 minutes. The results show that lightweight expanded clay cylindrical columns confined with basalt fiber mesh withstood higher load compared to the columns with just dispersed chopped basalt fiber and without it.

Numerical Analysis of Mechanical Properties of Chopped Basalt Fiber Reinforced Concrete

In order to study the influence of the blending of chopped basalt fiber on the mechanical properties of concrete, this paper uses basalt fiber content as a variable to simulate the basalt fiber concrete. Simulate its cubic compression, axial compression, splitting tensile, flexural test and working performance, and compare the simulation results with other people's physical and mechanical test data. The results show that the addition of basalt fiber has a great influence on the crack resistance and mechanical properties of concrete.

The effects of fiber silane modification on the mechanical performance of chopped basalt fiber/ABS composites

The purpose of this study was to examine the effects of silane coupling agent modifications on the mechanical performance of the basalt fiber (BF)-reinforced acrylonitrile–butadiene–styrene (ABS) composites. Three different silane coupling agents were used. The mechanical properties of the composites were determined by the tensile, flexural, impact tests, and dynamic mechanical analysis (DMA). According to the test results, the tensile strength increased with the use of (3-aminopropyl) triethoxysilane (AP) and 3-(trimethoxysilyl) propylmethacrylate (MA), while the use of (3-glycidyloxypropyl) trimethoxysilane (GP) reduced the tensile strength. All the silane modifications improved the flexural strength and modulus and the highest improvement was achieved with the use of AP. No remarkable difference was observed in impact properties with the use of silane coupling agents. The addition of BF significantly improved the elastic modulus of the ABS regardless of the modification type, while the further improvements were achieved through the use of AP and MA. In brief, AP showed the highest performance among the studied silane coupling agents due to the covalent bond formation between the amino group of AP and the nitrile group of styrene–acrylonitrile (SAN) matrix.

Flexural Behavior of Carbon Textile-Reinforced Geopolymer Composite Thin Plate

Textile-reinforced Portland cement-based concrete has been researched and developed over the last few decades. It was widely used in a different range of applications, such as repair and/or strengthening of structural elements, thin walls, lightweight structures, façade elements, and others. Due to its varied application, this study aims to develop the carbon textile-reinforced geopolymer composite. Specimens of rectangular form with the dimensions of 400 × 100 × 15 mm3, reinforced with carbon textile, were produced. Four-point bending test was used to evaluate the effect of carbon textile on the mechanical strength of reinforced geopolymer composite based on the three factors: the different mortar compositions corresponding to the addition of the chopped basalt fiber (BF), the number of carbon textile layers, and the different thicknesses of the mortar cover layer. Besides that, a small part of the pull-out test was also considered to assess the adhesion strength at the interface between carbon textile and geopolymer mortar. The experimental results from the four-point bending test showed that the mechanical strength of composite specimens increased when the content of the chopped basalt fiber increased. With the increasing number of the textile layers, the specimens improved the flexural strength significantly. However, the flexural toughness of the specimens reinforced with three textile layers did not improve, as compared to those reinforced with two textile layers. The experimental results for the specimens related to the mortar cover thicknesses indicated that specimens with the mortar cover thickness of 2 mm provide the best strength. The experimental results from the pull-out tests showed that all the specimens have the same failure mode by slipping of the fiber yarn from the matrix.