Fiber-reinforced Concrete Research Articles

An effect of nano alumina and nano titanium di oxide with polypropylene fiber on the concrete: mechanical and durability study

For a long time, researchers have worked to improve the qualities of cement-based mixes. Because of their small size, strong reactivity, and huge surface area, nanoparticles are becoming more and more regarded as one of the greatest substitutes for cement because of their capacity to increase durability and strength. This work presents the results of an experimental investigation into the strength and durability properties of fiber-reinforced concretes with polypropylene (PP) fibers added to the concrete by volume and nano Al2O3 and nano TiO2 are used as partial substitutes for cement. Nano Al2O3 and nano TiO2 particles used ranged in size from 30 to 300 nm. The specimens were cast using cement blended nano Al2O3 and nano TiO2 percentages of 1%, 2%, 3%, and 4% by weight of cement. M55 grade concrete was employed for the casting process. The addition of PP fibers to the concrete was 0.5% by volume. The specimens underwent a battery of mechanical tests, including microstructural testing, compression testing, split tensile strength testing, and rupture modulus testing. Furthermore, tests for durability factors such as porosity, sorptivity, and degradation were conducted, and the findings are presented. By comparing the outcomes, it was shown that the inclusion of 0.5% PP fibers and 2% nano Al2O3 or nano TiO2 improved the mechanical qualities, but a decrease followed this in strength. The findings demonstrated that 2% nano Al2O3 combined with 0.5% PP fiber had a greater mechanical strength than 2% nano TiO2.

Optimization of Mechanical Properties and Durability of Steel Fiber-Reinforced Concrete by Nano CaCO3 and Nano TiC to Improve Material Sustainability

To meet the growing demand for sustainable building materials in modern construction projects, nanomaterials are widely used in concrete to improve its mechanical properties, durability, and environmental adaptability. The effects of different calcium carbonate nanoparticles (NC) and titanium carbide nanoparticles (NT) substitution rates (0%, 0.5%, 1% and 1.5%) on the mechanical and durability properties of steel fiber-reinforced concrete (SFRC) were analyzed by experimental studies. We also analyzed the evolution of the microstructure, chemical composition, and the evolution of functional groups of concrete by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The results demonstrated that NC replacement of 0.5% and NT replacement of 1% was the optimal combination for the preparation of composite concrete. Compared to SFRC with 0% substitution for both NC and NT (CG), the 28-day compressive strength of NC0.5NT1 increased by 35.5%, the flexural strength increased by 26.5%, and the splitting tensile strength increased by 16.3%. The durability performance of SFRC has been significantly improved. After 150 freeze–thaw cycles, the quality loss rate of SFRC cured for 28 days decreased by 40.6%, and the relative dynamic elastic modulus increased by 7.7%. Microscopic analysis indicates that an appropriate amount of NC and NT replacing cement improves the hydration reaction process of SFRC, increases the content of chemically more stable C-S-H gel, but does not change the types of hydration products of the cement. NC and NT have a filling effect, improving the pore structure of concrete, which helps enhance the mechanical and durability performance of concrete. The results of the study provide a theoretical basis for the application of NC and NT as reinforcing particles for cementitious materials in sustainable building materials.

Regolith-Rich PEEK Composite Bricks: Steps Towards Space-Ready Lunar Construction Materials

This study introduces a novel composite construction material composed of lunar regolith combined with PEEK in dry powder form. The work demonstrates significant advantages over alternative methods, primarily by reducing production power consumption and simplifying the manufacturing process. Building on previous research that explored binder optimization through process simplification and targeting predefined shapes, this work delves deeper into a comparative analysis of high-performance thermoplastics. Among the various options, PEEK demonstrates the most favorable properties. The study investigates key processing parameters and evaluates the effects of vacuum processing and temperature testing on mechanical properties. The research also evaluates the effects of vacuum processing and temperature testing to assess the material’s performance under lunar conditions. Comparative analysis is performed with standard performance of various reinforced and unreinforced concretes and with standard requirements for construction bricks as per ASTM standards. This shows that the composite, with an organic binder content as low as 5 wt%, has great potential. Notably, the improvements achieved through vacuum curing ensure compliance with lunar environmental conditions and alignment with most Earth-based engineering standards. Samples compacted at 7.50 MPa with 10 wt% binder, and tested at room temperature, achieve a compression strength of 16.3 MPa, exceeding that of industrial floor bricks and matching that of building bricks used on Earth. Bending strength (7.4 MPa) aligns with steel fiber-reinforced and high-strength concretes. Vacuum curing further enhances these properties, with an observed increase of +66% in bending strength and +33% in compression strength.

A review of five years’ experience on the effect of fibers on the autogenous healing of Ultra High-Performance Fiber-Reinforced Concrete

A review of five years’ experience on the effect of fibers on the autogenous healing of Ultra High-Performance Fiber-Reinforced Concrete

Digital-image Correlation and Cohesive Fracture Analysis of Fibre-reinforced Concrete Experiments: The Sergipe Test

Fibres are added to the concrete mix to improve its tensile strength and fracture properties, and they are used in several engineering applications. Therefore, fracture energy is a well-known quantity worth measuring. Some experiments in the technical literature are designed to quantify fracture energy. This paper proposes a new experiment to analyze the mechanical properties of fibre-reinforced concrete, named the Sergipe test. Such experiment consists of a square hollowed specimen submitted to a flexural test, where tensile cracks appear in different locations. Digital image correlation was used to analyze the cracking behaviour and crack opening displacement (COD). Regarding the experimental results of the Sergipe test, both specimens reached similar force-displacement and force-COD results despite different cracking locations at the specimens’ bottom. Such characteristics might indicate the suitability of the proposed experiment for fracture energy measurement. Regardless, the proposed experiment may be a benchmark for future non-linear models. To analyze such conditions, the well-established cohesive fracture model implemented in ABAQUS® is used to reproduce the experimental observations numerically, achieving good accuracy. Keywords: Cohesive fracture, Digital image correlation, Fracture energy, Fibre-reinforced concrete, Sergipe test.

Study on the mechanical properties and microstructure of PVA fiber-reinforced waste glass powder concrete

Study on the mechanical properties and microstructure of PVA fiber-reinforced waste glass powder concrete

Durability and microstructure of fiber-reinforced geopolymer concrete with FA and GGBS

Durability and microstructure of fiber-reinforced geopolymer concrete with FA and GGBS

Mechanical properties and flexural toughness evaluation method of mono/hybrid fiber-reinforced ultra-high performance seawater sea sand concrete

Mechanical properties and flexural toughness evaluation method of mono/hybrid fiber-reinforced ultra-high performance seawater sea sand concrete

Structural Performance of Lightweight Fibre-Reinforced Oil Palm Shell Concrete Subjected to Impact Loadings Under Varying Boundary Conditions

Structural Performance of Lightweight Fibre-Reinforced Oil Palm Shell Concrete Subjected to Impact Loadings Under Varying Boundary Conditions

Cracked Membrane Model for Strain-Softening Fiber-Reinforced Concrete

Cracked Membrane Model for Strain-Softening Fiber-Reinforced Concrete

Experimental and mesoscale numerical investigation on tensile properties of steel fibre-reinforced concrete

Experimental and mesoscale numerical investigation on tensile properties of steel fibre-reinforced concrete

Multi-target machine learning-assisted design of sustainable steel fibre-reinforced concrete

Multi-target machine learning-assisted design of sustainable steel fibre-reinforced concrete

Evaluating the Flexural Strengthening Performance of Concrete Beams Reinforced with Fiber-Enhanced Spray Materials

This study examined the compressive and tensile strengths of spray-applied strengthening materials and the flexural performance of concrete beams reinforced using these materials to assess the effectiveness of spray-based reinforcement techniques. The findings revealed substantial variations in performance influenced by fiber type, dosage, and casting method. Key factors affecting performance included fiber dispersion and bond strength within the spray-applied layer. The PE (polyethylene) fibers exhibited stable performance, while PVA (polyvinyl alcohol) fibers experienced significant degradation due to moisture absorption. These results offer valuable insights for optimizing the design and application of fiber-reinforced concrete, advancing repair and reinforcement methods in the construction sector.

Study on chloride penetration resistance of hybrid fiber-reinforced concrete in winter construction

Study on chloride penetration resistance of hybrid fiber-reinforced concrete in winter construction

Study on Mechanical Properties and Carbon Emission Analysis of Polypropylene Fiber-Reinforced Brick Aggregate Concrete.

Given the current construction waste accumulation problem, to utilize the resource of red brick solid waste, construction waste red brick was used as a concrete coarse aggregate combined with polypropylene fiber to prepare PPF (polypropylene fiber)-reinforced recycled brick aggregate concrete. Through a cube compression test, axial compression test, and four-point bending test of 15 groups of specimens, the influences of the aggregate replacement rate of recycled brick and the PPF volume on the mechanical properties of recycled brick aggregate concrete reinforced by PPF were studied, and a strength parameter calculation formula was constructed and modified based on the above. Finally, combined with a life cycle assessment (LCA), the carbon emissions of raw materials were analyzed and evaluated. It was found that the mechanical properties of recycled concrete enhanced by PPF are critical at an addition rate of 50% and then decrease slowly with an increase in the aggregate content. PPF effectively alleviates the problem of strength reductions caused by regenerated aggregate substitution through the fiber-bridging effect. Based on the experimental data, a mechanical transformation model considering fiber reinforcement and BA weakening was constructed, and the regression accuracy R2 was around 0.90. The environmental benefit obtained when only replacing the natural aggregate is low. Although the incorporation of fiber improves the carbon emissions of the material to a certain extent, the benefits are more noticeable compared with the increase in strength. The results show that garbage recovery and strength demand benefits are achieved when the amount of recycled brick aggregate is 50% of the total. The strength conversion model established in this paper has of high accuracy and was created with careful consideration of fiber reinforcement and the regenerated aggregate weakening correction, providing it with more robust adaptability and extensibility. The mechanical properties of the recycled brick aggregate concrete enhanced by PPF are excellent and sustainable when the replacement rate of BA is 50% and the PPF volume is 0.1%.

A Review on the Effect of Synthetic Fibres, Including Macro Fibres, on the Thermal Behaviour of Fibre-Reinforced Concrete

The mechanical properties of concrete degrade rapidly when exposed to elevated temperatures. Adding fibres to concrete can enhance its thermal stability and residual mechanical characteristics under high-temperature conditions. Various types of fibres, including steel, synthetic and natural fibres, are available for this purpose. This paper provides a comprehensive review of the impact of synthetic fibres on the performance of fibre-reinforced concrete at high temperatures. It evaluates conventional synthetic fibres, including polypropylene (PP), polyethylene (PE), and polyvinyl alcohol (PVA) fibres, as well as newly emerging macro fibres that improve concrete’s fire resistance properties. The novelty of this review lies in its focus on macro fibres as a promising alternative to conventional synthetic fibres. The findings reveal that PE fibres significantly influence the residual mechanical properties of fibre-reinforced concrete at high temperatures. Although PVA fibres may reduce compressive strength at elevated temperatures, they help reduce micro-cracking and increase flexibility and flexural strength. Finally, this review demonstrates that while conventional synthetic fibres are effective in limiting fire-induced damage, macro fibres offer enhanced benefits, including improved toughness, energy absorption, durability, corrosion resistance, and post-cracking capacity. This study provides valuable insights for developing fibre-reinforced concrete with superior high-temperature performance. Steel fibres offer superior strength but are prone to corrosion and spalling, while PP fibres effectively reduce explosive spalling but provide limited strength improvement. PE fibres enhance flexural performance, and PVA fibres improve tensile strength and shrinkage control, although their performance decreases at high temperatures. Macro fibres stand out for their post-cracking capacity and toughness, offering a lightweight alternative with better overall durability.

Uniaxial Compression Behavior of Polypropylene and Glass Fiber-Reinforced Desert Sand Concrete

Uniaxial Compression Behavior of Polypropylene and Glass Fiber-Reinforced Desert Sand Concrete

New insights on rheology, durability and mechanical and thermal properties of polyester and steel fiber-reinforced self-compacting concretes

Self-compacting concrete improves fresh-state fluidity while maintaining mechanical properties, and presents an increasing research interest in fiber incorporation. However, the effects of fibers on rheological behavior and durability remain insufficiently studied in existing literature. This study provides new insights on the effect of polyester and steel fibers on the rheological, mechanical, durability, microstructural, and thermal properties of SCC. Nine different mixtures were studied: one reference SCC (without fibers), four SCC incorporating steel fibers, and four other mixtures incorporating polyester fibers. The four percentages studied for each fiber type were 0.25%, 0.5%, 0.75%, and 1%. The results showed that whatever their type, adding fibers reduces workability while improving compressive strength of SCC. Incorporating 1% of steel fibers increased flexural strength of SCC by 97%, whereas polyester fibers had no significant effect. In terms of durability, adding fibers increased SCC porosity but reduced its sorptivity. For instance, adding 1% of polyester fibers increased porosity by 9.5% whilst reducing sorptivity of SCC by 23% compared to the reference one. Polyester fibers also improved SCC thermal conductivity, whereas steel fibers had an inverse effect. An inverse proportionality between plastic viscosity and sorptivity was identified, highlighting the importance of plastic viscosity in influencing the transport properties of hardened SCC. Based on these findings, it is recommended that careful attention should be taken on the change of both rheological and transport properties when incorporating a given percentage of fibers into SCC.

Fatigue of SFRC in compression: Size effect & autogenous self-healing

This review synthesizes prior research on size effect and autogenous self-healing in steel fiber-reinforced concrete (SFRC) under compressive fatigue. It explores the fatigue behavior of SFRC, focusing on fiber reinforcement’s role in post-cracking toughness, crack propagation, and fatigue endurance. The review demonstrates that larger SFRC specimens have reduced fatigue lives, attributed to increased elastic energy driving microcrack growth, aligning with classical size effect theory. Additionally, it highlights autogenous self-healing, where fatigue-induced microcracks release occluded water, promoting rehydration and calcium carbonate precipitation, which enhances residual strength. The interaction between size effect, fiber content, and self-healing is examined, offering insights into improving SFRC’s durability under cyclic loading. These findings have practical implications for designing SFRC structures subjected to compressive fatigue, such as wind turbine towers and railway slabs.

Freeze-thaw and drop-weight impact resistance of fiber-reinforced pervious concretes produced using recycled pervious concrete aggregate

Pervious concrete can rapidly drain stormwater from the top layer to the sublayer. However, the porous structure of this concrete also results in low mechanical properties, which prevent the widespread use of pervious concrete around the world. This study investigated the freeze-thaw and drop-weight resistances of pervious concrete produced with recycled pervious concrete aggregate. Two different aggregate types (limestone and recycled) and two different aggregate size fractions (15/25 mm and 5/15 mm) were used to examine the effect of aggregate type and gradation. Additionally, for improving mechanical and durability properties, polypropylene fibers were used at three different dosages by the volume of mixtures (0.1%, 0.2%, and 0.3%). Within the scope of the study, compressive, splitting-tensile, and flexural strengths, effective porosity, freeze-thaw, abrasion, and impact resistance of pervious concrete were determined. The results showed that concrete produced with recycled aggregate had some advantages in terms of porosity; however, its mechanical properties, freeze-thaw, and impact resistance were lower than those of pervious concretes produced with limestone aggregate. Additionally, fiber addition decreased the compressive strength and effective porosity of pervious concrete. However, up to a certain point (0.2%), fiber addition improved abrasion, freeze-thaw, and impact resistance, as well as splitting tensile and flexural behavior of pervious concrete.