Combination Of Fillers Research Articles

Fragmentation and release of pristine and functionalized carbon nanotubes from epoxy-nanocomposites during accelerated weathering.

There is an increasing volume of nano-enabled materials in the market. Once composites containing nano-additives are disposed of, weathering could deteriorate their structures, releasing nanoparticles and risking exposure of humans and aquatic organisms. Composite degradation due to environmental aging continues, including structural deterioration resulting in cracking, fragmentation, and release of microplastics and nano-additives to the environment. This research aims to study the degradation and release of initially embedded nanomaterials (NMs) from composites and their toxicity. The molecular interaction of carbon nanotube (CNT)/polymer composites is critical for modifying the polymer properties. This study investigated the interactions of functional multiwalled carbon nanotube (MWCNT) composites which affect their release during accelerated weathering processes. Different epoxy-MWCNT composites were prepared by filling a polymer with pure MWCNTs and MWCNTs functionalized with acid () and amine () groups. The physical and chemical changes of aged composites were characterized by gravimetric analysis, contact angle measurements, FTIR, SEM, and laser confocal microscopy. A loss of hydrophobicity was observed for composite surfaces long before surface cracks materialized. Released polymer fragments and nanoparticles were analyzed in wash water using TEM, FTIR and Raman spectroscopy. The environmental risks for long-term use of CNT-polymer composites and the influence of fillers on the extent of chemical photodegradation depended on the combination of polymer and fillers. If nanoparticles are released from the matrix, the high surface-to-volume ratio and reactivity of NMs make them highly dynamic in environmental systems. Exposure to these released NMs could negatively affect human health and the environment. This study provides fragmentation and CNT particle release data that could describe how molecular-level interactions between functionalized CNTs and epoxy polymers affect the aging and release of CNTs. A toxicity assessment based on a reactive oxygen species (ROS) formation assay and MTS assay for cell viability and activity of the released polymer and CNT fragments and leachate showed moderate levels of cytotoxicity of released materials as compared to pristine epoxy plates.

Changes in smile index after correction of deep nasolabial fold using a combination of polydioxanone thread and hyaluronic acid filler

Changes in smile index after correction of deep nasolabial fold using a combination of polydioxanone thread and hyaluronic acid filler

Improvement of Fire Resistance and Mechanical Properties of Glass Fiber Reinforced Plastic (GFRP) Composite Prepared from Combination of Active Nano Filler of Modified Pumice and Commercial Active Fillers

Glass fiber reinforced plastic (GFRP) composites have great potential to replace metal components in vehicles by maintaining their mechanical properties and improving fire resistance. Ease of form, anti-corrosion, lightweight, fast production cycle, durability and high strength-to-weight ratio are the advantages of GFRP compared to conventional materials. The transition to the use of plastic materials can be performed by increasing their mechanical, thermal and fire resistance properties. This research aims to improve the fire resistance of GFRP composite and maintain its strength by a combination of pumice-based active nano filler and commercial active filler. The nano active filler of pumice particle (nAFPP) was obtained by the sol-gel method. Aluminum trihydroxide (ATH), sodium silicate (SS) and boric acid (BA) were commercial active fillers that were used in this study. The GFRP composite was prepared by a combination of woven roving (WR) and chopped strand mat (CSM) glass fibers with an unsaturated polyester matrix. The composite specimens were produced using a press mold method for controlling the thickness of specimens. Composites were tested with a burning test apparatus, flexural bending machine and Izod impact tester. Composites were also analyzed by SEM, TGA, DSC, FT-IR spectroscopy and macro photographs. The addition of nAFPP and reducing the amount of ATH increased ignition time significantly and decreased the burning rate of specimens. The higher content of nAFPP significantly increased the flexural and impact strength. TGA analysis shows that higher ATH content had a good contribution to reducing specimen weight loss. It is also strengthened by the lower exothermic of the specimen with higher ATH content. The use of SS and BA inhibited combustion by forming charcoal or protective film; however, excessive use of them produced porosity and lowered mechanical properties.

Advances and Development in Hybrid Polymer Composite: The Way Forward

This paper presents the unique and outstanding properties of hybrid polymer composite (HPC). The various classification of HPC based on the combination of matrices, fibres and fillers in use are brought to bear. The different techniques/methods employed in the production of hybrid polymer composites, ranging from hot press to cold press are being discussed. It is paramount to note that the production process of HPC from start to finish is not without some inherent and external challenges, such as agglomeration of fibre, fillers and weak interfacial adhesion between fillers and matrices. Chemical modification of fibre was identified as one of the ways of proffering solution to this drawback. This study also presents a wide range of the application of HPC as enumerated in this work. The degradation of HPC as a result of natural and accelerated weathering conditions such as ultra violet (UV) rays, heat caused by high temperature, rain and humidity was also discussed. The durability and lifespan of these HPC can be strengthened and prolonged through the use of intumescents and other additives. All of these can help in improving the resistance of HPC to adverse weathering conditions.

Determination of the softening temperature of bitumen with different modifiers

Road construction is an important part of economic development, and the most pressing problem is improving the quality of road surfaces. Road pavements are a combination of mineral fillers and bitumen, in which bitumen is used as a durable waterproof binder. Bitumen modification can improve the quality of bitumen, by increasing the plasticity interval, increasing adhesion to metal and mineral materials, increasing resistance to aging, and expanding the operating temperature range. Softening point characterizes the thermal resistance of bitumen: the transition from the elastic-plastic state to a viscous-fluid state, in which the bitumen loses its adhesive properties. And this paper presented the investigation of the properties of bitumen by modifying it and determining the softening temperature on the device Ring and ball. The analysis of the obtained results of the use of various modifiers, their comparative characteristics, and the formulation of conclusions about the possibility of involving them in the production of bitumen to improve their quality.

Physical properties of wood-based materials for liquid deposition modeling

Purpose The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for liquid deposition modeling. Design/methodology/approach The overall hypothesis was that a well-chosen combination of binders, fibers and fillers could reduce shrinkage in the Z dimension and increase compressive and flexural strength (DIN 52185, 52186). To test this assumption, eight sub-hypotheses were formulated. Mixtures of the ingredients were chosen in different ratios to measure the performance of prints. For time efficiency, an iterative heuristic approach was used – not testing all variations of all variables in even increments, but cutting off lines of testing when mixtures were clearly performing poorly. Findings The results showed that some mixtures had high dimensional accuracy and strength, while others had neither, and others had one but not the other. Shrinkage of 3D printed objects was mainly caused by water release during drying. An increase of the wood as well as the cement, sand, salt and gypsum content led to reduced vertical shrinkage, which varied between 0 and 23%. Compressive and flexural strength showed mixed trends. An increase in wood and salt content worsened both strength properties. The addition of fibers improved flexural, and the addition of cement improved compression strength. The highest strength values of 14 MPa for compressive and 8 MPa for flexural strength were obtained in the test series with gypsum. Originality/value This paper is an important milestone in the development of environmentally friendly materials for additive manufacturing. The potential of many ingredients to improve physical properties could be demonstrated.

Mechanical, Barrier, Antioxidant and Antimicrobial Properties of Alginate Films: Effect of Seaweed Powder and Plasma-Activated Water

The incorporation of natural fillers such as seaweed may potentially enhance the properties of biopolymer films. In this study, we investigated the effect of seaweed powder as a bio-filler in alginate-based films at different concentrations (10, 30, and 50%, w/w alginate) and particle sizes (100 and 200 μm) on the mechanical, barrier, antioxidant, and antimicrobial properties of alginate which are essential for food packaging applications. Initially, mechanical properties of the alginate films prepared at different temperatures were evaluated to find the optimal temperature for preparing alginate solution. The addition of seaweed powder did not have any positive effect on the mechanical properties of the alginate films. However, the barrier (water vapor transmission rate) and antioxidant properties were improved with the addition of seaweed filler regardless of concentration. In addition, selected films were prepared in plasma-activated water (PAW). The mechanical properties (tensile strength, but not elongation at break) of the films prepared with PAW improved compared to the films prepared in distilled water, while a significant decrease was observed when incorporated with the seaweed filler. The films prepared in PAW also showed improved barrier properties compared to those prepared in distilled water. The antimicrobial activity of the alginate-seaweed film-forming solution was in general more pronounced when prepared with PAW and stored at 10 °C, particularly at the highest concentration of the film-forming solution (83.3% v/v). A more pronounced inhibitory effect was observed on the Gram-positive S. aureus than on the Gram-negative E. coli, which has been attributed to the different composition and structure of the respective cell walls. This study has demonstrated the potential of seaweed filler in combination with PAW towards enhanced functionality and bioactivity of alginate films for potential food packaging applications.

Physical effects of nanoaluminum oxide and nanographene on kenaf epoxy composite; vacuum bagging process

AbstractIn this study, the effect of secondary filler nanographene and primary filler nanoaluminum oxide with kenaf epoxy was investigated. The vacuum bagging process was performed, and a magnetic stirrer was used for blending additives. Water absorption (borewell, distilled, normal, and seawater) and chemical absorption (acid, base, and neutral solution) tests were carried out to evaluate the water absorption, chemical absorption, thickness swelling, and diffusivity of the composite with varying percentages of fillers. The result demonstrates that the addition of 6% primary and 3% secondary filler together, increases the density of the sample by 13.5% and decreases void content by 77%. The addition of secondary filler lowers water absorption in normal water by 1.3% compared to other types of water, as the addition of secondary filler increases the water absorption decreases by 70% in borewell water, 75% in distilled water, 76% in normal water, and 69% in seawater. Thickness swelling of the samples decreases upon the addition of secondary fillers. In acid, the primary and secondary fillers increase the resistance to dissolution. The diffusivity rate of the sample with a combination of fillers 1.3 × 10−5.

Understanding the Flame Retardant Mechanism of Intumescent Flame Retardant on Improving the Fire Safety of Rigid Polyurethane Foam.

Combinations of multiple inorganic fillers have emerged as viable synergistic agents for boosting the flame retardancy of intumescent flame retardant (IFR) polymer materials. However, few studies on the effect of multiple inorganic fillers on the flame retardant behavior of rigid polyurethane (RPU) foam have been carried out. In this paper, a flame retardant combination of aluminum hydroxide (ATH) and traditional flame retardants ammonium polyphosphate (APP), pentaerythritol (PER), melamine cyanurate (MC), calcium carbonate (CC), and expandable graphite (EG) was incorporated into RPU foam to investigate the synergistic effects of the combination of multiple IFR materials on the thermal stability and fire resistance of RPU foam. Scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) revealed that 8 parts per hundred polyols by weight (php) filler concentrations were compatible with RPU foam and yielded an increased amount of char residue compared to the rest of the RPU samples. The flame retardancy of multiple fillers on intumescent flame retardant RPU foam was also investigated using cone calorimeter (CCTs) and limiting oxygen index (LOI) tests, which showed that RPU/IFR1 (APP/PER/MC/EG/CC/ATH) had the best flame retardant performance, with a low peak heat release rate (PHRR) of 82.12 kW/m2, total heat release rate (THR) of 15.15 MJ/m2, and high LOI value of 36%. Furthermore, char residue analysis revealed that the use of multiple fillers contributed to the generation of more intact and homogeneous char after combustion, which led to reduced decomposition of the RPU foam and hindered heat transfer between the gas and condensed phases.

Influence of Novel Experimental Light-Cured Resin Cement on Microtensile Bond Strength.

The purpose of this study was to evaluate the microtensile bond strength (µTBS) and Knoop hardness number (KHN) of a novel experimental light-cured resin cement (HL). Eighteen flat dentin surfaces of human molars were polished using #600 SiC paper and bonded to CAD/CAM resin blocks with the respective resin cements and composites: HL, Panavia V5 (PV), and Clearfil AP-X (AP). All specimens were stored in distilled water at 37 °C for 24 h and 7 days. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) observations were performed to evaluate filler morphology and to detect the elements. The resin cements had a significant effect on the immediate µTBS (F = 22.59, p < 0.05) and after water storage µTBS (F = 22.83, p < 0.05). Significant differences (p < 0.05) in the KHN between the tested materials were observed, and HL indicated the highest KHN when compared with PV. HL showed a combination of the regular-shaped filler and spherical-shaped filler within the matrix. Silicon was detected in HL from the EDX evaluation. HL exhibited better bonding performance and polymerization, which may have contributed to the improvement of the adhesive strength.

Thermal and Mechanical Characterization of the New Functional Composites Used for 3D Printing of Static Mixers.

This paper investigates the possibility of integrating the combination of nanofillers, titanium dioxide (TiO2) and carbon nanotubes (CNT) into the thermoplastic polymer matrix. This combination of fillers can possibly modify the physico-chemical properties of composites compared to the pure polymer matrix. The composites were blended using the extrusion method. The composite filament produced was used to manufacture static mixers on a 3D printer using the additive manufacturing technology fused filament fabrication (FFF). The aim of this work was to inspect the influence of the filler addition on the thermal and mechanical properties of glycol-modified polyethylene terephthalate (PET-G) polymer composites. The fillers were added to the PET-G polymer matrix in several ratios. Tensile test results showed an increase in the overall strength and decrease in the elongation at break of the material. Melt flow rate (MFR) showed a decrease in the viscosity with the initial filler addition and reaching a plateau after 2 wt% filler was added. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed minor changes in the thermal properties. Scanning electron microscope (SEM) results showed homogenous distribution of the filler in the matrix and strong filler–matrix adhesion. The results indicate suitable properties of new functional composites for the 3D printing of static mixers for application in tubular reactors.

Enhancement of Magneto-Induced Modulus by the Combination of Filler and Plasticizer Additives-Based Magnetorheological Elastomer

Filler additive is used to provide superior bonding in rubber matrix to enhance the storage modulus of magnetorheological elastomer (MRE). However, the magneto-induced modulus is reduced as the initial storage modulus increases. Therefore, this paper aims to increase the magneto-induced modulus and maintain the initial storage modulus by combining filler and plasticizer additives. Both types of additives have different functions, where cobalt ferrite (CoFe2O4) is capable of enhancing the maximum storage modulus and silicone oil (SO) reduces the initial storage modulus. Thus, four MRE samples have been fabricated using (a) no additive, (b) CoFe2O4, (c) SO, and (d) a combination of CoFe2O4 and SO. The sample’s hardness and magnetic properties were investigated via Durometer Shore A and Vibrating Sample Magnetometer (VSM), respectively. Furthermore, the rheological properties of MRE samples in terms of storage modulus were investigated upon the frequency and magnetic field sweep using a rheometer. The results demonstrated that the storage modulus of the MRE samples has increased with increasing the oscillation frequency from 0.1 to 50 Hz. Interestingly, the combination of additives has produced the largest value of magneto-induced modulus of 0.90 MPa as compared to other samples. Furthermore, their initial storage modulus was in between samples with SO (lowest) and without additive (highest). Therefore, fundamental knowledge in adding the combination of additives can offer solutions for a wide range of stiffness in MR device applications such as vibration and noise control devices, sensing devices, and actuators.

PENGARUH SUBSTITUSI PET DAN ABU BUNGA PINUS MENGGUNAKAN METODE PENCAMPURAN BASAH DAN METODE PENCAMPURAN KERING PADA CAMPURAN LASTON AC-WC TERHADAP STABILITAS

Consumption of plastic waste in Indonesia is very high disrupting environmental sustainability, plastic waste takes hundreds of years to decompose making it a problem to be addressed immediately. So, in recent times, research has been carried out to utilize plastic waste into plastic-mix asphalt technology. One of them is by modifying the asphalt mixture with plastic bottle waste the type of Polyethylene Terephthalate (PET) as an additive. In addition, this study also used additional filler in the form of pine flower ash (PFA). This study aims to determine the characteristics of the AC-WC asphalt concrete mixture through Marshall testing of the substitution of PET into 60/70 penetration asphalt and filler ABP with using wet mixing methods and dry mixing methods. This research was started by examining the physical properties of asphalt, modified asphalt, and aggregates. Furthermore, the manufacture of test specimens with variations in asphalt content was carried out to determine the optimum bitumen content (OBC) and obtained OBC values of 5.29%, 5.79%, and 6.29%. Then made a PET substitution test object of 3%, 5%, and 7% and a combination of filler PFA 6% of the total weight of the filler on each asphalt content with wet mixing method and dry mixing method through Marshall test. The results of this study indicate that the stability for both methods of mixing the best levels is found in the substitution of 7% PET and the combination of ABP filler with an asphalt content of 6.29%, 1226.12 kg for the wet mixing method and 1291.43 kg for the dry mixing method. The durability value for the wet mixing method was obtained at 90.87% and for the dry mixing method it was obtained at 91.55%, both of these durability tests had met the specifications of 90%.

Porous Fly Ash/Aluminosilicate Microspheres-Based Composites Containing Lightweight Granules Using Liquid Glass as Binder

The modern energy-saving vector of development in building materials science is being implemented in a complex way through the development of new heat-insulating materials with the simultaneous exclusion of low-ecological cement from them. This article presents the results of the development of resource-saving technology for a heat-insulating composite material. The research is devoted to the development of scientific ideas about the technology and properties of effective cementless lightweight concretes. The aim of the work is to create a heat-insulating composite material based on porous granules and a matrix from mixtures of liquid glass and thermal energy waste. The novelty of the work lies in establishing the patterns of formation of a stable structure of a porous material during thermal curing of liquid glass with technogenic fillers. Studies of liquid glass mixtures with different contents of fly ash and aluminosilicate microspheres revealed the possibility of controlling the properties of molding masses in a wide range. To obtain a granular material, liquid glass mixtures of plastic consistency with a predominance of aluminosilicate microspheres are proposed. The matrix of composite materials is formed by a mobile mixture of liquid glass and a combined filler, in which fly ash predominates. The parameters of heat treatment of granular and composite materials are established to ensure the formation of a strong porous waterproof structure. The possibility of regulating the structure of composite materials due to different degrees of filling the liquid glass matrix with porous granules is shown. A heat-insulating concrete based on porous aggregate has been developed, characterized by the genetic commonality of the matrix and the granular component, density of 380–650 kg/m3, thermal conductivity of 0.095–0.100 W/(m °C) and strength of 3.5–9.0 MPa, resistance under conditions of variable values of humidity and temperature. A basic technological scheme for the joint production of granular and composite materials from liquid glass mixtures is proposed.

Electromagnetic Interference Shielding Effectiveness of Natural and Chlorobutyl Rubber Blend Nanocomposite

The science and technology of electrical equipment for communication experience a rapid growth rate. However, the unwanted interference of electromagnetic waves of different electronic devices brought serious anxiety about human health as well as the lifetime and performance of the systems. To combat these consequences, we need to lessen the electromagnetic wave emission by making our devices more noise-sensitive. Herein, we incorporated carbon nanotubes (CNTs) at different ratios into natural rubber (NR) and chlorobutyl rubber (CIIR) to achieve shielding efficiency, along with carbon nanofibers (CNFs), nanoclay (NC), and carbon black (CB) to manipulate EMI shielding performance. The blend of CIIR/NR in a 70/30 (w/w) ratio also mixed with CNT, CNF, CB and NC. The effect of different fillers and their concentration/combination was analyzed by UV spectroscopy, demonstrating an absorbance peak in CIIR in 320 nm. From FTIR spectroscopy, it was evident that CIIR/CNT (5 phr), NR (30 wt.%)/CIIR (70 wt.%)/CB (5 phr), and NR (30 wt.%)/CIIR (70 wt.%)/CNT (5 phr) new bonding signatures were detected. The dielectric spectroscopic analyses were reflected in dielectric loss, dielectric permittivity and AC conductivity, where NR (30 wt.%)/CIIR (70 wt.%)/CB (5 phr) blend nanocomposite with 5 dB showed significantly higher EMI shielding performance compared to CIIR/CNT (5 phr) and CIIR/CNF (5 phr) with 29 and 15 dB, respectively. The greater the concentration of nanofiller, the lower the electromagnetic interference (EMI) shielding, i.e., CIIR/CNT (10 phr) with 15 dB (≈−48% dB), but with more agglomeration. Surprisingly, even a combination of fillers did not lead to higher EMI performance, such that CIIR/CNT (5 phr)-CB (20 phr) showed an EMI shielding value of 59 dB.

Enhanced thermal and electrical properties of hybrid polymer composites containing Al2O3 microspheres and nanowires

Thermal interface materials efficiently transfer heat from high-temperature electronic devices to heat management components to alleviate the overheating that deteriorates component lifetimes of electronic devices. Recently, high-performance polymer composites, made of polymer matrices and thermally conducting fillers, have been actively researched due to their low densities and controllable properties. However, the conventional polymer composites produced by mixing methods of homogeneous fillers have significantly low percolation and poor heat dispersion, which afford reduced mechanical and thermal performances. Herein we propose a strategy for fabricating epoxy composites that provide good electrical insulation and enhanced thermal conductivity using a combination of heterogeneous Al2O3 fillers. The epoxy composites were prepared by using a hybrid filler system comprising microspheres and nanowires, which were fabricated by spray drying and hydrothermal methods, respectively. The use of these two filler components produces a continuous network of fillers throughout the polymer matrix. The thermal conductivity of the hybrid composite is enhanced by 107.9% compared to that of the composite containing only microspheres at the same filler loading (30 wt%). Additionally, the epoxy composites produced with the hybrid filler system provide enhanced electrical insulation (with a dielectric constant of 3.5 at 1 kHz). This hybrid composite approach has the potential to be applied with a wide range of polymers and fillers for use in diverse applications (e.g., wearable devices and electrical vehicles).

Performance of various fillers in ecological floating beds planted with Myriophyllum aquaticum treating municipal wastewater

The performance of different suspended fillers (zeolite, drinking water treatment residual, biochar, woodchip and stereo-elastic packing) and their combinations in treating municipal wastewater in ecological floating beds (Eco-FBs) planted with Myriophyllum aquaticum was assessed. Six sets of enhanced Eco-FBs were developed to assess the individual and synergistic effects of combinations of the various fillers and microorganisms on nutrient elimination. The results demonstrated mean TN, NH4-N, TP and COD purification efficiencies of 99.2 ± 11.2 %, 99.82 ± 16.4 %, 98.3 ± 14.3 %, and 96.1 ± 12.3 %, respectively in the Eco-FBs strengthened with all five fillers. The corresponding purification rates were 0.89 ± 0.14, 0.75 ± 0.12, 0.08 ± 0.016, and 7.05 ± 1.09 g m−2 d−1, which were 2–3 times higher than those of the conventional Eco-FB system. High-throughput sequencing showed that some genera related to nutrient transformation, including Proteobacteria (24.13–51.95 %), followed by Chloroflexi (5.64–25.01 %), Planctomycetes (8.48–14.43 %) and Acidobacteria (2.29–11.65 %), were abundantly enriched in the strengthened Eco-FBs. Enhancement of the Eco-FBs with various fillers significantly increased microbial species richness and diversity as demonstrated by Chao1, Shannon and Simpson's indexes, particularly when all the five fillers were combined. Therefore, introducing suspended fillers into Eco-FBs is an appropriate approach for improving nutrient elimination from municipal wastewater.

Influence of ionic liquid on rheological behaviors of candle soot and cellulose nanocrystal filled natural rubber nanocomposites

Carbonaceous soot nanoparticles are used as novel filler in combination with cellulose nanocrystal (CNC) to prepare natural rubber (NR) nanocomposites to which ionic liquid (IL) 1-allyl-3-methylimidazolium chloride is used to enhance the filler-rubber interaction. Nanocomposites of candle soot (CS) and CNC well dispersed in NR were prepared by latex mixing and mechanical mixing followed by vulcanization. The presence of IL causes a slight agglomeration of the fillers but it improves bound rubber content and crosslinking degree. Both the fillers and IL improve dynamic modulus and tensile stress while they lower loss tangent in the linear viscoelastic region, providing a perspective for manufacturing high–performance rubber materials using novel fillers and modifiers.

Experimental and numerical investigation of flexural behavior of hybrid fiber reinforced high strength incorporating binary and ternary blend of ultra fines

Hybrid Fiber-reinforced High Strength Concrete (HFHSC) with superior ductile and durable properties is an advanced concrete material for structural applications. The inherent flaw of micro-crack development during the hardening of concrete was addressed by hybrid fibers (micro and macro fibers) for better mechanical and structural performance. However, the behavior of structural members of high-strength concrete with hybrid fiber in a combination of binary and ternary blend of ultrafine filler still needs to be explored. Therefore, current research work was planned to investigate the flexural behavior of hybrid fiber (steel/Polyvinyl alcoholic fiber) reinforced concrete incorporating a binary and ternary combination of ultrafine fillers (i.e., Ultrafine Quartz filler, silica fume, fly ash). The mechanical properties of HFHSC were evaluated. Full-scale beams with HFHSC incorporating different binary and ternary mixtures of ultrafine were cast and tested for flexural behavior evaluation. A numerical simulation of the tested specimen was carried out to predict the flexural behavior of HFHSC. Test results revealed that the flexural behavior of beams incorporating hybrid fiber showed significant improvement in the initial crack strength, ductility, and deflection capacity compared to control beams without fibers. Results showed an increase of around 5% and 50% in load carrying capacity and ductility, respectively, with the addition of hybrid fibers. The results from the numerical model were in good agreement with experimental load carrying capacity and moment capacity predicted by using the concrete damage plasticity CDP model. Hence, it can be deduced that high-strength concrete using hybrid fibers can be used in the construction industry for enhanced structural performance with smaller cross-sectional members leading to reduced structural weight and more clear space.

Porous composite material based on liquid glass

The article presents the results of experimental studies of a composite material obtained on the basis of liquid glass and mineral fillers of technogenic origin. The structure of the composite material is formed by porous granules bonded with a liquid-glass matrix. The porous filler is synthesized from a mixture of liquid glass and combined filler (cullet, flake overburden, coal mining waste, and ash microsphere). Regulation of composition and content of the filler in the raw mixture ensures porous granules production with a bulk density of 270 – 330 kg/m3. Analysis of mathematical models reflecting the dependence of the density and strength of the composite material on the composition of the moulding mixture allowed us to establish a reasonable ratio between the liquid glass and the filler, the matrix, and the porous filler. Optimal proportions of the composite material are characterized by a density of 450 – 600 kg/m3and compressive strength of at least 5.5 MPa. Strong adhesion of the liquid-glass matrix to the surface of the porous filler ensures the resistance of the composite material to diverse effects. The structure of the materials was studied by electron microscopy. The development of composite material is aimed at improving the energy efficiency of construction.