Improved Strength Properties Research Articles

CREATION OF LONG-ACTING DISINFECTANT EMULSIONS BASED ON POLYACRYLAMIDE POLYMERS AND FUNCTIONAL ADDITIVES

The principles of creating a water-organic disinfectant emulsion (WODE) are described. The emulsion can be applied to various types of surfaces and form a film with a prolonged bacteriostatic/bactericidal effect. When applied to the surface under treatment in a dropwise manner, the composition based on polyacrylamide and special additives will form a durable film, which, in turn, will promote the provision for high sanitary and anti-epidemic measures. The film formed on the surface can be removed by wetting with water and subsequent wiping, which will not lead to the disruption of the general disinfection regime. The water-organic disinfectant emulsion is a composition based on polyacrylamide, a surfactant, polyalcohol (glycerol) and zinc/copper sulphate. The factors responsible for the uniformity of WODE film formation were studied. The criteria for improving rheological and technological properties (wettability, spreadability, moisture absorption) under environmental conditions have been determined. It has been established that higher spreadability and improved strength properties of water-soluble polymer films are achieved by adding surfactants (especially nonionic ones) and a polyalcohol to the composition. By modelling the abrasion process, the mechanical parameters of water-soluble polymer biocidal films were studied. The disinfectant effect of the developed aqueous-organic film-forming composition was studied with respect to the strains of microorganisms: Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. It is proven that the provision of bacteriostatic and bactericidal properties is explained not only by the introduction of copper sulphate or zinc sulphate into the biocide composition, but also by the inhibitory properties of polyacrylamides of various brands themselves. It has been established that polyacrylamide, despite the presence of carbon and nitrogen in its composition, is not an accessible source of nutrition for the cells of pathogenic microorganisms.

Creation of a nickel composite using surface structuring of the reinforcing phase with titanium carbide nanostructures to improve strength properties

Abstract The development of metal matrix composite (MMC) materials is one of the demanded areas of research in materials science. In line with this trend, there is an increasing interest in nickel-based MMC materials, which have already become classic in science and technology. This is due to the high demand for Ni-based materials with high strength characteristics, high hardness, and increased heat resistance. In this research, we proposed an approach to obtain a MMC material using the surface structuring process, ALD (Atomic Layer Deposition) and powder metallurgy method. The developed approach provides a composite with TiC nanostructures (1-5 nm) uniformly distributed throughout the Ni matrix. The absence of interphase boundaries between the Ni matrix particles and carbide nanostructures made it possible to minimize the internal porosity of the sample. This is due to the strength of the interphase boundaries between the matrix and the reinforcing phase in the composite and to the solidity of the structure. As a result, the created material effectively resists plastic deformation and stress. This allows not only to enhance the strength properties of the composite, but also to maintain the MMC plasticity, which increases its processing ability.

The influence of graphene nanoplatelet content on the mechanical properties and microstructure of sustainable concrete

The effects of the content of graphene nanoplatelets (GNPs) on the mechanical properties and microstructure of sustainable concrete were investigated. Aqueous solutions were prepared, using a wet-dispersion technique to disperse GNPs in the mixing water. Concrete batches were prepared using different GNP fractions (0.05, 0.1, 0.25, 0.5, 1 and 2% by weight of cement), and their compressive, flexural and tensile strengths were determined at 28 days. Qualitative microstructural analyses were performed using scanning electron microscopy and energy dispersive X-ray analysis. The results obtained were analysed using analysis of variance (Anova), which demonstrated improvements in all strength properties when using GNP filaments regardless of their weight fraction. The batch containing 0.5% GNPs showed the largest strength improvements, with improvements in compressive, flexural and tensile strength properties of 22.6%, 23.9% and 255.4%, respectively. Microstructural analysis showed a good dispersion of nanofilaments inside the concrete matrix through the dispersion technique used in this study. Finally, Anova revealed statistically significant relationships between the GNP content and the compressive, flexural and tensile strengths of the concrete specimens. The results highlight the importance of the GNP content in influencing the concrete's mechanical properties.

APPLICATION OF SPARK PLASMA SINTERING AS A METHOD FOR PRODUCING NEW CERAMIC MATERIALS FROM SILICON PRODUCTION WASTE

The article presents some existing methods of producing silicon carbide, forms and types of silicon carbide, various compositions and formulations, production technology. The authors proposed a new method of processing silicon production waste - microsilica by spark plasma sintering with a carbon-containing reducing agent (soot) which produces a silicon carbide compound. Studies have shown that sintered silicon carbide has improved strength properties. Thus, the possibility of application of production wastes to create new composite materials characterized by a certain complex of properties is confirmed.

EFFECTS OF POLYCHLORINATED N-ALKANES ON THE CHEMICAL STRUCTURE, MECHANICAL AND THERMAL PROPERTIES OF THE STYRENE-BUTADIENE STYRENE TRIBLOCK COPOLYMER

The development of new functional materials based on modified styrene-butadiene block copolymers will enable the creation of materials with improved resistance to gasoline, heat, light, ozone, and enhanced adhesive properties. This study investigates the influence of chlorinated paraffin on the properties of the styrene-butadiene-styrene triblock copolymer. Chlorinated paraffins (CP), complex mixtures of polychlorinated n-alkanes, were used as halogen-containing modifiers for the thermoplastic elastomer to enhance its tensile and adhesive strength and thermal properties. Composite materials based on styrene-butadiene-styrene copolymer (SBS) with various amounts of chlorinated paraffin were prepared using a solution mixing method. The analysis of the ATR/FT-IR spectra of neat SBS and SBS/CP revealed the appearance of new characteristic absorption bands at 1260, 1090, 1020, and 800 cm-1. The study determined that the amount of chlorinated paraffin strongly influenced specific properties of the examined TPE. It was observed that chlorinated paraffin improved the thermal stability of the composites. The onset temperature of degradation increased to 262 °C (a rise of 57 °C), while the maximum degradation temperature slightly increased from 463 to 467 °C. The impact of the concentration of chlorinated paraffin on the chemical structure and tensile properties was evaluated and compared to those of neat styrene-butadiene-styrene. It was estimated that SBS composites with 5 ppm. CPs are characterized by improved strength properties in comparison with the original SBS sample. For citation: Sukhareva K.V., Buluchevskaya A.D., Besedina V.O., Grosheva Yu.V., Lyusova L.R., Popov А.А. Effects of polychlorinated n-alkanes on the chemical structure, mechanical and thermal properties of the styrene-butadiene styrene triblock copolymer. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 6. P. 100-108. DOI: 10.6060/ivkkt.20246706.6973.

Workability and strength of recycled aggregate concrete reinforced with nylon fibers

The demolishing waste generated due to demolishing of the structures has proved difficult to handle due to scarcity of the dumping space particularly in urban areas. Its use in new concrete solves the problem to some extent but developed products differ in properties both at fresh and hardened states. To overcome the deficiency nylon fibers are proposed in this work. The compressive and tensile strength of the proposed concrete at a hardened state and workability as fresh properties of concrete are studied. Conventional and recycled aggregates were used in equal proportions. Nylon fibers of 1 mm diameter and 25 mm length were used from 0.25% to 2% with a 0.25% increment in each successive batch were used. Using 1:2:4 mix with water cement ratio equal to 0.5, a total of 10 mixes were designed. The workability of each mix was evaluated by the slump cone test. Water curing for 28 days was used for five samples in each batch. Compressive and tensile strength were computed from the crushing load determined in the universal testing machine. Comparison of the results with those of control concrete revealed that 1.5% of nylon fibers along with 50% recycled aggregates produce maximum compressive strength of 930.16 (MPa) with 24% more than conventional concrete (24.16 MPa) and 56% more than recycled aggregate concrete (19.27 MPa) without nylon fibers. The tensile strength of the proposed concrete (3.66 MPa) was noticed 22% and 55% higher than the conventional concrete (3.0 MPa) and recycled aggregate concrete (2.36 MPa) at optimum dosage. Hence the impact of optimized doze of the nylon fiber shows improved strength properties of the concrete.

Utilization of Nano Silica and Plantain Leaf Ash for Improving Strength Properties of Expansive Soil

This study investigates the effect of nanosilica and plantain leaf ash on the sustainable stabilization of expansive soil. This study conducted various strength tests, including Unconfined Compressive Strength (UCS), direct shear, and California Bearing Ratio (CBR) tests, to analyze the enhancement of mechanical properties by adding nano silica and plantain leaf ash. Scanning Electron Microscopy (SEM) analysis was conducted to investigate the interaction mechanism between the soil and the combination of nano silica and plantain leaf ash. Three different combinations of plantain leaf ash were utilized, ranging from 5% to 15%, alongside nano silica ranging from 0.4% to 1.2%. The reinforced soil’s compressive strength, shear strength, and bearing capacity were assessed through UCS, direct shear, and CBR tests. The results demonstrated significant improvements in compressive strength, up to 4.6 times, and enhancements in cohesion and frictional angle, up to 3.3 and 1.6 times, respectively, at 28 days. Moreover, the addition of nano silica and plantain leaf ash led to increased bearing capacity and reduced soil swelling potential, contributing to the overall stability and strength improvement in expansive soil. The SEM test results demonstrate that maximum bonding and compaction occur when 1.2% nano silica and 15% plantain leaf ash are added to the soil.

Peeler core and slabwood fibre properties for Pinus radiata D.Don pulp production

Background: Pulp production based on Pinus radiata D.Don is constantly improving the value recovery of logs. One example is using the peeler cores and slabwood derived from sawing and peeling processes to produce pulp. However, these two raw materials have not been characterised for their fibre properties. Methods: We report on four wood fibre quality attributes derived from peeler cores and slabwood, directly influencing pulp quality and pulping process: fibre length (mm), fibre width (µm), fines content (%), and coarseness (µg/m). This pilot study sampled two P. radiata stands grown on different sites and early silvicultural regimes in the Araucanía Region of Chile. Analysis of wood fibre consisted of three trees per stand, and six discs per tree: two at the bottom, two at breast height (1.3 m), and the last two at 5.23 m height. Results: The trajectory of mean annual increment in diameter at breast height (MAI) and periodic annual increment in diameter at breast height (PAI) for trees in the two stands aligned with their respective site qualities and silvicultural regimes. In Stand 1, with a site index of 36, and Stand 2, with a site index of 31, the average proportions of juvenile wood (measured at 1.3 m) were 50% and 53%, respectively. Thus, despite weed control and fertiliser application in Stand 1, there was no increase observed in the proportion of juvenile wood. There were significant differences in fibre properties between peeler core and slabwood, and these differences were present across the range of tree heights and diameters (p<0.05). While there were no statistically significant differences among disc positions, significant distinctions emerged between stands and wood types. The interaction between these factors was also found to be statistically significant (p<0.05). Conclusions: Our study suggests that adding these two materials into the mix for producing pulp would have positive implications due to pulp from peeler core is more suitable for printing and writing grades and addition of mature wood from slabwood, could improve strength properties of paper manufacture. However, it is necessary to test the optimal proportion for the final mix.

A comparative study between linear regression analysis and various codes for predicting the mechanical characteristics of poly-mer concrete using R-sand and M-sand

Numerous research studies have concentrated on advancing a sustainable construction industry through innovative concrete methods and materials. In this context, the present research specifically investigates polymer concrete, utilizing both River sand (R-sand) and Manufacturing sand (M-sand). The polymer content was incorporated into the concrete mix based on the weight of the cement, with varying percentages specifically 2%, 4%, 5%, 6%, and 8%. A slump cone test was conducted to assess the workability of the polymer concrete. Based on experimental studies, the optimal polymer percentage was determined to be 5%. This optimal dosage of polymer content significantly improved the mechanical properties of the polymer concrete. The Compressive Strength (CS), Split Tensile Strength (STS), Flexural Strength (FS), and Modulus of Elasticity (ME) were evaluated at both 7 and 28 days. When using R-sand, the mechanical properties of CS, STS, and FS increased by 13.65%, 12.20%, and 11.42%, respectively. Conversely, employing M-sand led to even greater improvements in strength properties: 19.18% for CS, 12.54% for STS, and 11.67% for FS. Based on the experimental results, the strength properties of polymer concrete M-sand mixes outperformed the R-sand mixes. Linear regression analysis and various codes were employed to predict the strength properties of CS, STS, FS and ME. The regression analysis and various codes successfully forecasted the strength properties of polymer concrete, with the predicted results closely correlated with the experimental results. Based on experimental investigations, the determined mix proportions are recommended for practical applications in various environmental conditions.Numerous research studies have concentrated on advancing a sustainable construction industry through innovative concrete methods and materials. In this context, the present research specifically investigates polymer concrete, utilizing both River sand (R-sand) and Manufacturing sand (M-sand). The polymer content was incorporated into the concrete mix based on the weight of the cement, with varying percentages specifically 2%, 4%, 5%, 6%, and 8%. A slump cone test was conducted to assess the workability of the polymer concrete. Based on experimental studies, the optimal polymer percentage was determined to be 5%. This optimal dosage of polymer content significantly improved the mechanical properties of the polymer concrete. The Compressive Strength (CS), Split Tensile Strength (STS), Flexural Strength (FS), and Modulus of Elasticity (ME) were evaluated at both 7 and 28 days. When using R-sand, the mechanical properties of CS, STS, and FS increased by 13.65%, 12.20%, and 11.42%, respectively. Conversely, employing M-sand led to even greater improvements in strength properties: 19.18% for CS, 12.54% for STS, and 11.67% for FS. Based on the experimental results, the strength properties of polymer concrete M-sand mixes outperformed the R-sand mixes. Linear regression analysis and various codes were employed to predict the strength properties of CS, STS, FS and ME. The regression analysis and various codes successfully forecasted the strength properties of polymer concrete, with the predicted results closely correlated with the experimental results. Based on experimental investigations, the determined mix proportions are recommended for practical applications in various environmental conditions.

Влияние технологии пластического деформирования на механические свойства композитов на основе политетрафторэтилена

This paper presents the results of research on the development of technology for plastic deformation of polymer blanks based on polytetrafluoroethylene (PTFE) and carbon fibers of the UVIS-AK-P brand in order to increase their strength and creep resistance. The dependence of the physico-mechanical, tribotechnical characteristics and structure formation of the obtained composites on the production technology is investigated. It is established that the composites obtained using various schemes of plastic deformation of polymer blanks differ in the nature of deformation under tension, structure formation and the nature of wear of the samples. It is shown that the use of a multidirectional scheme of plastic deformation of workpieces based on PTFE makes it possible to obtain isotropic polymer materials with improved strength properties and increased resistance to deformation under load.

Enhancing Strength and Impact Resistance of Latex Rubberized Concrete through Steel Fiber Incorporation

Rubberized concrete, which incorporates crumb rubber, offers improved impact resistance, toughness, and ductility compared to regular concrete. However, its strength is typically lower due to weak interfacial transition zones (ITZ) between the crumb rubber and hardened cement paste. This study aims to investigate the potential of steel fiber and SBR Latex in compensating for the strength reduction caused by the inclusion of crumb rubber. Specifically, the research focuses on the effect of incorporating steel fiber into latex rubberized concrete (LRC) on compressive strength, flexural strength, splitting tensile strength, and impact resistance. To determine the optimal mix proportion, trial mixes of LRC and Latex-based rubberized concrete with 15 kg/m3 steel fiber (LRC-15% SF) were tested for their compressive strength, splitting tensile strength, flexural strength, and impact resistance. The selected mix proportion had achieved a minimum of 55 Mpa of 28-day characteristic strength. Experimental results indicated that the inclusion of steel fiber led to improved strength properties in LRC. The optimal LRC-15% SF mixture, with a water-to-cement (w/c) ratio of 0.28, outperformed the control mix (w/c ratio of 0.28) by 3.18%, 10.70%, and 17.94% in compressive, splitting tensile, and flexural strengths, respectively, at 56 days. Additionally, the LRC-15% SF exhibited higher impact resistance, showing a 46.27% and 14.71% increase in the 400 mm and 200 mm span length impact tests, respectively, at 56 days. By incorporating steel fiber into latex rubberized concrete, this research demonstrates the potential to enhance the strength properties and impact resistance of the material. These findings contribute to the development of more durable and resilient rubberized concrete formulations, highlighting their potential for various construction applications.

Preparation of chitosan derivative and its application in papermaking

To improve the paper strength, a number of resins and polymeric materials are being used, which is not environmental friendly and sustainable. Therefore, bio-based paper additives for the papermaking industry are essential. In this investigation, a water soluble biopolymer like carboxymethyl chitosan (CMCh) was prepared. The degree of substitution of the prepared CMCh was 2.49. The solubility of the prepared CMCh was 2.0 (w/v) % at 50 °C, and the conductivity increased with the increase of CMCh concentration in water. The prepared CMCh was applied as dry and wet strength agent of unrefined and refined softwood pulps. Both pulp increased dry and wet strength with increasing CMCh dose. An addition of 2.0 % CMCh increased dry strength by 125 % and wet strength by 293 % of unrefined pulp. On the other hand, the dry and wet tensile index of refined pulp increased from 59.48 N·m/g to 66.11 N·m/g and 2.48 N·m/g to 3.47 N·m/g, respectively, with the addition of 1.0 % CMCh. The CMCh was also used in filler modification. The precipitated calcium carbonate (PCC) modified with CMCh increased the ash content in paper with improved strength properties. The CMCh can be used in papermaking both for improving paper strength and filler retention.

Effect of softening duration on physical, mechanical and microstructural properties of flattened densified Bambusa bambos

The half-split Bambusa bambos culms were flattened after subjecting them to different steaming durations in the range of 20–40 min. The flattened bamboos from bottom, middle and top sections were further subjected to the densification process using a hot press. Various physical and mechanical properties of the flattened and densified bamboo (FDB) were evaluated and compared with control. Analytical techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were applied to study the microstructure and chemical changes due to flattening and densification. The results showed that softening duration had significant effect on all the properties of the FDB. The flattened sheets prepared from the bottom, middle and top portions of bamboo showed different properties. The density of the FDB was observed to increase significantly compared to untreated bamboo. The significant density improvements lead to relatively uniform distribution of the vascular bundles through the radial direction of the culm wall. Although the water absorption of the FDB boards was significantly reduced compared to control, no improvement was observed in the dimensional stability after water submersion for 24 h. With the increase in softening duration, various mechanical properties such as flexural strength, flexural stiffness and tensile strength parallel to fibre direction of FDB were improved significantly. The SEM observations showed that the microstructure of parenchyma and vessel elements changed significantly while fibre microstructure was undisturbed. FTIR analysis showed that hemicellulose content was slightly reduced while other chemical constituents of bamboo were not much affected. The crystallinity of the bamboo was found to be increased after flattening and densification leading to improvement in strength properties. These findings may be of practical importance for efficient utilization of bamboo in production of value-added FDB composites.

Strength attributes and microstructural characterization of basalt fibre incorporated self-compacting concrete

The transformation to produce environment-friendly materials around the world demands the construction industry to promote both high-performance and sustainable construction materials. The focus of the study is to develop basalt fibre (BF) incorporated self–compacting concrete (SCC) which provides a plausible solution to meet the demands of the current scenario. BF is known for its excellent strength, durability, and thermal properties. BF is added to the concrete in a volume fraction of 0.1%–0.5%. The characterization of BF and its utilization in SCC is experimentally investigated to determine its compressive, split-tensile, flexural, residual, and impact strength properties. According to the research findings, BF has reduced the diameter of the flow (695 mm–663 mm) and increased the time of flow (3–5.6 s). In contrast, the compressive strength (=52.86 N/mm2) and split-tensile strength (=4.46 N/mm2) has increased at 0.3% volume fraction of BF whereas the flexural strength (=7.06 N/mm2), residual strength (= 2.724 MPa), and impact strength (=4457.44 kNmm) has increased at 0.4% volume fraction of BF. The improved strength properties are due to the bridging effect and prevention of microcrack progression. The predicted regression-based analytical models exhibited a good correlation with analytical models of international codes. BF showed good interfacial bonding with the surrounding concrete matrix and improved the thermal stability of the concrete. Eventually, the characterization and strength assessment of BF validates that SCC is a potential material that can be performed better in all of its strength attributes with the inclusion of BF.

Hydration, Microstructure, and Properties of Fly Ash–Based Geopolymer: A Review

Abstract Geopolymers have gained attention as a potential eco-friendly alternative to Portland cement, primarily due to their reduced carbon dioxide emissions and the opportunity to repurpose industrial waste materials. Fly ash (FA), a byproduct of coal combustion, has been favored as a raw material for geopolymer concrete owing to its widespread availability and high concentrations of alumina and silica. The development and application of fly ash–based geopolymer concrete can contribute significantly to production of sustainable construction materials. An in-depth analysis of fly ash–based geopolymer concrete has been conducted to explore its potential as a substitute for traditional concrete. This review encompasses the underlying reaction mechanism, strength, long-term durability, and microstructural characteristics of geopolymer concrete. The present review paper shows that adding the optimal quantity of fly ash improves the performance of fly ash–based geopolymer when exposed to extreme durability conditions, as well as improving strength properties. The microstructural analysis shows that when fly ash is added, the microstructure of the concrete matrix would be dense and packed. However, challenges remain in adopting fly ash–based geopolymer concrete for large-scale construction projects, as the existing literature presents inconsistencies in the reported strength, durability, and test results. Further research is necessary to consolidate knowledge on the behavior and mechanism of fly ash–based geopolymer concrete and to ultimately provide comprehensive data to support its widespread implementation in the construction industry.

Optimization of Printing Parameters to Enhance Tensile Properties of ABS and Nylon Produced by Fused Filament Fabrication.

This study aimed to identify the optimum printing parameters for the fused filament fabrication (FFF) of acrylonitrile butadiene styrene (ABS) and polyamide (nylon), to improve strength properties. For this purpose, the methodology of the paper involves an experimental study that used Taguchi's method to identify the effects of the infill pattern, infill density, and printing speed on the mechanical properties of the materials. ABS and nylon plastic parts were tested in tension to failure. Based on the results of the tensile tests, it was found that ABS material produced the highest ultimate tensile strength when printed using a tri-hexagonal infill pattern, 100% infill density, and a printing speed of 65 mm/s. On the other hand, nylon material exhibited a better performance when printed using an octet geometric structure, with identical other parameters.

Preliminary tests on additive-manufactured Al-Sc specimens for the setup of a numerical model for Laser Shock Peening

Aluminum-Scandium alloys offer a great potential in aerospace applications due their high corrosion resistance and improved strength properties. Furthermore, these alloys have been qualified for laser additive manufacturing (AM), producing parts with static strengths rivalling their conventionally manufactured counterparts. However, laser processing also results in large residual stresses that can severely affect fatigue properties and result in geometric distortion. A proven method for reducing the fatigue-related problems in metallic structures is to drive compressive residual stresses into the affected area by means of Laser Shock Peening (LSP). This surface treatment is very effective in bulk structures, improving life performances of fatigue-sensitive aeronautical components, such as jet engines turbine blades or helicopter gearboxes. On the other hand, quite a limited number of studies has been presented on the effect of LSP on fatigue crack growth in thin components and laser AM structures. This work presents first the results of preliminary tensile tests on additive manufactured Al-Sc specimens. The tensile strengths of as-built and heat-treated samples are compared. Then, a reliable and computationally time-effective numerical model of laser peening is reviewed, referring to case studies investigated earlier. In view of applying LSP to additive manufactured Al-Sc components, the effects of different laser parameters and geometries are discussed. Finally, the possible drawbacks of the LSP treatment are addressed, in order to exploit its full potential in increasing the fatigue life of AM components.

Experimental studies on use of bamboo mat as stone column encasement in clayey soils

With the rapid urbanization and industrialization; scarcity of useful land is experienced for the infrastructure projects particularly in the urban areas. This has resulted in the use of sites with weak soil deposits such as soft clayey soils. Numerous problems are associated with these soils are high volumetric changes, heave, low bearing capacity, etc. So as to minimize the constructional difficulties associated with the soils; ground improvement techniques are practiced quite frequently on the sites. Stone column provision is one such approach used widely in the fields to enhance the properties of the weak soils. The stone column installation involves partial replacement of 10–35% of weak soils by gravelly materials to form stiffer composite mass.In the present study, an experimental program was undertaken to observe the improvement in strength properties of soft clayey soils collected from Nagpur area, Maharashtra State, India on insertion of stone column. Stone columns were placed single and in group with triangular arrangement. Effects of varying length (L) to diameter (D) ratios (i.e. L / D ratio) of stone columns on the strength properties were analyzed.As an attempt towards sustainable construction; demolition aggregates was used as partial replacement to the natural aggregate while preparing the stone columns. To increase the stiffness of stone column, cement was attempted in small quantity (4% by weight of aggregate) while preparing the specimen. Further, the use of bamboo mat as encasement was planned to study further improvement in load carrying capacity of stone column by increased lateral confinement.The experimental observations depict overall improvement in the load carrying capacity of clay beds on insertion of stone columns. Laboratory testing confirms the possibility of use of demolition waste in stone column construction, as the observed strength (uni-axial compressive strength) is 60–75% of the natural aggregate stone column. Use of bamboo as encasement is effective and shows noticeable improvement in the load carrying capacities (nearly 35–60%) and reduced settlement. Further, study illustrate that the use of single stone column is more effective.

Synthesis and characterisation of magnesium-based nano-composite – A review

In the recent decades, the need for light weight and high specific strength has been the hot issue in many engineering field and also biomedical sectors. Magnesium and its alloys are considered as a light weight material due to its low density that can replaced aluminium, steel and titanium. However, at room temperature, magnesium alloys have closely packed hexagonal crystalline structure with restricted number of freely actuated independent slip system that suffers from poor ductility by 5%–8% approximately. Therefore, Magnesium alloy creates some challenges for the application of many industrial sectors. One technique that can improve strength properties without significant reduction of ductility is to add reinforcing nanoparticles within the magnesium matrix and making them an attractive choice for light weight structural application. The performance of magnesium matrix-based composites to a current stage depends upon the proper selection of composition and combination of reinforcement particles within the matrix materials. In light of the writing overview, the inclusion of reinforcing particles, for example, TiC, SiC, B4C, Al2O3, hybrid reinforcement and so forth is the way to betterment of the tribological behaviour and the mechanical properties of magnesium matrix composites. This paper presents a brief overview based on the available literature survey that the effect of different geometries and percentage contribution of reinforcement particles in various processing techniques on the mechanical properties, microstructure and wear behaviour of magnesium-based metal composites.

Structural Behaviour of Hybrid Fibres Concrete Using Regression Analysis

Abstract: The main objective of the current effort is to create hybrid fibre reinforced concrete with improved strength properties, structural behaviour, and structural performance by adding the right dosage amount of hybrid fibre. In this work, it is suggested to employ hybrid fibres of two different types, one of which is Steel fibre, a metallic fibre, and the other is Polyvinyl Alcohol fibre, which has a synthetic foundation. In this way, the concrete gains high tensile strength, flexural strength, and compressive strength due to the inclusion of steel fibre with a high Young's modulus and tensile strength. The steel fibre functions as a crack arrestor, stopping the growth of cracks at the macro level. The microscopic cracks are stopped from spreading by the use of synthetic Polyvinyl Alcohol (PVA) fibre, which is more flexible and ductile, increasing the strength and hardness of the concrete. The objective of the current study is to assess the structural behaviour and strength features of hybrid fibre reinforced concrete. For different mix proportions, such as 0% Steel fibre and 1% PVA fibre, 0.25% Steel fibre and 0.75% PVA fibre, 0.50% Steel fibre and 0.50% PVA fibre, 0.75% Steel fibre and 0.25% PVA fibre, and 1% Steel fibre and 0% PVA fibre by the volume of concrete, the specimens were cast with the addition of hybrid fibres at a total volume fraction of 1%.