Cellular Reinforcement Research Articles

Utilizing PET bottles for sustainable cellular reinforcement: A study on enhancing fly ash backfill bearing strength with innovative geocell alternative

The slow degradation rate is one of the major global concerns. Only, 60 % produced is being recycled. Among these waste materials, Polyethylene Terephthalate (PET) bottles contribute around 10 % to the total plastic waste produced. The recycling process of PET bottles considering existing capacity in environmentally responsible ways is limited. It is estimated that 60 % of PET bottles produced are being disposed of in landfills. To overcome this, past studies have suggested novel approaches for using it as substitute for conventional geocell as soil reinforcement and stability. However, past studies mostly focused on application of PET bottles as flaked, shreds and sliced form. The present study attempts on application of PET bottles under fly ash (FA) backfills without mechanical alterations. Full-scale experiments were conducted on FA backfill system, for both unreinforced and reinforced conditions. A comparative study was performed between high-density polyethylene (HDPE) geocell and PET bottle mattress to assess the bearing strength of the FA backfill. Experiments were performed in a 1 m3 tank with a loading plate width of 200 mm. Vertical loading was applied onto the backfill footing (for all the trial series), till the footing settlement of 40 mm is achieved. An aspect ratio of 2 was considered for HDPE geocell and PET bottles. Rock quarry dust (RQD) was considered as cell infill and overlay material on FA backfill. The test results showed that settlement accumulation rate was low under reinforced scenario compared to the unreinforced condition, with higher resilient (elastic) settlement. RQD over the PET-reinforced zone was also seen to have enhanced the load distribution aspect, thereby reducing deformation in PET reinforcement. This usage of waste material will contribute towards sustainable development. This work demonstrates the feasibility and effectiveness of PET reinforcement to be used as replacement for HDPE geocell, which eventually can agument the design methodology of structural backfills.

Evaluation of commercial and scrap tyre cellular reinforcement infilled with demolition waste for granular sub-base of flexible pavements: A sustainable approach

Nowadays, use of geocell is gaining more importance in pavement industry as it offers improved performance through confinement and tensioned membrane actions. In the recent years, solid waste management seeks greater attention as it poses serious issues related to their disposal, health and environmental hazards. Effective recycling and reuse of these wastes could be a viable and economical approach towards sustainable construction. In this regard, two such wastes (scrap tyres and construction & demolition (C&D) waste) are considered for investigation. The recycled concrete aggregates (RCA) obtained from the C&D waste is used as granular sub-base material and its performance is compared with conventional crushed aggregates (CCA). Scrap tyre is used as cellular reinforcement (recycled tyre cell (RTC)) and its effectiveness as a reinforcing material is compared with the commercial cellular reinforcement (commercially available geocell (CGC)). The study involves construction of laboratory pavement sections under unreinforced and reinforced conditions and testing under repeated loading. The pavement sections supplemented with CGC and RTC reinforcement shows reduced permanent deformation by 27 & 33% and 30 & 35% respectively for CCA and RCA infill materials. The comparable performance of RCA with CCA is attributed to the self-cementation effect offered by the adhered residual cement mortar. With CGC and RTC reinforcement, residual pressure at the subgrade level reduces by 30 and 37% respectively. Provision of cellular reinforcement improves the stress distribution angle than the respective unreinforced pavements and highest improvement is observed in case RTC. Improved behaviour with RTC is due to the increased strip thickness and tensile strength of recycled tyre strip than the ones used in the preparation of CGC. Irrespective of the infill material, higher strains are experienced under the loading zone than the neighbouring cells. Overall, the study promotes use of scrap tyres and RCA in bulk volume for pavement construction offering an eco-friendly, cost-effective, sustainable and long-lasting pavements.

Applications of natural geotextile in geotechnical engineering

Ground improvement deals with the modification of the soil in existing foundation to give better performance after construction and to handle operational loading stresses during construction. Increased stability, bearing capacity and decrease in the settlement of foundation are the major outcomes of reinforcing the soil with fibres. Several advancements are made in the geotextiles in the form of providing three-dimensional cellular reinforcement. The increasing cost of geosynthetics and the growing problem toward sustainability led researchers to recognition on natural products as a possibility to synthetic ones. Natural fibres like sisal, jute, coir, banana, palm, water hyacinth, rice husk, bamboo, hemp, and many other fibres have certain properties within them, which satisfies the condition to be used as geotextile. These geotextiles are widely used for improving the performance and durability of highways with reduced construction cost. Geotextiles have a wide range of applications including soil stabilization, erosion control, drainage systems, and reinforcement of asphalt and concrete. It is also used in the prevention of soil erosion on the riverbanks by enhancing the grass vegetation as the natural fibres have 500 % water holding capacity on dry soil. The properties of natural geotextiles are deteriorated over a period due to biodegradation. The performance and durability of these natural geotextiles are improved using several treatments. In this paper a detailed review of various physio-chemical and mechanical properties of natural geotextiles and their treatment to improve durability are discussed.

The development of laser powder bed fused nano-TiC/NiTi superelastic composites with hierarchically heterogeneous microstructure and considerable tensile recoverable strain

In this study, we fabricated the TiC nanoparticles decorated NiTi-based superelastic composites via laser powder bed fusion (LPBF) technology. Different from reactionlessness between TiC and NiTi in the conventional processes, high energy density of laser beam triggered strong diffusion behavior of carbon atoms from TiC nanoparticles and resulted in the precipitation of TiCx and attendant Ni-rich even Ti-rich intermetallics. Interestingly, these nanoprecipitates distributed along the intricate network of connected dislocations, architecting a novel submicron-scale cellular reinforcement structure and facilitating the formation of a hierarchically heterogeneous microstructure. The migration and distribution of TiC nanoparticles as well as the forming mechanism of the submicron cellular reinforcement structure were then elaborated. The study indicated laser scanning speed had significant influence on the distribution of TiC nanoparticles, the size of cellular structure and the matrix grain orientation. At the optimized parameter, the LPBF-fabricated nano-TiC/NiTi composites exhibited a weak orientation texture along the building direction, finer cellular structure and a considerable steady recoverable strain of 2.3% at a maximum tensile loading of 300 MPa.

Laboratory and Numerical Studies on the Performance of Geocell Reinforced Base Layer Overlying Soft Subgrade

The use of geocells for support of foundations on weak subgrades has been gaining popularity in recent years. Detailed studies were performed in this work through laboratory tests and numerical simulations to investigate the influence of different parameters on the geocell supported foundations on soft subgrades. A series of large-scale laboratory plate load tests were performed on the geocell-reinforced base layer overlying soft subgrade. The soft foundation soil was simulated using blocks of Expanded Polystyrene (EPS) in the laboratory tests for obtaining consistent subgrade conditions between the tests. The numerical analyses were performed in three-dimensional finite difference numerical program Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D). The numerical models were calibrated against the data obtained from laboratory tests. This paper deals with investigating the influence of different parameters such as pocket opening size, height and size of the footing on the performance of geocell-reinforced base layer overlying soft subgrade. The provision of three-dimensional cellular reinforcement (geocells) in the base layer has substantially increased the bearing capacity of the pavement section and the optimum aspect ratio of geocell pocket was found to be close to unity. From the parametric study, it is observed that the potential benefits of geocell reinforcement increases with reduction in weld spacing and height of geocell while the influence decreases with increasing loading area for constant height of geocell layer.

Numerical investigation of geocell reinforced slopes behaviorby considering geocell geometry effect

The present study evaluates geocell reinforced slope behavior. A three dimensional analysis is carried out to simulate soil and geocell elastoplastic behavior using the finite difference software FLAC3D. In order to investigate the geocell reinforcement effect, the geocell aperture size, thickness, geocell placement condition and soil compaction had been considered as variable parameters. Moreover, a comparison is evaluated between geocell reinforcing system and conventional planar reinforcement. The obtained results showed that the pocket size, thickness and soil compaction have considerable influence on the geocell reinforcement slope performance. Moreover, it was found that the critical sliding surface was bounded by the first geocell reinforcement and the slope stability increases, by increasing the vertical space between geocell layers. In addition, the comparison between geocell and geogrid reinforcement indicates the efficiency of using cellular honeycomb geosynthetic reinforcement.

Polysaccharides in Asparagus and Asparagus Juice

Polysaccharides in Asparagus and Asparagus Juice

Pavement Subgrade Stabilization with Lime and Cellular Confinement System

In this study effectiveness of lime stabilization and geocell reinforcement techniques of roads was investigated for low bearing capacity subgrades. For this purpose, a large-scale plate load test was designed and used. Clayey soil with high moisture content was reinforced with different percentages of hydrated lime (5%, 10%, 15% dry weight of the soil). The deflection and stress results indicated that lime stabilization or geocell reinforcement alone did not significantly increase subgrade reaction coefficient and bearing capacity values. Promising results were obtained on stabilization of weak subgrade when both techniques were used together. It was determined that cellular reinforcement increased the reaction modulus coefficient value and bearing capacity of the subgrade soil by more than 15% compared to the lime stabilization.

Numerical Analyses of Loaded Strip Footing Resting on Cellular Mattress and Strips: Reinforced Fly Ash Slope

In this paper, unreinforced and cellular reinforced fly ash slopes were analyzed using numerical modelling to simulate the laboratory model studies by applying similar geometry and reinforcement parameters to understand its deformation behavior on rigid foundation. Small scale laboratory experimental models were performed on fly ash slopes by applying strip loading at a 60° inclination. In the current study an approach was made to use cellular reinforcement (CR) material which is made up of from post-consumer waste plastic water bottles along with steel grid-jute geotextile composite reinforcement at slope facia. A numerical analyses using finite-element analysis (FEA) PLAXIS 3D was conducted to validate the experimental laboratory model test results. In FEA, fly ash as backfill material and reinforcing materials like steel grid-jute geotextile and cellular/geocell reinforcement were modeled systematically. Here, fly ash modeled with Mohr–Coulomb failure criteria as linear elastic plastic material and, for cellular/geocell reinforcement it was modeled as elastoplastic material. The numerical model analyses were consistently substantiated with experimental results. Parametric analysis were conducted by using validated numerical model to evaluate the influence of various cellular properties along with steel grid-jute geotextile composite reinforcement on the performance of reinforced fly ash slopes. The numerical finite element simulation (FES) results are in good agreement with the model test results.

Expanded Polystyrene Geofoam Based Cellular Reinforcement

Abstract This paper reports the effectiveness of proposed expanded polystyrene (EPS) geofoam cellular reinforcement with fly ash as filling material overlying a soft clay bed through small-scale laboratory model tests. The test beds were subjected to uniformly distributed load by means of a rigid steel plate. Loads with corresponding settlement were measured during the testing. EPS geofoam cellular reinforcement of densities 15, 20, 22, and 30 kg/m3 were prepared in the form of a mattress with three different heights of 50, 75, and 100 mm. The effects of density of EPS geofoam, height of cellular reinforcement, and the planar jute geotextile layer at the base of cellular reinforcement were tested through a series of tests to systematically study the overall performance of the system in terms of load carrying capacity and settlement behavior. Test results indicated that the provision of EPS geofoam cellular reinforcement in fly ash bed significantly improved load carrying capacity above the clay bed. The load carrying capacity decreased with increasing density of EPS geofoam and increased with increase in height of cellular reinforcement. A layer of jute geotextile placed at the base of cellular reinforcement further enhanced load carrying capacity for less height of cellular reinforcement. However, the effect of planer reinforcement was decreased with the increase in height of cellular reinforcement.

Model studies on cellular reinforced fly ash walls

In India, thermal power stations produce enormous quantity of fly ash as a byproduct of combustion. It requires huge disposal area and creates environmental problems. In India, where land to population ratio is too small, acquiring huge area of land for the disposal of fly ash is not easy. The utilization of fly ash and its disposal in an environment friendly manner is a foremost concern for developing country like India. In the present study, a series of model experiments were carried out for proper utilization of fly ash as an alternative backfill material in the cellular reinforced fly ash wall. Locally available waste plastic water bottles were used to prepare the cellular reinforcement. The diameter of bottles used for cellular reinforcement is 50 mm and with varying heights of 10 and 20 mm. The effect of change in length and spacing of the cellular reinforcement on the horizontal displacement of full height facing panel and settlement of the backfill were studied. For all the types of reinforcement cases, the variation in length and spacing of the reinforcement showed significant effect on the horizontal displacement of facing panel and on settlement of the backfill. The cellular reinforcement of height 20 mm showed better performance over 10 mm height cellular reinforcement.

Behavior of Cellular-Reinforced Fly-Ash Walls under Strip Loading

AbstractIn India, pulverized coal is used at thermal power stations as a fuel to generate electricity, thereby producing enormous quantities of fly ash. The amount of fly ash has been increased with the increasing demand of electric utilities. The utilization of fly ash and its disposal in an environmentally friendly manner is a foremost concern for developing countries like India. In this present study, with the aim of proper utilization of fly ash, a series of model experiments was conducted by using fly ash as a backfill material in a cellular-reinforced fly-ash wall subjected to strip loading. Two different types of locally available waste water bottles were used to make cellular reinforcements. The reinforcements were laid in two different patterns, mattress and strip. This paper studies and presents the effects of changes in length, spacing, coverage ratio, and dimensions of the cellular reinforcements on the horizontal displacement behavior of a full height facing panel and on the settlement of bac...

Study of cellular reinforced fly ash under triaxial loading conditions

Fly ash produced from thermal power plants as byproduct requires large area for storage. The quantity of fly ash and its hazardous impact on the environment is continuously growing. Tireless efforts are being carried out by many researchers to utilize the fly ash in geotechnical applications. In the present study, the behavior of cellular reinforcement (geocell) in fly ash under the static triaxial tests is emphasized. Triaxial tests were conducted on unreinforced and reinforced fly ash sample of 75 mm diameter and 150 mm height. The cellular reinforcement is made up of used and wasted locally available plastic water bottles. The diameters of the reinforcement used in this present study are 35 and 50 mm, with thickness 1 mm. Four different heights of the reinforcement, 10, 20, 30 and 40 mm, are used for both the diameters to study the effect of cellular reinforcement. The tests were conducted by placing cellular reinforcement in one layer as well as in two layers. Deviator stress–strain patterns due to the effect of cellular reinforcement are studied under three different cell pressures 100, 150 and 200 kPa. Peak deviator stress and shear strength parameters are found increasing with increasing in the height of cellular reinforcement for both the diameters of reinforcement. The 50 mm diameter cellular reinforcement showed high peak deviator stress–strain and shear strength parameters over 35 mm diameter. The placement, number of layers, height and diameter of reinforcement are found to have effect on the peak deviator stress. Finite element simulation is carried out using Plaxis 2D professional version to envisage the failure patterns, horizontal displacement and deviator stress–strain patterns, and results of finite element simulation are found to be in reasonably good agreement with the experimental results.

Multiple Hydrogen-Bond Array Reinforced Cellular Polymer Films from Colloidal Crystalline Assemblies of Soft Latex Particles.

Waterborne polymer films made from soft polymer latex dispersions generally suffer from deterioration of chemical resistance and physical barrier properties under high humidity conditions and upon solvent exposure. Here we demonstrate the fabrication of robust polyhedral cellular polymer films from poly(methyl methacrylate-co-butyl acrylate) latexes, which were made by emulsion polymerization using a 2-ureido-4-pyrimidinone (UPy) functional methacrylate comonomer. Multiple hydrogen bond (MHB) arrays provided by UPy groups arrest the film formation process thereby creating a cellular reinforcement. The cellular polymer films exhibit impressive physical and mechanical properties. Upon solvent exposure, the films show colloidal crystalline-type Bragg diffraction features and do not suffer excessive and deteriorative uptake of water and, more remarkably, can absorb high amounts of organic solvents, thereby turning into an organogel with preservation of shape, up to a 14-fold volumetric swelling ratio of the polymer films in case of chloroform.

Behaviour of Cellular Reinforced Sand Under Triaxial Loading Conditions

Cellular reinforcement is a three dimensional reinforcement used for reinforced soil structures. Behaviour of such reinforcement is important for its use in actual practice. Present paper focuses on the behavior of cellular reinforcement in sand under the triaxial loading conditions. Series of triaxial tests are performed on unreinforced and reinforced sand with single layer as well as double layers of cellular reinforcements with 75 mm sample diameter. Six different reinforcement heights of cellular reinforcements (varying from 3 to 50 mm) are used along with one sheet reinforcement of thickness 1 mm. From the experimental failure patterns of the triaxial samples, multiple zones of failure are observed as an effect of cellular reinforcement. Deviator stress–strain curves are studied for single and double layers of cellular reinforcement under three different confining pressures. Peak deviator stress is found increasing with increasing height of cellular reinforcement, which shows the confining effect of cellular reinforcement. Shear strength parameters are evaluated and are found increasing with increase in height of cellular reinforcement, also cellular reinforcement with heights 10 mm and more have showed increased shear strength parameters, as compared to 1 mm thick sheet reinforcement. This assures better behavior performance of cellular reinforcement over the planar one. Failure patterns are also visualized by finite element analysis and found in accord with experimental observations Horizontal displacement for reinforced samples visualized multi-zoned failure pattern. Finite element results for deviator stress–strain relationship are found in reasonably good accord with experimental results.

Glucocorticoids cause VE-cadherin upregulation and cytoskeletal rearrangements in the blood-brain barrier endothelial cEND cell line

The demonstration that glucocorticoid-mediated activation can control occludin expression in brain capillary endothelial cells has provided a new avenue of research in the field of blood brain-barrier (BBB) permeability regulation. In order to identify more key genes involved in glucocorticoid-mediated regulation of BBB permeability, we used cDNA microarrays to study changes in gene expression in dexamethasone-treated brain capillary endothelial cEND cells: Primarily, we observed changes in expression of the VE-cadherin gene involved in cell adhesion. Vascular-endothelial-cadherin (VE-cadherin) is an endothelial cell-specific adhesion protein localized in cell-cell contacts. It is known as an important determinant of vascular architecture and endothelial cell survival. Quantitative real-time PCR showed an upregulation of VE-cadherin expression exclusively in cEND cells, in accordance to previous observations made for the occludin gene. Subsequently, we verified divergent transcriptional activation of the VE-cadherin gene by dexamethasone. Furthermore, we measured the change in protein levels of VE-cadherin and demonstrated a transactivation of the VE-cadherin promoter in cEND cells via dexamethasone. Dexamethasone was further shown to induce cellular differentiation into a cobblestone cellular morphology and reinforcement of adherens junctions concomitant with the increased anchorage of VE-cadherin to the actin cytoskeleton. We thus propose that glucocorticoid effects on VE-cadherin protein synthesis and organization are important for the formation of both adherens and tight junction, and for improved barrier properties in microvascular brain endothelial cells. To find cell- or tissue-specific ligands that could be used in therapeutic regime of barrier disorder diseases it is necessary to study and understand the molecular mechanisms of beneficial effects of glucocorticoid action on BBB-genes involved in BBB-permeability regulation.

Pullout behaviour of cellular reinforcements

Reinforcements like bars, strips, textiles and grids are used for the reinforcement of soil walls in the modern era of civil engineering, but the use of cellular type of reinforcements is still under consideration and there is still a need of study the probable use of cellular reinforcement in reinforced soil retaining walls. Pullout test is commonly used to predict actual field pullout behaviour of reinforcements. In this paper, laboratory pullout tests are carried out with different height of cellular reinforcements along with planar sheet reinforcement, under two different normal pressures of 75 kPa and 100 kPa. Dimension optimization analysis for cellular reinforcement is done and longitudinal spacing to height ratio of 3.3 is found as optimum. Finite element method is used to compare the experimental pullout behaviour and found in good accord with the laboratory test results. Experimental results are also compared to the theoretical analysis. It is found that the interference in between transverse member is increasing with increase in height of cellular reinforcement, yet the ultimate pullout resistance is found more with higher reinforcement heights, for spacing to height ratio greater than 3.3.

Pullout response of cellular reinforcement under low normal pressures

Pullout failure of reinforcement is one of the very important criteria in the ultimate limit sate analysis of internal stability of reinforced soil retaining wall. This is particularly of critical importance in upper layers of wall where the normal pressure on the reinforcement is low. Cellular reinforcement is found very effective and better performing for reinforced soil applications. However, pullout experimental study of such reinforcement has not been focused till date. Therefore, in the present paper, full scale laboratory pullout test set up has been designed, fabricated and developed to test the pullout resistance of cellular reinforcement. A series of pullout test was carried out with different heights of reinforcement, under low normal pressures of 25 kPa and 50 kPa. Deformation patterns of all reinforcement in pullout are studied. Finite element simulation is used to verify the experimental pullout response and found in good agreement with experimental load-displacement relationships. Suggested reduction factor <i>‘k’</i> is found decreasing with increase in height of reinforcement; yet, ultimate pullout resistance is found increasing with increase in the reinforcement height, to the height of 20 mm to 30 mm; after which, greater interference between the transverse members caused decrease in pullout resistance. Pullout interaction factor for cellular reinforcement is found increasing with increase in the reinforcement height.

Optimization of a Violin Top with a Combined Laminate Theory and Honeycomb Model of Wood

Summary Stochastic optimization with the simulated annealing method (SA) is performed on a violin top made of Norway spruce (Picea Abies). A numerical example is presented which shows that it is possible, through changes in thickness variables, to compensate for changes in vibration properties caused by a variation in the material parameters in the top. A material model is also presented for the blank which considers the influence of density variations in the annual rings, the cellular structure of wood and reinforcement from the wood rays.

Cellular investigations of behavioral reinforcement

Using the hippocampal-slice preparation, we attempted to demonstrate operant conditioning of pyramidal cell activity using local micropressure applications of transmitters and drugs as reinforcement; the same injections administered independently of bursting provided a control for direct pharmacological stimulation or facilitation of firing. The results suggested that the spontaneous bursting of individual CA1 pyramidal neurons may be reinforced with activity-contingent injections of dopamine and cocaine, whereas, CA3-bursting responses may be reinforced with contingently-applied dynorphin A. We sought to confirm these indications of cellular reinforcement at the behavioral level in studies of hippocampal self-administration (despite the fact that the hippocampus has been ignored as a brain site for chemical self-administration experiments). The results suggested that dynorphin A is a powerful reinforcer of hippocampal self-administration behavior when injected in the CA3 field; experiments still in progress suggest that dopamine can reinforce self-administration behavior when injected in the CA1 field. Successful prediction of new behavioral data from operant-conditioning data at the cellular level helps to validate the cellular data by providing suggestive evidence of interrelationship between cellular and behavioral operant conditioning processes.