Alternative Reinforcement Research Articles

Experimental study of precast concrete walls using bamboo as alternative reinforcement

The public's demand for simple, livable houses means that material studies to support this continue to be carried out today, starting from using natural materials such as bamboo as precast concrete walls. This study aims to conduct an experimental study using bamboo rope from the Gigantochloa Apus variety as an alternative reinforcement for precast concrete walls. Research was carried out on 12 precast concrete wall test specimens, and the flexural properties, flexural strength, and crack patterns were formulated when subjected to a quasi-static load concentrated in the middle of the span. The concrete slab measures 600800 mm with a 50 and 75 mm thickness. The three configurations of bamboo bones used include (1) Gedhek-type woven bamboo slats, (2) bamboo slat type, and (3) Sasak-type woven bamboo slats. The research results show that Sasak-type woven bamboo slat reinforcement is the most effective alternative reinforcement. The behavior of the test specimen shows a ductile failure pattern similar to conventional reinforced concrete. The maximum moment capacity achieved is 1.5 to 2.2 times greater than the theoretical nominal moment capacity. Meanwhile, the behavior of test specimens with conventional plate-type woven bamboo slat reinforcement showed sudden and brittle failure due to slippage at the bond between the bamboo reinforcement and concrete. The average maximum moment from the test results is 60% of the theoretical nominal moment. The results of this research recommend that woven bamboo slats of the conventional plate reinforcement type are less effective as alternative reinforcement if they are not given special treatment to increase their adhesion to concrete. Gedhek-type woven bamboo slats are not effective as alternative reinforcement because they cause separation of the top and bottom parts of the woven concrete, thereby reducing the integrity of the cross-section and causing the cross-sectional capacity to be relatively small.

Benefits and risks of application of non-metallic composites as an alternative to steel reinforcement in concrete elements

The paper presents an overview of possible alternative reinforcement solutions to the most popular steel reinforcement currently used for concrete elements. Particular emphasis was placed on the use of composite reinforcement, taking into account the types of components concerned, possible applications and presenting an analysis of the risks and opportunities facing the construction industry related to the use of this type of reinforcement. In addition, an analysis of the material parameters taking into account the division of composite reinforcement due to the different types of fibers used in their production is presented. The paper also presents a comparative analysis of the parameters of steel and composite reinforcement, among others: tensile strength, susceptibility to corrosion, compressive and bending strength, fire resistance. It also analysed the needs of the construction market in the search for alternative concrete reinforcement in reinforced concrete structures, particularly in the context of recent events such as the Covid-19 pandemic and armed conflicts, which disrupt the supply chain and force the search for alternative materials that can replace reinforced steel. The availability of standards and instructions for the design of concrete elements and the related responsibilities of structural designers were analysed, identifying the research directions necessary to popularize and ensure the safety of the design of concrete elements with the use of alternative material solutions – in particular composite reinforcement in concrete slabs.

Experimental Investigation on Beam with Composite Reinforcement Using Mild Steel Tube In-Filled with Crumb Rubber

In today developing consequence, innovative alternates are being familiarized from recycled wastages used in concrete construction. This study concentrates on alternate reinforcement in the structural elements. The conventional reinforcement is replaced by the rubber composite reinforcement using in-filled tubes. The bond relation among the mild steel tube and concrete is simply good. The performance of the composite reinforcement using rubber in-filled tubes are comparing to the conventional reinforcement. The composite reinforcement is made by in-filling the mild steel tubes with cement slurry and crumb rubber. And the crumb rubber gained from the cracker mill. This crumb rubber institutes to the solid waste management. The scrap tires are prepared into crumb rubber and mixed with water – cement in a mortar ratio of 1:1:2 (water: cement: sand) to attain the colloidal consistency. 40% of 177-micron size crumb rubber sieves replaced instead of sand. This crumb rubber constitutes to the solid waste management and light weight. Hence these composite reinforcements will reduce weight of steel in reinforced concrete along with the decrease in cost of construction. This idea inspects the flexural strength of concrete beam with composite reinforcement, Mild steel pipe reinforcement and ordinary reinforcement by third point loading.

FLEXURAL AND DURABILITY CHARACTERIZATION OF CONCRETE REINFORCED WITH TREATED BAMBOO AS AN ALTERNATIVE BUILDING MATERIAL

Abstract The cost and environmental problems associated with steel as a reinforcement material in concrete has necessitated the need to research for alternative reinforcement materials, and bamboo is one of them. The flexural and durability characteristics of bamboo reinforced concrete (BRC) samples under harsh environmental condition was simulated by curing samples in an alkaline solution. Bamboo splints that were coated with sanded bitumen were used to reinforce the concrete samples with unreinforced concrete (UC) serving as control. The BRC samples were cured in normal water and an equal number were cured in 5% Sodium Hydroxide (NaOH) alkaline solution. Samples from both curing conditions and another of the control were tested for flexural strengths after 7, 14, 28, 56, and 76 days of curing respectively and results compared. Water absorption rates after each curing period were also taken. Ultrasonic pulse velocity (UPV) tests were also conducted on the samples to find out the composite qualities. The results showed that BRC had twice as much flexural strength than UC but reduced in strength by 17.9% in the alkaline environment after 28 days of curing. In addition to possessing acceptable strength values under normal water and alkaline solution curing situations by ponding, all the samples had elastic dynamic modulus and static modulus values that exceeded minimum recommended values by the relevant standards.

Evaluation of flexural failure for concrete beams partially reinforced by geogrid sheets

ABSTRACT The behavior of reinforced concrete beams with biaxial and uniaxial geogrids as a partial reinforcement with traditional steel bars under flexural loads has been experimentally studied. The effect of geogrid layers with traditional steel reinforcement in concrete beam specimens in compression and tension zones has also been investigated. Geogrid is one of the geosynthetic materials that exhibits both tensile and flexural behavior similar to traditional steel. To examine the effect of geogrids on traditional steel as a composite reinforcement system, strain gauges were fixed to the concrete beams and bottom reinforcement (steel bars). The studied parameters in this investigation are the number of geogrid layers, types of geogrids, and their position in concrete beams. First cracking load, failure load, initial and post-cracking, deflection, and ductility of beam specimen were investigated. The experimental results indicated that using geogrid sheet layers as partial reinforcement greatly contributed to resisting flexural stresses of concrete beams. An increase in the ductility and the capacity load of the concrete beam specimen was also observed. Based on this experimental investigation, the geogrids can be applied as additional or alternative reinforcement with/without traditional steel bars in concrete beams.

Viscoelastic behaviour of poly(ether-ketone)/fly ash composites fabricated by powder metallurgical route

Poly(ether-ketone)/fly ash (FA) composites reinforced with 0-30 wt% FA were fabricated using ball milling followed by hot compaction. The composites were investigated for mechanical and viscoelastic properties. Scanning electron microscopy revealed excellent dispersion and good adhesion of FA particles with the matrix. The addition of FA increased the microhardness by 70% and the storage modulus (below glass transition) by 75%. The reinforcing efficiency was better above the glass transition, which increased to around 177% at 250°C. This research indicates that the FA can be used as an alternative reinforcement of costly ceramic powder for the electronic packaging substrate or printed circuit board applications.

Facilitators and Barriers to Understanding and Accepting People with a Sexual Interest in Children: A Thematic Analysis.

The widespread conflation between having a sexual interest in children and engaging in sexually abusive behavior contributes significantly to elevated levels of stigma targeted at people living with a sexual interest in children. Stigmatization and societal punitiveness surrounding people living with these interests can impact their well-being, obstruct help-seeking, and potentially increase risk of offending behavior. Recent quantitative research employing stigma intervention strategies has produced encouraging results in reducing stigmatizing attitudes toward this population. The current study sought to expand on quantitative research findings to explore qualitatively the facilitators and barriers to understanding and accepting people living with sexual interest in children. Thirty participants were interviewed following completion of an online stigma intervention study. Participants were asked about their attitudinal responses to the earlier study and how personal and professional experiences contributed to shaping their attitudes surrounding people living with a sexual interest in children. Reflexive inductive thematic analysis was used to explore what factors promote understanding and what factors act as barriers to understanding people with sexual interest in children. The significance of experiences which challenged the dominant social narrative was identified across several themes which facilitated understanding and acceptance of people who have a sexual interest in children. Themes which reflected barriers to understanding included difficulty comprehending alternate narratives, parental concern, and reinforcement of current stereotypes. Implications for developing stigma-reduction interventions and future research are discussed.

Effects of naltrexone on amphetamine choice in rhesus monkeys and rats.

Clinical amphetamine use is constrained by high abuse potential, and amphetamine use disorder is a persistent clinical problem with no approved medications for its treatment. The opioid antagonist naltrexone has been reported to reduce some abuse-related effects of amphetamine. This study used an amphetamine-versus-food choice procedure in rhesus monkeys and rats to test the hypothesis that naltrexone might serve as either (a) a maintenance medication for amphetamine use disorder treatment or (b) an "abuse-deterrent" adjunct to clinical amphetamine formulations. Male rhesus monkeys and male and female rats were trained to choose between increasing unit doses of intravenous amphetamine and an alternative food reinforcer during daily behavioral sessions. Experiment 1 evaluated effectiveness of continuous naltrexone maintenance to reduce amphetamine-versus-food choice in both monkeys and rats. Experiment 2 combined naltrexone with amphetamine in fixed-proportion amphetamine + naltrexone mixtures to evaluate the effectiveness of naltrexone in both species to reduce mixture choice relative to amphetamine-alone choice. Amphetamine maintained a dose-dependent increase in amphetamine choice in both monkeys and rats. Naltrexone maintenance did not significantly decrease amphetamine choice in either species. Addition of naltrexone to amphetamine reduced amphetamine choices per session in monkeys, but behavior was not reallocated to food choice, and in rats, the addition of naltrexone only decreased food choice without significantly affecting amphetamine choice. These results argue against the use of naltrexone as either (a) a maintenance medication for treatment of amphetamine use disorder or (b) an "abuse-deterrent" adjunct to amphetamine for clinical applications. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Cocaine abstinence during the “critical period” of a contingency management trial predicts future abstinence in people with cocaine use disorder

BackgroundContingency Management (CM) is being piloted as a treatment for stimulant use disorder in several US states, highlighting the need for treatment optimization. One important goal of optimization is decreasing drug use during the early stages of treatment, which has predicted success in other interventions. However, this “critical period” has not been reported in CM trials. The purpose of this analysis was to determine if, after accounting for baseline abstinence and incentive condition, abstinence in a CM trial for people with Cocaine Use Disorder (CUD) could be predicted by cocaine use during a first-week critical period. MethodsEighty-seven participants with CUD were randomized to receive contingent high or low value incentives for cocaine abstinence or were in a non-contingent control group. Generalized estimating equations (GEE) were used to analyze urine test results over 36 timepoints during the 12-week intervention. To assess for a critical period, the first three visits were included in the GEE as a covariate for remaining urine test results. ResultsParticipants who provided more negative samples during the critical period were significantly more likely to produce a negative urine sample during the remainder of the trial, though some effects of group remained after controlling for the critical period. ConclusionsThese results indicate that a critical period exists for CM trials, and it can explain a substantial amount of future performance. Early contact with an abstinence-contingent high magnitude alternative reinforcer may explain additional performance beyond the critical period, further justifying the use of high magnitude alternative reinforcers.

Extraction and Characterization of Natural Fiber from the Stem of Dombeya Buettneri Plant for Biodegradable Polymeric Composites Application

ABSTRACT The global drive for a circular economy emphasizing sustainability in composite manufacturing processes has been the driving force for current ongoing research studies in natural fibers as sustainable substitutes for non-biodegradable synthetic fibers. The present study was carried out to characterize Dombeya buettneri fiber (DBF) extracted manually from the bark of the plant stem. Determination of physical and mechanical properties, quantitative chemical analysis, Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis and scanning electron microscopy were used to characterize the extracted fiber. Fiber constituents and XRD results showed higher cellulose content (58.45%), crystallinity index (62.32%) and percent crystalline (72.63%). The fiber had a crystallite size of 2.16 nm as determined using the Debye-Scherrer’s equation while FTIR analysis confirmed the presence of various functional groups of lignin, hemicellulose and cellulose on the fiber structure. The results revealed that DBF fiber had a thermal resistance that is up to 229.57°C with a maximum thermal degradation temperature of 356.27°C. Based on the results of this research that are comparable with other studies on cellulosic fiber, DBF fiber has a great potential as an alternative reinforcement for the development of polymer-based bio-composites.

Performance Prediction of Hybrid Bamboo-Reinforced Concrete Beams Using Gene Expression Programming for Sustainable Construction.

The building and construction industry's demand for steel reinforcement bars has increased with the rapid growth and development in the world. However, steel production contributes to harmful waste and emissions that cause environmental pollution and climate change-related problems. In light of sustainable construction practices, bamboo, a readily accessible and eco-friendly building material, is suggested as a viable replacement for steel rebars. Its cost-effectiveness, environmental sustainability, and considerable tensile strength make it a promising option. In this research, hybrid beams underwent analysis through the use of thoroughly validated finite element models (FEMs), wherein the replacement of steel rebars with bamboo was explored as an alternative reinforcement material. The standard-size beams were subjected to three-point loading using FEMs to study parameters such as the load-deflection response, energy absorption, maximum capacity, and failure patterns. Then, gene expression programming was integrated to aid in developing a more straightforward equation for predicting the flexural strength of bamboo-reinforced concrete beams. The results of this study support the conclusion that the replacement of a portion of flexural steel with bamboo in reinforced concrete beams does not have a detrimental impact on the overall load-bearing capacity and energy absorption of the structure. Furthermore, it may offer a cost-effective and feasible alternative.

Resurgence of goal-directed actions and habits.

This study investigated how goal-directed and habitual behaviors recover after extinction within the context of the resurgence effect, a form of relapse induced by the removal or worsening of alternative reinforcement. Rats were trained to press a target lever with one reinforcer (O1) for either minimal (4) or extended (16) sessions. An extinction test after the completion of O1 devaluation confirmed that minimal and extended training formed goal-directed and habitual behaviors, respectively. Then, pressing an alternative lever was reinforced with a second reinforcer (O2) while the target response was placed on extinction. When O2 was discontinued, the minimally trained target response resurged with goal-directed status as in the extinction test. However, the extinguished habitual behavior in the extensively trained rats did not recover as a habit but instead with goal-directed status, possibly due to the context specificity of habits or the introduction of a new response-reinforcer contingency. The critical finding that reinforcer devaluation consistently led to less resurgence regardless of the amount of acquisition training provides a clinical implication that coupling differential-reinforcement-of-alternative-behavior (DRA) treatments with the devaluation of the associated reinforcer of problematic behavior could effectively diminish its recurrence.

Translational evaluation of on/off alternative reinforcement cycling.

Cycling between the availability and unavailability of reinforcement for alternative responding has successfully reduced resurgence in basic laboratory evaluations, but this approach represents a marked departure from current standards of care when treating problem behavior, warranting careful translation before its use clinically. Therefore, with extinction arranged for target responding across groups in Phase 2, we evaluated the effects of cycling between the availability and unavailability of differential reinforcement of alternative behavior (DRA) using a computer-based task with adult humans recruited through Amazon MTurk. Two control groups experienced constant DRA in Phase 2, with one group experiencing a dense DRA schedule and another group experiencing a lean DRA schedule. The cycling DRA group tended to show greater reductions in target responding and improved discrimination in Phase 2 and less target responding across Phases 2 and 3 than the lean DRA and dense DRA groups. These preliminary findings suggest that on/off DRA cycling procedures may produce more desirable treatment outcomes than constant DRA without producing negative side effects; however, further research is needed to confirm these possibilities.

Article of RILEM TC 292-MCC: life cycle assessment (LCA) of non-metallic reinforcement for reinforcing concrete: manufacturing, durability, dismantling, recycling and reuse: a review

The potential of non-metallic reinforcement to be an environmentally sustainable alternative to classic steel reinforcement in concrete has become evident in recent years. The high-performance fibres used to produce non-metallic reinforcement elements have a considerably lower weight to transferable tensile forces ratio and are almost non-corrosive under common exposures. These indicators allow for a high environmental performance throughout the extended life cycle of the product. At the same time, substantially more resources and energy per unit weight are required for their production in some cases, e.g. for carbon fibres, compared to conventional reinforcing steel. The presented work addresses this conflict by closing a number of obvious research gaps. Despite an increasing number of publications during the last years, so far there are no comprehensive sets of data available on the environmental impact of various concrete reinforcing materials. With the data compiled in this work, for the first time, an objective comparison of different reinforcement systems (conventional and alternative) is presented that differentiates various environmental impact categories and therefore enables to perform Life Cycle Assessment (LCA). Other often observed shortcomings in sustainability assessments in concrete constructions are that an extension of the service life due to improved durability and the burden a material poses at the end of its life cycle are not considered. Comprehensive reviews of durability considerations help to develop an estimation of the service life. In addition, a state-of-the-art on possible strategies for dismantling, recycling and reuse of alternative non-metallic reinforcement systems shows that the composition of the FRPs, i.e., fibre and matrix materials, not only has a strong influence on the environmental impact in the production phase, but also on the durability as well as on a possible reuse.

Analysis of Consolidation Grouting Effect on The Stability of Portal Slope of The Spillway Tunnel in The Bulango Ulu Dam, Gorontalo, Indonesia

The problem of portal slope instability often occurs caused by the poor lithological conditions composing the slope. During the portal excavation of the outlet spillway tunnel in the Bulango Ulu Dam, the slope failed. The slope was then reinforced by consolidation grouting. The objectives of this research were to characterize the soil and rock masses composing the slope, evaluate the grouting effectiveness by Limit Equilibrium Method (LEM), and recommend an alternative slope reinforcement method. Surface engineering geological mapping, borehole data evaluation, and laboratory testing were conducted to obtain slope stability analysis parameters. The results showed that the slope consisted of diorite having poor to very poor rock masses. After 7 days of grouting, the triaxial test showed that the soil samples had similar cohesion and increased internal friction angle insignificantly, as compared to the soil samples prior to grouting. The LEM analysis indicated that the portal slope was unstable and consolidation grouting did not increase the slope safety factor (Fs) significantly. As the grouting effect may take significantly long, an alternative slope reinforcement method by soil nailing was proposed. The LEM analysis showed that the soil nailing increased the slope Fs from 0.63 to 1.49.

EFFECT OF ADDITION RAMIE AND COCONUT COIR FIBERS WITH DIFFERENT CONCENTRATIONS ON TENSILE STRENGTH OF ACRYLIC DENTURE BASE

Background: Acrylic denture base material has advantages such as good aesthetics, ease of repair, and affordable price, but this denture has mechanical properties, one of which is low tensile strength so fractures often occur during use. Utilization of natural fibers such as ramie (Boehmeria Nivea) and coconut coir (Coco Nucifera L) can be used as an alternative reinforcement for acrylic denture bases. Purpose: To determine the effect of adding ramie fiber and coconut coir fiber at different concentrations on the tensile strength of the acrylic denture base. Method: This study used a laboratory experimental method with a flat dumbell-shaped specimen with a size of 75 × 10 × 3 mm based on ISO 527-1 (2019). The specimens consisted of 42 plates which were divided into 7 groups, namely 6 specimens each group without fiber addition (control), with the addition of ramie fiber 1%, 2%, 3%, and the addition of coconut coir fiber 1%, 2%, 3%. Tensile strength testing using Universal Testing Machine (UTM), data were analyzed by One-way ANOVA test and Post Hoc LSD test. Result: The 3% ramie fiber addition group had the highest tensile strength (76.47 MPa), the 1% coconut coir fiber addition group had the lowest tensile strength (58.91 MPa). There was a significant difference in the results of the control group's tensile strength test and the addition of 3% ramie fiber and 1% coconut coir fiber (p-value < 0.05). Conclusion: The greater the concentration of ramie and coconut fiber additions, the higher the tensile strength value, although the tensile strength value in the coconut fiber addition group was lower than the control group and ramie fiber addition.

Polylactic acid/silicon nitride biodegradable and biomedical Nanocomposites with optimized rheological and thermomechanical response for material extrusion additive manufacturing

Silicon nitride (Si3N4) is a well-known bio-ceramic that is widely used for medical and healthcare purposes, due to its biocompatibility and superior chemical, physical and mechanical properties, which make it suitable for implants. Due to its unique features, examining its efficiency as a cost-effective reinforcement agent for thermoplastics in material extrusion (MEX) Additive Manufacturing (AM) seems promising for the development of composites for biomedical applications. The mainstream thermoplastic in MEX AM is the biodegradable and biocompatible Polylactic Acid (PLA). Herein, a biomedical grade PLA was used as a matrix for Si3N4 nanopowder in various filler loadings. Filaments were prepared with melt extrusion, whereas MEX 3D printing was engaged to prepare specimens for mechanical evaluation, according to standardized tests. The effect of the Si3N4 nanoparticles loading and its optimization was carried out by means of fifteen (15) different tests. The nanocomposites were fully characterized with Raman, Thermogravimetric Analysis, and Scanning Electron Microscopy, among others. Aspects of the process, such as rheology and processability, were also assessed and quantified. A more than 40% increase in both flexural and tensile strength of the samples was found, proving the hypothesis for the effectiveness of Si3N4 nanoparticles as a compelling alternative reinforcement agent in MEX AM of biomedical PLA-based parts.

Compressive strength improvements from noncircular carbon fibers: A numerical study

The benefits of high-performance unidirectional carbon fiber composites are limited in many cost-driven industries due to the high cost relative to alternative reinforcement fibers. Low-cost carbon fibers have been previously proposed, but the longitudinal compressive strength continues to be a limiting factor or studies are based on simplifications that warrant further analysis. A micromechanical model is used to (1) determine if the longitudinal compressive strength of composites can be improved with noncircular carbon fiber shapes and (2) characterize why some shapes are stronger than others in compression. In comparison to circular fibers, the results suggest that the strength can be increased by 10%–13% by using a specific six-lobe fiber shape and by 6%–9% for a three-lobe fiber shape. A slight increase is predicted in the compressive strength of the study two-lobe fiber but has the highest uncertainty and sensitivity to fiber orientation and misalignment direction. The underlying mechanism governing the compressive failure of the composites was linked to the unique stress fields created by the lobes, particularly the pressure stress in the matrix. This work provides mechanics-based evidence of strength improvements from noncircular fiber shapes and insight on how matrix yielding is altered with alternative fiber shapes.

Resurgence of destructive behavior following differential rates of alternative reinforcement.

Behavioral momentum theory (BMT) suggests that resurgence of destructive behavior may be at least partly determined by the rate of alternative reinforcement, with lean schedules of reinforcement producing less resurgence than dense schedules. Findings from basic and translational studies have been mixed, and the effects of alternative reinforcement rate on resurgence remain unclear. In the current study, we conducted a within-subject evaluation of resurgence during extinction with four children following functional communication training using dense and lean (BMT-informed) schedules of alternative reinforcement. We observed no reliable differences in resurgence across the dense and lean conditions. We discuss implications of these findings in relation to future research using quantitative analyses to evaluate the relative effects of alternative reinforcement rate and other BMT-based strategies for mitigating resurgence in applied settings.

Flexural behaviour of fly ash incorporated ferrochrome slag aggregate reinforced concrete beam

The structural behaviour of fly ash integrated ferrochrome slag aggregate concrete (FCSAC) is not widely understood owing to lack of research, although some studies have focused on its mechanical and environmental performance. The real-world use of FCSAC relies on its large-scale structural tests. This research investigates the flexural response of reinforced concrete beams fabricated with fly ash and ferrochrome slag (FCS) aggregate. A total of sixteen full-scale beams were built and tested. The beams were cast using four different concrete compositions: natural aggregate concrete (NAC) without any fly ash and FCS as the reference; FCSAC comprising 100% FCS as coarse aggregate and fly ash as partial substitution of cement at different percentages: 0%, 20% and 30%. The beams were fabricated with two different longitudinal reinforcement ratios of 0.69% and 1.86%. An eco-efficient mix proportioning method based on Particle packing optimization technique (PPOT) was adopted aiming to develop sustainable concrete. The effect of alternate resources (FCS and fly ash) and reinforcement ratios on the flexural response, cracking, ultimate load, failure pattern, ductility and toughness were examined. The experimental outcomes were compared to the predictions derived from the existing code provisions. Results revealed that the flexural performance of the FCSAC with fly ash beams was superior to that of NAC beam, despite having a lower flexural capacity than the FCSAC without fly ash beams. Moreover, the comparative study demonstrated that the fly ash-based FCSAC beams may be designed in accordance with the same guidelines as conventional concrete.