Wire Mesh Layers Research Articles

An approach to improve conventional square ferrocement jacket for strengthening application of short square RC column

The confinement effect over the cross-section of a square column is non-uniform compared to the same of a circular column. Concentration of stresses and subsequent cracking in the confining external jacket occurs at the corners of a square column; and thus the effectiveness of external jacket in such column is reduced significantly. The conventional square ferrocement jacket consists of rich mix cement mortar with single or multiple layers of wire mesh. This type of external jacket also experience similar problems in confining core columns. This study aims to develop efficient techniques to overcome the drawbacks of conventional square ferrocement jackets in strengthening of short square-shaped RC columns. Three techniques and variations in those techniques are proposed to address the problem. Experimental studies of selected variation from each technique affirm the effectiveness of the proposed techniques in addressing the problem associated with conventional square ferrocement jackets. The experimental investigation reveals that all the retrofitted square ferrocement-jacketed short columns exhibit higher load carrying and deflection capacities before failure compared with non-jacketed as well as conventional square ferrocement-jacketed columns. The findings indicated that the proposed techniques are efficacious to address the problem of conventional square ferrocement jacket.

Behaviour of Ferrocement SlabsContaining SBR Under Impact Loads

The main aim of this work is to investigate the behavior of Ferrocement slabs under impact loading. A total of 48 Ferrocement slabs were constructed and tested, 36 slabs tested under low velocity impact and 12 slabs tested under high velocity impact, in addition,the main parameter considered in the present investigation was number of wire mesh layers, content of (SBR) polymer andheight of falling mass (falling velocity). For low velocity impact,This test was performed in terms of the number of blows required to cause first crack and ultimate failure. The test was applied on square slabs of dimensions (500 × 500 × 50 mm) subjected to repeated impact blows by falling mass (1300 gm) dropped from three heights (2.4 m) , (1.2 m) and (0.83 m) at 56 day age. The number of required blows for the first crack and final failure was recorded. The mode of failure and the crack pattern were also observed. For high velocity impact test, a (500×500×50 mm) slabs were tested by 7.62 mm bullets fired from a distance of (15m) with a striking velocity of (720m/sec.). The spalling, scabbing and perforation were observed and discussed. The results exhibited that the number of blows which were required to make the first crack and failure, increased with increase of polymer content and number of wire mesh layers. Also for high velocity impact test, it can be noted that the area of scabbing and area of spalling decreased with the increase of polymer content and number of wire mesh layers compared with reference mixes. The compressive strength, splitting tensile strength and flexural strength increased with increase the polymer content. Based on extensive works , found that low velocity impact resistance of polymer modified Ferrocement slabs was greater than the reference mix slabs, it was found that the number of blows that needed to produce the first crack and ultimate failure increased with increase the polymer ratio of 3% to 5% and to 10%, and with increased the number of layers of reinforcing with wire mesh when comparing these results reference mix.

Experimental study of operating range and radiation efficiency of a metal porous burner

In this paper, a radiant metal porous burner which is formed from wire mesh layers is studied. Surface temperature of the burner is measured in different equivalence ratios and firing rates and radiation efficiency is calculated for each case. The experiments are performed for different thicknesses of the porous medium. The results show that the surface temperature increases with increasing firing rate and maximum surface temperature occurs in a lean mixture. Comparing the results for different thicknesses shows that maximum surface temperature is obtained in a medium with three-layer of wire mesh. The radiation efficiency of the burner decreases with increasing firing rate. The maximum radiation efficiency is about 30 percent which is obtained in the three-layer of wire mesh in the minimum firing rate. Comparison of the results with the other works shows a good agreement between them.

Investigation of single and double pass solar air heater with transverse fins and a package wire mesh layer

The purpose of this work is to construct and test single-pass and double-pass solar air heaters (SAHs) with four transverse fins. These fins were painted dark black and placed transversely to create four equal-spaced sections. Sixteen steel wire mesh layers were located between these fins as an alternative to an absorber plate; they had a cross-sectional area of 0.18cm×0.18cm and an internal diameter of 0.02-cm. In this project, the thermal efficiency and outlet temperature were studied in a geographic area located in the city of Famagusta, North Cyprus. The experimental results indicate that the thermal efficiency increases as the air flow rate increases for the range of (0.011-0.032)kg/s. The maximum efficiency obtained using the 7.5-cm high collector was 62.50% for the double-pass SAH and 55% for the single-pass SAH at an air flow rate of 0.032kg/s. Moreover, the thermal efficiency further increases by decreasing the height of the lower air pass of the double-pass SAH. The difference between the inlet temperature and outlet temperature, ΔT, indicated an inverse relationship with air flow rate: ΔT increased as the air mass flow rate decreased. The maximum differences (ΔT) observed were 45.30K for the double-passes SAH and 39.9K for the single-pass SAH at 0.011kg/s, which were recorded during the middle of the day with a maximum solar intensity. The results demonstrate a significant improvement in the thermal efficiency and outlet air temperature.

Finned Single-pass Solar Air Heaters with Wire Mesh as an Absorber Plate

Single-pass solar air heaters (SAHs) with two and six fins attached and packed with wire mesh layers were experimentally investigated. Wire mesh layers were used between the fins in the place of an absorber plate. The effects of air mass flow rate on the outlet temperature and thermal efficiency were studied. The results showed an increase in the thermal efficiency as the air mass flow rate was increased. The range of the mass flow rate used in this work was between 0.0121and 0.042 kg/s. It was found that for the same mass flow rate the SAH having six fins has higher efficiency compared to the system that has two fins. The maximum efficiencies for the SAHs were obtained at the mass flow rate of 0.042 kg/s. The maximum efficiencies for the six-finned and two-finned SAHs were 79.81% and 71.8%, respectively. In addition, the maximum temperature difference between the inlet and the outlet, ΔT, for the SAH with six fins exceeded the two-finned SAH for the same mass flow rates. The maximum ΔT was 51.1°C for the six-finned SAH and 44.2°C for the two-finned SAH. As expected, the maximum ΔT for each SAH was obtained at the lowest air mass flow rate (i.e., 0.0121 kg/s). A substantial enhancement in the thermal efficiency was achieved in comparison to the results of a single-flow packed bed collector with those of conventional collectors.

English

This paper presents the results of an experimental investigation into the flexural performance of hybrid polyvinyl alcohol (PVA) fibre ferrocement (HFF) composites panels. The primary focus is on the influence of mixture matrix and wire mesh content in the panels which have different thicknesses. The effect of using fly ash and silica fume in the mixtures is investigated from the testing of 21 panels. Best performed mixes are then chosen to prepare additional 27 ferrocement panelswith varying thicknesses and wire mesh layers. The observation of deflection hardening, energy absorption, and flexural stress is significant in this experiment. The energy absorption at post cracking and the toughness indexes are calculated from the flexure test results, and are used for the evaluation of strength capacity of this type of cementitious composites.

Parametric Study of Concrete Load Bearing Wall with Opening Based on Stress Criterion

In load bearing wall, reinforcement is only provided to control cracking, not for strength. In this paper A 3D linear finite element stress analysis of concrete load bearing wall reinforced with a single layer of wire mesh for use in double storey houses is performed. Opening in the wall for doors and windows inclusion is included in the model. Haunches are also considered at the opening corners to strengthen the wall section above the opening. Critical stress in the wall based on an appropriate stress criterion is compared with allowable tensile and compressive stress of the concrete in accordance with Eurocode 2. Parametric studies are carried out on dimensions of rectangular opening and also on sizes of haunches in the load bearing wall with openings. This research states that the reduction in the height and length of the rectangular opening together has more effect in decreasing the critical maximum principal stress of the load bearing concrete walls. Also, adding haunches to the corners of rectangular opening causes to decrease the maximum principal stresses significantly, especially for bigger dimension of haunches.

Effect of Polypropylene Fiber on the Flexural Strength of Ferrocement

This paper presents effect of Polypropylene Fiber (PPF) on the flexural strength of ferrocement. Various percentage of PPF content which are 0%, 1.0%, 1.5% were added into mortar matrix during preparing of ferrocement specimens. For each percentage of PPF, three specimen of ferrocement were produced. Each specimen were reinforced with different number of steel wire mesh layers which are 2 layers, 4 layers and 6 layers. Each specimens were tested under 3-poimt loading to obtain its flexural strength. It is observed that optimal percentage of PPF adding into mortar matrix will improve the flexural strength when it is in a range of 1% to 1.5%.

FLEXURAL BEHAVIOUR OF FERROCEMENT SLAB PANELS USING WELDED SQUARE MESH BY INCORPORATING STEEL FIBERS

The present study describes the results of testing flat ferrocement panels reinforced with different number of wire mesh layers. The main objective of this work is to study the effect of using different no of wire mesh layers on the flexural strength of flat ferrocement panels and to compare the effect of varying the no of wire mesh layers and use of steel fibers on the ultimate strength and ductility of ferrocement slab panels. The no of layers used are two, three and four. Slab panels of size (550*200) with thickness 25 mm are reinforced with welded square mesh with varying no of layers of mesh. Panels were casted with mortar of mix proportion (1:1.75) and water cement ratio (0.38) including super plasticizer (Perma PC-202) with dosage of 1% of total weight of cement. Some panels were casted with steel fibers (0.5%) of total volume of composite and aspect ratio (l/d) =57. Panels were tested under two point loading system in UTM machine after curing period of 28 days. Test result shows that panels with more no of layers exhibits greater flexural strength and less deflection as that compared with panels having less no of layers of mesh.

Investigation Strength Of One Way Slab Panel Using Steel Fibers And Wire Mesh (Ferro Cement)

This paper presents a study of the flexural behavior of the reinforced mortar slabs using both of steel fiber concept and ferrocement layer in tension zone cover as an additional reinforcement to the main steel bars .The concept of steel fibers mean that substitution the common types of steel fibers by alternative material exhibit the same action that produced by the tradition fibers. This material represented by short length of steel nails (SLSN) ,which is cheapest and more available than the first type in the local markets .The efficiency of this material have been checked using seven samples of beam prototypes tested under flexural behavior and reinforced with the nails. Results produced that the nails will improve ultimate flexural strength of mortar noticeably .The increasing ratio in flexural strength of mortar was in the range of (400-1200)% related with these seven beams .Therefore, and according to this advantage, eight one way reinforced slab panel have tested under flexural loading. They reinforced with the nails ,one layer of wire mesh to produce ferrocement cover, and the both material . After testing these eight panels ,the once reinforced with SLSN as an additional reinforcement exhibit the best performance in resisting flexural stresses by increasing flexural load capacity from 17.25kN to about 20kN. Furthermore, maximum central deflection was also reduced by this material from 24.75mm for non fiber reinforced panels to 4.9mm for reinforced once. Although the action of ferrocement was less than the results produced by the fibers ,ferrocement cover increases the ultimate flexural load capacity for panels reinforced with single layer of wire mesh as well as decreasing in the maximum central deflection for these panels in comparison with the control specimens .

Behavior of Ferro-Cement Slabs Modified by Polymer under Low Velocity Impact

Ferro-cement is a type of thin reinforced concrete made of cement-sand mortar mixture with closely spaced of relatively small diameter wire meshes. The main aim of this work was to study investigate the behavior of Ferro-cement slabs under impact loading. A total of 36 Ferro-cement slabs were constructed and tested under low velocity impact, The main parameter considered in the present investigation was number of wire mesh layers, content of (SBR) polymer and height of falling mass (falling velocity). A special testing rig was used to achieve the impact forces using a falling mass (1300 gm steel ball) dropped from (2.5, 1.2 and 0.83 m) height. (500 ×500×50 mm) slabs were used for each test. The polymer (SBR) was used as a ratio by weight of cement of 3%, 5% and 10%. The number of required blows for caused the first crack and final failure was recorded. The results exhibited that the number of blows which were required to make the first crack and failure, increased with increase of polymer content and number of wire mesh layers.

Response Simulation of a Micro Reinforced Concrete Target Under Ballistic Impact

The response of concrete structures subjected to impact loading has received extensive attention in both civil and military applications. Research on improving the shock resistance of concrete has led to the development of cementitious composites. Micro Reinforced Concrete (MRC), a type of cementitious composite, is a concrete matrix embedded with multilayered steel wire meshes. This paper presents 3D hydrocode simulations of MRC panels subjected to impact under a ballistic range. A finite element model based on Lagrange formulation is used to represent both a 300 mm × 300 mm × 100 mm target with 30 layers of wire mesh and a 5.56 × 45 mm projectile in simulations. Penetration depth and damage patterns of the MRC mesh cement composite panel are numerically compared with those of the field experiment. The results show a relatively good agreement.

The use of wire mesh–epoxy composite for enhancing the flexural performance of concrete beams

This paper presents a study of an ongoing research project on the use of new composites for enhancement of the performance of concrete beams. A plain concrete beam was externally bonded with wire mesh–epoxy composite using one to five wire mesh layers. The flexural performance of the beam specimens bonded with wire mesh layers was compared with the beam specimens bonded with carbon fibre as well as a hybrid of wire mesh–epoxy–carbon fibre composite. The test results show that the use of wire mesh with epoxy is an efficient way to improve the flexural performance of concrete beam specimens. The increase in wire mesh layers significantly enhances the flexural strength, cracking behaviour and energy absorption capability. In comparison with carbon fibre, wire mesh–epoxy composite is more efficient in flexural strength and ductility. In addition, it was found that a concrete beam bonded with a hybrid wire mesh–epoxy–carbon fibre composite has significantly more energy absorption capability compared to specimens bonded with only carbon fibre.

Modified Formalin-Ether Concentration Technique for Diagnosis of Human Strongyloidiasis

We compared the efficacy and applicability of a modified formalin-ether concentration technique (M-FECT) to the conventional FECT (C-FECT) and the agar plate culture (APC) method for the detection of Strongyloides stercoralis larvae. For this purpose, we used 600 human fecal specimens collected in an endemic area of southern Thailand. In the M-FECT, we used 2 layers of wire meshes, instead of gauze, to avoid the loss by absorption/adhesion of larvae to the gauze during filtration, and we reduced the exposure time of S. stercoralis larvae in stool samples to formalin. By such simple modifications, the efficacy of M-FECT has become comparable to APC and was much better than that of C-FECT for the diagnosis of strongyloidiasis.

Influence of Number of Wire Mesh Layers on the Behavior Strengthened Reinforced Concrete Columns-ENG

The main objective of the present experimental program is to study the behavior of reinforced concrete short columns subjected to combined axial load and flexure strengthened with ferrocement. To carry out the investigation, seven columns were tested. Out of which, one is the control un-strengthened column tested to failure to find out their load carrying capacity, six columns strengthened with ferrocement. The main objective of the present work is to investigate the effects of ferrocement thickness and number of wire meshes on the load capacity of those columns. Increasing wire mesh layers from 2 to 5 causes an increase in the ultimate load of the strengthened column with ferrocement compared with the control column. Using 20mm ferrocement thickness with a 5-wire mesh layers, the ultimate load increases 36.8% when compared with the control column. Similarly, for 30mm ferrocement thickness with 5 wire mesh layers the increase is 48%. Key Words:Column, Ferrocement, Reinforced Concrete, Strengthening.

Study of the Flexural Behavior of Ferrocement Element Subjected to Heating Conditions by High Degrees of Temperature

The research study has performed to investigate the ferrocement beam element which is subjected to rise of temperature under different flexural loads. The experimental program includes a ferrocement beams fabricated of cement mortar contained varying number of layers (or variable volume fraction ratio) of steel welded wire mesh of square openings (4, 6, and 8 layers). Four groups of beams were studied ; all beams have the same dimensions, and exposed to three temperature rates namely ( 333°C, 453 °C and 600°C) and compared to the control ferrocement beams (reference group) without exposing to temperature rate. The main three parameters of the ferrocement beams (mix ratio, number of steel wire mesh layers and rising of temperature degree) as a structural performance parameters used for comparing ultimate flexure failure load and load- deflection relations . Throughout this study, the properties of ferrocement elements subjected to heating conditions are very important for structural stability, structural behavior and durability.

Double Pass Solar Air Heater with Transvers Fins and without Absorber Plate

The single pass solar air heater, with transverse fins and wire mesh used as an absorber plate, is constructed and tested for thermal efficiency at a geographic location of Cyprus in the city of Famagusta. The absorber plate was replaced by sixteen steel wire mesh layers, 0.18 x 0.18cm in cross section opening and a 0.02cm in diameter. The fins were painted with black color and positioned transversely along the bed such that four equally spaced sections were created. The transversely fins are arranged in a way to force the air to flow through the bed like eight letter path. The obtained results show that for air mass flow rate rang between 0.011-0.032 kg/s, the thermal efficiency increases with increasing the air mass flow. The maximum efficiency obtained is 58% for the mass flow rate of 0.037 kg/s. Moreover, the temperature difference between the outlet flow and the ambient, ΔT, reduces as the air mass flow rate increases. The maximum difference between the outlet and ambient temperature obtained was 40.6 o C for mass flow rate of 0.011kg/s. Comparison with a conventional single pass collector shows a substantially enhancement in the thermal efficiency. INTRODUCTION: Heating air with solar energy is much cleaner than heating with fossil fuel, the delivered heat from air solar device can be used for drying agricultural products such as crop, grains, seeds, fruits, and vegetables. Solar air heaters are also used as pre heaters in industries and as auxiliary heaters in building to save energy during winter times [1]. Conventional solar air heaters mainly consist of panels, insulated hot air ducts and air blowers in active systems. The panel consists of an absorber plate and a transparent cover. There are many different parameters affecting on the solar air heater efficiency, e.g. collector length, collector depth, type of absorber plate, glass cover plate, wind speed, etc. [2]. The absorber plate area and heat transfer coefficient between the air and the absorber plate are two important parameters affecting the efficiency of the collector. When increased these parameters will increase the collector efficiency. On the other hand it will increase the pressure drops inside the solar air heater and increases the pumping power required [2]. The convective heat transfer rate between air flow and absorber plate could be augmented by increasing the absorber surface area and by increasing turbulence inside the bed [3]. The use of Vgroove absorber was found to be more efficient by 12% than the flat plate collector of similar design [4] [5]. Using corrugated plates is a suitable method to increase the thermal performance and provides higher compactness [6]. A mathematical model that allows the determination of the thermal performances of the single-pass solar air collector with offset rectangular plate fin absorber plate is developed by [7]. Experimental and theoretical investigations are carried out on sheet metal absorber in the form of a chevron pattern [8]. The effect of using absorber plates coated with various selective coating materials on the heater performance was also investigated by [9]. Comparisons were made among four types of solar air collectors by Suleyman [10]. It has been found that the performance of a solar air heating system can be improved by operating several sub collectors in series in place of a single large collector with the same total area [11] [12]. The study concludes that the performance of solar air heater with single plastic glazing and flat plate absorber were approximately 9% more than the collector with double plastic glazing. Another study was carried out to determine the comparative performance of one-pass for fixed and free fins,

Effects of Ferrocement in Strengthening the Serviceability Properties of Reinforced Concrete Structures

The aim of this paper is to investigate the serviceability performance of RC beams strengthened through two Ferrocement strengthening techniques as Cast in situ Wire-mesh layers and precast Ferrocement Laminates. To assess the effectiveness of these strengthening techniques, eight (08) RC beams have been intentionally designed and detailed as a tension-controlled section and tested under two-point loading up to service load of 40 kN. Then, beams were strengthened by Cast in situ Wire-mesh layers and by precast Ferrocement Laminates. Experimental results in terms of stiffness have been compared within and across the groups to assess the effect of variation of development length and no. of wire-mesh layers.

Monotonic Behavior of Reinforced Concrete Columns Confined with High-Performance Ferrocement

In this study, a method of strengthening circular columns using high-performance ferrocement (HPF) is proposed. This is achieved by replacing the concrete cover by HPF (i.e., comprising rendering material and wire mesh). Direct tensile tests were carried out on HPF specimens. For rendering material with high tensile strength, it is necessary to incorporate its tensile strength in the estimation of the tensile strength of HPF. Nineteen full-scale circular plain or RC columns were tested under monotonic compression. Eleven were detailed with a volumetric ratio of transverse reinforcement ρs at 0.230%. HPF, having three different rendering materials and with one or three layers of wire mesh, was used to confine eight of these columns. Test variables included volume fraction of wire mesh and tensile strength of rendering material. Plain-concrete columns strengthened with HPF have peak strengths at 30–59% higher than control specimens. RC columns having a low ρs at 0.230% and strengthened with HPF can achieve peak strengths comparable with columns having a high ρs at 0.918%. A set of empirical equations for predicting the peak strength of plain-concrete or RC columns strengthened with HPF is derived, showing good agreement with the test data. Lastly, a design procedure for strengthening a RC column by replacing the concrete cover using HPF is proposed.

Effect of Initial Stress Levels on Strength Parameters of Reinforced Concrete Beams Retrofitted Using Ferrocement Jackets

Abstract Ferrocement jackets and sheets can be used for local rehabilitation and retrofitting of structures due to their high tensile strength, light weight, overall economy, water tightness, and ease of application. In the present paper the effects of number of layers of wire mesh in the ferrocement jackets, type of section (balanced or under reinforced) and initial stress level on the strength of retrofitted stressed reinforced cement concrete beams have been studied. The results show that there is higher increase in the maximum load, safe load carrying capacity, ductility and toughness for beams with three layers woven wire mesh ferrocement jackets as compared to beams reinforced with two layers of woven wire mesh. It is further seen that the percentage improvement in above properties decreases with increase in initial stress level and change in type of section from under reinforced to balanced. Subsequently an analytical model, based on principles of compatibility of strain and equilibrium of forces, has been presented to predict the safe and maximum load carrying capacity. It is found that predicted safe and maximum load carrying capacities are within 5 % of the experimental one.