Ferrocement Layers Research Articles

A Review on Pull out Test on Exterior Beam-Column joint

Conventional concrete loses its tensile resistance after the formation of multiple cracks. However, fibrous concrete can sustain a portion of its resistance following cracking to resist more loading. Use of the headed bar can offer a potential solution for these problems and may also ease fabrication, construction, and concrete placement. There have been many catastrophic failures reported in the past earthquakes, with Turkey and Taiwan earthquakes occurred in 1999, which have been attributed to beam–column joint failures. To achieve this performance level, special steel reinforcement details are required in the beam–column joint region of reinforced concrete framed structures. The experimental work carried out on four different arrangements of reinforcement of beam column joints. The aim of the research is to investigate the pull-out behavior such as strength, failure mode, and crack patterns of different arrangements of reinforcement in exterior beam column junctions. The transverse reinforcement of a joint reduces stresses by improving the confinement of concrete. All joints were tested by using reversed cyclic loading. In the first arrangement, the beam bars are extended in the column for distance Ld + (10xDia) from the inner face of column. This research studies the experimental behavior of full-scale beam-column space (three-dimensional) joints under displacement-controlled cyclic loading. Eleven joint specimens, included a traditionally reinforced one (without adequate shear reinforcement), a reference one with sufficient shear reinforcement according to ACI 318, and nine specimens retrofitted by ferrocement layers, were experimentally tested to evaluate a retrofit technique for strengthening shear deficient beam column joints.

Finite element modeling of exterior beam-column joints strengthened by ferrocement under cyclic loading

This paper aims to study the seismic performance of exterior beam-column joints in building frames strengthened by ferrocement using nonlinear finite element analysis. Firstly, the proposed model was used to predict experimental results successfully. Secondly, a parametric study was carried out to assess the behavior of such joints with different additional variables. The studied variables were the level of axial loading on the column, compressive strength of specimens, percentage of longitudinal reinforcement in the beam, and orientation of expanded wire mesh in ferrocement layer, for specimens strengthened by different number of ferrocement layers. It was found that strengthening specimens by ferrocement reduced the effect of axial loading level and longitudinal steel ratio in the beam on the ultimate load of studied specimens. In addition, changing the orientation angle of expanded wire mesh from 60° per ferrocement layer to 45° has a minor effect on the ultimate load but it has a significant effect on the ductility of studied specimens. The effect of orientation angle became less significant on the ductility with increasing the number of ferrocement layers used for strengthening. These findings would be helpful to the engineers to develop suitable, feasible and efficient upgrading technique for poorly designed building frame structural joints in seismic zones.

Experimental and Theoretical Behavior of Reinforced Concrete Two Way Slabs Strengthened by Steel Fiber Ferrocement Layers at Tension Zone

An experimental and analytical behavior of strengthened reinforced concrete two way slabs by steel fiber ferrocement layers ,this study included testing 14 simply supported two way slabs, which include 1 control slab, 13 strengthened slabs. In the strengthened slabs the effect of the ferrocement layers with; steel fiber content in the ferrocement mortar of (0.25,0.5,0.75.1.1.25%), thickness of ferrocement layers, the compressive strength for ferrocement mortar and wire mesh layers number of ferrocement was investigated. The mid span deflection at ultimate load and cracks pattern were discussed. All the reinforced concrete slab specimens were designed of the same dimensions and reinforced identically to fail in flexure. Simply supported conditions for all slabs has bean tested under central concentrated load. The experimental results show that; the ultimate loads and mid span deflection of strengthened reinforced concrete slabs were more effected by using the steel fiber on the ferrocement mortar, increasing the thickness of ferrocement and the compressive strength of ferrocement. Three-dimensional nonlinear finite element analysis has been used to conduct the analytical investigation, ANSYS (Version 16.0) computer program was used in this study. The analytical result from modeling in ANSYS program exhibited a good agreement with experimental results.

The importance of education and training for construction workers about requirements of the earthquake-safe house and retrofitting method using ferrocement layers

Construction workers play an important role in attaining a good construction and safe building. However, it has not been getting enough attention to the importance of worker’s roles since it is assumed that engineer has already enough knowledge to control and supervise the construction workers. Based on the survey results, more than 95% of workers in West Sumatera have lack of knowledge about the earthquake-safe house requirements and retrofitting of damaged houses. In this study, the expert team of Andalas University conducted training for the construction workers in Padang City and Padang Pariaman District. The training provides all activities that support the whole construction process of the earthquake-safe house and the retrofitting method for unreinforced masonry houses using ferrocement layers, which is presented by slides presentation and practice on the field. The result of the training program shows that the knowledge of the construction workers on requirements of the earthquake-safe house and retrofitting method using ferrocement layer improved significantly. The construction workers understood how to build the earthquake-safe house and to retrofit the weak or damaged houses. This training program is an effective way in disaster risk reduction to prevent the damage to houses due to the earthquake.

Serviceability limit state of two-way reinforced concrete slab strengthened with different techniques

The experimental results for service load of sixteen simply supported two way reinforced concrete slabs under the action of concentrated patch load were determined based on the amount of permissible deflections and the crack widths.All the slabs had the same overall dimensions and flexural steel reinforcement. Five types of strengthening were adopted. The first and second methods include applying either near surface mounted (NSM) or near reinforcement mounted (NRM) ferrocement layers. While the third method includes applying a concrete layer reinforced with welded wire fabric mesh of various diameters. The fourth and fifth methods include fixing CFRP rods and laminates, respectively, on the bottom surface of slabs. Strengthening techniques were applied on the bottom surface of fifteen slab specimens. In addition, a control slab specimen without any strengthening was used for the purpose of comparison. The calculated results for ultimate loads based on serviceability requirements (deflection and crack width according to both ACI and BS formulae) were lower than the experimental results.

Gradual changes of houses after the reconstruction program – a case study in Yogyakarta after the 2006 Yogya earthquake

Since 2006, a survey about the reconstruction of houses after the May 2006 Yogya earthquake has been conducted related to the quality of construction and additional works. The gradual changes after the reconstruction program was terminated, were based on owner’s preferences and capabilities. After the 2009 West Sumatra earthquake, many damaged houses and schools were retrofitted using ferrocement layers. The purpose of this study is to investigate the possibility to disseminate the same retrofitting method for existing houses in Yogya.

Experimental behavior of full-scale exterior beam-column space joints retrofitted by ferrocement layers under cyclic loading

A majority of the traditional reinforced concrete frame buildings, existing across the Middle East, lack adequate confinement in beam-column joints, or in other words, are shear deficient because they were constructed before the introduction of seismic codes for construction. This research studies the experimental behavior of full-scale beam-column space (three-dimensional) joints under displacement-controlled cyclic loading. Eleven joint specimens, included a traditionally reinforced one (without adequate shear reinforcement), a reference one with sufficient shear reinforcement according to ACI 318, and nine specimens retrofitted by ferrocement layers, were experimentally tested to evaluate a retrofit technique for strengthening shear deficient beam column joints. The studied variables were the number of layers, orientation angle of expanded wire mesh per layer, and presence of steel angles in the corners of joint specimen prior to wrapping with ferrocement layers. The experimental results showed that proper shear reinforcement for the test joints, according to ACI 318, enhanced the behavior of the specimen over that of the traditionally reinforced specimens without adequate shear reinforcement. The joints retrofitted by ferrocement layers showed higher ultimate capacity, higher ultimate displacement prior to failure (better ductility), and they did not suffer heavily damage as observed for the traditionally reinforced one. Increasing the number of ferrocement layers for retrofitted specimens led to improving performance for such specimens compared to the traditionally reinforced ones in terms of enhancing the ultimate capacity and ultimate displacement. Specimens retrofitted by ferrocement layers reinforced by expanded wire mesh of 60° orientation angle showed slightly better performance than those of 45° orientation angles. Retrofitting using steel angles in addition to ferrocement layers improves the seismic performance of the specimens, achieves better stability for stiffness degradation, attains higher capacity of the dissipated energy, and reduces the vulnerability of joints to excessive damage. Based on the experimental work in this study, it is recommended to retrofit beam-column joint specimens by two ferrocement layers in addition to steel angles as stiffeners taking the orientation angle of expanded wire mesh into consideration.

Experimental Study of Behavior of Reinforced Concrete One-Way Slabs Strengthened and Repaired by Ferrocement at Tension Zone

The principal objective of this paper is to investigation the experimental of the flexural behavior of strengthened and repaired reinforced concrete slabs with ferrocement tension zone. The result of tests on 10 simply supported one way slabs were presented, at which include 1control slab, 5strengthened slabs and 4repaired one way slabs. In the strengthened slabs, the cover of the control slab replacing with ferrocement cover, cold joint between ferrocement layer and the slab, connection type between the ferrocement layer and the slab, on the ultimate load, first crack load, the mid span-deflection, crack width and spacing were examined. In the repaired part the slabs were loaded to (55 %) of measured ultimate load of control slab, the effect of the thickness and number of wire mesh layers on crack pattern, mid span deflection and ultimate load was examined. In the repaired part the slabs were loaded to (55 %) of measured ultimate load of control slab, effect of the number of wire mesh layers of ferrocement on the mid span deflection, ultimate load and crack pattern was examined. The experimental results of strengthened and repaired slabs indicate that; the ultimate loads and mid span deflection were more effected by using ferrocement mortar at tension zone. The increase in ultimate load (8.2-18%) for strengthen slab and (9.1-17.3%) for repaired slab respect to the control slab.

Flexural Strength of Reinforced Concrete Two way Slabs Strengthened and Repaired by High Strength Ferrocement at Tension Zone

This paper presents a study of the flexural behavior of strengthened and repaired reinforced concrete two slabs by ferrocement layers. This study included testing 11 simply supported two way slabs, which include 1 control slabs, 8 strengthened slabs and 2 repaired slabs. In the strengthened slabs the effect of the thickness of ferrocement layers, the compressive strength for mortar and number of wire mesh layers of ferrocement on the ultimate load, mid span deflection at ultimate load and intensity of cracks was investigate. In the repaired part the slabs were loaded to (74 %) of measured ultimate load of control slab. The effect of connection method between repaired slabs and ferrocement jacket on the ultimate load, mid span deflection at ultimate load and intensity of cracks was examined. All reinforced concrete slab specimens were designed of the same dimensions and reinforce identically to fail in flexure. All slabs have been tested in simply supported conditions subjected to central concentrated load. The experimental results show that the ultimate loads are increased by about (4.6-19.2%) for the slabs strengthened with ferrocement with respect to the unstrengthened reinforced concrete slab (control slab).

REPAIR AND STRENGTHENING OF RC SLABS USING FERROCEMENT LAYERS REINFORCED WITH DIFFERENT FRP MESHES

Ferrocement is one of the recent methods for repair and strengthening of reinforced concrete members. It can be described as a type of thin composite material made of cement mortar reinforced with wire meshes. The wire meshes are uniformly distributed in continuous layers with relatively small diameters. In this research, an experimental test program consists of eleven RC slab specimens repaired and strengthened by ferrocement layers reinforced by traditional steel reinforcement and steel wire meshes as well as manufactured glass and carbon fiber reinforced polymer meshes. The tested slabs classified in three groups. The first group consists of three specimens as reference slabs. The second group for repaired slabs consists of four specimens. They were loaded first by 80% of the ultimate loads and then cracks were repaired and then additional ferrocement layers with different wire meshes were added. The third group for strengthened slabs consists of four specimens. They were strengthened with additional ferrocement layers with different wire meshes without preloading. Slab specimens were tested under two-point loading and subjected to incremental loads till failure. Performance of the tested slabs such as deflections, cracking and ultimate loads as well as crack patterns were investigated, analyzed and discussed in this research. The test results confirm that repair and strengthening technique using ferrocement layers gives good results. Intertwined manufactured carbon fiber wire mesh gave best results for increasing the flexural capacity of RC slabs.

Behaviour of Reinforced Concrete Columns Strengthened with Ferrocement under Compression Conditions: Experimental Approach

This paper reports a study based upon experimental investigation which aims to assess the behaviour of reinforced concrete columns strengthened with a new configuration of steel wire mesh as part of ferrocement layer under the action of axial compression loads. Square and circular small scale columns with three different slenderness ratios of 5, 6.7 and 10 were adopted. A comprehensive experimental progarmme was then running to measure the load capacity and both lateral and vertical displacements. The failure mode was also monitored for each tested case. The results obtained was compared with the reference column samples (without wire mesh) and with some expressions suggested by ACI Code. The experimental results showed that the most influential parameter on the property of load carrying capacity is the slenderness of column. As the slenderness increases, the load capacity clearly decreases. The use of wire mesh enhanced the capability of column to resist the axial loads due to confinement role provided by such material. The maximum percentage increase in load carrying capacity for the modified columns compared with those for the reference samples was 53% for the circular column at slenderness ratio of 10. The critical path of the failure mode was similar for all of the tested columns and normally began from the top or bottom ends, then, in some cases, passed through the middle zone of the column. A suitable expression was suggested to be used for calculating the modulus of elasticity of the tested column based upon the value of load carrying capacity under compression loads.

Brief Report of Shaking Table Test on Masonry Building Strengthened with Ferrocement Layers

Millions of non-engineered constructions in Indonesia are vulnerable to earthquake. Therefore, a simple, affordable and replicable method to strengthen the existing non-engineered construction in Indonesia is introduced. The retrofitting method described in this report is based on the principle of sandwich structures, having a masonry wall as core and covered on both sides with ferrocement layers. Numerical analysis result and shaking table test is included in this paper.

Behavior of Multilayer Composite Ferrocement Slabs with Intermediate Rubberized Cement Mortar Layer

Laboratory investigation was undertaken to study the behavior of multilayer composite ferrocement slabs. The slabs include two ferrocement layers with an intermediate rubberized cement mortar layer. The aim of this investigation is to find out the effect of an intermediate layer rubberized cement mortar (RCM) on the behavior of multilayer ferrocement slabs subject to static and dynamic loads. Different rubber ratios, different thickness of RCM layer, and shear connectors to connect the upper and lower reinforcement layers were used. The specimens were cast in 500 × 500 mm, with an overall thickness not exceeding 50 mm. Compressive strength, modulus of rupture, and impact resistance were also tested for RCM cubes, prisms, and cylindrical cement mortar specimens to illustrate mechanical properties for using cement mortar. The increase in the RCM layer thickness, with an increase in the crumb rubber ratio, and using shear connectors; it increases impact energy to cause first a crack and then full perforation. Static test results show that thicker RCM layers reduce yield load and slab stiffness at yield, but using shear connectors increases yield load and slab stiffness. The results show that the RCM layer enhances the impact resistance of the ferrocement composite slab. The results also show the effect of the shear connector is small in static and dynamic loads: that are using a RCM with the thickness 0.4 of the total thickness of the slab; or those using a rubber ratio that is more than or equal to 50 % in the RCM layer.

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 .

Numerical Analysis for Ferro Cement Panels Resisting Projectile Penetration with Different Initial Velocities

Resistance to penetration by high velocity projectiles through concrete target is an essential design parameter for fortification structures. Due to the expensive costs of field test experiments, numerical modeling is considered one of the most efficient procedures to predict the response of concrete panels under the effect of impact loads. The change in strain rate influences the material behavior. Studying this behavior needs experimental test. In this study, the experimental work is conducted to record the penetration depth through the concrete panels using the bullet at the industry. Two different panels are tested. Each panel has a different arrangement in the ferrocement layers. The finite element analysis (FEA) isused to model the concrete panels subjected to the penetration of the bullet. The results obtained by the FEA are compared with those obtained by the experimental work to verify the proposed finite element model. Different initial velocities of the projectile are set to study the response of the target. The penetration depth and the strain energy are compared for each panel. The difference between the penetration depth and the strain energy, can describe the influence of the strain rate on the target behavior. The performance of the concrete panel reinforced by the ferrocement isimproved to reduce the penetration of the bullet.

Ferrocement sandwich and hollow core panels for floor construction

This paper presents the results of a research work to develop ferrocement sandwich and hollow core panels for use as precast one way slab elements. Sandwich panels consisted of two thin ferrocement layers reinforced with steel wire mesh and a core of autoclaved aerated lightweight concrete bricks. The hollow core panels are made of the same ferrocement mortar matrix with three circular holes of 75 mm diameter running along the length of the specimen. A total of 15 sandwich panels and 12 hollow core panels were cast and tested under flexural loadings. The experimental results showed that high ultimate and service loads, crack resistance control, high ductility, and good energy absorption could be achieved by using the proposed panels. A theoretical model based on the ultimate strength method for reinforced concrete was developed to determine the ultimate moment and mode of failure of the panels. The theoretical and experimental results showed good agreement.

Experimental Evaluation of Lightweight AAC Masonry Wall Prisms with Ferrocement Layers in Compression and Flexure

An experimental program is designed to evaluate the performance of lightweight autoclaved aerated concrete masonry wall strengthened using ferrocement layers, in a sandwich structure, under in-plane compression and out-of-plane bending. The 25 mm thick ferrocement mortar is reinforced with steel welded wire mesh of 1 mm diameters at 15 mm spacing. Different types of shear connectors are used to evaluate their effect on failure loads. The effect of different design parameters on the wall strength are considered including wall thickness, mortar strength, and type and distribution of shear connectors. A total of 20 prisms are tested in compression and 5 prisms are tested under bending. The proposed ferrocement strengthening technique is easy to apply on existing wall system and results in significant strength and stiffness enhancement of the tested wall specimens.

Strengthening of lightweight reinforced concrete slabs using different techniques

The present study examines the potential of using four different techniques in repairing and strengthening of preloaded, cracked, lightweight, reinforced concrete one-way solid slabs. Nineteen lightweight reinforced concrete (LWRC) slabs specimens were casted with one-third scale dimensions from prototype structure in buildings. The slabs dimensions were 1.2 m in length and cross section of (70 × 500) mm in depth and width. The slabs were reinforced with 3φ10 for the main reinforcement and tested under a four-point loading system. The tested slabs were divided into two groups according to preloading level to study the effect of cracking level. Two preloadings were selected, i.e. 60% and 80% from the ultimate load. The strengthening techniques used were ferrocement layer, steel plate, carbon fibre reinforced polymers (CFRP) sheets and CFRP strips. The slabs were loaded up to failure and the structural response of each slab specimen was predicted in terms of the onset of cracking, deflection, collapse load ...

Development of interlocking mechanism for shear transfer in composite floor

Semi-pre-cast floor slab (called half slab in Malaysia) has been used widely in different parts of the world. It consists of a reinforced concrete pre-cast layer that acts initially as a formwork connected in situ with another concrete layer using shear connectors. Steel reinforcement (shear link, studs and/or steel truss) is commonly used to transfer the horizontal shear between the two composite layers. Longitudinal shear failure is the most common type of failure in the composite floor slab. This paper proposes a new system to transfer the horizontal shear between the interfaces of the pre-cast and cast in situ layers of concrete slab. The proposed system implements an interlocking concept and does not require any shear reinforcement. The composite floor slab used to illustrate the interlocking concept consists of a pre-cast inverted ferrocement layer interconnected with the cast in situ brick–mortar layer. The effectiveness of the interlocking mechanism in transferring the stresses developed due to the applied load is investigated. Eleven composite slab specimens having different shear connectors between the two layers were cast and tested under pure shear loading (push-off test). In the tested specimens, different interlocking mechanisms, continuous truss shear connectors and no connectivity between the two layers were used to connect the layers of slabs. The results indicate that the interlocking mechanism proposed is, as effective as, the steel trusses in resisting shear stresses and can be used to replace the steel trusses, which in turn will reduce the cost of the composite slab.

Structural behaviour of ferrocement–brick composite floor slab panel

This study introduces a semi-fabricated system for the construction of floor slab. The slab panel consists of two layers joined together using truss type shear connectors. The first layer is a precast ferrocement layer which acts initially as a formwork, while the second layer consists of bricks and mortar. Continuous truss shear connectors are used to connect the two layers. The paper experimentally investigates the structural response of ferrocement–brick composite panel under flexural load. Four full scale specimens were cast and tested under two-line loads. The study highlights the effect of shear connectors and brick layout on the overall structural response of the slab. The results in terms of load–deflection, crack pattern, strain distribution and failure loads indicate that the response of the composite slab to the flexural loading is satisfactory and can be used as a floor slab in construction sector.