Ferrocement Slabs Research Articles

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.

The Effect of Using Multi Layers of Expanded Steel Mesh on Penetration Resistance of Ferrocement slabs

The Effect of Using Multi Layers of Expanded Steel Mesh on Penetration Resistance of Ferrocement slabs

EXPERIMENTAL PERFORMANCE OF FLEXURAL CREEP BEHAVIOR OF FERROCEMENT SLAB

Experimental flexural creep behavior of ferrocement slab and RCC slab was studied. Fourteen slab panels were casted and tested. The first cracking load and collapse load along with the deflections were measured during the test for every increment of gradual load. The gradual load was kept constant for 24 hours and the deflections were measured at 0, 1, 3, 6, 9, 12, 24 hours for each increment of load. It was found that the first cracking load depends upon the specific surface of the reinforcement. Also the behavior of ferrocement slab found to be more ductile as compared to RCC slab designed for same moment of resistance. The theoretical moment of resistance by using IS method and Hongestad’s method was found and the results were compared with RCC slab. The efficiency ratios at cracking and collapse were found. The flexural creep behavior of ferrocement slabs were found superior to RCC slab.

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.

Experimental Investigations on Ferrocement Roof Slab System for Low Cost Housing

The work presents the results of an experimental investigation carried out to assess the strength of pre-cast roof slab system comprising of ferrocement slab panels resting over RC beams. In the ferrocement panels, the cement was replaced by 0 and 20 % fly ash. This roof slab system proves out to be a cost effective and structurally safe and viable alternative for low cost housing, much better than the conventional roofing system comprising of steel girder and brittle sand stone panels commonly used in regions where sand stone panels are easily available. The testing includes three sets of roof system comprising of 12 ferrocement panels placed on two pre-cast RC beams, and an enclosure of brick walls on four sides. A similar set of roof slab system comprising of 12 sand stone panels in place of ferrocement panels were also tested for comparison. The testing was continued till the cracks were pronounced. It was observed that load carrying capacity of RC beam and ferrocement panel system with same thickness is higher as compared to similar arrangement of RC beam and sand stone panels. The crack propagation phenomenon was also studied. The ferrocement roof slab system exhibited ductile failure whereas brittle failure was observed in case of sand stone roof slab system. Cost analysis reveals that two pre-cast systems of RC beams and ferrocement panels with and without fly ash are economical as compared to red sand stone panels or RC slab system. The theoretical calculations have also been carried out to establish the adequacy of the sections to sustain the flexural loading applied in the present investigation.

Properties of Ferrocement Slabs Containing Sawdust

This research included the study of influence of sawdust addition on the properties of mortar and ferrocement slabs and study the influence of treatment sawdust on the static and dynamic properties of the Sawdust Ferrocement Slabs (SFS). In the present work, addition a different sawdust percentage ranged between (10% to 50%) of the volume of fine aggregate to cement mortar and superplasticizer was used to increase compressive strength and workability of cement mortar. The tests include, samples of cubes and prisms were tested for compressive strength and modulus of rupture and calculated the thermal conductivity for Sawdust Cement Mortar (SCM). The results show a significant improvement in the properties of cement mortar in terms of thermal insulation, the values of thermal conductivity ranged between (0.54 to 0.31) W/(m.K) ) to the ratio mixes respectively. While for the ferrocement mix without any sawdust ratio up to 0.65 W/(m.K) and this mean an improvement in the performance of mixtures of thermal insulation by 17% to 52%. The best sawdust ratio for the compressive strength is 30% where the value of thermal conductivity then is 0.38 W/(m.K) and the value of compressive strength of (29 Mpa). Also, Sawdust Ferrocement Slabs (SFS) (treated and untreated) were cast and tested under static and dynamic loads effect. The results show a good improvement in the mechanical properties of (SFS) under these loads.

An experimental investigation on the flexural behavior of geopolymer ferrocement slabs

Efforts are needed to develop innovative and environmentally friendly material in order to reduce the greenhouse gas emissions. An experimental investigation on the flexural behavior of thin cement-less composite plates reinforced with welded rectangular wire mesh and chicken mesh with varying number of mesh layers as well as varying concentration of alkaline solution is presented. A total of 30 slabs have been tested under flexural loading. The size of the slab is 1000 mm (length) × 200 mm (width) × 25 mm (thickness) and 1000 mm (length) × 200 mm (width) × 30 mm (thickness). The parameters studied in this investigation include varying the concentration of sodium hydroxide 8 M, 10 M, 12 M, 14 M and thickness of composite panels. In this work, cement is replaced by geopolymer mix to bind the ferrocement skeletal and its' flexural behavior are studied. It is concluded that the first crack and ultimate loads increase with the increase in the thickness of the element and the concentration of alkaline solution. From the studies, it is observed that the load carrying capacities, energy absorption, deformation at ultimate load are high in the case of geopolymer ferrocement element. Further, it is observed that there is a reduction in crack width and increase in number of cracks in the case of geopolymer ferrocement indicates delay in crack growth.

Missile Effect on Penetration Resistance of Ferrocement slabs

Missile Effect on Penetration Resistance of Ferrocement slabs

Nonlinear Finite Element Analysis of Ferro-cement Slabs and Shell Roofs

The present work involves developing an analytical model to study the behavior of ferro-cement slabs and shell roofs, and to adopt the most realable constitutive relationships for the mortar material to predict the nonlinear response of ferro-cement roofs by using the finite element method. To represent the mortar and wire mesh, a layered approach is used. Mortar is considered as a strain-hardening material and exhibiting strain-hardening behavior till it reaches the peak stress, beyond which, mortar enters the descending portion (strain softening) until it reaches the crushing strain. Tension stiffening is used to model the post- cracking tensile strength of the mortar. Under further loading in post-cracking stage shear retention is used to model the shear transfer throughout the cracks. The behavior of steel reinforcement and wire mesh is considered as elastic perfectly plastic with linear strain hardening. The predicted results of ferro-cement slab and cylindrical shell roofs had shown a good agreement with the published experimental results.

Impact resistance of composite plate

Structures are often subjected to various types of dynamic loads and the need to accurately predict the structural response and reserve capacity under such loading has led to an interest in the properties of composite materials. Fibre reinforcement improves the dynamic behaviour of reinforced concrete and ferro cement under impact loading. This paper reports an experimental investigation of the dynamic behaviour of composite slab panels under impact loads. Impact tests were carried out on various types of fibre-reinforced cement concrete slabs and fibre-reinforced ferro-cement slabs to study the influence of fibres on the energy absorption. The response of all the above specimens were examined and compared. Analytical solutions were obtained from a finite element analysis and the results are also compared.

Impact resistance of composite plate

Structures are often subjected to various types of dynamic loads and the need to accurately predict the structural response and reserve capacity under such loading has led to an interest in the properties of composite materials. Fibre reinforcement improves the dynamic behaviour of reinforced concrete and ferro cement under impact loading. This paper reports an experimental investigation of the dynamic behaviour of composite slab panels under impact loads. Impact tests were carried out on various types of fibre-reinforced cement concrete slabs and fibre-reinforced ferro-cement slabs to study the influence of fibres on the energy absorption. The response of all the above specimens were examined and compared. Analytical solutions were obtained from a finite element analysis and the results are also compared.

Performance of ferrocement panels in different environments

To exploit the potential of ferrocement as a construction material, a proper understanding of material behaviour under different environmental conditions is essential. The main objective of this investigation is to study the performance of ferrocement panels under normal, moderate, and hostile environments. These conditions were created using potable and saline water for mixing and curing. Fly ash, a waste material, was also used as partial replacement of cement. The ferrocement slab panels cast with varying number of woven and hexagonal mesh layers were tested under flexure. Compressive and tensile strength of control specimens and load-carrying capacity of the panels under flexure with and without fly ash were investigated. Addition of fly ash in different environments affects the flexural strength of panel for both woven and hexagonal wire fabric. Scanned images of specimens provide an insight into the texture for virgin and distressed states.

Punching Shear Strength of Simply Supported Ferrocement Slabs

The results of punching shear tests on 31 square ferrocement slabs are reported in this paper. The slabs were simply supported on all four sides and tested under a central concentrated load. The parameters investigated include the width of square loaded area w, mortar strength f′c, volume fraction of reinforcement Vf, depth of slab h, and the effective span l. All slabs failed first in punching without total separation, and then exhibited a second peak in the load-deflection history. Both cracking load and punching shear load increased with an increase in w, Vf, f′c, or h, but decreased as l is increased. The critical perimeter for punching shear failure was found to be located at a distance of 1.5h from the edge of the loading plate. Based on the present test data as well as those available in the literature, an equation has been proposed for predicting the punching shear strength of ferrocement.

Punching Shear Behavior of Restrained Ferrocement Slabs

Punching Shear Behavior of Restrained Ferrocement Slabs

Punching Shear Strength of Ferrocement Slabs

The behavior of ferrocement slabs under punching shear load was investigated. Fifteen square slabs were tested with the effective span-to-depth ratio, steel contents, slab thickness, mortar strength, load-bearing plate size, and spacing of skeletal steel as test parameters. The load deflection and cracking characteristics of the slabs were studied and compared. Test results on the punching shear strength were compared with predictions of the formulas proposed by codes of practice and previous researchers, and an empirical relation is proposed to determine the punching shear strength of square ferrocement slabs, simply supported on 4 edges and subjected to a concentrated load at its center.

Reliability of ferrocement slabs under cyclic thermal-shock loading

The reliability of ferrocement slabs subjected to cyclic thermal-shock loading induced by raindrops during service is investigated. The data are obtained experimentally by subjecting specimens to heating and wetting cycles and monitoring the residual first-crack strength at different periods. The imposed thermal-shock loads simulate actual service conditions and are estimated by monitoring the temperature of typical roofing slabs just before the commencement of rain over a period of time. The mean deterioration in strength obtained after correcting for curing effects due to ageing and temperature, as well as the uncertainty present, are used to assess the reliability of slabs having residual first-crack strengths above some prescribed values at different periods. The results indicate that ferrocement slabs posses good flexural resistance with respect to the cyclic loadings studied and are suitable for use as roofing elements.

Early-Age Reliability of Ferrocement Slabs

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Fatigue Reliability of Ferrocement Slabs

A simple probabilistic approach to fatigue-strength studies for ferrocement slabs is presented, supplemented by the relevant statistics obtained from a preliminary experimental program. Unlike conventional fatigue-strength studies where the specimens are cyclically loaded to a failure, the approach employed here involves obtaining the residual strength of the specimen after it has been subjected to some predetermined number of cycles of loading, n. Probability of failure curves against specified cracking and ultimate strength, conditioned on different values of n, are presented. Within the load range considered, the results show that ferrocement possesses good fatigue properties.

Ferrocement: Alternative Material for Secondary Roofing Elements

The appcicability of ferrocement as an alternative material for secondary roofing slabs was investigated. The performance of such slabs was compared to those of cellular concrete slabs and commercially available 'hollow blocks.' Tests carried out include flexural and patch load tests, initial surface absorption tests, and shrinkage measurements. The effects of carbonation, weathering, and thermal stresses were also studied. Results indicated that ferrocement slabs have a higher resistance against cracking and carbonation. They are more impermeable and have lower long-term shrinkage. In general, the effects of weathering and thermal stresses are found to be least detrimental in ferrocement slabs than in cellular concrete slabs and hollow blocks.

Influence of reinforcement on fatigue of ferrocement

The paper describes a programme of flexural fatigue tests on ferrocement slabs with four different types of reinforcement. The results are used to discuss the effect on the fatigue strength of the size of wire, galvanizing of the wire, and the placing of wire mesh in layers. Samples of the wire were also fatigue-tested in air and a relationship is developed between the fatigue strength of each type in air and in the composite.