الفهرس 
Why Ferrocement TechnologyOnly 14 pages are availabe for public view
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Abstract
The main objective of this research is to study the structural behavior of ferrocement concrete composite plates reinforced with various reinforcing materials. The dimensions of the developed ferrocement and control test specimens were kept constant as 600 mm width and 1200 mm length. The thickness was varied from 60 to 100 mm. The test specimens were loaded under four points’ loadings until failure. The effects of the main parameters were studied. High resistance ferrocement plates will be developed with crack resistance, high deformation characteristics, high strength, high ductility and energy absorption properties could be used with great economic advantages very useful as an alternative to the steel panels in some of its uses in developed and developing countries alike. The experimental program was divided into two phases, the first phase regarding the thickness; the main objective was studying the effect of the plate thickness from 60 mm to 100 mm. The second phase, the main objective was studying the ultimate load, flexural behavior, ductility ratio, energy absorption and mode of failure at collapse of the ferrocement plates, which were reinforced with expanded metal mesh and welded metal mesh. In this program, eighteen specimens were cast and tested until failure in order to study their behavior under flexural loadings. The plates were divided into five groups according to the reinforcement configurations. Group A is the control group, which reinforced with four steel bars of 6 mm diameter at the bottom of the plate and six steel bars of 6 mm diameter at the transverse direction. For the other groups, B, C, D, F, plates were cast in different thicknesses but with the same steel distribution for each group. Two types of steel mesh were used to reinforce the ferrocement plates. These types are: (12 X12mm) welded galvanized wire mesh, and (33 X16.5 mm) expanded metal mesh. Single layer, double layers and three layers of each type of the steel mesh were employed. Mortar was used for producing the ferrocement plates. The mortar consisted of sand and ordinary Portland cement with a sand-cement ratio of 2.0. To improve the properties of the mortar, 15% of the cement was replaced by silica fume and 1.4 kg/m3 of polypropylene fibers was added. The used water-cement/silica fume ratio was 0.35. Superplasticizer (seka ment 163) with ratio of 1.5% by weight of (cement + silica fume) was used to improve the workability.
Five models comprise eighteen reinforced concrete plates were cast and tested. All plates have same length (1100 mm) and width (550 mm) and with different thicknesses 60, 80 and 100 mm. The plates were cured for 28 days before testing. After 28 days, the specimens were painted with white paint to facilitate the crack detection during testing process. A set of four “demec” points was placed on one side of the specimen to allow measuring the strain versus load during the test. The load-deflection relationship can be divided into three regions:
a) Linear relationship up to first cracking of ferrocement.
b) Transition region, where the relation deviated from linearity due to continuous cracking of the plate.
c) Large plastic deformation due to yielding of the reinforcing steel bars and the steel mesh. The load at which the load-deflection relationship started to deviate from the linearity and the extent of the plastic deformation varied with the type of steel mesh in the ferrocement plates. A simple computer program was used to predict the behavior of these plates. The experimental results were used to verify the predicted results obtained using computer program. The analytical and experimental results of reinforced ferrocement plates emphasized that, better control of cracking behavior for all tested plates reinforced with welded steel mesh. Also it was found that the ultimate strength of the plates is affected by modified volume fraction. The ductility ratio and energy absorption properties of the tested plates were improved by this method of reinforcement.
In general the experimental results proved the effectiveness of expanded steel mesh and welded steel mesh in reinforcing ferrocement plates. Ferrocement plates were developed with high strength, high ductility and energy absorption properties and lighter in weight, which could be useful for developed and developing countries alike.