Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : ferrocement


Strengthening of Ferrocement Beams in Torsion by CFRP Strips

Aseel Sami Al-Obaidy; Kaiss F.Sarsam; Alaa K. Abdul Karim

Engineering and Technology Journal, 2014, Volume 32, Issue 3, Pages 702-719

Torsion is resisted well by closed form reinforcement, due to the circulatory nature of the torsion inducing shear flow stresses in a beam. Therefore, it will be more efficient to have strengthening schemes, which are wrapped in closed form around the cross section. An experimental work was carried out and used superplasticizer with mix 1:1.5 to improve the mechanical properties of mortar. 12 rectangular beams (50x120)mm and 1m length are cast, strengthened and tested under pure torsion. The Variables considered in the test program include: effect number of wire mesh layers ( unit ), this unit consists of two layers of wire mesh with skeletal steel, (2, 3, 4) units and effect spacing of CFRP strips, (100,160,200) mm c/c. Test results are discussed based on torque – rotation behavior and influence of parameters on ultimate torque and failure modes. Generally, using optimum dosage of super plasticizer (1.4 % of weight of cement) gave compressive strength 65.65 MPa. Increasing the number of units from 2 to 4(reinforcement near the surface of beam section) led to increased ultimate torque by (13.44 %) and from 2 to 3(uniformly distributed reinforcement) led to increases the ultimate torque by only (3.24 %). When the beams are strengthened with CFRP strips, the lowest and highest increase in torque is at 112 % (4-units,@200 spacing) and 312 % (4-units,@100 spacing), respectively. The ultimate torque of beams with CFRP strips @ 100 mm and 160 mm spacing is greater than beams with CFRP strips @ 200 mm spacing by ( 94.34,45.28) %, respectively for the group having 4-units.

High Performance of Silica Fume Mortars for Ferrocement Applications

M. A. Mashrei; Gh. M. Kamil; H. M. Oleiwi

Engineering and Technology Journal, 2013, Volume 31, Issue 13, Pages 2477-2488

The current study deals with obtaining the high performance mortars to use in the
applications of ferrocement. The main problem that has greatly affected the
performance of mortar is the workability. A low water-cement ratio mostly resulted in
increases in the compressive strength and led to the enhancement of durability
characteristics, but decreases in the workability.
Workability becomes an important factors, as the mortar has to easily penetrate
between the layers of the mesh wires. A reasonably workable with high strength
cement mortar can be obtained by using a high cement content coupled with the use
of silica fume and superplasticizers. In this investigation a series of compression tests
were conducted on 50 mm cube and 150 ×300 mm, cylindrical specimens to obtain
the compressive strength and the stress-strain behavior of mortar with silica fume and
superplasticizers and flexural tests were conducted on 50 ×5 0 × 200 mm prism to
obtain the modulus of rupture. The results of this study indicated that the variation in
mortar strength depend on the water-to-binder ratio of the mix and percentages of
cement replacing. The effects of these parameters on the stress-strain curves are
presented. The best replacement percentage of silica is 3% was concluded in this
study. From the experimental results a mathematical model has been developed to
predict the 28-day compressive strength of silica fume mortar with different water-tocementitious
ratios and superplasticizers percentage

Fusion Face and Palmprint for Human Recognition via Spectral Eigenvector

Hana; a M. Salman

Engineering and Technology Journal, 2009, Volume 27, Issue 4, Pages 787-798

The Biometrics recognition systems act as an efficient method with broad
applications in the area of: security access control, personal identification to humancomputer
communication. From other hand, some biometrics have only little variation
over the population, have large intra-variability over time, or/and are not present in all
the population. To fill these gaps, a use of multimodal biometrics is a first choice
solution [1].
This paper describes a multibiometrics method for human recognition based on
new teacher vector identified as spectrum eigenface, and spectrum eigenpalm. The
proposed combination scheme exploits parallel mode capabilities of the fusion feature
vectors in matching level and invokes certain normalization techniques that increase its
robustness to variations in geometry and illumination for face and palmprint. The
correlation distance is used as a similarity measure. A threshold value is used to
prevent the imposter for being recognized. Experimental results demonstrate the
effectiveness of the new method compared to the unimodal biometrics for spectrum
eigenface/eigenpalm.

Modeling Time to Corrosion Initiation in High-Performance Ferrocement Exposed to Chlorides Environments

J. Forth; Maan S. Hassan; S. A. Salih

Engineering and Technology Journal, 2009, Volume 27, Issue 1, Pages 18-31

The applications of a mineral admixture, or a zinc coating to steel surface, or a
combination of both are methods used for the corrosion prevention of ferrocement
element in this study. Results of a study to evaluate many corrosion protection systems
with metakaolin and/or galvanized steel mesh are presented in six U-shaped specimens.
Specimens were built to simulate exposure conditions typical for marine environment.
Laboratory data collected along duration of 40 weeks of exposure were used in
modeling the cover depth as a function of time to corrosion initiation of the investigated
corrosion prevention methods. Methods used to assess the condition of specimens
included chloride concentration measurements, and corrosion rates. Model predictions
show that the ferrocement specimen of high-performance mortar with metakaolin
provides much better level of protection against moisture and chlorides than the
conventional specimen, by delay rate of chloride ingress. Application of a galvanized
steel mesh causes an elevation of the chloride threshold resulting in an additional
increase in the predicted time to corrosion initiation.