Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Concrete


Investigate and Comparison Effect add Amorphous and Crystalline - Nano SiO2 on Properties of Concrete

Rami Joseph Aghajan Sldozian

Engineering and Technology Journal, 2015, Volume 33, Issue 3, Pages 547-555

In this paper, the study included the comparison between amorphous silica and crystalline silica (quartz), and with nano scale size, two types of silicawere added to concrete by ratios (5%, 10%, 15%, and 20%) as a replacement by the weight of cement. Destructive and non-destructive tests wereconducted on the specimens, the results show in destructive test the compressive and tensile strength increase in 15%wt addition ratio in both types of silica, but in amorphous silica was high than in quartz.The results of non-destructive tests show in (Schmidt Hammer) the 15% ratio in both kinds of silica show high hardness than other ratios. Ultra sonic (pules velocity) test, noted the better quality was in 15% ratio in amorphous silica and also show fastest pules velocity.

Optimum Position of Shear Reinforcement of High-Strength Reinforced Concrete Beams

Omar Qarani Aziz; Sinan Abdulkhaleq Yaseen

Engineering and Technology Journal, 2013, Volume 31, Issue Issue1A [Engineering], Pages 42-52
DOI: 10.30684/etj.2013.71247

This paper reports experimental data on the behavior and strength of high-strength concrete slender beams reinforced with vertical shear reinforcement. Tests were conducted on ten reinforced concrete beams with stirrups in different positions using high-strength concrete (compressive strength about 85.0 MPa). The beams measured 2000 mm long, 100 mm wide and 200 mm deep, and were tested under two point loads. The test variables were position and amount of web reinforcement; conventional steel bars were used as longitudinal reinforcement in this investigation. The test results indicated that beams with shear reinforcement (vfy = 1.65 to 4.24MPa) within the shear span (G1) and along the beam length (G2), were failed in flexure, while beams with shear reinforcement (vfy = 1.65 to 4.24MPa) between two point loads (G3) and the beam without shear reinforcement (G4) were failed in shear. The optimum position of stirrups is the shear span for high strength concrete beams and for different amounts

Experimental Evaluation of Effect of Flange Dimensions on Shear Behavior of NSC and SCC Double Tee Beams

Ali H. Aziz; Mohammad Zohair Yousif; Laye K. Salman

Engineering and Technology Journal, 2012, Volume 30, Issue 17, Pages 3039-3053

This study deals with, experimentally, the effect of flange dimensions on shear
behavior of normal strength concrete (NSC) and self-compacting concrete (SCC)
double Tee beams.
Twelve beam specimens as well as a series of control specimens are tested. The
beam specimens were divided into two groups (based on concrete type) and each
group are divided into five subgroups (based on flange dimensions).The webs
dimensions, beam depth, beam length, spacing between webs, longitudinal
(tension) reinforcement and transverse reinforcement (stirrups) were kept constant
in all beam specimens.
Experimental results showed that the ultimate capacity increased about (6%-
12) and (9%-20) when the flange width (dimensions) increased from (320mm) to
(450mm) for NSC and SCC respectively. Presence of large compression flange
lead to increase the stiffness of tested beams due to contribution of additional
concrete parts, and this leads to increase in carrying capacity.

Bond Strength-Splice Length in Concrete Beams Confined by Transverse Reinforcement

Sameh Badry Tobeia Shuker

Engineering and Technology Journal, 2010, Volume 28, Issue 2, Pages 322-339

This work aim to study the effect of transverse reinforcement , area of splice
bar, concrete cover thickness , rib area and the increasing in concrete strength (highstrength
concrete) on bond strength between concrete and reinforcing spliced bars .
Therefore, a new simple equation is derived for beams with spliced bars and
confined by transverse reinforcement to calculate bond strength and reflects the
effects of these factors .Where many of existing codes and provisions used to
calculate the spliced strength do not include or reflect the influencing of these factors
in bond strength estimation . Based on experimental results from previous works ,
(116) confined beams with spliced bars are investigated in this study , where
concrete compressive strength ( c f ¢
) ranging from 25 MPa to 113.793 MPa ,amount
of transverse reinforcement vary in a wide range and , conventional and high
relative rib area of deformed bars are present in these beams . The proposed method
exceed the limitation of ( f MPa c ¢ £ 69 ) that given by ACI code .Where the
proposed method is examined and applicable for concrete compressive strength up
to 113 MPa . Also, in this work the second root of c f ¢
is examined , as concrete
strength increased with high-strength concrete , to reach a suitable value for both
normal and high- strength concrete and to be more appropriate with the heavy
present of transverse reinforcement . Power of (0.35) is adopted and used in this
work instead of the second root of c f ¢

Analysis Up To Failure of Straight and Horizontally Curved Composite Precast Beam and Cast-In-Place Slab with Partial Interaction

Husain M. Husain; Mohammed J. Hamood; Shaima; a Tariq Sakin

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2509-2522

In this study, a nonlinear three dimensional finite element analysis has been used to conduct an analytical investigation on the behavior of curved in plan composite concrete-concrete beam using the analysis system computer program (ANSYS v.9.0 2004). Various types of beams, with available experimental results are chosen to check the validity and the accuracy of the adopted models. In general good agreement is obtained. The maximum percentage difference in ultimate loadcarrying
capacity is 12%. Parametric studies are carried out to study the influence of the curvature (L/R ratio of 0, 0.1, 0.15 and 0.2) on the behavior of the curved in plan composite concrete beams. Also, some important material and solution parameters that affect the structure behavior are studied. These include the slab thickness, support condition, compressive strength of concrete and the percentage
of steel across the interface between the stem and the slab of the composite beam.

Effect of Dual Reinforcement on Wear Resistance by Aluminum Compacts Reinforce by SiC, Al2O3

Mohammed Moanes Ezzaldean Ali; Hanan A. R. Akkar; A. K. M. AL-Shaikhli; Ali K. Shayyish; Muhsin J. Jweeg; Wisam Auday Hussain; Mohammed T. Hussein; Mohammad A. Al-Neami; Farah S. Al-Jabary; Jafar M. Hassan; Ali H. Tarrad; Mohammed N. Abdullah; Ahmed T. Mahdi; Eyad K. Sayhood; Husain M. Husain; Nidaa F. Hassan; Rehab F. Hassan; Akbas E. Ali; Assim H Yousif; Kassim K Abbas; Aqeel M Jary; Shakir A. Salih; Ali T. Jasim; Ammar A. Ali; Hosham Salim; JafarM. Daif; Ali H. Al Aboodi; Ammar S. Dawood; Sarmad A. Abbas; Salah Mahdi Saleh; Roshen T. Ahmed; Aseel B. Al-Zubaidi; Mohammed Y. Hassan; Majid A. Oleiwi; Shaimaa Mahmood Mahdy; Husain M. Husain; Mohammed J. Hamood; Shaima; a Tariq Sakin

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 423-429

The producing composite materials of dual reinforcement in which the matrix material is aluminum reinforced with two types of ceramic particles : which are Alumina (50μm

Keywords

composite materials; wear test ; Al2O3; SiC: Al

Factors Affecting the Relationship Between Total Porosity and Electrical Resistivity for Concrete Repair Materials

Maan Salman Hassan

Engineering and Technology Journal, 2008, Volume 26, Issue 8, Pages 1016-1024

The paper examines the properties of five different types of repair and substrate
materials, including conventional mortar, fly ash mortar, silica fume mortar, conventional
concrete substrate, and high-performance concrete substrate materials. Assessment was
carried out on the basis of some physical properties (total porosity, and electrical resistivity).
These properties were measured at early age and later after 14 weeks of exposure conditions
to 6 % (by weight) of sodium chloride solution to simulate typical marine environment.
The results show that the electrical resistivity and total porosity measurements appear
to be related and the measurements obtained are affected by the pore structure of the
materials. It is also expresses that if a material has grater proportion of coarse aggregates (e.g.
the substrate concrete in this study) it will appear to have a lower porosity although the
porosity of mortar surrounding the aggregates could be higher. This makes comparisons
between materials containing different aggregates proportions and size difficult.