Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Concrete


A Comparative Investigation on Mechanical Properties of Various Fibers Reinforced Concrete

Ahmed M. Al-Ghaban; Hussein A. Jaber; Aya A. Shaher

Engineering and Technology Journal, 2019, Volume 37, Issue 1A, Pages 28-36
DOI: 10.30684/etj.37.1A.5

The present work presents an investigation the effect of adding various fiber materials such as (glass, nylon, and carbon) into the concrete mix for inspecting and compare the mechanical properties of different fibers reinforced concrete. Two different fiber length states of (short=3cm and long=10cm) are used in this work. The concrete of ordinary Portland cement of (1:1.5:3), (cement: sand: gravel), were mixed with each of the fiber materials at four different weight percentages (0, 0.4, 0.8, and 1.2) wt% per cement content. Compressive strength and flexural strength were experimentally investigated of different fibers reinforced concrete specimens after curing for 28 days. The results showed that the incorporation of various fibers with the concrete mix generally improved the strength of concrete by improving the toughness. The flexural strength of concrete with addition of various fibers was strongly enhanced than compression. Addition 0.8% of nylon fiber to concrete resulted in the maximum increase of its compressive strength, reaching the rate of increasing to 11.08% for short fiber and 20.75% for long fiber. Addition 1.2% of nylon fiber to concrete mix resulted in the maximum increase of the flexural strength, reaching rate of increasing to 120.02% for short fiber and 211.49% for long fiber. Increasing the length of fibers increases the strength of the concrete but a little extent. Among these fibers, nylon containing concrete composite exhibits promising mechanical strength that could be easily used as low-cost partitioning wall, false ceiling, and other household purposes.

Influence of Incorporating Construction Building Demolition as Recycled Aggregate on Concrete Behavior

Shatha Sadiq Hussen

Engineering and Technology Journal, 2016, Volume 34, Issue 1, Pages 33-49

Because of increasing waste production and public concerns about the environment, it is desirable to recycle materials from construction and building demolition. This study aimed to find a technique for producing recycled aggregate concrete obtained from construction and building demolition waste. Laboratory trials were conducted to investigate the possibility of using recycled aggregate from different sources in Iraq, as a partial replacement of both coarse and fine natural aggregates or one of them. Recycled aggregate consists of crushed concrete (CC) or acombination of crushed brick (CB) and crushed concrete (CC). The aggregate in concrete was replaced with 10%, 20%, 30% and 50% by weight of crushedconcrete (CC) or crushed brick (CB) and crushed concrete CC. Some of mechanical properties of recycled aggregate concrete as compared to those of conventional normal aggregate concrete are studied. Compressive strength and the splitting tensile strength were determined after curing for 7, 28, and 90 days while density was determined after28 days.From these results, it is reasonable to assume that the use of recycled concrete aggregate does not jeopardize the mechanical properties of concretefor replacement ratios up to 50%. The concrete prepared with the crushed concrete only as a partial replacement of natural aggregate achieved the highest strength values at 7, 28and 90 days. The results suggested that an aggregate that contains 50% recycled aggregate is optimum for producing recycled aggregate concrete The test results showed that the replacement of coarse or fine natural aggregate by recycled brick aggregate at the levels of 10,20,30 and 50% had little effect on the compressive strength of the specimens.

Pretreatment of Sawdust for Producing Sawdust Concrete

Haitham H. Saeed

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 541-549

Sawdust concrete has some shortcomings due to the harmful effects of some organic soluble components existing in the sawdust which affects setting and strength of sawdust concrete. Also, volume changes of sawdust as an aggregate due to variation of moisture content, cause large volume changes in the sawdust concrete. In this work, sawdust was treated before using as an aggregate for making sawdust concrete. The treatment included boiling the sawdust in water containing hydrated lime in order to dissolve all soluble organic components. To reduce water absorption of sawdust, it was dried and treated with waterproofing material. Two types of waterproofing materials were used (cutback asphalt and classic varnish). The properties of sawdust concrete were highly improved using pretreated sawdust. The increase of compressive strength was up to 50% for moderate sawdust ratios. Flexural strength is also increased, water absorption and thermal conductivity were highly reduced, while the basic advantages of sawdust concrete such as lightness of weight, sawability and nailability were not affected.

Determination of the Stresses Concentration Factor and Cracks Growth in the Buildings by Finite Element Method

Alyaa Hassan Abood; Hani Aziz Ameen

Engineering and Technology Journal, 2010, Volume 28, Issue 21, Pages 6347-6365

The novel analysis of two buildings A and B, by finite element method via ANSYS software and experimentally are presented. The investigation is carried out to show the stresses distribution and the deflections and the cracks propagation in the walls and concrete slabs and beams for the two buildings. In both buildings the investigation included load-deflection curves, stresses and cracks patterns. The stress concentration factor is calculated for two buildings. Results are shown that the factor of concentrated for building A is between (8.4-11.4) for walls contain four windows and (6.1-7.4) for walls contain two doors, while in building B the factor of concentrated is between (13.4-14.1) for walls contain one door, and (13.9-14.6) for walls contain three windows. Also the results indicated that the cracks growth in the sites of high concentrated stresses and the load-deflection curve are approximately linear even with different loads.

Finite Element Analysis Up To Failure Of Composite Concrete – Corrugated Steel Cylindrical Shells

Ahmed T. Mahdi; Eyad K. Sayhood; Husain M. Husain

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2339-2351

This study presents three-dimensional finite element analysis to the behavior of composite concrete-corrugated steel cylindrical shell. This type of construction utilizes the advantages of both of ordinary reinforced concrete and the composite action of cylindrical shell with corrugated steel plates. The 8-node brick elements in (ANSYS v.9.0) have been used to represent the concrete, while the steel bars
are modeled as discrete axial members connected with concrete elements at shared nodes with the assumption of prefect bond between the concrete and the steel bars. The corrugated steel plate is modeled by four-node shell elements. The interface elements are modeled by using three-dimensional surface to surface contact elements connected with the nodes of concrete and steel channel elements. Comparison is made between the results obtained from the finite element analysis and the available experimental results of previous studies

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