Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Compressive strength


Effect of domestic dry sewage sludge on concrete compressive strength

Alaa R. Al-Obaidi; Riyad H. Al-Anbari; maan S. hassan

Engineering and Technology Journal, 2022, Volume 40, Issue 5, Pages 1-8
DOI: 10.30684/etj.2021.131284.1022

The possibility of saving and sustaining natural materials by reusing waste is one of the most important goals researchers seek to achieve and prove its effectiveness and positive impact on the environment. In this study, domestic wastewater sludge was utilized in concrete production as partial cement changing with different ratios (0, 5, 10, and 15) % with dry sludge. The study showed that the compressive strength test showed that the partial replacement of cement by dry sludge caused reduction increased directly with the increase of sludge ratio compared with concrete reference specimens. The study found that dry sludge can be used up to 15% as a replacement in concrete sidewalks and roads because these applications use horizontal construction, which does not require the same high strength resistance as vertical construction. In addition, it was also found that using up to 10% dry sludge content in concrete may positively impact reducing sludge levels in the environment and the cost of cement production without a significant effect on the compressive and flexural strength of concrete. The study aimed to encourage government agencies and the business sector to employ excess quantities of domestic sludge in the construction industry, as well as to investigate the influence of partial replacement of cement with dry sludge on the compressive strength of concrete.

The Effect of Process Parameters on the Compression Property of Acrylonitrile Butadiene Styrene Produced by 3D Printer

Sabreen A. Oudah; Hind B. Al-Attraqchi; Nassir A. Nassir

Engineering and Technology Journal, 2022, Volume 40, Issue 1, Pages 189-194
DOI: 10.30684/etj.v40i1.2118

Additive manufacturing (AM) by Fused Deposition Modelling (FDM) provides an innovative manufacturing method for complex geometry components. 3D printers have become easily accessible to the public. The technology used by these 3D printers is Fused Deposition Modelling. The majority of these 3D printers mainly use acrylonitrile butadiene styrene (ABS) to fabricate 3D objects. This study aims to investigate the influence of some printing parameters like infill pattern (Tri-Hexagon, Zig - Zag, and Gyroid), infill density (25%, 50%, and 75%), and layer thickness (0.1, 0.2, and 0.3 mm) on the compressive strength of ABS materials. The design of the experiment was achieved by Taguchi method. A total of nine specimens were fabricated with different processing parameters using a commercial FDM 3D printer and then were tested according to the ASTM D695 standard. Findings presented in this research showed that the compressive strength of printed parts depends on the printing parameters employed. Analysis of variance revealed that the infill density is the most sensitive parameter among the three parameters examined. The optimal printing parameters were (0.3 mm 75 %, Gyroid) for improving compression strength according to signal-to-noise (S/N) ratio analysis. Experiment number (9) showed the highest compression strength with a value of 44.64 MPa.

Effect of Inclination of Rectangular Reinforced Concrete Short Columns on the Confinement

Eyad K. Sayhood; Bassman R. Muhammed; Ahmed A. Hatem

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1821-1827
DOI: 10.30684/etj.v39i12.437

The main objective of this paper is to study the confinement of the rectangular reinforced concrete short inclined columns. This paper was based on theoretical analysis using the MATLAB program according to Universal Codes, and variables that were carefully selected to be the most influential factor. The angle of the inclination (α) was taken as a major variable in the paper, in addition other variables which in turn affect directly on the behavior of inclined columns such as the percentage of reinforcing steel in the concrete section of the column (ρ), the compressive strength of the concrete (fʹc), yield strength of steel bars (fy) and effective depth ratio (γ). The results show that best ratio of reinforcing steel that improves the value of the confinement ranges from 0.4 - 0.6 which leads to an increase in the confinement of (60 – 100) %, and these rates increase with increasing α, and the increase in fʹc leads to a significant increase in the confinement, especially when HSC is used..On the other hand, decreasing  fy leads to increase in confinement, and the value of the γ had a considerable effect on the confinement that was decreased by about 11% when γ equals 0.9, compared with the corresponding γ equals 0.6.

Effect of Adding Polypropylene Fibers in Met kaolin-Based Geopolymer Concrete

Qais J. Frieh; Mushtaq H. Kamil

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1814-1820
DOI: 10.30684/etj.v39i12.2224

Geopolymer is a binder material that was created as a result of efforts to decrease Portland cement's negative environmental effects.  Geopolymer concrete shares certain properties with ordinary concrete, including brittleness. Like ordinary concrete, geopolymer concrete, when exposed to stresses, cracks and fails under these stresses. The purpose of adding fibers to geopolymer concrete is to overcome the matrix's brittleness and enhance its strength (particularly flexural strength). This study used metakaolin, a range of alkaline activators, and different quantities of polypropylene fibers to produce geopolymer concrete. Metakaolin's chemical composition, workability, density, flexural and compressive strength of geopolymer concrete were all examined for the purpose of determining the effect of polypropylene fibers on geopolymer concrete. Polypropylene fibers were used to make the mixes, which were then added to the mix at various percentages of 0 %, 0.5 %, and 1 % of the total volume of concrete. The results of the experiments showed that increasing the polypropylene fiber content to 0.5 % boosts the compressive strength of geopolymer concrete. On the seventh day, the compressive strength increased to 21 %. The density of geopolymer concrete was increased by adding polypropylene fibers, and there was a decrease in the workability with different fiber ratios.

Optimum Steel Fiber Content of High Strength Pozzolime Concrete

Sabreen M. Hamza; Ahmed Sh. J. Al-Zuheriy; Sabreen M. Hamza

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1869-1874
DOI: 10.30684/etj.v39i12.2213

Pozzolime is a promising alternative binder, compared to Portland cement because of its low CO2 emission. it is produced by mixing hydrated lime, silica fume, and fly ash. Fiber is added to concrete to improve the durability, mechanical properties of the structure, and others. In this study, high-strength Pozzolime concrete was reinforced with hooked-end steel fiber which was added as fractions of volume of 0.5, 1, 1.5, and 2%. Optimization for fiber content was performed according to the workability and strength of the fiber-reinforced mixture. Obtained results showed that the compressive strengths at 14d and 90d increased by 71.4% and 58.3% respectively when adding 1.5% steel fiber. Correspondingly, the 14d, 28d, and 90d flexural strength of pozzolime concrete increased by 170.4%, 203.2%, and 191.4% respectively at 1.5% and a further increase in fiber content caused a reduction in strength. The finding presented in this research confirmed that the volume fraction (1.5%) can be considered as the optimum content.

Properties of Self-Compacting Cementitious Composite Materials Containing Cement Kiln Dust Powder

Ahmed S. Kadhim; Alaa A. Atiyah; Shakir A. Salih

Engineering and Technology Journal, 2020, Volume 38, Issue 6, Pages 879-886
DOI: 10.30684/etj.v38i6A.592

This paper aims to investigate the influence of utilization micro cement kiln dust as a sustainable materials additive in order to reduce the voids and micro cracks in the cementitious mortar materials which cause a drastic reduction in the load carrying capacity of the element. Its therefore very important to decrease the pores and enhance the mechanical strength of the cementitious composite materials. In this article, the properties of self-compacting mortar containing micro cement dust additive was experimentally assessed. Micro cement dust powder was added to the self-compacting mortar in (1, 2, 3, 4 and 5 %) percentage by weight of cement to be used as cementitious sustainable materials. The experimental results indicated that the modification and enhancement of the workability of fresh mixture and the mechanical strengths of self-compacting mortar were increased as micro cement dust additives increases. Also; the water absorption and total porosity were decreased with increases of micro cement dust powder.

Influence of Recycled Fine Aggregates on Strength Properties of Reactive Powder Mortar

Doaa H. Nayyef; Shatha S. Hasan

Engineering and Technology Journal, 2020, Volume 38, Issue 3A, Pages 288-294
DOI: 10.30684/etj.v38i3A.265

Although many researchers have done many studies on recycled aggregate concrete, information is very little about the influence of utilizing recycled aggregate in the production of reactive powder concrete. Experimental work was executed to investigate the influence of utilizing recycled concrete as fine aggregate in reactive powder concrete. Five different mixes were prepared, the first mix, or control mix, was prepared with natural sand, four additional mixes were prepared with different percentage of substitution of fine aggregates(20%,40%,60%, and 80%). The investigation was carried out using compressive strength test, direct tensile strength test and flexural strength test, and two methods of curing were used standard curing at 20 °C and steam curing at 90°C. the results indicated that the strength decreases with increased the percentage of recycled fine aggregate, and the best percentage was 40% replacement where the percentages of decrease at this percentage at 28-day steam curing were 2.46, 6.66, and 2.14 for compressive strength, flexural strength, and direct tensile strength respectively.

The Characterization and Modeling the Mechanical Properties of High Strength Concrete (HSC) Modified with Fly Ash (FA)

Saman M. Kamal; Jalal A. Saeed; Ahmed Mohammed

Engineering and Technology Journal, 2020, Volume 38, Issue 2, Pages 173-184
DOI: 10.30684/etj.v38i2A.278

One of the main challenges facing Civil Engineering community is to modify cement quantity in the mix design by admixtures to enhance the mechanical properties. According to more than 1000 data from literature, mechanical characteristics of concrete modified with FA were discussed. The statistical variation with modeling were achieved by set of data. The cement was replaced up to 70% with FA (weight of dry cement) and by cube of concrete testing up to 90 days of curing time and different w/c ratio. The compressive strength of concrete varied from 18-67 MPa, while, for modified concrete with FA, compressive strength ranged from 21-94 MPa, tensile strength ranged from 1-9 MPa and flexural strengths ranged from 3 - 10 MPa. The w/c ratio of concrete modified with FA varied from 0.24-0.53, also the FA content varied from 0-50 %. Vipulanandan correlation model was effective by connecting mechanical properties and compare with Hoek-Brown model. The nonlinear model was used to investigate the effect of FA on properties of normal and high strength concrete. Study results presented a worthy correlation between compressive strength and curing time, w/c ratio and FA content. By using the interactive linked (model) for compressive, tensile, and flexural strengths of concrete quantified well as a function of w/c ratio, curing time and FA content by using a nonlinear relationship.

Mechanical Properties of Cement Mortar Made with Black Tea Waste Ash as a Partial Replacement of Cement

Mohammed S. Nasr; Zaid A. Hasan; Mohammed K. Abed

Engineering and Technology Journal, 2019, Volume 37, Issue 1C, Pages 45-48
DOI: 10.30684/etj.37.1C.7

Environmental pollution and the relatively high cost of waste disposal has been a major focus for scientists around the world, leading researchers to find a solution to reuse waste materials in different applications. Iraqi people consume hundreds of tons of black tea each year, which produce a large quantity of the used tea, leaves as waste. These large quantities go to landfills without any benefit or recycling. Additionally, landfills are considered one of the biggest crisis facing the Iraqi government. Therefore, this study aims to recycle the black tea waste ash (BTWA) by utilizing it as a partial replacement of cement. Cement mortar mixes containing five replacement levels of cement with BTWA (0%, 2.5%, 5%, 7.5% and 10% by weight) were carried out. The compressive strength and flexural strength tests were adopted to show the effect of BTWA on mechanical properties of cement mortar. The flow rate of fresh mortar was also measured. Results indicated that, up to 7.5% replacement, the compressive strength values were improved. For 10% replacement, the compressive strength values were equal to that for control specimens. In contrast, the BTWA had a negative impact on the flexure strength of mortar at replacement levels 5%, 7.5% and10%. For 2.5% substitution, however, the flexure strength was enhanced slightly (about 2%).

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.

Some Properties of No-Fines Concrete Produced by Using Demolished Concrete as Recycled Coarse Aggregate

Sh. A. Salih; I.N. Gorgis; W.F. Abd

Engineering and Technology Journal, 2017, Volume 35, Issue 7, Pages 741-748

This paper investigate some mechanical properties of no-fines concrete produced by using demolished concrete as coarse aggregate after crushing to different sizes. Different no-fine mixes were considered using Portland cement type I with two types of coarse aggregates, crushed natural gravel and crushed demolished concrete were used with two ratios by weight (1:5 and 1:7) cement/aggregate. Single size and graded aggregate were used with a maximum size of 20 mm. W /C ratio was kept as 0.4 for all mixes and supper plasticizer was used to keep the same flow and compaction factor value for all mixes . Using demolished concrete as coarse aggregate in no fine concrete led to decrease in the workability. As a comparison with natural coarse aggregate mixes, the average percentages of decreases for the flow, compaction factor and the fresh density were 2%, 2.3% and 6.4%, respectively. As well as the test results indicated that the compressive strength, splitting tensile strength, flexural strength and oven dry density for no fine made with crushed demolished concrete at age 28 days were decreased by about 29%, 22 %, 21% and 4% respectively as compared with no fine made by natural crushed aggregate.

Effect of Accelerated Weathering on the Compressive Strength for PMMA Nano Composites and PMMA Hybrids Nano Composites Used in Dental Applications

S.I. Salih; J.K. Oleiwi; A.M. Talia

Engineering and Technology Journal, 2017, Volume 35, Issue 3, Pages 204-215

In the present research, efforts are made to develop the properties of PMMA resin that used for upper and lower prosthesis complete denture, by addition four different types of nanoparticles powders, which are fly ash, fly dust, zirconia and aluminum that added with different ratios of volume fractions of (0.01, 0.02 and 0.03) to poly methyl methacrylate (PMMA), cold cured resin (castavaria) is the new fluid resin (pour type) as a matrix. The nano composite and hybrid nano composite for prosthetic dentures specimens, preparation was done by using (Hand Lay-Up) method as six groups which includes: the first three groups consists of PMMA resin reinforced by fly ash , fly dust and ZrO2 nanoparticles respectively, the second three groups consists of three types of hybrid nano composites, which includes ((PMMA:X% fly ash) - (1%Al + 3%ZrO2)), ((PMMA:X% fly dust) - (1% Al + 3%ZrO2)) and ((PMMA:nZrO2) - (1% fly ash+ 3% fly dust)) respectively. As well as, the effect of moisture and UV was taking into consideration in this study. The compression test results shows that the values of compressive strength, compressive elastic modulus, and compressive strength under the effect of accelerated weathering (moisture and UV radiation) increased with the addition of nano powders (fly ash, fly dust, zirconia and aluminum). As well as, the results showed that the maximum values of compressive strength reach to (286.25MPa) for (PMMA + 2%nZrO2) nano composite. In addition, the results showed that the compressive elastic modulus reach to the maximum value (25.4166GPa) in the nano composite material (PMMA + 2%nZrO2). Moreover, the results showed that the compressive strength under the effect of accelerated weathering (moisture and UV radiation) reach to the maximum value to (315MPa) for the nano composite material (PMMA + 3%nZrO2).

Influence of Adding Different Amounts of Super Plasticizers on the Mechanical Properties of Concrete (Impact and Abrasion)

Ali Hussain Ali; Mohammed Hazim Yasin

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 530-550

Trial laboratory batches were used to study the effect of adding different amounts of superp lasticizers on the mechanical properties (Compressive strength, abrasion resistance, and impact resistance) of concrete. A series of five different concrete mixtures including: Normal concrete mixture C1 (without superp lasticizers) as a reference mix and four concrete mixtures (C2, C3, C4, and C5) with different amounts of superp lasticizers (0.25, 0.50, 0.75, and 1.00) % as a percentage of cement content, respectively. Results show that the (1.00)% addition of superp lasticizers in the concrete mixture leads to (19.84)% increasing in the compressive strength and records an improvement in the abrasion resistance by (38.06)% and recorded an improvement in the impact resistance by (386.67)% as compared with the reference mixture. On the other hand, increasing the percentages of superp lasticizers lead to increase in compressive strength, abrasion resistance and impact resistance for all concrete mixtures.

Improvement of The Mechanical and Thermal Properties of Clay Bricks by Using Local Materials in Iraq

Haqi Ismael Qatta

Engineering and Technology Journal, 2012, Volume 30, Issue 19, Pages 3308-3327

This research studies the effect of adding industrial wastes materials with
different percentages on the thermal and mechanical properties of clay
bricks . Different types of admixtures were used in this work, including
rubber cuttings, wood saw dust and barley reeds ash with ( 5%,10% 15%
,20% ) by weight of each one respectively. Thermal conductivity, specific heat
capacity, compressive strength, flexural tensile strength, porosity and variation
of density have been examined for each samples at all percent of addition
and comparing with the reference clay bricks samples . Test results show that
the admixtures effect on the properties of clay bricks, when used barley reeds
ash which the best additives because take good properties, the density of clay
bricks is reduced 33%,thermal conductivity reduced 46% and the compressive
strength increased 20% comparing with the standard bricks. The experimental
work carried in the industrial factory of clay bricks in the Nahrawon city in
Baghdad.

Effect of Rubber Treated by Acidic Solution On Some Mechanical Properties of Rubberize Cement Mortar

Aziz Ibrahim Abdulla; Salwa Hadi Ahmed

Engineering and Technology Journal, 2011, Volume 29, Issue 13, Pages 2793-2806

In the present work, the properties of rubberize cement mortar containingcrumb rubber treated by acidic solution are tested and compared with normal rubberize and normal cement mortar.The rubber, which is treated by different acidic solution such as: (H2SO4, HCl and CH3COOH) is used as a fine aggregate as avolumetric partial
replacement of sand in cement mortar. The percent of replacement ranged from 5 to 30%.Compressive strength, modulus of rupture and modulus of elasticity (static and dynamic) a retested for all mixes. Cubes of cement mortar also tested by ultrasonic pulse velocity (UPV) and hammer tests method to show the effect of treated rubber on the UPV and hammer tests and to demonstrate the possibility of this methods for
estimating the compressive strength of rubberize cement mortar.The results show that the treatment of rubber by acidic solution significantly improves the properties of rubberize cement mortar. Moreover the results show that CH3COOH gives better improvement compared withH2SO4. The treatment of rubber by HCl shows negative
effects on all cement mortar properties.