scholarly journals Utilization Iron Filings and Microwave Heating in Roughening the Surface of Smoothed Coarse Aggregates

2018 ◽  
Vol 7 (4.20) ◽  
pp. 395
Author(s):  
Laith Mohammed Ridha Mahmmod Wajde ◽  
S. S. Alyhya Zainab ◽  
M. R. Abdul Rasoul ◽  
Abdulrasool T. Abdulrasool ◽  
. .
Keyword(s):  
Compressive Strength ◽  
Significant Influence ◽  
Smooth Surface ◽  
Coarse Aggregate ◽  
Microwave Treatment ◽  
Hardened Concrete ◽  
Equal Weight ◽  
Coarse Aggregates ◽  
Water Curing ◽  
Adhesion Process

Properties of coarse aggregate such as texture have a significant influence on the performance of fresh and hardened concrete. A smooth surface can enhance workability, yet a rougher one offers a stronger bond between aggregate and paste, resulting in higher strength. This research aims to roughen the texture of white smoothed aggregate by using cement-iron filings mortar with the aid of microwave maturation to accelerate the adhesion process of mortar-aggregate surface. The mortar was prepared by mixing an equal weight of cement and iron filings, of a particular size, with sand. Four different periods (2, 4, 6 and 8 mints.)  of microwave treatment in addition to water curing were considered plus one reference mortar which cured in only air for 24 hrs. The treated aggregate was then used for casting concrete specimens with a w/c ratio of 0.5 in which their properties being determined by means of density, compressive and tensile strengths observations. The main findings revealed that the concrete specimens contained microwave treated aggregate attained higher compressive strength compared with those treated in the air. Data also showed that concrete specimens with microwave treated aggregate possess better tensile properties as a consequence of the improvement in the transition zone.   

Effect of Mixing Steel Dust and Shred-Like Steel Fibres on the Properties of Concrete

2019 ◽  
Vol 7 (1) ◽  
pp. 24-29
Author(s):  
A. Ajwad ◽  
N. Khadim ◽  
Abdullah ◽  
U. Ilyas ◽  
M. U. Rashid ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Strength Test ◽  
Hardened Concrete ◽  
Normal Concrete ◽  
Steel Fibres ◽  
Coarse Aggregates ◽  
Mix Proportion ◽  
Steel Dust

In this research, fine and coarse aggregates present in the concrete are replaced with steel dust and shred-like steel fibres, respectively in different ratios and its effect on the properties of concrete is studied. Eight batches of concrete were mixed, each with the mix proportion of 1:2:4 and water cement ratio of 0.52. Batch A was of normal concrete. In batches B, C, and D, 5%, 10%, and 15% of sand was replaced with steel dust. In batches, E, F, and G, 2%, 5%, and 8% of coarse aggregate were replaced with steel fibres. In the last batch H, both 5% of sand and 5% of coarse aggregate were replaced with steel fine and steel fibres respectively. British as well as American standards were followed during the research. Slump test was performed in a fresh state of each mix to find the effect of these replacements on workability. 12 cubes of 150mm x 150mm x 150mm for compressive strength test and 12 cylinders of 150mm diameter and 300mm height of each, for tensile strength test were made for each batch to check these strength after 3, 7, 14, 28 days. It was found that the workability of fresh concrete decreases while density of fresh as well as hardened concrete increases with these replacements. It also results in an increase in initial compressive strength and a decrease in final compressive strength as compared to those of normal concrete. As far as tensile strength is concerned an increase in initial as well as final strength was observed.

scholarly journals A Study of the Replacement of Natural Coarse Aggregate by Spherically-Shaped and Crushed Waste Cathode Ray Tube Glass in Concrete

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
N. N. M. Pauzi ◽  
◽  
M. R. Karim ◽  
M. Jamil ◽  
R. Hamid ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Smooth Surface ◽  
Coarse Aggregate ◽  
Control Specimen ◽  
Test Results ◽  
Complete Replacement ◽  
Ordinary Concrete ◽  
Coarse Aggregates ◽  
Optimum Proportion ◽  
Cathode Ray Tube

The aim of this study is to conduct an experimental investigation on the influence of complete replacement of natural coarse aggregate with spherically-shape and crushed waste cathode ray tube (CRT) glass to the aspect of workability, density, and compressive strength of the concrete. After characterizing the glass, a group of concrete mixes was prepared to contain a 40% spherical CRT glass and 60% crushed CRT glass as a complete (100%) replacement of natural coarse aggregates. From a total of 16 types of concrete mixes, the optimum proportion was selected based on its best performance. The test results showed that the use of spherical and crushed glass that possesses a smooth surface, rounded, irregular and elongated shape, and low water absorption affects the workability of concrete. Due to a higher specific gravity of crushed glass, concrete mixes containing CRT glass had a higher density compared to ordinary concrete. Despite the spherical and crushed CRT glass being stronger than gravel, the results revealed a reduction in compressive strength of the concrete. However, using a lower water to binder (w/b) ratio and a higher superplasticizer (SP) dosage, it is found to enhance the compressive strength of 60.97 MPa at 28 days that is lower by 13% than the control specimen. These findings indicate that waste CRT glass in the form of spherical and crushed could be used as an alternative of coarse aggregate that may pave the way for the disposal of hazardous e-waste.

scholarly journals Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Strength Reduction ◽  
Recycled Aggregate ◽  
Two Stage ◽  
Conventional Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

scholarly journals Effect of Water Cement Ratios on Compressive Strength of Palm Kernel Shell Concrete

2019 ◽  
Vol 2 (Issue 1) ◽  
Author(s):  
A.O Adeyemi ◽  
M.A Anifowose ◽  
I.O Amototo ◽  
S.A Adebara ◽  
M.Y Olawuyi
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Palm Kernel ◽  
Hardened Concrete ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Palm Kernel Shell ◽  
Compressive Strength Of Concrete ◽  
Palm Kernel Shells

This study examined the effect of varying water cement ratio on the compressive strength of concrete produced using palm kernel shell (PKS) as coarse aggregate at different replacement levels. The replacement levels of coarse aggregate with palm kernel shells (PKS) were 0%, 25%, 50%, and 100% respectively. PKS concrete cubes (144 specimens) of sizes 150mm x 150mm x 150mm were cast and cured in water for 7, 14, 21 and 28 days respectively. A mix ratio of 1:2:4 was adopted with water-cement ratio of 0.45, 0.5, and 0.6 respectively while the batching was done by weight. Slump test was conducted on fresh concrete while compressive strength test was carried out on the hardened concrete cubes using a compression testing machine of 2000kN capacity. The result of tests on fresh concrete shows that the slump height of 0.45 water cement ratio (w/c) increases with an increase in PKS%. This trend was similar to 0.50 and 0.60 w/c. However, the compressive strength of concrete cube decreases with an increase in w/c (from 0.45 to 0.60) but increases with respect to curing age and also decreases with increase in PKS%. Concrete with 0.45 water-cement ratio possess the highest compressive strength. It was observed that PKS is not a good substitute for coarse aggregate in mix ratio 1:2:4 for concrete productions. Hence, the study suggest the use of chemical admixture such as superplasticizer or calcium chloride in order to improve the strength of palm kernel shells-concrete.

scholarly journals Effect of Recycled Coarse Aggregates in Properties of Concrete

2008 ◽  
Vol 3 (4) ◽  
pp. 130-137 ◽  
Author(s):  
R Kumutha ◽  
K Vijai
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Split Tensile Strength ◽  
Coarse Aggregates ◽  
The Cost

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.

scholarly journals Examining Polyethylene Terephthalate (PET) as Artificial Coarse Aggregates in Concrete

2020 ◽  
Vol 6 (12) ◽  
pp. 2416-2424
Author(s):  
Erniati Bachtiar ◽  
Mustaan Mustaan ◽  
Faris Jumawan ◽  
Meldawati Artayani ◽  
Tahang Tahang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Polyethylene Terephthalate ◽  
Coarse Aggregate ◽  
Fresh Concrete ◽  
Coarse Aggregates ◽  
Volume Weight ◽  
Concrete Mixtures ◽  
Strength Tests ◽  
Recycled Polyethylene

This study aims to examine the effect of recycled Polyethylene Terephthalate (PET) artificial aggregate as a substitute for coarse aggregate on the compressive strength and flexural strength, and the volume weight of the concrete. PET plastic waste is recycled by heating to a boiling point of approximately 300°C. There are five variations of concrete mixtures, defined the percentage of PET artificial aggregate to the total coarse aggregate, by 0, 25, 50, 75 and 100%. Tests carried out on fresh concrete mixtures are slump, bleeding, and segregation tests. Compressive and flexural strength tests proceeded based on ASTM 39/C39M-99 and ASTM C293-79 standards at the age of 28 days. The results showed that the use of PET artificial aggregate could improve the workability of the concrete mixture. The effect of PET artificial aggregate as a substitute for coarse aggregate on the compressive and flexural strength of concrete is considered very significant. The higher the percentage of PET plastic artificial aggregate, the lower the compressive and flexural strength, and the volume weight, of the concrete. Substitution of 25, 50, 75 and 100% of PET artificial aggregate gave decreases in compressive strength of 30.06, 32.39, 41.73 and 44.06% of the compressive strength of the standard concrete (18.20 MPa), respectively. The reductions in flexural strength were by respectively 19.03, 54.50, 53.95 and 61.00% of the standard concrete's flexural strength (3.59 MPa). The reductions in volume weight of concrete were by respectively 8.45, 17.71, 25.07 and 34.60% of the weight of the standard concrete volume of 2335.4 kg/m3 Doi: 10.28991/cej-2020-03091626 Full Text: PDF

scholarly journals Influence of Reduced Water Cement Ratio on Behaviour of Concrete Having Plastic Aggregate

2018 ◽  
Vol 4 (12) ◽  
pp. 2971 ◽  
Author(s):  
Saad Tayyab ◽  
Asad Ullah ◽  
Kamal Shah ◽  
Faial Mehmood ◽  
Akhtar Gul
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Stress Strain ◽  
Cement Ratio ◽  
Coarse Aggregates ◽  
Alternative Materials ◽  
Super Plasticizer ◽  
Strain Relationship ◽  
Natural Aggregates ◽  
Reduced Water

The production and use of plastic bottles is increasing tremendously with passing time. These plastic bottles become a problem when they are disposed as they are non-biodegradable. This means that the waste plastic, when dumped, does not decompose naturally and stays in the environment affecting the ecological system. The use of alternative aggregates like Plastic Coarse Aggregate (PCA) is a natural step in solving part of reduction of natural aggregates as well as to solve the issue discussed above. The researchers are trying from half a century to investigate the alternative materials to be replaced in concrete mixture in place of either aggregate or cement.  In this research, the concrete made from plastic waste as coarse aggregates were investigated for compressive strength and Stress-strain relationship. Plastic coarse aggregate have been replaced in place of natural coarse aggregate by different percentages with w/c 0.5, 0.4 and 0.3. The percentage replacement of plastic aggregate in place of mineral coarse aggregate was 25%, 30%, 35% and 40 %. Using Super-plasticizer Chemrite 520-BAS. OPC-53 grade cement was used. Total of forty five Cylinders were prepared based on different combination of Percentage of Plastic aggregate replaced and W/C as discussed above and checked for compressive strength and stress-strain relationship. The compressive strength increases by about 19.25% due to the decrease in W/C from 0.5 to 0.3 for plastic percentage addition of 40%.

scholarly journals Acidic solution effects on no-fines concrete produced by using recycled concrete as coarse aggregate

2018 ◽  
Vol 162 ◽  
pp. 02002
Author(s):  
Ikbal Gorgis ◽  
Whab Faleh Abd ◽  
Shaker Al-Mishhadani
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Maximum Size ◽  
Recycled Concrete ◽  
Type I ◽  
Coarse Aggregates ◽  
Crushed Concrete ◽  
Compaction Factor ◽  
Single Size ◽  
Better Than

This paper investigates durability of no fine concrete containing demolished concrete as coarse aggregate after crushing to different sizes. Different no fine concrete mixes were considered using Portland cement type I with two types of coarse aggregates, crushed demolished concrete and crushed natural gravel were used with two ratios by weight (1:5 and 1:7) C/Agg. Graded aggregate and single size were used with a maximum size of 20 mm. W /C ratio was kept as 0.4 for all mixes and super-plasticizer was required to keep the same flow and compaction factor value for all mixes. Cube specimens with 150mm were cured and divided to two parts, the first part was exposed to 60 cycles of freezing- thawing; the second part of the sample was immersed in Nitric Acids solution with pH of 3.5 for (7, 28, 90 and 180 days) and then tested for compressive strength. The results indicated that it is possible to produce homogenous and workable mixes by using demolished crushed concrete as coarse aggregate. The compressive strength after cycles of freezing- thawing and immersing in Nitric acid (HNO3) at (7, 28, 90 and 180) days was decreased for samples made with crushed demolished concrete. Also it is found that the performance of concrete mixes containing graded coarse aggregate and 1:5 cement/aggregate ratios was better than other mixes.

scholarly journals The effect of coarse aggregate hardness on the fracture toughness and compressive strength of concrete

2019 ◽  
Vol 258 ◽  
pp. 04011
Author(s):  
Atur P. N. Siregar ◽  
Emma L. Pasaribu ◽  
I Wayan Suarnita
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Los Angeles ◽  
Coarse Aggregate ◽  
Concrete Aggregate ◽  
Beam Size ◽  
Intensity Factors ◽  
Coarse Aggregates ◽  
Los Angeles Abrasion ◽  
Compressive Strength Of Concrete

Coarse aggregate is the dominant constituent in concrete. Aggregate hardness is a variable needed to investigate in determining its effect on the critical stress intensity factors (KIC), dissipated fracture energy (Gf) and compressive strength (fc’) of the concrete. The hardness of coarse aggregate based on Los Angeles abrasion values of 16.7%., 22.6%, and 23.1% was used incorporated with Portland Composite Cement (PCC), and superplasticizer to create specimens. Cubes of 150x150x150 mm were employed to determine the fc’, and four beam sizes: 50x100x350 mm, 50x150x500 mm, 50x300x950 mm and 50x450x1250 mm were engaged to determine KIC and Gf. The fc’ and Gf of specimens manufactured by three different hardness of coarse aggregates were 45, 43, 40 MPa and 89.4, 54.0, 56.3 N/m respectively. KIC of specimens was 138.9, 119.4 and 114.1 MPa.mm1/2 for beam size of 50x100x350 mm; 148.2, 115.8 and 108.8 MPa.mm1/2 for beam size of 50x150x500 mm; 230.9, 183.1 and 157.9 MPa.mm1/2 for beam size of 50x300x950 mm; and 293.2, 248.1 and 244.3 MPa.mm1/2 for beam size of 50x450x1250 mm. Experimental results showed that decreasing hardness of coarse aggregate was found to have significant effect on the fracture toughness rather than on the compressive strength of concrete.

Recycled CRT Funnel Glass as Coarse Aggregate and Fine Aggregate in the Radiation Protection Concrete

2016 ◽  
Vol 847 ◽  
pp. 437-444 ◽  
Author(s):  
Ying Liang Tian ◽  
Wen Cai Liu ◽  
Su Ping Cui ◽  
Shi Bing Sun ◽  
Yi Wang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Electrical Equipment ◽  
Radiation Shielding ◽  
High Tech ◽  
Fine Aggregate ◽  
Volume Percentage ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
High Level

In recent decades, high-tech electrical equipment has drastically proliferated instead of Cathode Ray Tube (CRT), making CRT funnel glass potential hazardous solid waste. Due to a relatively high level of lead, CRT funnel glass could be used as a potential material for the production of anti-radioactive concrete. In our study the CRT funnel glass , which was separated as aggregate in the concrete, was reduced to 4.75-25 mm (coarse aggregates) and less 4.75 mm (fine aggregates) in the production of anti-radioactive concrete. Mixes containing 0%, 20%, 40% , 60%, 80% and 100% (volume percentage) of CRT funnel glass to replace fine aggregate and coarse aggregate (respectively or simultaneously)) were prepared. The influence of the size, shape and replacement percentage of aggregates on workability, compressive strength and radiation shielding performance were determined. It was found that the replacement of natural aggregate with recycled CRT glass considerably improved the slump and radiation shielding performance but reduced compressive strength. The optimum percentage of waste funnel glass used as fine aggregate and coarse aggregate was 40%. The results clearly showed that the CRT funnel glass performed a significant enhancement in radiation shielding properties.

Sign in / Sign up

Export Citation Format

Share Document