scholarly journals Impact of Magnetically Treated Water on Compressive and Flexural Strength of Concrete

2021 ◽  
Vol 18 (3) ◽  
pp. 251-257
Author(s):  
K.O. Yusuf ◽  
T.D. Akpenpuun ◽  
S.O. David ◽  
C.H. Oluwayemi
Keyword(s):  
Impact Test ◽  
Coarse Aggregate ◽  
Testing Machine ◽  
Fine Aggregate ◽  
Treated Water ◽  
Universal Testing ◽  
Impact Tester ◽  
The Mean ◽  
Compressive And Flexural Strengths ◽  
The Impact

This study was conducted to determine the effect of Magnetically Treated Water (MTW) on compressive, flexural and impact  strengths of concrete. The compressive strength, flexural and impact test were determined using 100 mm cube, 100x100x500 mm, 100mm diameter and 64 mm high, respectively. MTW was produced by passing water through magnetic flux densities: 400(T1), 600(T2), 800(T3) and 997G(T4) as the treatments while Non-MTW (NMTW, T0 as control). The ratio of cement, fine aggregate and coarse aggregate was 1:2:4 and curing duration for the concretes were 7, 14, 21 and 28 days. Universal Testing Machine was used to determine the compressive and flexural strengths while drop weighing impact tester was used for determining the impact strength of the concrete. The mean forces at peak to break the concrete cured for 28 days for T0, T1, T2, T3 and T4 were 106.79, 121.25, 114.15, 107.06 and 196.68 kN, while the compressive strengths were 10.68, 12.13, 11.42, 10.71 and 19.67 Nmm-2, respectively. The maximum compressive, flexural and impact strengths of the concrete were 84.17, 22.37 and 96.93%, respectively. The effect of MTW was statistically significant on compressive, flexural and impact strengths and is recommended for use.

Effect of Hydrogen Content on Impact Property of A357 Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 1201-1204 ◽  
Author(s):  
Yang Li ◽  
Zheng Bing Xu ◽  
Jian Min Zeng
Keyword(s):  
Crack Propagation ◽  
Hydrogen Content ◽  
Impact Test ◽  
Testing Machine ◽  
Initial Crack ◽  
Impact Testing ◽  
Total Absorption ◽  
A357 Alloy ◽  
Absorption Energy ◽  
The Impact

The impact specimens with different hydrogen contents were solution treated at 540±3°C for 12h; water quenched at 60-100°C; and aged at 165±1°C for 6h. The impact test was carried out at Roell450 pendulum impact testing machine. The impact test results show that the impact energy has strong relation with the hydrogen content. The total absorption energy increases with the increasing of hydrogen content. The crack propagation energy Avp and present larger proportion than the initial crack energy Avi in the total absorption energy Av. The number of the pinholes increases and the pinholes turn from smaller irregular ones into sub-circular shape ones. The specimen with irregular sub-circular pinholes has larger KI, and has more crack propagation resistance.

scholarly journals Predicting the Mechanical Properties of RCA-Based Concrete Using Supervised Machine Learning Algorithms

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 647
Author(s):  
Meijun Shang ◽  
Hejun Li ◽  
Ayaz Ahmad ◽  
Waqas Ahmad ◽  
Krzysztof Adam Ostrowski ◽  
...  
Keyword(s):  
Machine Learning ◽  
Mechanical Properties ◽  
Mean Square Error ◽  
Coarse Aggregate ◽  
Machine Learning Algorithms ◽  
Supervised Machine Learning ◽  
Environmental Damage ◽  
Fine Aggregate ◽  
Mean Square ◽  
The Impact

Environment-friendly concrete is gaining popularity these days because it consumes less energy and causes less damage to the environment. Rapid increases in the population and demand for construction throughout the world lead to a significant deterioration or reduction in natural resources. Meanwhile, construction waste continues to grow at a high rate as older buildings are destroyed and demolished. As a result, the use of recycled materials may contribute to improving the quality of life and preventing environmental damage. Additionally, the application of recycled coarse aggregate (RCA) in concrete is essential for minimizing environmental issues. The compressive strength (CS) and splitting tensile strength (STS) of concrete containing RCA are predicted in this article using decision tree (DT) and AdaBoost machine learning (ML) techniques. A total of 344 data points with nine input variables (water, cement, fine aggregate, natural coarse aggregate, RCA, superplasticizers, water absorption of RCA and maximum size of RCA, density of RCA) were used to run the models. The data was validated using k-fold cross-validation and the coefficient correlation coefficient (R2), mean square error (MSE), mean absolute error (MAE), and root mean square error values (RMSE). However, the model’s performance was assessed using statistical checks. Additionally, sensitivity analysis was used to determine the impact of each variable on the forecasting of mechanical properties.

scholarly journals Experimental Study on Dynamic Mechanical Properties of Coal Gangue Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Zhishu Yao ◽  
Yu Fang ◽  
Weihao Kong ◽  
Xianwen Huang ◽  
Xuesong Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Coal Gangue ◽  
Fine Aggregate ◽  
Dynamic Mechanical ◽  
Fine Aggregates ◽  
Mine Support ◽  
The Impact

In order to study the static and dynamic mechanical characteristics of the coal gangue concrete used in the mine support structure, the compressive strength test, the drop weight impact test, and the Split Hopkinson Pressure Bar (SHPB) test were conducted. The compressive strength, initial and final impacting energy, dynamic strength, and failure characteristic of concrete were obtained of the concrete single-doped with coal gangue coarse aggregate, single-doped with coal gangue fine aggregate, and codoped with coal gangue coarse and fine aggregates. The results show that (1) it is feasible that employing coal gangue to replace natural coarse and fine aggregates in concrete can prepare C30 and C40 concrete; (2) the addition of coal gangue fine aggregate has a positive effect on the impact energy of the initial and final cracks of concrete, while the addition of coal gangue coarse aggregate has a negative effect on it; (3) compared with the static strength, the dynamic strength of concrete is improved no matter whether coal gangue is added to concrete; (4) the incorporation of coal gangue coarse aggregate will make the concrete shear surface smooth; (5) at the given impacting pressure, the concrete with coal gangue coarse aggregate has greater particle breakage and those with coal gangue fine aggregate has less. The research of this study can be a reference for the application of gangue concrete in mine support structures.

Test of Physical Mechanical Properties of Gingko，Hickory Nut and their Stalks

2012 ◽  
Vol 479-481 ◽  
pp. 1145-1150
Author(s):  
Xiao Feng Xu ◽  
Wen Bin Yao ◽  
Jiu Hua Xu ◽  
Wei Zhang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Testing Machine ◽  
Physical Characteristics ◽  
Harvest Time ◽  
Cutting Resistance ◽  
Moisture Contents ◽  
Universal Testing ◽  
The Impact ◽  
Physical Mechanics

In order to get the physical mechanics of gingko，hickory nut and their stalks, microprocessor controlled electronic universal testing machine (WDW-5E) was used to study the basic physical characteristics，pulling resistance and cutting resistance of their stalk in different harvest time and moisture contents. The impact of physical mechanics of cones and stalks on the picking process were analyzed and some concrete suggestions were put forward in the paper. This experimental study provides an important theory basis on designing and manufacturing different cones picking machine.

The Effect of Thermoforming on Tear Strength of Ethylene Vinyl Acetate Mouthguard Material in Various Thicknesses

2017 ◽  
Vol 751 ◽  
pp. 657-662
Author(s):  
Phakphum Srinuan ◽  
Jeerapatr O. Baiyokvichit ◽  
Rasana Boonpeng ◽  
Tanapol Wongwisatekit ◽  
Pacharaporn Pattanasukwasan ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Testing Machine ◽  
Ethylene Vinyl Acetate ◽  
Strength Test ◽  
Tear Strength ◽  
Universal Testing ◽  
Significant Difference ◽  
The Mean ◽  
Thermoforming Process ◽  
One Way Anova

The effect of thermoforming on the tear strength of ethylene vinyl acetate (EVA) mouthguard material (Bioplast®) has not been widely investigated. The present study compared the tear strengths of non-processed and processed EVA specimens in various thicknesses. Two groups of EVA sheet (non-processed and processed) in three different thicknesses of 3, 4 and 5 mm were used in specimen fabrication. The processed EVA sheets were achieved by forming the EVA sheet on the cylindrical stone model with the pressure-molding device (Biostar®). Twelve of tear strength specimens of non-processed and processed group in each thickness were prepared following the modified ASTM D 624-00 guideline. The tear strength test was conducted using universal testing machine (Lloyd® 1K series) with the speed of 500 mm/min. The mean thickness and tear strength of the non-processed and processed specimens in each thickness were compared using independent T-test. The differences in the mean tear strength for each thickness of non-processed and process specimens were determined using one-way ANOVA. The mean tear strength and mean thickness of processed EVA specimens was significantly lower than the non-processed EVA specimens for every thickness (P ≤ 0.05). There was no significant difference in the mean tear strength of EVA specimens among each thickness in both non-processed and processed groups. It can be concluded that the thermoforming process has the significant effect on the tear strength of the EVA mouthguard material formed by pressure molding device in every thicknesses. The tear strength of processed specimens were significant lower than the non-processed. Thus, it is more relevant for testing properties of the processed mouthguard material that the mouthguard material before processing.

Effect of Artificial Aging and Surface Treatment on Bond Strengths to Dental Zirconia

2013 ◽  
Vol 38 (2) ◽  
pp. 168-176 ◽  
Author(s):  
J Perdigão ◽  
SD Fernandes ◽  
AM Pinto ◽  
FA Oliveira
Keyword(s):  
Surface Treatment ◽  
Artificial Aging ◽  
Testing Machine ◽  
Significance Level ◽  
Diamond Blade ◽  
Universal Testing ◽  
Bond Strengths ◽  
The Mean ◽  
Post Hoc ◽  
Adhesive Cement

SUMMARY The objective of this project was to study the influence of artificial aging and surface treatment on the microtensile bond strengths (μTBS) between zirconia and a phosphate monomer–based self-adhesive cement. Thirty zirconia disks (IPS e.max ZirCAD, Ivoclar Vivadent) were randomly assigned to two aging regimens: AR, used as received, which served as a control, and AG, artificial aging to simulate low-temperature degradation. Subsequently, the disks of each aging regimen were assigned to three surface treatments: NT, no surface treatment; CO, surface silicatization with CoJet sand (3M ESPE); and ZP, zirconia surface treated with Z-Prime Plus (Bisco Inc). Thirty discs were made of Filtek Z250 (3M ESPE) composite resin and luted to the zirconia discs using RelyX Unicem (3M ESPE). The specimens were sectioned with a diamond blade in X and Y directions to obtain bonded beams with a cross-section of 1.0 ± 0.2 mm. The beams were tested in tensile mode in a universal testing machine at a speed of 0.5 mm/min to measure μTBS. Selected beams were selected for fractographic analysis under the SEM. Statistical analysis was carried out with two-way analysis of variance and Dunnett T3 post hoc test at a significance level of 95%. The mean μTBS for the three AR subgroups (AR-NT, AR-CO, and AR-ZP) were significantly higher than those of the corresponding AG groups (p<0.0001). Both AR-CO and AR-ZP resulted in statistically significant higher mean bond strengths than the group AR-NT (p<0.006 and p<0.0001, respectively). Both AG-CO and AG-ZP resulted in statistically significant higher mean bond strengths than the group AG-NT (both at p<0.0001). Overall, AG decreased mean μTBS. Under the SEM, mixed failures showed residual cement attached to the zirconia side of the beams. CO resulted in a characteristic roughness of the zirconia surface. AR-ZP was the only group for which the amount of residual cement occupied at least 50% of the interface in mixed failures.

Experimental Investigation of Static and Dynamic Characteristics of Multiwall Carbon Nanotubes Reinforced Polypropylene

2014 ◽  
Vol 592-594 ◽  
pp. 927-931
Author(s):  
Sachin O. Gajbhiye ◽  
Satinder P. Singh
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Test ◽  
Dynamic Characteristics ◽  
Test Specimen ◽  
Impact Test ◽  
Testing Machine ◽  
Laser Doppler Vibrometer ◽  
Nanocomposite Material ◽  
Static And Dynamic Characteristics ◽  
The Impact

The change in static and dynamic characteristics of polypropylene (PP) of grade H110MA by adding 2% multi walled carbon nanotubes (MWCNT) was investigated experimentally in this paper. The nanocomposite material is prepared by mixing neat PP and MWCNT in an extruder in a specified proportion. The extruded material is then used in an injection molding machine to make tensile test and impact test specimen. Tensile test specimen is tested on universal testing machine (UTM) to check the Young’s modulus of nanocomposite material. The impact test specimen is used to find the dynamic characteristics of this material by using the technique of experimental modal analysis using Single point Laser Doppler Vibrometer (SLDV), modal hammer and FFT analyzer. The scanning electron microscopic (SEM) images were taken to check the orientation and dispersion of carbon nanotubes in polypropylene.

scholarly journals Effects of various liquid-to-powder ratios on the compressive strength of calcium enriched mixture: Original research

2021 ◽  
Vol 15 (2) ◽  
pp. 129-132
Author(s):  
Mohammad Forough Reyhani ◽  
Sheida Hosseinian Ahangarnezhad ◽  
Negin Ghasemi ◽  
Amin Salem Milani
Keyword(s):  
Compressive Strength ◽  
Testing Machine ◽  
Original Research ◽  
Significance Level ◽  
Cem Cement ◽  
Universal Testing ◽  
Demineralized Water ◽  
Compressive Strength Test ◽  
The Mean ◽  
One Way Anova

Background. Calcium-enriched mixture (CEM) cement has been introduced and marketed as a biomaterial for use in furcal perforation repair and apexogenesis procedures, in which the compressive strength that indicates the material’s resistance against crushing is of utmost importance. This study evaluated the effect of various liquid-to-powder ratios on CEM cement’s compressive strength. Methods. One gram of the cement was mixed with 0.5, 0.34, and 0.25 mL of demineralized water and transferred to stainless steel molds (6 and 4 mm in height and diameter, respectively). Five cells in the mold were considered for each group. The compressive strength test was conducted using the universal testing machine after incubating for seven days under 95% humidity at 37°C. One-way ANOVA was applied for data analysis at P≤0.05 significance level. Results. The mean compressive strength in the liquid-to-powder ratios of 0.5, 0.34, and 0.25 were 3.4456, 3.2960, and 3.3485, respectively, with no significant differences between them. Conclusion. Under this study’s limitations, changing the liquid-to-powder ratio did not affect CEM cement’s compressive strength.

Incline Impact: A Case Study

2021 ◽  
Vol 9 (1) ◽  
pp. 327-333
Author(s):  
S. Malasri ◽  
◽  
T. Podesta ◽  
R. Moats ◽  
T. Waddell ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Impact Test ◽  
Free Fall ◽  
Rolling Friction ◽  
Shock Test ◽  
Platform Location ◽  
Christian Brothers ◽  
Impact Tester ◽  
The Impact

An incline impact test can be used as a shock test in lieu of a drop test in several test protocols, including ISTA Procedure 1A [1]. Some test protocols, such as ISTA Procedure 1E [2], only allow for an incline impact test and horizontal impact test. In this case study, a graph was developed for a 500-lb impact tester at Christian Brothers University (CBU) Packaging Laboratory. It determines sliding platform location on the incline for a given packaged-product weight to meet the impact velocity recommended by the International Safe Transit Association (ISTA). One station of the platform location higher than the station obtained from the graph is recommended to ensure the meeting of ISTA recommended impact velocity. It is well known that weight is not used in impact velocity of a free fall drop. However, this case study shows that weight contributes to impact velocity of an incline impact test. It contributes to the rolling friction. A heavier weight yields a smaller coefficient of rolling friction ( 𝜇𝑘 ), which results in a higher impact velocity. The coefficient of rolling friction for CBU’s incline impact tester can be computed from 𝜇𝑘 = −9 −5𝑤 + 0.1092, where w is the total weight of the sliding platform and packaged product.

scholarly journals Evaluation of the shear bond strength of the union between two CoCr-alloys and a dental ceramic

2004 ◽  
Vol 12 (4) ◽  
pp. 280-284 ◽  
Author(s):  
Mariana Pretti ◽  
Edson Hilgert ◽  
Marco Antônio Bottino ◽  
Rander Pereira Avelar
Keyword(s):  
Shear Strength ◽  
Standard Deviation ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Casting Technique ◽  
Universal Testing ◽  
Significant Difference ◽  
Metal Ceramic ◽  
The Mean

INTRODUCTION: Based on the importance of the integrity of the metal/ceramic interface, the purpose of this work was to evaluate the shear bond strength of the metal-ceramic union of two Co-Cr alloys (Wirobond C, Bego; Remanium 2000, Dentaurum) combined with Omega 900 ceramic (Vita Zahnfabrik). MATERIAL AND METHOD: Eleven cylindrical matrixes were made for each alloy, and the metallic portion was obtained with the lost wax casting technique with standardized waxing of 4mm of height and of 4mm of diameter. The ceramic was applied according to the manufacturer's recommendations with the aid of a teflon matrix that allowed its dimension to be standardized in the same size as the metallic portion. The specimens were submitted to the shear bond test in an universal testing machine (EMIC), with the aid of a device developed for such intention, and constant speed of 0.5mm/min. RESULTS AND CONCLUSIONS: The mean resistance was 48.387MPa for Wirobond C alloy, with standard deviation of 17.718, and 55.956MPa for Remanium 2000, with standard deviation of 17.198. No statistically significant difference was observed between the shear strength of the two metal-ceramic alloys.

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