scholarly journals Effects of GO/Al2O3 and Al2O3 Nanoparticles on Concrete Durability against High Temperature, Freeze-Thaw Cycles, and Acidic Environments

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Mehdi Saliani ◽  
Amin Honarbakhsh ◽  
Rahele Zhiani ◽  
Seyed Mojtaba Movahedifar ◽  
Alireza Motavalizadehkakhky
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Mix Design ◽  
Al2o3 Nanoparticles ◽  
Concrete Durability ◽  
Acidic Environment ◽  
Synthesis Of Nanoparticles ◽  
Freeze Thaw ◽  
Ft Ir ◽  
Acidic Environments

In this paper, the effect of GO/Al2O3 and Al2O3 synthesized nanoparticles on the durability of concrete is studied. To this end, after the synthesis of nanoparticles and confirmation of nanoparticles fabrication by SEM and FT-IR spectra, three concrete samples for each experiment related to each mix design were prepared and subjected to freeze-thaw cycles, high temperature, and acidic environment. The results show that the samples containing GO/Al2O3 nanoparticles had the least weight loss in freeze-thaw cycles as well as better resistance against acidic environment and the lowest apparent changes at high temperature compared to the samples containing nano-Al2O3 and the samples without nanoparticles. The replacement of 2 wt.% of cement with GO/Al2O3 nanoparticles results in the highest increase in concrete durability. The presence of nanoparticles in the concrete microstructure and the validation of the results are investigated by FT-IR, SEM, and EDX spectra.

Oxidation Resistant of Silicon-Boron Pitch Carbonization Product

2013 ◽  
Vol 652-654 ◽  
pp. 356-361
Author(s):  
Xiao Hua Zuo ◽  
Xuan Ke Li ◽  
Zhi Jun Dong ◽  
Guan Ming Yuan ◽  
Zheng Wei Cui
Keyword(s):  
Weight Loss ◽  
High Temperature ◽  
Thermal Treatment ◽  
Treatment Method ◽  
Oxidation Temperature ◽  
Coal Pitch ◽  
Air Atmosphere ◽  
Carbonization Product ◽  
Ft Ir ◽  
Oxidation Resistant

The silicon-boron(Si-B) pitch was successfully synthesized by solution-thermal treatment method using coal pitch, polycarbosilane and borane pyridine as starting materials. The B-Si pitch carbonization product was attained by carbonization in the temperature 900°C under flowing argon. The Si-B pitch prepared and its carbonization product were characterized by SEM, FT-IR, TG-DSC and XRD. The results show that the carbonization product has C-Si and C-B bonds and the silicon and boron components of the product is still amorphous when it is treated at 900°C. The weight loss of the Si-B pitch carbonization product at 900°C for 12h in air atmosphere is only 3.76wt%. The weight loss of the product is less than 4 wt% when the oxidation temperature reaches 1180°C. The prepared B-Si pitch carbonization product possesses good anti-oxidation property at high temperature in air atmosphere.

Valeriana wallichii root extract as a green & sustainable corrosion inhibitor for mild steel in acidic environments: experimental and theoretical study

2018 ◽  
Vol 2 (6) ◽  
pp. 1225-1237 ◽  
Author(s):  
Rajesh Haldhar ◽  
Dwarika Prasad ◽  
Akhil Saxena ◽  
Priyanka Singh
Keyword(s):  
Weight Loss ◽  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Corrosion Inhibition ◽  
Theoretical Study ◽  
Root Extract ◽  
Adsorption Behaviour ◽  
Ft Ir ◽  
Acidic Environments ◽  
Inhibition Analysis

Corrosion inhibition analysis and the adsorption behaviour of Valeriana wallichii root extract for mild steel in 0.5 M H2SO4 solution has been investigated utilizing weight loss, electrochemical, FT-IR, UV along with SEM and AFM.

Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu
Keyword(s):  
Normal State ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Normal Concrete ◽  
Strength Criteria ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

Synthesis and Characterization of Silver Nanoparticles from Psidium Guajava Leaf Extract

2021 ◽  
Vol 14 (5) ◽  
pp. 5634-5638
Author(s):  
Sruthi Radhakrishnan
Keyword(s):  
Silver Nanoparticles ◽  
Silver Nanoparticle ◽  
Leaf Extract ◽  
Nanoparticle Synthesis ◽  
Ethanolic Extract ◽  
Psidium Guajava ◽  
Sem Analysis ◽  
Synthesis Of Nanoparticles ◽  
Elemental Silver ◽  
Ft Ir

Green route for the synthesis of nanoparticles has become more acceptable than the other chemical as well as biological route. In the present study, silver nanoparticle is synthesized using ethanolic extract of Psidium guajava leaves. Further the synthesized silver nanoparticles were characterized by UV-Visible Spec, FT-IR, X-Ray Diffraction FESEM and E-DAX. The results of FT-IR provided evidence of the involvement of phytochemicals present in the leaf extract in the reduction of silver nitrate to silver nanoparticles. XRD confirmed the crystalline structure as well as shape of the synthesized nanoparticle as face-centred cubic. E-DAX profiling helped in determining the presence of elemental silver. The size of the nanoparticle procured by SEM analysis was found to be approximately 30-50 nm in size. Thus, the findings of this study showed that the plant assisted method for silver nanoparticle synthesis is more effective and further application level studies can shed lights on their use in healing of various human ailments.   

scholarly journals Acidophilic green algal genome provides insights into adaptation to an acidic environment

2017 ◽  
Vol 114 (39) ◽  
pp. E8304-E8313 ◽  
Author(s):  
Shunsuke Hirooka ◽  
Yuu Hirose ◽  
Yu Kanesaki ◽  
Sumio Higuchi ◽  
Takayuki Fujiwara ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Draft Genome ◽  
Acidic Environment ◽  
Green Algal ◽  
Genes Encoding ◽  
Acidic Environments ◽  
Arsenic Detoxification ◽  
Shock Proteins ◽  
Acidophilic Algae ◽  
Algal Genome

Some microalgae are adapted to extremely acidic environments in which toxic metals are present at high levels. However, little is known about how acidophilic algae evolved from their respective neutrophilic ancestors by adapting to particular acidic environments. To gain insights into this issue, we determined the draft genome sequence of the acidophilic green alga Chlamydomonas eustigma and performed comparative genome and transcriptome analyses between C. eustigma and its neutrophilic relative Chlamydomonas reinhardtii. The results revealed the following features in C. eustigma that probably contributed to the adaptation to an acidic environment. Genes encoding heat-shock proteins and plasma membrane H+-ATPase are highly expressed in C. eustigma. This species has also lost fermentation pathways that acidify the cytosol and has acquired an energy shuttle and buffering system and arsenic detoxification genes through horizontal gene transfer. Moreover, the arsenic detoxification genes have been multiplied in the genome. These features have also been found in other acidophilic green and red algae, suggesting the existence of common mechanisms in the adaptation to acidic environments.

Can Soy Methyl Esters Improve Concrete Pavement Joint Durability?

2012 ◽  
Vol 2290 (1) ◽  
pp. 60-68 ◽  
Author(s):  
Michael Golias ◽  
Javier Castro ◽  
Alva Peled ◽  
Tommy Nantung ◽  
Bernard Tao ◽  
...  
Keyword(s):  
Methyl Esters ◽  
Field Trials ◽  
Chemical Degradation ◽  
Maintenance Cost ◽  
Concrete Durability ◽  
Concrete Pavements ◽  
Freeze Thaw ◽  
Fluid Saturation ◽  
Soy Methyl Ester ◽  
Term Performance

Although many concrete pavements provide excellent long-term performance, some pavements (primarily in the Midwest) have shown premature deterioration at the joints. This premature deterioration is a concern because such deterioration can shorten the life of pavements that are otherwise functioning well. Previous work has hypothesized that these joints may be susceptible to preferential fluid saturation, which can lead to freeze–thaw damage or chemical degradation. This work examines the use of soy methyl ester–polystyrene (SME-PS) blends as a method to reduce the rate of fluid ingress into the pore system of the concrete and thereby make the concrete more resistant to deterioration. SME-PS is derived from soybeans and has demonstrated an ability to reduce fluid absorption in concrete when used as a topical treatment. A series of experiments was developed to evaluate the effectiveness of various dosage rates of SME-PS for increasing concrete durability at pavement joints. The experiments show that SME-PS reduces fluid ingress, salt ingress, and the potential for freeze–thaw damage. As a result of the positive experimental results, the Indiana Department of Transportation is conducting field trials that use SME-PS on concrete pavements that are beginning to show signs of premature deterioration with the expectation that SME-PS will extend the life of the joints and thereby reduce maintenance cost and extend the life of concrete pavements.

Durability of concrete containing chloride-based accelerating admixtures

1990 ◽  
Vol 17 (1) ◽  
pp. 102-112
Author(s):  
T. Rezansoff ◽  
D. Stott
Keyword(s):  
Calcium Chloride ◽  
Dynamic Modulus ◽  
Linseed Oil ◽  
Standard Test ◽  
Test Method ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Cement Ratio ◽  
Freeze Thaw ◽  
Water To Cement Ratio

The influence of CaCl2 or a chloride-based accelerating admixture on the freeze–thaw resistance of concrete was evaluated. Three air entrained mix designs were investigated using ASTM C666-84, Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing. All mix designs were similar, using cement contents of 340–357 kg/m3 of concrete, except for the addition of either 2% calcium chloride or 2% High Early Pozzolith, while no accelerating admixture was added to the control mix. The entire test program was repeated four times with water-to-cement ratio of 0.46 and three times with the ratio of 0.43. For the Pozzolith-accelerated concrete, half the samples were coated with boiled linseed oil in all seven series. For the control (unaccelerated) concrete, half the samples were coated with boiled linseed oil in one series for each water-to-cement ratio. Performance was monitored using the dynamic modulus of elasticity as obtained from transverse resonant frequency measurements. Weight loss of the specimens was also measured. Only the control samples (no accelerators) showed sufficient durability to satisfy the standard of maintaining at least 60% of the original dynamic modulus after 300 cycles of alternate freezing and thawing. Sealing with linseed oil showed inconsistent improvement in the durability in the various test series when defined in terms of the dynamic modulus; however, weight losses were the lowest of all categories and surface scaling was minimal. Key words: concrete, durability, freeze–thaw testing, calcium chloride, admixtures, sealants, air void system.

Feasibility Study on Optimisation of Material Selection for High Temperature Sour Gas Producer

2021 ◽  
Author(s):  
M. Helmi Nordin ◽  
M. Wahidullah Moh Wahi ◽  
Amresh Sashidharan ◽  
Nurfuzaini A. Karim ◽  
Alif Syahrizad Ramli
Keyword(s):  
Weight Loss ◽  
Stainless Steel ◽  
High Temperature ◽  
Corrosion Rate ◽  
Stress Corrosion Cracking ◽  
Martensitic Stainless Steel ◽  
Material Selection ◽  
Working Temperature ◽  
Fit For Purpose ◽  
Selection For

Abstract K field is a green field in East Malaysia with prolific gas reserves that is being developed with six high rate gas producing wells from high temperature (190 °C) carbonate reservoir. Tubular material feasibility study is one of the key subjects of scrutiny when it comes to completing wells in high temperature environment coupled with existence of significant level of H2S and CO2 contents. Material testing was conducted at the specified test environments (102 bar CO2 + 120ppm H2S) and load cases to assess susceptibility of Martensitic Stainless Steel to Stress Corrosion Cracking (SCC), corrosion rate and compatibility with completion brine. The aim was to optimize the material selection that is fit for purpose (lower completion and flow-wetted area of production casing) and reduce well cost up to USD 2.5 million. The base case of material selection for flow-wetted section is 17CR110 ksi, which meets the design requirements of these wells based on fit for purpose test conducted in the data base. Flow-wetted section in this case is production liner and flow-wetted section of production casing below production packer. Super 13CR -110 ksi and 15CR125 ksi material grades were considered for design optimization for this section of interest. Four Point Bend Method was used for SCC test sets while weight loss method for corrosion rate measurement. For brine compatibility test, calcium bromide (without additive) was used as test solution for 17CR 110 ksi, 15CR 125 ksi and Super 13CR -110 ksi with elevated temperature of 190 °C. Post-test assessment was conducted by visual examination by stereomicroscope to check for surface indication and dye-penetrant examination to determine any indication of cracks. It was observed that the Super 13CR -110 ksi and 15CR 125 ksi test specimens survived the test with no pitting observed. Meanwhile, test specimens were weighed to determine corrosion rates, resulted to Super 13CR -110 ksi sample having an average corrosion rate of 0.2195 mm/year. This translates to less than 30% weight loss throughout well production life and therefore accepted for open-hole production liner and production casing flow-wetted section. Key enabler in this design optimization effort is the understanding of the Stress Corrosion Cracking for martensitic stainless steel in high temperature sour environment where commonly, martensitic stainless steel (Super 13Cr / Modified Super 13Cr) working temperature is 165 °C. The test manages to extend the working temperature up to 190 °C.

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