scholarly journals Isothermal Drying Process and its Effect on Compressive Strength of Concrete in Multiscale

2019 ◽  
Vol 9 (19) ◽  
pp. 4015
Author(s):  
Du ◽  
Li ◽  
Tong ◽  
Li ◽  
Liu
Keyword(s):  
Compressive Strength ◽  
Pore Diameter ◽  
Strengthening Effect ◽  
Drying Process ◽  
Average Pore ◽  
Competition Result ◽  
Compressive Strength Of Concrete ◽  
Paste Content ◽  
Isothermal Drying ◽  
Microstructural Studies

Drying could change the microstructure of cement-based materials and inevitably affect their mechanical properties. The isothermal drying process of concrete at three scales and its effect on compressive behavior and microstructure were investigated. The deformations of cement paste, mortar, and concrete in the drying process all exhibit the characteristics of expansion first and then shrinkage. The porosity and average pore diameter increase after drying, which is mainly attributed to the increase of pores less than 100 nm diameter for paste and to the pores within 100~1000 nm for mortar. Drying makes paste denser, while the bonding between paste and aggregate is weakened. Microstructural studies indicate that the increase in compressive strength of concrete caused by isothermal drying is the competition result between the strengthening effect and the weakening effect, and is related to the paste content.

Preparation and Research of Porous Hydroxyapatite Whiskers/KGM Composite Bone Scaffolds

2013 ◽  
Vol 712-715 ◽  
pp. 415-419
Author(s):  
Ming Hua Huang ◽  
Qing Hua Chen ◽  
Li Lei ◽  
Duan Cheng Wang ◽  
Ting Ting Yan
Keyword(s):  
Compressive Strength ◽  
Degradation Rate ◽  
Pore Diameter ◽  
Sol Gel ◽  
Crosslinking Agent ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Bone Scaffolds ◽  
Composite Bone

Sol-gel method and freeze-drying method were adopted to prepare the porous HAPw/KGM composite bone scaffolds and ammonia was used as a crosslinking agent. The porosity, average pore diameter, compressive strength and degradation rate in vitro were measured according to the related standard. The curves of each factor and lever affecting comprehensive properties were drew through the orthogonal design L9 (34) experiment. SEM and XRD were applied in characterization. The results show that the optimal preparation program of the composite scaffolds is KGM (2g), HAPw (4.5g), ammonia (0.1 ml) and the freeze temperature (-20 ° C); the prepared scaffolds are porous three-dimensional network structures; the porosity of optimal scaffold is more than 90%; the average pore diameter is between 200-300μm; the compressive strength is about 0.8Mpa and the degradation rate is about 50% within 9 weeks.

Investigation of Composite Deflocculant Influence on the Properties of the Refractory Castable with Chamotte Aggregate

2014 ◽  
Vol 682 ◽  
pp. 256-260 ◽  
Author(s):  
Ina Pundienė ◽  
Irina Demidova-Buiziniene ◽  
A. Volochko
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Comparative Studies ◽  
Sodium Tripolyphosphate ◽  
Strength Properties ◽  
Cement Matrix ◽  
Hydration Products ◽  
Drying Process ◽  
Different Types ◽  
Compressive Strength Of Concrete

The influence of different types of deflocculants, PCE and sodium tripolyphosphate, on the rheological properties of the cement matrix was studied. It was established that composite deflocculant consisting of sodium tripolyphosphate and PCE Castament FS 20 provides the best rheological properties of the cement matrix and affects the composition of the hydration products. During the drying process of matrix with composite deflocculants mineral stratlingite additionally formed, which contributes to increment of strength properties. Comparative studies of refractory castable strength properties with chamotte aggregate showed that the compressive strength of concrete samples with composite deflocculants after hardening and after drying and burning is almost two times higher than the strength of samples with separate deflocculants.

Effect of Low Content of Metakaolin Addition on the Properties and Pore Structure of Concrete

2016 ◽  
Vol 680 ◽  
pp. 411-419
Author(s):  
Hai Ning Geng ◽  
Qiu Li ◽  
Zhi Guang Shi ◽  
Zhong He Shui
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Pore Diameter ◽  
Analytical Techniques ◽  
Average Pore Diameter ◽  
Average Pore

The properties and microstructure of concrete containing 0-6wt% metakaolin (MK) were studied by analytical techniques. The compressive strength increased with the content of MK and reached the maximum by 5wt% MK addition, where the compressive strength increased by 33% at 28 days comparing to the control. The pore structure was refined in the concrete containing MK due to the increase of amount of pores smaller than 10 nm. There is a relationship between average pore diameter and compressive strength.

Effects of Pore Former on Properties of Alumina Porous Ceramic for Application in Micro-Filtration Membrane Supports

2015 ◽  
Vol 655 ◽  
pp. 97-102 ◽  
Author(s):  
Qi Fu Bao ◽  
Wei Xia Dong ◽  
Jian Er Zhou ◽  
Yong Qing Wang ◽  
Yang Liu
Keyword(s):  
Compressive Strength ◽  
Pore Diameter ◽  
Porous Ceramic ◽  
Pore Former ◽  
Average Pore ◽  
Temperature Resistance ◽  
Ceramic Composition ◽  
Filtration Membrane ◽  
First Choice ◽  
Mercury Porosimeter

Due to its excellent chemical stability, high temperature resistance and mechanical properties, alumina porous ceramic was the first choice of the production of microfiltration membrane support body material. In this paper, alumina porous ceramic was prepared by alumina as main materials and adding proper amount of adhesives and sintering additives. Effects of the kinds and addition of pore formers, such as starch, graphite and carbon-black, on properties of alumina porous ceramic was studied. The porosity of the fired samples was evaluated by Archimedes law. The fired samples were characterized by scanning electron microscopy (SEM), compressive strength and mercury porosimeter measurements. Alumina porous ceramic composition was prepared by mixing 100% alumina with different particle size and 8 % graphite pore former. The sample was pressured at 10 MPa and fired at 1650 °C for 2 h, and endowed with 6-8 μm of the average pore diameter, 37.65 % of the porosity and 40.33 MPa of the compressive strength, respectively. The influence law of the kinds and addition of graphite pore former on the performance of alumina porous ceramic was studied for application in micro-filtration mmembrane supports.

Fabrication of Glass Foams from Industrial Wastes Used as Insulating Board

2013 ◽  
Vol 770 ◽  
pp. 205-208 ◽  
Author(s):  
K. Pawanawichian ◽  
W. Thiemsorn ◽  
Anucha Wannagon ◽  
P. Laoarun
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Cell Walls ◽  
Pore Diameter ◽  
Sintering Temperature ◽  
Industrial Wastes ◽  
Average Pore ◽  
Wet Process ◽  
Commercial Soap ◽  
Glass Foam

nsulating glass foam (IGF) was successfully fabricated by wet process. The starting proportion of 65 wt% waste glass, 12 wt% slag, 23 wt% commercial soap was added with 15 wt% Na2SiO3 and represented then was sintered at 725 °C. The IGF had cellular structure with the macro-pore size at 0.428 mm and thin cell walls. Density, thermal conductivity and compressive strength were 0.310 g/cm3, 0.130 W/m.K and 0.78 MPa, respectively. The average pore diameter and porosity increased with increasing the Na2SiO3 concentration and the sintering temperature. On the other hand, the density, thermal conductivity and compressive strength were decreased.

Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Astm Method ◽  
Additive Type ◽  
Composition Variation ◽  
Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

2012 ◽  
Vol 12 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Oldřich Sucharda ◽  
David Mikolášek ◽  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Linear Analysis ◽  
Bending Tests ◽  
Cube Strength ◽  
Non Linear ◽  
Compressive Strength Of Concrete ◽  
Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

Fuels Desulphurisation by Adsorbtion on Fe / Bentonite

2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Adsorption Process ◽  
Continuous System ◽  
Gas Oil ◽  
Average Pore ◽  
Atmospheric Distillation

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.

scholarly journals Towards Sustainable Concrete Composites through Waste Valorisation of Plastic Food Trays as Low-Cost Fibrous Materials

2021 ◽  
Vol 13 (4) ◽  
pp. 2073 ◽  
Author(s):  
Hossein Mohammadhosseini ◽  
Rayed Alyousef ◽  
Mahmood Md. Tahir
Keyword(s):  
Compressive Strength ◽  
Low Cost ◽  
Impact Resistance ◽  
Food Tray ◽  
World Population ◽  
Fibrous Materials ◽  
Palm Oil Fuel Ash ◽  
Waste Plastic ◽  
Compressive Strength Of Concrete ◽  
The Impact

Recycling of waste plastics is an essential phase towards cleaner production and circular economy. Plastics in different forms, which are non-biodegradable polymers, have become an indispensable ingredient of human life. The rapid growth of the world population has led to increased demand for commodity plastics such as food packaging. Therefore, to avert environment pollution with plastic wastes, sufficient management to recycle this waste is vital. In this study, experimental investigations and statistical analysis were conducted to assess the feasibility of polypropylene type of waste plastic food tray (WPFT) as fibrous materials on the mechanical and impact resistance of concrete composites. The WPFT fibres with a length of 20 mm were used at dosages of 0–1% in two groups of concrete with 100% ordinary Portland cement (OPC) and 30% palm oil fuel ash (POFA) as partial cement replacement. The results revealed that WPFT fibres had an adverse effect on the workability and compressive strength of concrete mixes. Despite a slight reduction in compressive strength of concrete mixtures, tensile and flexural strengths significantly enhanced up to 25% with the addition of WPFT fibres. The impact resistance and energy absorption values of concrete specimens reinforced with 1% WPFT fibres were found to be about 7.5 times higher than those of plain concrete mix. The utilisation of waste plastic food trays in the production of concrete makes it low-cost and aids in decreasing waste discarding harms. The development of new construction materials using WPFT is significant to the environment and construction industry.

scholarly journals Photocatalytic activity of Pr-modified TiO2 for the degradation of bisphenol A

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Denise S. Cordeiro ◽  
Fernando L. Cassio ◽  
Larissa Ciccotti ◽  
Thiago L. R. Hewer ◽  
Paola Corio ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Pore Diameter ◽  
Sol Gel ◽  
Bandgap Energy ◽  
Photocatalytic Efficiency ◽  
Average Pore ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Adsorption Desorption

AbstractPraseodymium doped TiO2 nanoparticles were successfully prepared by the sol–gel method and characterized by X-ray powder diffraction, N2 adsorption–desorption isotherm, and UV–vis spectroscopy. The effects of the dopant on the crystallite size, specific surface area, average pore diameter, pore volume, and bandgap energy were investigated. The photocatalytic activity of the catalysts was evaluated by bisphenol A degradation and mineralization, which is a representative endocrine disruptor. Furthermore, under visible light irradiation the Pr-modified TiO2 photocatalysts exhibited higher photocatalytic efficiency than unmodified TiO2. When praseodymium was loaded (1.0–5.0%) onto the surface of TiO2, the rates of degradation and mineralization were increased 3–5 times.

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