scholarly journals Tailoring the strength and porosity of rapid-hardening magnesia phosphate paste via the pre-foaming method

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Li-Jie Liu ◽  
Jin-Hong Li ◽  
Xiang Wang ◽  
Ting-Ting Qian ◽  
Xiao-Hui Li
Keyword(s):  
Compressive Strength ◽  
Porous Structure ◽  
Bulk Density ◽  
Sodium Silicate ◽  
Average Pore Size ◽  
Hydration Product ◽  
Polypropylene Fibers ◽  
High Porosity ◽  
Average Pore ◽  
Maximum Compressive Strength

Abstract High-porosity magnesia phosphate paste (HPMPP) was prepared via the pre-foaming method. In the pre-foaming method, sintering treatment was not required. The bulk density and maximum compressive strength of the HPMPP prepared according to the ratio of water to solids (W/So) of 0.32 reached 464.00 ± 5.00 Kg/m3 and 0.30 ± 0.05 MPa, respectively. The compressive strength increased with the increases in the addition amounts of sodium silicate and polypropylene fibers. The bulk density of HPMPP increased with the increase in the addition of sodium silicate and decreased with the increase in the addition of polypropylene fibers. Besides, the porosity of the magnesia phosphate paste increased from 79.85% to 81.27% and from 80.31% to 83.75% after the addition of sodium silicate and polypropylene fibers respectively. The highest porosity (83.75%) of the prepared HPMPP was realized under the addition proportion (sodium silicate: polypropylene fibers: solids = 0.06:0.0025:1). The average pore size of the prepared HPMPP is about 180 μm and the pore distribution range is relatively narrow. The hydration product (struvite) is combined with MgO particle one by one and then coated on the surface of bubbles. With the decrease of the water content, after breaking bubbles, the porous structure can be achieved.

scholarly journals Effect of microsilica content on microstructure and properties of foamed ceramics with needle-like mullite

2019 ◽  
Vol 13 (2) ◽  
pp. 202-209 ◽  
Author(s):  
Wenying Zhou ◽  
Wen Yan ◽  
Nan Li ◽  
Yuanbing Li ◽  
Yajie Dai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Raw Materials ◽  
Average Pore Size ◽  
High Porosity ◽  
Sintering Process ◽  
Average Pore ◽  
Linear Change ◽  
Direct Foaming Method ◽  
Industrial Alumina

In this study, five foamed ceramics with struts containing needle-like mullite were prepared by direct-foaming method using white clay, industrial alumina and microsilica powder as raw materials. The effects of microsilica content on the phase compositions, microstructures and properties of foamed ceramics were investigated. The results showed that the adding of microsilica decreased the average pore size and apparent porosity and increased the compressive strength and thermal conductivity of the foamed ceramics by affecting the properties of foamed slurry and reaction sintering process. The foamed ceramics with 10 wt.% microsilica content showed the best properties with high porosity of 75.8%, positive reheating linear change, compressive strength of 1.44MPa and low thermal conductivity of 0.219W/(m?K) (at 350?C).

Evaluation of 5% Na2O-Incorporated Calcium Metaphosphate as a Scaffold for Tissue-Engineered Bone Regeneration

2006 ◽  
Vol 309-311 ◽  
pp. 985-988 ◽  
Author(s):  
J.H. Yoon ◽  
J.T. Kim ◽  
Eui Kyun Park ◽  
Shin Yoon Kim ◽  
Chang Kuk You ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Bone Regeneration ◽  
Average Pore Size ◽  
Ectopic Bone Formation ◽  
Cellular Reaction ◽  
Average Pore ◽  
Cellular Attachment ◽  
Ectopic Bone ◽  
Osteogenic Effect

As a part of the effort to develop a suitable scaffold for tissue-engineered bone regeneration, we modified calcium metaphosphate (CMP) ceramic with Na20 and evaluated its efficiency as a scaffold. We incorporate 5% Na20 into pure CMP and prepare for an average pore size of 250 or 450 µm average pore sizes. The incorporation of 5% Na2O caused reduced compressive strength and there was no change in biodegradability. The in vitro cellular attachment and proliferation rate, however, were slightly improved. The 5% Na2O-incorporated macroporous CMP ceramic-cell constructs treated with Emdogain induced ectopic bone formation more effectively than those without Emdogain treatment. These results suggest that the incorporation of 5% Na2O into pure CMP is not effective for improving the physical characteristics of pure CMP but it is positive for improving the cellular reaction and osteogenic effect with the addition of Emdogain.

The effects of biochar on soil physical properties and winter wheat growth

2012 ◽  
Vol 103 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Rachel C. Devereux ◽  
Craig J. Sturrock ◽  
Sacha J. Mooney
Keyword(s):  
Pore Size ◽  
Bulk Density ◽  
Water Retention ◽  
Average Pore Size ◽  
Water Repellency ◽  
Soil Bulk Density ◽  
Average Pore ◽  
Wheat Growth ◽  
Wetting Ability ◽  
X Ray Computed

ABSTRACTBiochar has been reported to improve soil quality and crop yield; however, less is known about its effects on the physical and, in particular, structural properties of soil. This study examines the potential ability of biochar to improve water retention and crop growth through a pot trial using biochar concentrations of 0%, 1·5%, 2·5% and 5% w/w. X-ray computed tomography was used to measure soil structure via pore size characteristics; this showed that pore size is significantly affected by biochar concentration. Increasing biochar is associated with decreasing average pore size, which we hypothesise would impact heavily on hydraulic performance. At the end of the experiment, average pore size had decreased from 0·07 mm2 in the 0% biochar soil to 0·046 mm2 in the 5% biochar soil. Increased biochar concentration also significantly decreases saturated hydraulic conductivity and soil bulk density. It was also observed that increased biochar significantly decreases soil water repellency. Increased water retention was also observed at low matric potentials, where it was shown that increased biochar is able to retain more water as the soil dried out. The application of biochar had little effect on short-term (<10 weeks) wheat growth, but did improve water retention through a change in soil porosity, pore size, bulk density and wetting ability.

scholarly journals Minimizing Drying Shrinkage and Enhancing Impermeability of Foam Concrete Modified with Epoxy Resin

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jianqing Gong ◽  
Ke Li
Keyword(s):  
Surface Energy ◽  
Pore Size ◽  
Epoxy Resin ◽  
Average Pore Size ◽  
Drying Shrinkage ◽  
Maximum Level ◽  
High Porosity ◽  
Foam Concrete ◽  
Average Pore ◽  
Internal Pore Structure

Relatively high drying shrinkage and permeability were two of the major challenges associated with foam concrete (FC), primarily due to its high porosity nature. This study was aimed at reducing the drying shrinkage and improving the impermeability of FC by blending and modifying it with epoxy resin (EP). Extensive laboratory testing yielded an optimum content of 4.0% EP, corresponding to a minimum drying shrinkage rate of 1.47 mm/m, which was 48% lower than that of the unmodified FC. At this optimum dosage of 4.0% EP, the permeability pressure was at a maximum level of 1.4 MPa, whereas the permeability coefficient was at its lowest value of 0.75 × 10−9  mm/h. Internal pore structure and EP distribution were characterized using the scanning electron microscopy and indicated that a microgrid structure of the FC was formed internally, featuring an increase in the number of pores, a reduction in the average pore size, and a uniform pore size distribution. Similarly, surface energy measurements using the tensiometry method yielded maximum surface energy values at 4.0% EP content, which could be used to explain the reduced drying shrinkage and the enhanced impermeability characteristics of the modified FC.

Effect of Reaction Conditions on Pore Configuration and Mechanical Property for Porous Hydroxyapatite Prepared by Polymer Sponge Method

2007 ◽  
Vol 336-338 ◽  
pp. 1567-1570 ◽  
Author(s):  
Sang Ho Min ◽  
Hyeong Ho Jin ◽  
B.S. Jun ◽  
Ik Min Park ◽  
Hong Chae Park ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Mechanical Strength ◽  
Porous Structure ◽  
Pore Wall ◽  
Pore Morphology ◽  
Reaction Conditions ◽  
Average Pore ◽  
Porous Hydroxyapatite ◽  
Pore Wall Thickness

Porous HAp scaffolds have been prepared by using the slurry including HAp and magnesia based on the replication of polymer sponge substrate. The influence of HAp and MgO content in slurry on the pore morphology and size, and density, porosity, and mechanical strength of porous HAp scaffolds was investigated. The obtained scaffolds with average pore sizes ranging 150 to 300 μm had open, relatively uniform, and interconnected porous structure regardless of HAp and MgO content. As the MgO content increased, the pore network frame of scaffolds became to be relatively stronger, even though the pore size was not much changed. The compressive strength of the scaffolds increased rapidly with the increase of MgO content at a fixed HAp content because of increasing the pore wall thickness and density of the scaffolds. As a result, the porosity, density, and compressive strength of the porous HAp scaffolds scaffolds prepared by the sponge method were significantly affected by the addition of MgO.

The Formation of Cobalt Chromium Molybdenum (CoCrMo) Foams Fabricated by Slurry Method

2016 ◽  
Vol 840 ◽  
pp. 197-201
Author(s):  
Sufizar Ahmad ◽  
M. Rosli ◽  
Nur Suliani Abdul Manaf ◽  
Murni Faridah Mahammad Rafter ◽  
Fazimah Mat Noor
Keyword(s):  
Sintering Temperature ◽  
Average Pore Size ◽  
Sem Analysis ◽  
High Porosity ◽  
Sintering Process ◽  
Cobalt Chromium ◽  
Average Pore ◽  
Slurry Method ◽  
Cobalt Chromium Molybdenum ◽  
Orthopedic Applications

Cobalt Chromium Molybdenum (CoCrMo) is a metal that are widely used in the biomedical field of orthopedic applications. CoCrMo foam was developed in the form of a porous structure where it has a high porosity on the surface with the different pore sizes and shapes. This research is intended to produce CoCrMo foam by using slurry method and to study the effect of composition and sintering temperature on the metal foams. The slurry of CoCrMo was prepared by mixing the binder materials of Methylcellulose (CMC), Polyethylene Glycol (PEG) and distilled water for an hour. Followed by mixing and stirring the CoCrMo powder for another 1 hour until it becomes slurries. Polyurethane (PU) foam was then impregnated into the slurry and dried for a day in the oven with 60 °C. Sintering process is carried out at temperature of 1000 °C, 1100 °C and 1200 °C using a tube furnace. Then sample of CoCrMo foam was going through a shrinkage measurement, microstructure analysis by using Scanning Electron Microscope (SEM), analysis of element by using Energy Diffraction X-ray (EDX) and also the density and porosity test by using Archimedes method. The sample with the composition of 65wt% was the best result in this experiment. While sintering temperature of 1200 °C produced the highest number of porosities. The shrinkage percentage is from 2.67% to 14.13%. The density obtained is in between 1.538 g/cm3 and 2.706 g/cm3 while the percentage of porosity is from 50.284% to 78.934%. The average pore size is in the range of 249.63μm to 445.38μm. The best sintering temperature and composition to produced high porosity were on 1200 °C and 65wt%.

scholarly journals Effect of firing temperature on physico-mechanical properties of contemporary clay brick productions in Lalitpur, Nepal

2020 ◽  
Vol 55 (1) ◽  
pp. 43-52 ◽  
Author(s):  
NB Bohara ◽  
DB Ghale ◽  
YP Chapagain ◽  
N Duwal ◽  
J Bhattarai
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical Properties ◽  
Bulk Density ◽  
Firing Temperature ◽  
Apparent Porosity ◽  
Clay Brick ◽  
Mechanical And Physical Properties ◽  
Fired Bricks ◽  
Maximum Compressive Strength

Effect of firing temperature on some physico-mechanical properties of ten brick samples, those were composed by feldspars, quartz, alumina-rich spinel, primary mullite and hematite phases, was investigated in accordance with ASTM standards. The brick samples fired between 700° to 1100° C showed 11-23 % water adsorptivity (WA), 19-37 % apparent porosity (AP) and 1.50-1.65 g/cm3 bulk density (BD) indicate good physical properties. The maximum compressive strength (CS) of the fired-bricks at 950° to 1000° C was found to be between 15.6 and 17.1 MPa. At 700°-1000° C firing temperatures, the CS of these bricks is found to be increased exponentially with decreasing of both WA and AP, however it is found to be increased with increasing the BD. Consequently, it can be said that there is good correlation between mechanical and physical properties of the fired-brick samples up to the firing temperature of 1000° C. Bangladesh J. Sci. Ind. Res.55(1), 43-52, 2020

Preparation and Research of Porous KGM/ Collagen II Composite Cartilage Scaffolds

2013 ◽  
Vol 774-776 ◽  
pp. 949-953
Author(s):  
Ming Hua Huang ◽  
Hui Dong ◽  
Di Ru Xu ◽  
Duan Cheng Wang ◽  
Yong Shun Cui ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Pore Size ◽  
Raw Materials ◽  
Average Pore Size ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Average Pore ◽  
Blending Method ◽  
Collagen Ii

KGM and Collagen II were selected as the main raw materials and ammonia served as the crosslinking agent to prepare the porous KGM / COLII composite cartilage scaffolds by blending method and freeze-drying method. The porosity, average pore size, compressive strength and water absorption were measured on the basis of the related standard. The scaffolds were characterized by SEM and XRD. The results show that the optimal program of preparing composite cartilage scaffolds is KGM (2g), COLII (1g), freeze temperature (-20 ° C) and ammonia (0.1 ml). The optimal cartilage scaffolds are porous three-dimensional network structures which the porosity is more than 90%; the average pore size is about 200μm; the compressive strength is about 0.75Mpa and the water absorption reaches up to 892%.

Micro-Porous Nickel Produced by Powder Metallurgy

2007 ◽  
Vol 534-536 ◽  
pp. 977-980
Author(s):  
Yasuo Yamada ◽  
Yun Cang Li ◽  
Takumi Banno ◽  
Zhen Kai Xie ◽  
Cui E Wen
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Porous Structure ◽  
Pore Size ◽  
Cell Structure ◽  
Deformation Behaviour ◽  
Average Pore Size ◽  
Chemical Vapour ◽  
Porous Nickel ◽  
Average Pore

Micro-porous nickel (Ni) with an open cell structure was fabricated by a special powder metallurgical process, which includes the adding of a space-holding material. The average pore size of the micro-porous Ni samples approximated 30 μm and 150 μm, and the porosity ranged from 60 % to 80 %. The porous characteristics of the Ni samples were observed using scanning electron microscopy (SEM) and the mechanical properties were evaluated using compressive tests. For comparison, porous Ni samples with a macro-porous structure prepared by both powder metallurgy (pore size 800 μm) and the traditional chemical vapour deposition (CVD) method (pore size 1300 μm) were also presented. Results indicated that the porous Ni samples with a micro-porous structure exhibited different deformation behaviour and dramatically increased mechanical properties, compared to those of the macro-porous Ni samples.

Flood Mud as Geopolymer Precursor Materials: Effect of Curing Regime on Compressive Strength

2015 ◽  
Vol 815 ◽  
pp. 177-181 ◽  
Author(s):  
Mohd Mustafa Al Bakri Abdullah ◽  
Mukridz Md Mohtar ◽  
Liew Yun Ming ◽  
Muhammad Faheem Mohd Tahir ◽  
Kamarudin Husin ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Strength Properties ◽  
Sem Analysis ◽  
Raw Material ◽  
Curing Temperature ◽  
Strength Tests ◽  
Maximum Compressive Strength ◽  
Curing Regime

This paper studies the effect of curing temperature and curing duration to the flood mud based geopolymer on compressive strength properties. Flood mud was used as a raw material for geopolymer and geopolymer samples were synthesized by using sodium silicate and sodium hydroxide 14M solution. These samples were cured at different temperature (100°C, 150°C, 200°C and 250°) for different curing duration (6h, 12h and 24h) respectively. Compressive strength tests were carried out at after 28 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Result showed that the maximum compressive strength was 24 MPa at temperature of 150°C for 24 hours. With increasing ageing day, densification of geopolymer gel was observed.

Sign in / Sign up

Export Citation Format

Share Document