Pore Structure and Compressive Strength of Tailings Concrete under Dry-Wet Cycles of Chloride Attack

2021 ◽  
Vol 35 (5) ◽  
pp. 04021048
Author(s):  
Yi Li ◽  
Yan Gao ◽  
Xiaotian Zheng ◽  
Fuzhou Wang
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Chloride Attack

Fabrication of Porous Al2O3 Ceramics by Freeze Drying Technique and Annealing Treatment

2016 ◽  
Vol 848 ◽  
pp. 272-278 ◽  
Author(s):  
Sha Qiu ◽  
Yu Fei Tang ◽  
Kang Zhao
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Pore Size ◽  
Annealing Time ◽  
Open Porosity ◽  
Sucrose Solution ◽  
Annealing Treatment ◽  
Porous Ceramics ◽  
Crystalline Solid ◽  
Directional Freezing

Porous Al2O3 ceramics were fabricated by directional freezing and low pressure drying with sucrose solution as the cryogenic medium. The pore structure of the porous ceramics was changed by annealing in the environment of higher than the glass transition temperature of sucrose solution after directional freezing because of changing the size and distribution of crystalline solid. The effects of the annealing time on the pore structure, open porosity and mechanical property of porous ceramics were investigated. The results showed that the pore size of porous ceramics increased substantially with the increase of annealing time. The open porosity of porous ceramics changed slightly with the increase of annealing time, while the compressive strength of porous ceramics showed a trend of decrease. The pore size range of porous Al2O3 ceramics fabricated is from 6.0μm to 110.2μm, the range of porosity was 40.35%-64.58%, the compressive strength range of porous Al2O3 ceramics was from 25.9MPa-126.6MPa. The porous Al2O3 ceramics with different pore structure can be obtained by changing the annealing time.

scholarly journals Preparation and properties of magnesite aggregate radiation - proof concrete

2018 ◽  
Vol 175 ◽  
pp. 01003
Author(s):  
Bingquan Sun ◽  
Jiajia Sun
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Water Content ◽  
Radiation Protection ◽  
Point Of View ◽  
Crystal Water ◽  
Ordinary Concrete ◽  
Mixing Water

This paper, from the point of view of improving compactness of density and crystal water content of radiation-proof concrete, using magnesite with high crystal water content as aggregate and alkaline potential water as mixing water, prepared ordinary density radiation-proof concrete and studied its mechanical properties, resistivity and pore structure. The results show that, compared to base ordinary concrete, the prepared concrete has better 28d compressive strength and resistivity, overall porosity decreases by 17%, and pore gradation at all ages improves significantly. It is indicated that the prepared magnesite aggregate radiation concrete has good density and durability, improves concrete radiation protection performance.

The Influence of Pore-Strucrure on the Campressive Strength of Hardened Cement Paste

1984 ◽  
Vol 42 ◽  
Author(s):  
Huang Yiun-Yuan ◽  
Ding Wei ◽  
Lu Ping
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cement Paste ◽  
Total Porosity ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
New Information ◽  
The Relationship ◽  
Empirical Constants

AbstractThe pore-structure strongly influences the carpressive strength of hardened cement paste (hcp) and other porous materials, as well as other mechanical properties. The simplest but most currently used expression representing the relationship between the pore-structure and compressive strength is fram Balshin: σ = σ0 (l-P)A, in which only the total porosity P is involved as a single parameter and σ0 and A are empirical constants. The influence of pore size distribution and pore shapes etc. are not considered.The authors introduce second parameter w - the factor of relative specific surface area of the pores other than the total porosity P into consideration and a new expression is proposed:σc=K11-p/1+2p(K2(1-p))K3w+K4 all the constants K1 - K4 can be determined experimentally. By using of this expression the new information relating the influence of pore-structure on the caopressive strength of hcp can be predicted.

scholarly journals Recycling of Oily Sludge as a Roadbed Material Utilizing Phosphogypsum-Based Cementitious Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Wei Xiao ◽  
Xiao Yao ◽  
Fuyang Zhang
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cementitious Materials ◽  
Solid Particles ◽  
Oily Sludge ◽  
Water Stability ◽  
Volume Stability ◽  
Freeze Thaw ◽  
Stability Performance

Oily sludge is a hazardous waste containing emulsified petroleum hydrocarbons, water, heavy metals, and solid particles. The objective of this work is to employ solidification/stabilization (S/S) techniques to utilize oily sludge as a roadbed material with ordinary Portland cement (OPC), fly ash (FA), and silica fume (SF) as binders and phosphogypsum (PG) as a stabilizer. The efficacy of the S/S process is assessed mainly through an unconfined compressive strength (UCS) test and a toxicity leaching test. Road performance, including water stability, freeze-thaw resistance, and volume stability, is also tested on the solidified samples. The mineralogical compositions, microstructures, and pore structure are characterized through X-ray diffractometry (XRD), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The results show that the addition of 20% binders (OPC : FA : SF = 1 : 0.7 : 0.8) in combination with phosphogypsum to the oily sludge not only increases the 28-day compressive strength of the solidified samples and remarkably decreases the release of heavy metals but also refines the pore structure and compacts the microstructure. The solidified body had sufficient strength and good water stability performance, freeze-thaw resistance, and volumetric stability. This solidification/stabilization (S/S) process, which combines oily sludge treatment and phosphogypsum resource utilization, significantly enhances environmental protection and renders the solidified product economically profitable.

Comparison of Porous Ti6Al4V Made by Sponge Replication and Directly 3D Fiber Deposition and Cancellous Bone

2007 ◽  
Vol 330-332 ◽  
pp. 999-1002 ◽  
Author(s):  
J.P. Li ◽  
J.R. Wijn ◽  
Clemens A. van Blitterswijk ◽  
K. de Groot
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Structure ◽  
Cancellous Bone ◽  
Structure And Properties ◽  
Porous Ti ◽  
Fiber Deposition ◽  
Regular Open

The present investigation gives a comparison of the structure and properties of porous Ti6Al4V made by sponge replication (Sponge Ti) and directly 3D fiber deposition (D3DF Ti) and cancellous bone. Although the macrostructure of these two materials differs, their microstructure seems to be similar. Both scaffolds reveal an open pore structure, while D3DF Ti shows a fairly regular open pore structure, sponge Ti6Al4V exhibit an irregular open pore structure similar to that of cancellous bone. The mechanisms resulting in mechanical properties like stiffness or strength are, accordingly, different. The compressive strength and E’ modulus of Ti6Al4V scaffold are higher than that of cancellous bone,. The permeability results show both Ti6Al4V scaffolds are quite comparable with cancellous bone.

Preparation of phenolic-based carbon foam with controllable pore structure and high compressive strength

Carbon ◽  
2010 ◽  
Vol 48 (9) ◽  
pp. 2644-2646 ◽  
Author(s):  
Shiwen Lei ◽  
Quangui Guo ◽  
Jingli Shi ◽  
Lang Liu
Keyword(s):  
Compressive Strength ◽  
Pore Structure ◽  
Carbon Foam ◽  
High Compressive Strength

Investigating the Application of DOE Method in Designing a High-Strength and High-Performance Concrete

2014 ◽  
Vol 875-877 ◽  
pp. 776-780
Author(s):  
Mojtaba Valinejad Shoubi ◽  
Azin Shakiba Barough ◽  
Iman Kiani
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Design Method ◽  
High Strength ◽  
Mix Design ◽  
Design Calculation ◽  
Concrete Mix Design ◽  
Compressive Strength Test ◽  
Chloride Attack

Concrete is the main material used in most of structures in the world. The use of high strength and high performance concrete to overcome deterioration due to static and dynamic load and some environmental burden in different situation such as chloride attack, sulphate attack and etc, is increasing worldwide. Achieving to a concrete with a high quality and saving in amount of material used for producing the concrete need a proper mix design method taken into account. DOE method is considered as an effective and substantial method in implementing the concrete mix design. In this paper, specifications and all mix design calculation steps using DOE method in achieving a high strength and high performance concrete for a tall building in a coastal environment based on three concrete cubes specimens produced in the lab, are investigated. The 7 and 14 day compressive strength test were implemented on the concrete cubes. At the end, it concluded that the specified compressive strength (45 N/mm2) can be achieved on the 28th day based on DOE method.

scholarly journals Study on the Pore Structure Characteristics of Ferronickel-Slag-Mixed Ternary-Blended Cement

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4863
Author(s):  
Won Jung Cho ◽  
Min Jae Kim ◽  
Ji Seok Kim
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Chloride Transport ◽  
Blended Cement ◽  
Cement Matrix ◽  
X Ray ◽  
Mercury Intrusion ◽  
Ferronickel Slag

Pore structure development in Portland cement, fly ash, or/and ferronickel slag (FNS) was investigated using mercury intrusion porosimetry and X-ray CT tomography. The progress of hydration was observed using X-ray diffraction (XRD) analysis and compressive strength while durability of concrete was monitored by chloride penetration resistance and chloride profiles. Mercury intrusion porosimetry (MIP) results suggested that the blended cement had a higher porosity while lower critical pore size. The major reason to this increased porosity was the formation of meso and micro pores compared to ordinary Portland cement (OPC). In terms of chloride transport, replaced cement, especially ternary-blended cement had higher resistance to chloride transport and exhibited slightly lower development of compressive strength. X-ray CT tomography shows that the influence of pore structure of ternary-blended cement on the ionic transport was strongly related to the pore connectivity of cement matrix.

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