Preparation of α High-Strength Gypsum from FGD Gypsum by Autoclaved Semi-Dry Process

2014 ◽  
Vol 1051 ◽  
pp. 230-236
Author(s):  
Ying Li ◽  
Peng Xuan Duan ◽  
Yuan Chao Miao ◽  
Qing Li
Keyword(s):  
Compressive Strength ◽  
Reaction Time ◽  
Citric Acid ◽  
Aspect Ratio ◽  
High Strength ◽  
Hydration Products ◽  
Fgd Gypsum ◽  
Dry Process ◽  
Conventional Process ◽  
New Process

This paper introduced the characteristics of α high-strength gypsum preparation from FGD gypsum by autoclaved semi-dry process. The compositions of the product in different stages of the reaction and the effects of crystal modifiers on the morphology of the α-HH crystals were examined and compared. The properties of α-HH and the feature of hydration products of α-HH were investigated. The results indicated that the α-HH crystals were well-shaped with the aspect ratio of 1 and the compressive strength of the α-HH could reach or exceed 60MPa. In the new process, the reaction time could be significantly shortened to 2.5hrs, which was much shorter than the conventional process. This process could be widely applied to prepare α high-strength gypsum with phosphogypsum, citric acid gypsum, etc.

Mechanical Property of Phosphoaluminate Cement

2010 ◽  
Vol 150-151 ◽  
pp. 1754-1757 ◽  
Author(s):  
Peng Liu ◽  
Zhi Wu Yu ◽  
Ling Kun Chen ◽  
Zhu Ding
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Phase Composition ◽  
Electrical Properties ◽  
Pore Size Distribution ◽  
Pore Size ◽  
High Strength ◽  
Curing Time ◽  
Hydration Products ◽  
Resistance Value

The influence of curing time on the mechanical property of the phosphoaluminate cement (PAC) was investigated, and the mechanism was discussed as well. The phase composition and morphology of hydration products, electrical properties, porosity and pore size distribution of PAC cured different age were analyzed with XRD, EIS and MIP. The results showed PAC has the property of early-high strength, and the compressive strength of PAC cured for 1 day was about 70% of 28 days’. The main hydration products of PAC are micro-crystal phase and gel of phosphate and phosphoaluminate which formed compacter microstructure. In addition, there are no calcium hydroxide (CH) and ettringite (AFt) produced during the process of hydration. The compressive strength of PAC increased with age, which was due to more products continuously produced. The ac resistance analysis manifested as the change of the nyquist pattern and resistance value.

Experimental Investigations of Shear Lag Effect in Orthotropic Composite Box Beam

2010 ◽  
Vol 150-151 ◽  
pp. 1750-1753
Author(s):  
Ya Ping Wu ◽  
Yin Hui Wang ◽  
Li Xia Wang ◽  
Zu Guang Bian
Keyword(s):  
Compressive Strength ◽  
High Strength ◽  
Experimental Investigations ◽  
Curing Time ◽  
Hydration Products ◽  
Shear Lag ◽  
Box Beam ◽  
Lag Effect ◽  
Composite Box Beam ◽  
Resistance Value

The influence of curing time on the mechanical property of the phosphoaluminate cement (PAC) was investigated, and the mechanism was discussed as well. The phase composition and morphology of hydration products, electrical properties, porosity and pore size distribution of PAC cured different age were analyzed with XRD, EIS and MIP. The results showed PAC has the property of early-high strength, and the compressive strength of PAC cured for 1 day was about 70% of 28 days’. The main hydration products of PAC are micro-crystal phase and gel of phosphate and phosphoaluminate which formed compacter microstructure. In addition, there are no calcium hydroxide (CH) and ettringite (AFt) produced during the process of hydration. The compressive strength of PAC increased with age, which was due to more products continuously produced. The ac resistance analysis manifested as the change of the nyquist pattern and resistance value.

Citric Acid Effect in High early Type Portland Cement Pastes and Mortars

2020 ◽  
Vol 1012 ◽  
pp. 284-288
Author(s):  
Beatryz Cardoso Mendes ◽  
Rita de Cássia Silva Sant’Ana Alvarenga ◽  
Délio Porto Fassoni ◽  
Leonardo Gonçalves Pedroti ◽  
Afonso Rangel Garcez de Azevedo ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Citric Acid ◽  
Portland Cement ◽  
High Strength ◽  
Early Type ◽  
Cement Pastes ◽  
Air Content ◽  
Setting Times ◽  
Acid Effect ◽  
Hardened Condition

The influence of citric acid in the properties of high strength Portland cement pastes and mortars, both in fresh and hardened condition, was evaluated. The content of citric acid varied from 0 to 0.8 wt%. Tests were carried out in cement pastes to determine the water required for normal consistency and initial and final setting times. Mortars cements were tested to define bulk density, consistency index, air content in the fresh condition and compressive strength after 7, 14, and 28 days. Analysis by XRD was also performed. The results showed that the use of citric acid as a retardant additive is a viable procedure, because it increased the mechanical strength after 14 days and improved the mortar workability.

Preparation of High Strength and Lightweight Wall Materials Using Oil Shale Ash as Raw Materials

2014 ◽  
Vol 602-603 ◽  
pp. 262-265
Author(s):  
Lei Ning ◽  
Jin Hong Li ◽  
Qi Zhang ◽  
Ting Ting Qian
Keyword(s):  
Compressive Strength ◽  
Bulk Density ◽  
Oil Shale ◽  
Raw Materials ◽  
High Strength ◽  
Xrd Analysis ◽  
Hydration Products ◽  
Oil Shale Ash ◽  
Wall Materials ◽  
Shale Ash

In this research, high strength and lightweight wall materials were made from oil shale ash (OSA) by grinding, mixing, casting molding, autoclave curing processes, et al. Factors influencing the bulk density and compressive strength of the wall materials were discussed in detail. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) analysis were used to characterize the samples. The results indicated that the compressive strength can reach up to 13.42 MPa when the bulk density reduced to 1.11g/cm3 introduced 72.00 % of OSA, the wall materials showed thermal conductivity of 0.12~0.14 W/m k. The main hydration products of the wall materials were calcium hydroxide [Ca (OH)2], C-S-H gelation and hydrogrossular [Ca3Al2(SiO4)(OH)8]. These hydration products are prodominently C-S-H gelation bonded the solid raw materials together tightly and play a great contribution to the compressive strength of wall materials.

ALCOA 7150-T7751 and T77511

Alloy Digest ◽  
2015 ◽  
Vol 64 (4) ◽  
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Tensile Properties ◽  
High Strength ◽  
Static Strength ◽  
Corrosion Resistant ◽  
Overaged Condition

Abstract This producer has pioneered the development of the -T77 temper, a high strength corrosion resistant temper for Alloy 7150 plate and extrusions. Alloy 7150-T77 provides weight savings opportunities in structure governed by static strength requirements but where "overaged" condition corrosion resistance is required. This datasheet provides information on composition, tensile properties, and compressive strength. It also includes information on corrosion resistance as well as forming. Filing Code: Al-442. Producer or source: Alcoa Mill Products Inc..

KUBOTA KNC-03

Alloy Digest ◽  
2010 ◽  
Vol 59 (1) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Kubota KNC-03 is a grade with a combination of high strength and excellent resistance to oxidation. These properties make this alloy suitable for long-term service at temperature up to 1250 deg C (2282 deg F). This datasheet provides information on physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: Ni-676. Producer or source: Kubota Metal Corporation, Fahramet Division. See also Alloy Digest Ni-662, April 2008.

MALLORY 53B

Alloy Digest ◽  
1965 ◽  
Vol 14 (9) ◽  
Keyword(s):  
Electrical Conductivity ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
High Strength ◽  
Heat Treating ◽  
High Heat ◽  
Excellent Corrosion Resistance

Abstract MALLORY 53B is an economical copper alloy combining high strength with high heat and electrical conductivity and excellent corrosion resistance. It is heat treatable. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: Cu-155. Producer or source: P. R. Mallory & Company Inc..

ELEKTRON AZM

Alloy Digest ◽  
1960 ◽  
Vol 9 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
High Strength Level ◽  
Extrusion Alloy

Abstract ELEKTRON AZM is a magnesium extrusion alloy having a high strength level. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Mg-45. Producer or source: Magnesium Elektron Ltd.

MEEHANITE GB300

Alloy Digest ◽  
2020 ◽  
Vol 69 (11) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Gray Cast Iron ◽  
High Strength ◽  
Heat Treating ◽  
Spheroidal Graphite ◽  
Cast Irons ◽  
Test Pieces ◽  
Temperature Performance

Abstract Meehanite GB300 is a pearlitic gray cast iron that has a minimum tensile strength of 300 MPa (44 ksi), when determined on test pieces machined from separately cast, 30 mm (1.2 in.) diameter test bars. This grade exhibits high strength while still maintaining good thermal conductivity and good machinability. It is generally used for applications where the thermal conductivity requirements preclude the use of other higher-strength materials, such as spheroidal graphite cast irons, which have inferior thermal properties. This datasheet provides information on physical properties, hardness, tensile properties, and compressive strength as well as fatigue. It also includes information on low and high temperature performance as well as heat treating, machining, and joining. Filing Code: CI-75. Producer or source: Meehanite Metal Corporation.

ALLEGHENY ALMAR-362

Alloy Digest ◽  
1970 ◽  
Vol 19 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Corrosion Resistance ◽  
Martensitic Stainless Steel ◽  
High Strength ◽  
Heat Treating ◽  
Chemical Processing ◽  
Processing Industry ◽  
Good Corrosion Resistance ◽  
Pneumatic Equipment

Abstract ALLEGHENY ALMAR-362 is an age-hardenable martensitic stainless steel recommended for applications requiring high strength and good corrosion resistance, such as aircraft and missile structures, hydraulic and pneumatic equipment components, and in the chemical processing industry. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on corrosion resistance as well as casting, forming, heat treating, machining, joining, and surface treatment. Filing Code: SS-234. Producer or source: Allegheny Ludlum Corporation.

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