scholarly journals Effect of mechanical activation on the properties of Portland cement

2021 ◽  
Vol 1205 (1) ◽  
pp. 012003
Author(s):  
S Ravaszová ◽  
K Dvořák
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Activation ◽  
Ball Mill ◽  
High Speed ◽  
Activation Effect ◽  
Cement Production ◽  
Grinding Method ◽  
Ground Material ◽  
Mechanical Activation Effect

Abstract The paper deals with the mechanical activation of cement by grinding in a high-speed mill, and compares the parameters found with the commonly used grinding method in cement production, which uses grinding of cement by means of a ball mill. The aim is to verify the influence of the aging time of the ground material on the preservation of the mechanical activation effect and on the properties of the final product at different stages of hydration. It evaluates the physical-mechanical properties, the compressive and tensile strength after 1, 2, 7, 14 and 28 days, as well as the course of the hydration process. The evaluated results suggest the existence of mechanical activation, but this effect is very difficult to achieve and depends on many other factors.

Effect of Ageing Period on Properties of Mechanically Activated Portland Cement

2018 ◽  
Vol 760 ◽  
pp. 37-42
Author(s):  
Karel Dvořák ◽  
Matěj Švéda
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Mechanical Activation ◽  
Aging Time ◽  
Ball Mill ◽  
High Speed ◽  
Aging Period ◽  
High Speed Grinding ◽  
Ageing Period ◽  
The Moment

This experiment describes the effects of the aging time since the moment of milling to Portland cements physico-mechanical properties. Possible mechanical activation effects to Portland cement particles has been found. For this experiment two kind of milling technology were used, the conventional milling in a ball mill and high-speed grinding technology in high speed disintegrator and influence of these technologies was also described. The aging period of the cement influences in particular physico-mechanical properties in the early stages of hydration but the final properties after 28 days were not influenced.

Effect of Coarse-Grained Ring on Mechanical Properties and Cutting Performance of 2011 Aluminum Alloy Extruded Bar

2021 ◽  
Vol 1035 ◽  
pp. 114-118
Author(s):  
Chang Liang Shi ◽  
Yan Ping Niu ◽  
Yi Min Lin ◽  
Quan Hu ◽  
Xin Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Tensile Testing ◽  
High Speed ◽  
Testing Machine ◽  
Eutectic Phase ◽  
Cutting Performance ◽  
Coarse Grained ◽  
Tensile Testing Machine

The effects of coarse-grained ring on the mechanical properties and cutting performance of 2011 aluminum alloy extruded bars were studied by metallographic microscope, scanning electron microscope, tensile testing machine and high-speed lathe. The results show that the microstructure of aluminum alloy extruded bar was composed of α-Al phase, Al7Cu2Fe phase, CuAl2 phase and SnBi eutectic phase. There was a coarse-grained ring in the aluminum alloy extruded bar. The coarse-grained ring reduced the mechanical properties and cutting performance of the aluminum alloy extruded bar. The aluminum alloy extruded bar with a diameter of 30 mm had a coarse-grained ring depth of 9 mm and lower mechanical properties, whose the tensile strength was 287.9 MPa, the elongation was 17%, the cutting performance was poor and the chips were long. The aluminum alloy extruded bar with a diameter of 40 mm had a coarse-grained ring depth of 1 mm, higher mechanical properties and better cutting performance, whose the tensile strength was 394.5 MPa, the elongation was 23.5%, the chips were fine and uniform.

Effect of Sintering Parameters and Flow Agent on the Mechanical Properties of High Speed Sintered Elastomer

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Farhana Norazman ◽  
Neil Hopkinson
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fumed Silica ◽  
High Speed ◽  
Tensile Modulus ◽  
Thermoplastic Elastomer ◽  
Elongation At Break ◽  
Bed Temperature ◽  
Laser Systems ◽  
Powder Particles

High speed sintering (HSS) is an additive manufacturing (AM) process that creates parts by sintering powder particles using inkjet and infrared (IR) lamp technology rather than laser systems employed in laser sintering (LS). This research investigated the effects of machine parameters (lamp speed, bed temperature) and the addition of fumed silica flow agent on the tensile properties of thermoplastic elastomer (TPE) parts processed using HSS. The results showed improved elongation at break (EaB) values by a factor of more than 2× compared to reported values for LS of the same TPE. At constant parameters, improved tensile strength and tensile modulus were observed with the addition of flow agent into the sintering mixture.

Processing and Mechanical Properties of Plasticized Starch by Different Plasticization Methods

2013 ◽  
Vol 763 ◽  
pp. 45-48 ◽  
Author(s):  
Wen Yong Liu ◽  
Yi Chen ◽  
Xiang Guai Li ◽  
Yu Gang Huang ◽  
Xiang Gang Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Speed ◽  
Thermoplastic Starch ◽  
Glycerol Content ◽  
Elongation Ratio ◽  
Breaking Elongation ◽  
Plasticized Starch ◽  
Suitable Processing

The thermoplastic processing and mechanical properties of starch were investigated by different plasticization methods. Glycerol was chosen as the plasticizer for starch. The effect of glycerol with different amount was studied. The two plasticizing methods of direct adding and high-speed mixing of glycerol were used to plasticize starch, respectively. The results showed that the suitable processing temperatures ranged from 105°C to 140°C. The tensile strength of the obtained thermoplastic starch decreased and the breaking elongation ratio increased with the increase of glycerol content. When the percent of glycerol was 30%, the extrudate of platicized starch has excellent liquidity and the appearance of the extrudate was smooth. Compared with the plasticizing method of direct adding, the plasticization method of high-speed mixing is more beneficial to plasticize starch.

HIGH SPEED PROCESSING OF NI-ALUMINIDES-REINFORCED NI-MATRIX COMPOSITES BY PULSED-CURRENT HOT PRESSING (PCHP)

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1672-1679 ◽  
Author(s):  
KIYOSHI MIZUUCHI ◽  
MASAMI SUGIOKA ◽  
MASAO ITAMI ◽  
KANRYU INOUE ◽  
JUN-HEE LEE ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reaction Temperature ◽  
Hot Pressing ◽  
Tensile Testing ◽  
High Speed ◽  
Room Temperature ◽  
Pulsed Current ◽  
Matrix Composites ◽  
Nickel Matrix

Nickel-aluminides-reinforced nickel-matrix composites were fabricated from 0.05mm-thick nickel foils and 0.012mm-thick aluminum foils, in a process using a pulsed-current hot pressing (PCHP) equipment, and the effect of reaction temperature on mechanical properties of the composites was investigated. The composites were of laminated structure and composed of Ni and reacted layers containing Ni -aluminides. The chemical composition of the reacted layers was dependent on reaction temperature in the temperature range employed. Tensile testing at room temperature revealed that the reaction temperature evidently influences mechanical properties, including tensile strength, elongation and fracture mode, of the composites. The tensile strength and elongation of composites fabricated at 1373K were 500MPa and 3.8%, respectively. Microstructure observations of fractured specimens revealed that Ni layers of the composite played a significant role in prohibiting the growth of numerous cracks emanating from Ni -aluminides. In the case of composites fabricated at 1373K, in addition, crack propagation between Ni -rich Al -solid-solution layers and cellular Ni 3 Al in the Ni -aluminides were prevented by mutual interaction.

Microstructure and Mechanical Properties of 3-Wire Electroslag Welded (ESW) High-Speed Pearlitic Rail Steel Joint

2020 ◽  
Vol 837 ◽  
pp. 28-34
Author(s):  
Adnan Raza Khan ◽  
Sheng Fu Yu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Colony Size ◽  
High Speed ◽  
Fusion Line ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Microstructure And Mechanical Properties ◽  
Pearlite Colony

The present paper aims at utilizing the 3-wire electroslag welding (ESW) to join high-speed pearlitic rail steels where microstructure and mechanical properties were investigated. The welded joint has produced an improved fracture force of 1396KN. WM was consisted of ferrite and pearlite having hardness of 27HRC, tensile strength of 748MPa and toughness of 12J, successively. HAZ was composed of pro-eutectoid ferrite and pearlite, where austenite grain size and pearlite colony size were reduced by moving away from the fusion line. In HAZ, near to the fusion line, the austenite grain size was 143±19μm, pearlite colony size was 52±9μm and pearlite interlamellar spacing was 90±27nm, which has produced hardness of 43.5HRC, tensile strength of 1228MPa, and toughness of 8J, successively. The entire investigation concludes that 3-wire ESW is an optimum and viable method, which has provided fine pearlite microstructure along with improved hardness and tensile strength.

Mechanical activation effect on the biostability of modified cement compositions

2020 ◽  
Vol 246 ◽  
pp. 118506 ◽  
Author(s):  
Victor Stroganov ◽  
Eugene Sagadeev ◽  
Ruslan Ibragimov ◽  
Ludmila Potapova
Keyword(s):  
Mechanical Activation ◽  
Activation Effect ◽  
Mechanical Activation Effect

scholarly journals The Analysis of the Mechanical Properties of High Carbon Steel Wires after Multipass High Speed Drawning Process in Conventional and Hydrodynamic Dies

2014 ◽  
Vol 59 (2) ◽  
pp. 681-685 ◽  
Author(s):  
M. Suliga
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Carbon Steel ◽  
Yield Strength ◽  
High Speed ◽  
High Carbon Steel ◽  
Strength Properties ◽  
High Carbon ◽  
Steel Wires ◽  
Drawing Speed

Abstract In this work the influence of the drawing speed on lubrication conditions and mechanical properties of high carbon steel wires drawn in conventional and hydrodynamic dies has been assessed. The drawing process of ϕ5.5 mm wires to the final wire of ϕ1.7 mm was conducted in 12 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15, 20 and 25 m/s. For final wires ϕ1.7 mm the investigation of mechanical properties has been carried out, in which yield strength, tensile strength, uniform and total elongation and also number of twists were determined. It has been shown that the increase of drawing speed from 5 m/s up to 25 m/s caused the increase by 6% strength properties and decrease of plasticity properties by 10%. Higher values of tensile strength and yield strength of the wires drawn conventionally with high speeds are associated with worse conditions, while in case of wires drawn hydrodynamically the main factor which caused the increase of strength properties was high lubricant pressure in hydrodynamic die, which caused the increase of total draft.

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