97/04458 Coke strength development in the coke oven. 1. Influence of maximum temperature and heating rate

Early cracks of box girder are widespread during the construction stage of PC box girder bridges. The cracking resistance of a prestressed concrete continuous beam bridge was conducted from the point of construction technique. Experimental study on hydration heat and mechanical properties of box girder concrete at early age were carried out. The results shown that the casting temperature of the concrete, the peak temperature and the maximum temperature difference between inside and outside of the hydration heat were very low, which were 15.7°C, 8°C and 10.2°C, respectively. The strength development of the concrete was stable, and the mixture ratio was optimal. The concrete appearance quality was fairly good without visible cracks in the construction stage. The study reveals that the crack of girder bridges during the construction stage can be avoided by taking effective measures in the construction.

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Influence of the Heating Rate on the Phase and Microstructural Transformations of Smectite Clays

Materials Science Forum ◽

10.4028/www.scientific.net/msf.820.46 ◽

2015 ◽

Vol 820 ◽

pp. 46-50

Author(s):

Wherllyson Patrício Gonçalves ◽

Valmir José da Silva ◽

Josileido Gomes ◽

Gelmires de Araújo Neves ◽

Romualdo Rodrigues Menezes ◽

...

Keyword(s):

Thermal Treatment ◽

Phase Transformations ◽

Heating Rate ◽

Raw Materials ◽

Maximum Temperature ◽

Mineralogical Analysis ◽

Mullite Phase ◽

Smectite Clays ◽

Silica Ratio

Clays are very important raw materials in the manufacturing of traditional ceramic products. The present study was intended to study the phase transformations of smectites submitted to thermal treatment in conventional stove, applying slow and fast cycles. We used three clays, two national and one imported, which were beneficiated and characterized by mineralogical analysis. Later, they were submitted to a thermal treatment at 1100, 1200 and 1250°C, with heating rate of 5 and 30°C/min, remaining under the maximum temperature for 60 minutes. We observed the presence of mullite peaks starting at 1100°C for all samples. It was verified that the sample with the highest alumina/silica ratio presented more intense mullite peaks, and the sample with the high MgO content, besides the mullite phase, also formed cordierite.

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Early Age Property Study of Phosphate Cement by Electrical Conductivity Measurement

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.544.409 ◽

2013 ◽

Vol 544 ◽

pp. 409-414

Author(s):

Zhu Ding ◽

Xiao Dong Wang ◽

Bi Qin Dong ◽

Zong Jin Li ◽

Feng Xing

Keyword(s):

Electrical Conductivity ◽

Fly Ash ◽

Temperature Rise ◽

Conductivity Measurement ◽

Maximum Temperature ◽

Strength Development ◽

Initial Reaction ◽

Early Age ◽

Electrical Conductivity Measurement ◽

Hardening Process

The properties and electrical conductivity at early age of magnesium phosphate cement (MPC) was studied. Electrical resistivity or conductivity had been used for explaining the microstructure development of cement materials. In the current study, an electrodeless resistivity meter (ERM) was used to study the early property of MPC, which was mixed with and without fly ash respectively. The hardening process was investigated by the conductivity variation, incorporating with strength development and temperature rise during the initial reaction. The products and microstructure morphology of MPC paste were analysed by XRD and SEM. Results showed the mechanical property of MPC can be improved by fly ash. Fly ash lowers the maximum temperature rise during initial reaction of MPC with water. The electrical conductivity results divids the hardening process of MPC into three stages: acceleration, deceleration and stabilization. Conductivity measurement is an excellent method to explain the hardening process of MPC.

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HEATING RATE EFFECTS ON THERMOLUMINESCENCE OF BaSO4:Eu+PTFE PREPARED AT ININ-MEXICO

Modern Physics Letters B ◽

10.1142/s0217984910022834 ◽

2010 ◽

Vol 24 (08) ◽

pp. 717-726 ◽

Cited By ~ 5

Author(s):

P. R. GONZALEZ ◽

C. FURETTA ◽

E. CRUZ-ZARAGOZA ◽

J. AZORÍN

Keyword(s):

Heating Rate ◽

Sequential Quadratic Programming ◽

Glow Curve ◽

Frequency Factor ◽

Glow Peak ◽

Maximum Temperature ◽

Kinetics Parameters ◽

Rate Effects ◽

Higher Temperature ◽

Reading System

In this work, we show the influence of heating rate (H.R.) on the thermoluminescence (TL) signal of BaSO 4 activated by Eu ions. The maximum temperature, the TL integral, the activation energy, the frequency factor and full width at half maximum of the TL glow-peak as a function of the H.R. were studied. The TL reading system used was a Harshaw TL reader model 4000, with constant H.R. in the range from 2 to 12 K/s. The irradiation dose was 0.1 Gy from 60 Co in all cases. The kinetic parameters and their dependence on the H.R. were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The experimental results showed that as the H.R. increases, the IM shifts to higher temperature; similar behavior of the kinetics parameters were obtained.

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Effect of Heating Rate on the Responses of LiF: Mg, Cu, Na, Si Thermoluminescent Phosphor

Communications in Physics ◽

10.15625/0868-3166/21/1/91 ◽

2011 ◽

Vol 21 (1) ◽

pp. 43 ◽

Cited By ~ 1

Author(s):

Vu Thi Thai Ha ◽

Nguyen Thi Quy Hai ◽

Nguyen Ngoc Long

Keyword(s):

Heating Rate ◽

Peak Height ◽

Glow Peak ◽

Maximum Temperature ◽

Full Width ◽

Half Maximum ◽

Temperature Peak ◽

Heating Rates ◽

First Order ◽

Area Increase

In the current work the glow curves for LiF:Mg,Cu,Na,Si thermoluminescent material were measured and analyzed by using a function approximating to the well-known Randall-Wilkins first-order expression. The influence of different heating rates on thermoluminescent glow-peak maximum temperature, peak height and integrated area of the glow peak was investigated for LiF:Mg,Cu,Na,Si phosphor. The results show that the glow-peak temperature, peak height and glow peak area increase with increasing heating rate, while the full width at half maximum of glow peak almost keeps constant in the range of heating rates studied.

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Fissure formation in coke. 2: Effect of heating rate, shrinkage and coke strength

Fuel ◽

10.1016/j.fuel.2009.08.007 ◽

2010 ◽

Vol 89 (7) ◽

pp. 1663-1674 ◽

Cited By ~ 17

Author(s):

D.R. Jenkins ◽

M.R. Mahoney

Keyword(s):

Heating Rate ◽

Coke Strength ◽

Fissure Formation

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