Influence of Molar Concentration of Sodium Hydroxide Solution on High Temperature Resistance of Geopolymer Paste

Author(s):  
T. Azeyanagi ◽  
A. Saludung ◽  
Y. Ogawa ◽  
K. Kawai
2007 ◽  
Vol 353-358 ◽  
pp. 3031-3034
Author(s):  
Rong Rong Zhou ◽  
Jian Ming Gong ◽  
Feng Li ◽  
Shan Tung Tu

Stress corrosion cracking (SCC) of austenitic stainless steel serviced in aggressive environment often occurs in power, petrochemical industry, and leads to premature equipment failure and great economic loss. This paper focuses on the problem of the SCC on the 304L stainless steel nozzle of a hydrogenation reactor, which is caused due to on-line alkali cleaning. Susceptibility for SCC was evaluated by Slow Strain Rate Test (SSRT) for as-rolled and sensitized 304L stainless steel in low concentration sodium hydroxide solution with high temperature. The effects of different strain rates, different concentration of sodium hydroxide and different solution temperatures on SCC were investigated. On the basis of this, the contrast tests were also performed in high temperature pure water. After SSRT, fractograph of the fractured specimens was analyzed by using scanning electron microscopy (SEM).


2019 ◽  
Vol 961 ◽  
pp. 45-50 ◽  
Author(s):  
Hoc Thang Nguyen

Inorganic polymer materials known as geopolymer-based materials are always interesting topics for researchers. Geopolymer is environmentally friendly material which has been potential applications for many different fields such as technical materials, building materials, insolation or refractories, and others. This study used ash of brickyard (AB) as a raw material for geopolymerization process to develop novel materials with high porosity. AB is industrial waste of the brick factories that need to be managed to reduce their negative impact to the environment. AB contains high alumino-silicate resources were mixed with sodium hydroxide solution for 10 minutes to obtain the geopolymer pastes. Sodium hydroxide solution was used as an alkaline activator to form geopolymer paste. The geopolymer paste was filled into 5-cm cube molds according to ASTM C109/C109M 99, and then cured at room temperature for 28 days. These products were then tested for compressive strength, volumetric weight, and water absorption. Results indicated that the material can be considered lightweight with a compressive strength at 28 days that are in the range of 8.1 to 15.4 MPa, volumetric weight around 600kg/m3 and water absorption is under 210.65 kg/m3. The properties of geopolymer products were also determined by analytical techniques that included mineral composition by X Ray Diffraction (XRD) and microstructure by scanning electron microscope (SEM).


2018 ◽  
Vol 877 ◽  
pp. 193-199 ◽  
Author(s):  
Suman Saha ◽  
C. Rajasekaran

Production of Ordinary Portland Cement (OPC) requires huge quantity of natural resources and energy and it releases large amount of carbon - di - oxide to the environment. Therefore, enormous studies have been carried out throughout the world to establish geopolymer as an alternative binder material for the replacement of OPC to protect the environment. This study intends to explore the effects of alkaline solution on the properties of geopolymer produced with ground granulated blast furnace slag. Properties such as Standard consistency, setting time of slag based geopolymer paste has been determined using Vicat’s apparatus (according to the guidelines given by Indian Standards for OPC). In order to determine the effects of alkaline solution on the properties of geopolymers, the concentration of sodium hydroxide solution has been varied from 6M to 16M and the ratio of sodium silicate solution to sodium hydroxide solution is also varied from 1.0 to 2.0. Results indicate higher standard consistency and significant less setting time for slag based geopolymer paste than that of OPC paste. Compressive strength of the geopolymer paste and mortar cube samples, cured in ambient conditions till the day of testing, is increasing with the increase of the concentration of sodium hydroxide solution. Highest compressive strength is obtained for the samples prepared with alkaline solution having the ratio of sodium silicate solution to sodium hydroxide solution as 1.5. But when the concentration of sodium hydroxide solution is beyond 14M, decreasing trend in compressive strength is observed.


Author(s):  
Jianming Gong ◽  
Jianjie Liu ◽  
Yong Jiang ◽  
Rongrong Zhou

Stress corrosion cracking (SCC) of austenitic stainless steel serviced in aggressive environment often occurs in power, petrochemical industry, and leads to premature equipment failure and great economic loss. This paper focuses on the problem of the SCC on the nozzle of hydrogenation reactor which is caused due to alkali cleaning. Susceptibility for SCC was evaluated by Slow Strain Rate Test (SSRT) for as-rolled 304L and 316L stainless steel (SS) in low concentration sodium hydroxide solution with high temperature. The effects of different concentration of sodium hydroxide and different solution temperatures on SCC were investigated at the strain rate of 1 × 10−6s−1. After SSRT was performed, fractograph of the fractured specimens was analyzed by using scanning electron microscopy (SEM). On the basis of this, fracture characteristic and susceptibility of SCC of 304L and 316L stainless steel were compared in low concentration sodium hydroxide solution with high temperature.


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