scholarly journals Simultaneous effects of rice husk silica and silicon carbide whiskers on the mechanical properties and morphology of sodium geopolymer

2020 ◽  
Vol 54 (29) ◽  
pp. 4611-4620 ◽  
Author(s):  
Akm Samsur Rahman ◽  
Chirag Shah ◽  
Nikhil Gupta

The current research is focused on developing a geopolymer binder using rice husk ash–derived silica nanoparticles. Four types of rice husks were collected directly from various rice fields of Bangladesh in order to evaluate the pozzolanic activity and compatibility of the derived rice husk ashes with precursors of sodium-based geopolymers. Silicon carbide whiskers were introduced into sodium-based geopolymers in order to evaluate the response of silicon carbide whiskers to the interfacial bonding and strength of sodium-based geopolymers along with rice husk ashes. Compression, flexural and short beam shear tests were performed to investigate the synergistic effect of rice husk ashes–derived silica and commercially available silicon carbide whiskers. Results show that rice husk ashes–derived spherical silica nanoparticles reduced nano-porosity of the geopolymers by ∼20% and doubled the compressive strength. The simultaneous additions of rice husk ashes and silicon carbide whiskers resulted in flexural strength improvement by ∼27% and ∼97%, respectively. The increase in compressive strength due to the inclusion of silica nanoparticles is related to the reduction in porosity. The increase in flexural strength due to simultaneous inclusion of silica and silicon carbide whiskers suggest that silica particles are compatible with the metakaolin-based geopolymers, which is effective in consolidation. Finally, microscopy suggest that silicon carbide whiskers are effective in increasing bridged network and crack resistance.

2007 ◽  
Vol 336-338 ◽  
pp. 1904-1905
Author(s):  
Chang Hong Dai ◽  
Ru Zhao ◽  
Li Shui ◽  
Bao Bao Zhang

A new method for preparing microporous ceramics by the silicon carbide whiskers was studied in this paper. The physical and chemical properties and the microstructure of the microporous ceramics were tested, while some influencing factors for the product, such as the amount of sintering aids and sintering temperature, were discussed. The results suggest that the apparent porosity of the microporous ceramics is 55.7-59.8% and the flexural strength is 127-176MPa. The pore distribution of the microporous ceramics is uniformity and the diameter of the pore ranges between 0.5μm and 7μm. The porosity and pore size of the microporous ceramic can be controlled by adjusting the sintering temperature and the amount of sintering aids.


2015 ◽  
Vol 754-755 ◽  
pp. 468-472 ◽  
Author(s):  
Chao Lung Hwang ◽  
Trong Phuoc Huynh

This work investigates the possibility of using fly ash (FA) and Vietnam residual rice husk ash (RHA) in producing unfired building bricks with applying densified mixture design algorithm (DMDA) method. In this research, little amount of cement was added into the mixtures as binder substitution. Unground rice husk ash (URHA), an agricultural by-product, was used as partial fine aggregate replacement (10% and 30%) in the mixtures. The solid bricks of 220×105×60 mm in size were prepared in this study. The hardened properties of the bricks were investigated including compressive strength, flexural strength and water absorption according to corresponding Vietnamese standards. Forming pressure of 35 MPa was applied to form the solid bricks in the mold. The test results show that all brick specimens obtained good mechanical properties, which were well conformed to Vietnamese standard. Compressive strength and flexural strength of the bricks were respectively in range of 13.81–22.06 MPa and 2.25–3.47 MPa. It was definitely proved many potential applications of FA and RHA in the production of unfired building bricks.


2020 ◽  
Vol 13 (3) ◽  
pp. 315-321
Author(s):  
Dhiraj Ahiwale ◽  
Rushikesh Khartode

Now days, the waste rice husk from rice mill, marble powder from tile industry and fly ash from steam power plant are necessary to utilize as partial replacement of cement for concrete production. Large scale production of cement required consumption of raw materials and energy as well as emissions to air which posse’s environmental threat in various areas of country. Apart from the environmental threat, there still exists the problem of shortage in many areas. Therefore, substitute material for concrete needs to be considered. The paper aims to analyze the compressive strength of concrete cubes and flexural strength of concrete beams made from partially replaced cement, sand, and coarse aggregate. This research study adopted in laboratory on 48 total specimens of grade M25 concrete cubes of size 150x150x150mm and concrte beams of size 100x100x500mm were casted. Out of the 48 concrete specimens cast, 6 each were made out 10%, 20%, and 30 % replacement of fly ash, rice husk ash and marble powder to cement in concrete. It was found that the compressive strength and flexural strength of concrete made from the mixture of 20 % partially replaced cement, sand and coarse aggregate was similar than the concrete made from without replaced cement , sand and coarse aggregate.


2007 ◽  
Vol 1044 ◽  
Author(s):  
Takashi Itoh ◽  
Nobuhisa Asari ◽  
Nobuyuki Kanetake ◽  
Akira Okada

AbstractThermoelectric power generation is a hopeful method harnessing waste thermal energy particularly covering a middle temperature range between 500 and 800K. A Zn4Sb3 compound is a promising “phonon glass electron crystal” material applicable to thermoelectric power generation around 700K. This material, however, has a problem of its brittleness. In this research, the silicon carbide whiskers were added into the Zn4Sb3 compound for overcoming the brittleness, and the fullerene nanoparticles were also added for improving the thermoelectric performance. The Zn4Sb3 compound was synthesized from mixture of pure zinc and antimony powders by a liquid-solid phase reactions method. Firstly, the synthesized compound powder was mixed with the fullerene nanoparticles. The planetary ball milling method was used in order to disentangle the fullerene agglomerate and to obtain a uniform mixture. Subsequently, the mixture was uniformly mixed with the SiC whiskers by the planetary ball milling. The final mixture was consolidated by the pulse discharge sintering. The synthesized phases were identified by XRD. The morphology of the whiskers after mixing was observed. The flexural strength and the thermoelectric properties of the sintered samples were measured. The length of SiC whiskers and the flexural strength were decreased with the mixing time. Though the addition of SiC whiskers lowered the thermoelectric performance, the combined addition of SiC whiskers and fullerene nanoparticles restored the performance by especially decrease of the thermoelectric conductivity owing to the phonon scattering.


2018 ◽  
Vol 44 (7) ◽  
pp. 8720-8724 ◽  
Author(s):  
S. Sankar ◽  
Narinder Kaur ◽  
Sejoon Lee ◽  
Deuk Young Kim

2019 ◽  
Vol 40 ◽  
pp. 67-72 ◽  
Author(s):  
Bimal Kumar Raut ◽  
Khim Prasad Panthi

Nanotechnology is the most emerging field in the area of different scientific research. Various methods of synthesis of nanoparticles are available. The wet chemical synthesis method is applicable in the extraction of silica nanoparticles from Rice Husk Ash (RHA). Rice husk is a form of waste product from the rice milling industries which is produced in an abundance amount in and around the country. Rice husk which is generally left on the field as a waste contains 60% silica content and can be economically viable raw materials for the extraction of silica [1-2]. Initially, Rice husk was burnt to obtain its ash. Then, a simple bottom-up approach, the sol-gel method was applied, and fine powder silica in the nanoscopic range was extracted. After extraction of it, internal arrangement and average particle size were recognized by XRD while molecular components and structure present in silica were identified by FTIR. The obtained silica was then used in making of ceramics matrix nanocomposites (particularly silica-sand cement block), and its mechanical properties were identified by compressive strength test using Instron testing machine which was found to be increased in comparing with the compressive strength of ceramics composite (Sand cement block) prepared in the same ratio and same size of mold as that of ceramics matrix nanocomposites. The ceramics matrix nanocomposites acquiring higher mechanical strength than Ceramics composite occurred due to the incorporation of Silica nanoparticles.


1991 ◽  
Vol 10 (4) ◽  
pp. 227-229 ◽  
Author(s):  
Ajoy Kumar Ray ◽  
Gyananjan Mahanty ◽  
Ambar Ghose

1987 ◽  
Vol 9 (4) ◽  
pp. 295-303 ◽  
Author(s):  
B V Radhakrishna Bhat ◽  
G P Sanghi

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