COMPRESSIVE MECHANICAL BEHAVIOR OF RED LOESS/BLACK-RICE HUSK ASH COMPOSITE MATERIAL UNDER VARIATIONS OF FIRING TEMPERATURE
Keywords:
Red loess, rice husk ash (RHA), compressive strength, mechanical behaviorAbstract
Red loess and black-rice husk ash (B-RHA) composite was investigated for its compressive strength. The loess was collected in Khon Kaen University and sieved through mesh No.60. Clay components of red loess were enhanced up to 9% by gravitational settling. This oriented loess was then mixed with black-rice husk ash (B-RHA) at a dry solid weight ratio of 1:1. The mixture was casted in a cylindrical mold with a diameter and height of 1.7 cm and 3.4 cm, respectively. The green bodies were fired under different fixed temperatures of 900, 1000, 1100, and 1200oC. Tridymite and cristobalite were dominant silica polymorphism found under the applied firing temperatures especially at 1200oC. Uniaxial compression tests were performed on un-oriented loess, unmixed oriented loess, and oriented loess/B-RHA composite. The oriented loess was found to be more rigid than the un-oriented loess and the loess composite. The elastic modulus of the oriented loess was found to be as high as 4 GPa, which is twice as much compared to that of the un-oriented loess at the same firing temperature of 1200oC. It can be surmised that the structural network of red ferric oxide-clay loess stabilizes the strength of the material when fine-grained silica is reduced, resulting in a higher strength of loess after orientation. Fired bodies of loess/B-RHA composite showed a significant decrease in its elastic modulus which is approximately 45 times less compared to that of the unmixed oriented loess. This is a result of an increased amount of voids of the composite due to the incineration of B-RHA. In addition to the reduction of its elastic modulus and compressive strength, the composite also shows extreme brittleness. However, the relationship of both yield strength and elastic modulus of the composite as a function of temperature shows a strong linear behavior in contrast to that of the un-oriented loess and unmixed oriented loess. It can be inferred that B-RHA in the composite decomposes into voids at a similar rate that quartz transforms to higher phases during the firing process.
References
ASTM C20-00. (2015). Standard test methods for apparent porosity, water absorption, apparent specific gravity, and bulk density of burned refractory brick and shapes by boiling water. ASTM International (Reapproved 2015). PA. USA.
ASTM C773-88. (2011). Standard test method for compressive (crushing) strength of fired whiteware materials. ASTM International (Reapproved 2011). PA. USA.
ASTM C136/136M-14. (2014). Standard test method for sieve analysis of fine and coarse aggregates. ASTM International. PA. USA.
Boonsaner, M. (1980). Structural geology, Khon Kaen University [in Thai].
Della, V.P., Hotza, D., Junkes, J.A., and Oliveira, A.P. (2006). Comparative study of silica obtained from acid leaching of rice husk and the silica obtained by thermal treatment of rice husk ash. Quimica Nova, 29:1175-1179.
Department of Mineral Resources. (2009). Zoning for geological and mineral resources management of Khon Kaen Province. In Department of Mineral Resources (Ed.), Ministry of Natural Resources and Environment. [in Thai]
Feng, E., Ma, G., Wu, Y., Wang, H., and Lei, Z. (2014). Preparation and properties of organic-inorganic composite superabsorbent based on xanthan gum and loess. Carbohydrate Polymers, 111:463–468.
Kordatos, K., Gavela, S., Ntziouni, A., Pistiolas, K.N., Kyritsi, A., and Kasselouri-Rigopoulou, V. (2008). Synthesis of highly siliceous ZSM-5 zeolite using silica from rice husk ash. Microporous Mesoporous Material, 115(1-2):189-196.
Oh, J.Y., inventors; Loess composite and loess mat made of the same, assignee. (2002). WO 2002096243 A1, Data provided by IFI CLAIMS Patent Services, Available from: http://www.google.com/patents/ WO2002096243A1?cl=en. Access date: March 1, 2016.
Phien-wej, N., Pientong, T., Balasubramaniam, A.S. (1992). Collapse and strength characteristics of loess in Thailand, Engineering Geology, 32:59-72.
Prasetyoko, D., Ramli, Z., Endud, S., Hamdan, H., and Sulikowski, B. (2006). Conversion of rice husk ash to zeolite beta. Waste Management, 26(10):1173- 1179.
Punrattanasin, P., Gasaluck, W. (2008). The bearing capacity of cement-treated loess: a case history of Khon Kaen loess, Thailand. August 11, 2008. International Conference on Case Histories in Geotechnical Engineering. Paper 34.
