Deepa, Nair G; Jagadish, K S; Alex, Fraaij(Elsevier, March , 2006)
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Abstract:
This paper discusses the properties of rice husk ash samples produced from different types of field ovens to compare the performance of the
ovens and to identify the most feasible method to produce a reactive pozzolana as an alternative to cement for building applications requiring
lower strengths. Different types of ashes are produced and long-term strength of rice husk ash pozzolanas with lime or cement is investigated to
suggest a sustainable affordable option in rural building applications, especially for rural housing in Kerala, a southern state of India
Deepa, Nair G; Alex, Fraaij; Adri, Klaassen A K; Arno, Kentgens P M(Elsevier, 2008)
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Abstract:
Various factors determine the applicability of rice husk ash (RHA) as a pozzolanic material. The amount and accessibility of reactive sites is
thought to be a key factor. A structural study of RHA samples in relation to their reactivity has been performed; Silica in RHA formed by burning
rice husk in a laboratory furnace under continuous supply of air have been characterized as a function of incineration temperature, time and
cooling regime. The characterization methods included chemical analyses, conductivity measurements, microscopic analysis, X-ray diffraction
(XRD) and 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR). In line with earlier observations, the analyses show that the
highest amounts of amorphous silica occur in samples burnt in the range of 500 °C–700 °C. The 29Si NMR data allow direct identification of the
reactive silanol sites in the RHA samples. De-convolution of the NMR spectra clearly shows that the quickly cooled RHA resulting from burning
rice husk for 12 h at 500 °C has the highest amount of silanol groups. This sample also induced the largest drop in conductivity when added to a
saturated calcium hydroxide solution giving an indication of its reactivity towards lime. Therefore, this RHA is the favorable sample to be used as
pozzolanic cement additive
High strength and high performance concrete are being widely used all over the world. Most of the applications of high strength concrete have been found in high rise buildings, long span bridges etc. The potential of rice husk ash as a cement replacement material is well established .Earlier researches showed an improvement in mechanical properties of high strength concrete with finely ground RHA as a partial cement replacement material. A review of literature urges the need for optimizing the replacement level of cement with RHA for improved mechanical properties at optimum water binder ratio. This paper discusses the mechanical properties of RHA- High strength concrete at optimized conditions
Description:
American Journal of Engineering Research (AJER),Volume-3 pp-14-19