Behavior of Cement Paste Blended Pozzolanic Material in the Application of Microwave Energy

Abstract

The objective of this research was to study the behavior of cement paste mixed with pozzolanicmaterials such as fly ash (FA) and rice husk ash (RHA) in the application of microwave energy. Thetemperature profile of hydration reaction, dielectric properties and specific heat capacity of cement pastespecimens were tested. The percentage replacements of FA and RHA by weight of Portland cement typeI were 0, 10 and 20 and water-to-binder ratios were 0.38 and 0.45.

From the tested results, the temperature from hydration reaction of cement paste with water-tobinderratio equal to 0.38 as higher than that with water-to-binder ratio equal to 0.45. The temperaturedecreased with increasing pozzolanic materials replacement and the hydration temperature of cement pastewith FA were higher than that with RHA. In the part of the dielectric value, it should be picked up duringthe initial setting time and after a period of incubation time, the energy should be reduced because the dielectricvalue will be reduced over time or there will be caused a moisture in the tested materials to reduceuntil dry resulting in the long term strength development decreased.

For the specific heat capacity was found that at any water-to-binder ratios of the same percentagereplacements, both FA and RHA with fineness equal to 4,000 cm2/g are evolved the heat less than the FAand RHA with fineness equal to 5,000 cm2/g because of fineness equal to 5,000 cm2/g, the material has asurface area to absorb water higher than a fineness equal to 4,000 cm2/g. So that the free water reducedresulted in temperature and evolved energy reduced accordingly.

Keywords : Cement Paste / Pozzolanic Material / Microwave Energy* Corresponding